To see the other types of publications on this topic, follow the link: Blade profile pressure.
Journal articles on the topic 'Blade profile pressure'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Blade profile pressure.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Curtis, E. M., H. P. Hodson, M. R. Banieghbal, J. D. Denton, R. J. Howell, and N. W. Harvey. "Development of Blade Profiles for Low-Pressure Turbine Applications." Journal of Turbomachinery 119, no. 3 (July 1, 1997): 531–38. http://dx.doi.org/10.1115/1.2841154.
Full textAbstract:
This paper describes a program of work, largely experimental, which was undertaken with the objective of developing an improved blade profile for the low-pressure turbine in aero-engine applications. Preliminary experiments were conducted using a novel technique. An existing cascade of datum blades was modified to enable the pressure distribution on the suction surface of one of the blades to be altered. Various means, such as shaped inserts, an adjustable flap at the trailing edge, and changing stagger were employed to change the geometry of the passage. These experiments provided boundary layer and lift data for a wide range of suction surface pressure distributions. The data were then used as a guide for the development of new blade profiles. The new blade profiles were then investigated in a low-speed cascade that included a set of moving bars upstream of the cascade of blades to simulate the effect of the incoming wakes from the previous blade row in a multistage turbine environment. Results are presented for two improved profiles that are compared with a datum representative of current practice. The experimental results include loss measurements by wake traverse, surface pressure distributions, and boundary layer measurements. The cascades were operated over a Reynolds number range from 0.7 × 105 to 4.0 × 105. The first profile is a “laminar flow” design that was intended to improve the efficiency at the same loading as the datum. The other is a more highly loaded blade profile intended to permit a reduction in blade numbers. The more highly loaded profile is the most promising candidate for inclusion in future designs. It enables blade numbers to be reduced by 20 percent, without incurring any efficiency penalty. The results also indicate that unsteady effects must be taken into consideration when selecting a blade profile for the low-pressure turbine.
2
Mailach, Ronald, and Konrad Vogeler. "Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor—Part I: Unsteady Profile Pressures and the Effect of Clocking." Journal of Turbomachinery 126, no. 4 (October 1, 2004): 507–18. http://dx.doi.org/10.1115/1.1791641.
Full textAbstract:
This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage Low-Speed Research Compressor of Dresden. In part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore, the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are calculated from the measured profile pressure distributions. The unsteady pressure distributions were analyzed in the first, a middle and the last compressor stage both on the rotor and stator blades. The measurements were carried out on pressure side and suction side at midspan. Several operating points were investigated. A complex behavior of the unsteady profile pressures can be observed, resulting from the superimposed influences of the wakes and the potential effects of several up- and downstream blade rows of the four-stage compressor. The profile pressure changes nearly simultaneously along the blade chord if a disturbance arrives at the leading edge or the trailing edge of the blade. Thus the unsteady profile pressure distribution is nearly independent of the convective wake propagation within the blade passage. A phase shift of the reaction of the blade to the disturbance on the pressure and suction side is observed. In addition, clocking investigations were carried out to distinguish between the different periodic influences from the surrounding blade rows. For this reason the unsteady profile pressure distribution on rotor 3 was measured, while stators 1–4 were separately traversed stepwise in the circumferential direction. Thus the wake and potential effects of the up- and downstream blade rows on the unsteady profile pressure could clearly be distinguished and quantified.
3
Spasic, Zivan, Sasa Milanovic, Vanja Sustersic, and Boban Nikolic. "Low-pressure reversible axial fan with straight profile blades and relatively high efficiency." Thermal Science 16, suppl. 2 (2012): 593–603. http://dx.doi.org/10.2298/tsci120503194s.
Full textAbstract:
The paper presents the design and operating characteristics of a model of reversible axial fan with only one impeller, whose reversibility is achieved by changing the direction of rotation. The fan is designed for the purpose of providing alternating air circulation in wood dryers in order to reduce the consumption of electricity for the fan and increase energy efficiency of the entire dryer. To satisfy the reversibility of flow, the shape of the blade profile is symmetrical along the longitudinal and transversal axes of the profile. The fan is designed with equal specific work of all elementary stages, using the method of lift forces. The impeller blades have straight mean line profiles. The shape of the blade profile was adopted after the numerical simulations were carried out and high efficiency was achieved. Based on the calculation and conducted numerical simulations, a physical model of the fan was created and tested on a standard test rig, with air loading at the suction side of the fan. The operating characteristics are shown for different blade angles. The obtained maximum efficiency was around 0.65, which represents a rather high value for axial fans with straight profile blades.
4
Mailach, Ronald, and Konrad Vogeler. "Aerodynamic Blade Row Interactions in an Axial Compressor—Part II: Unsteady Profile Pressure Distribution and Blade Forces." Journal of Turbomachinery 126, no. 1 (January 1, 2004): 45–51. http://dx.doi.org/10.1115/1.1649742.
Full textAbstract:
This two-part paper presents experimental investigations of unsteady aerodynamic blade row interactions in the first stage of the four-stage low-speed research compressor of Dresden. Both the unsteady boundary layer development and the unsteady pressure distribution of the stator blades are investigated for several operating points. The measurements were carried out on pressure side and suction side at midspan. In Part II of the paper the investigations of the unsteady pressure distribution on the stator blades are presented. The experiments were carried out using piezoresistive miniature pressure sensors, which are embedded into the pressure and suction side surface of a single blade. The unsteady pressure distribution on the blade is analyzed for the design point and an operating point near the stability limit. The investigations show that it is strongly influenced by both the incoming wakes and the potential flow field of the downstream rotor blade row. If a disturbance arrives the leading edge or the trailing edge of the blade the pressure changes nearly simultaneously along the blade chord. Thus the unsteady profile pressure distribution is independent of the wake propagation within the blade passage. A phase shift of the reaction on pressure and suction side is observed. The unsteady response of the boundary layer and the profile pressure distribution is compared. Based on the unsteady pressure distribution the unsteady pressure forces of the blades are calculated and discussed.
5
Xu, C., and R. S. Amano. "Meridional Considerations of the Centrifugal Compressor Development." International Journal of Rotating Machinery 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/518381.
Full textAbstract:
Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.
6
Pullan, Graham, and Neil W. Harvey. "Influence of Sweep on Axial Flow Turbine Aerodynamics at Midspan." Journal of Turbomachinery 129, no. 3 (July 14, 2006): 591–98. http://dx.doi.org/10.1115/1.2472397.
Full textAbstract:
Sweep, when the stacking axis of the blade is not perpendicular to the axisymmetric streamsurface in the meridional view, is often an unavoidable feature of turbine design. Although a high aspect ratio swept blade can be designed to achieve the same pressure distribution as an unswept design, this paper shows that the swept blade will inevitably have a higher profile loss. A modified Zweifel loading parameter, taking sweep into account, is first derived. If this loading coefficient is held constant, it is shown that sweep reduces the required pitch-to-chord ratio and thus increases the wetted area of the blades. Assuming fully turbulent boundary layers and a constant dissipation coefficient, the effect of sweep on profile loss is then estimated. A combination of increased blade area and a raised pressure surface velocity means that the profile loss rises with increasing sweep. The theory is then validated using experimental results from two linear cascade tests of highly loaded blade profiles of the type found in low-pressure aeroengine turbines: one cascade is unswept, the other has 45deg of sweep. The swept cascade is designed to perform the same duty with the same loading coefficient and pressure distribution as the unswept case. The measurements show that the simple method used to estimate the change in profile loss due to sweep is sufficiently accurate to be a useful aid in turbine design.
7
Gamal, Ahmed M., Bugra H. Ertas, and John M. Vance. "High-Pressure Pocket Damper Seals: Leakage Rates and Cavity Pressures." Journal of Turbomachinery 129, no. 4 (September 3, 2006): 826–34. http://dx.doi.org/10.1115/1.2720871.
Full textAbstract:
The turbomachinery component of interest in this paper, the pocket damper seal, has the dual purpose of limiting leakage and providing an additional source of damping at the seal location. The rotordynamic coefficients of these seals (primarily the direct stiffness and damping) are highly dependent on the leakage rates through the seals and the pressures in the seals’ cavities. This paper presents both numerical predictions and experimentally obtained results for the leakage and the cavity pressures of pocket damper seals operating at high pressures. The seals were tested with air, at pressures up to 1000psi(6.92MPa), as the working fluid. Earlier flow-prediction models were modified and used to obtain theoretical reference values for both mass flow rates and pressures. Leakage and static pressure measurements on straight-through and diverging-clearance configurations of eight-bladed and twelve-bladed seals were used for code validation and for calculation of seal discharge coefficients. Higher than expected leakage rates were measured in the case of the twelve-bladed seal, while the leakage rates for the eight-bladed seals were predicted with reasonable accuracy. Differences in the axial pitch lengths of the cavities and the blade profiles of the seals are used to explain the discrepancy in the case of the twelve-bladed seal. The analysis code used also predicted the static cavity pressures reasonably well. Tests conducted on a six-bladed pocket damper seal to further investigate the effect of blade profile supported the results of the eight-bladed and twelve-bladed seal tests and matched theoretical predictions with satisfactory accuracy.
8
Ozoliņš, Ilmārs, Ēriks Ozoliņš, and Valērija Fedotova. "Development of a Method for Calculating the Working Blade Stress Profile of the Aviation Gas Turbine Engine for Student Training." Transport and Aerospace Engineering 6, no. 1 (November 1, 2018): 55–66. http://dx.doi.org/10.2478/tae-2018-0007.
Full textAbstract:
Abstract The paper presents a method of calculation gas turbine engine compressor or low-pressure turbine working blade profile for student training. This method of calculation was prepared for working blades with and without shroud shelves. This method provides a calculation technique to reduce the load on blade root part and the determination of blade profile stress distribution and the comparison before and after reduction of load.
9
Wei, Yikun, Cunlie Ying, Jun Xu, Wenbin Cao, Zhengdao Wang, and Zuchao Zhu. "Effects of Single-arc Blade Profile Length on the Performance of a Forward Multiblade Fan." Processes 7, no. 9 (September 17, 2019): 629. http://dx.doi.org/10.3390/pr7090629.
Full textAbstract:
The effects of single-arc blade profile length on the performance of a forward multiblade fan are investigated in this paper by computational fluid dynamics and experimental measurement. The present work emphasizes that the use of a properly reduced blade inlet angle (β1A) and properly improved blade outlet angle (β2A) is to increase the length blade profile, which suggests a good physical understanding of internal complex flow characteristics and the aerodynamic performance of the fan. Numerical results indicate that the gradient of the absolute velocity among the blades in model-L (reducing the blade inlet angle and improving blade outlet angle) is clearly lower than that of the baseline model and model-S (improving the blade inlet angle and reducing blade outlet angle), where a number of secondary flows arise on the exit surface of baseline model and model-S. However, no secondary flow occurs in model-L, and the flow loss at the exit surface of the volute (scroll-shaped flow patterns) for model-L is obviously lower than that of the baseline model at the design point. The comparison of the test results further shows that to improve the blade profile length is to increase the static pressure and the efficiency of the static pressure, since the improved static pressure of the model-L rises as much as 22.5 Pa and 26.2%, and the improved static pressure efficiency of the model-L rises as much as 5 % at the design flow rates. It is further indicated that increasing the blade working area provides significant physical insight into increasing the static pressure, total pressure, the efficiency of the static pressure and the total pressure efficiency.
10
Howell, R. J., and K. M. Roman. "Loss reduction on ultra high lift low-pressure turbine blades using selective roughness and wake unsteadiness." Aeronautical Journal 111, no. 1118 (April 2007): 257–66. http://dx.doi.org/10.1017/s0001924000004504.
Full textAbstract:
This paper describes how it is possible to reduce the profile losses on ultra high lift low pressure (LP) turbine blade profiles with the application of selected surface roughness and wake unsteadiness. Over the past several years, an understanding of wake interactions with the suction surface boundary layer on LP turbines has allowed the design of blades with ever increasing levels of lift. Under steady flow conditions, ultra high lift profiles would have large (and possibly open) separation bubbles present on the suction side which result from the very high diffusion levels. The separation bubble losses produced by it are reduced when unsteady wake flows are present. However, LP turbine blades have now reached a level of loading and diffusion where profile losses can no longer be controlled by wake unsteadiness alone. The ultra high lift profiles investigated here were created by attaching a flap to the trailing edge of another blade in a linear cascade — the so called flap-test technique. The experimental set-up used in this investigation allows for the simulation of upstream wakes by using a moving bar system. Hotwire and hotfilm measurements were used to obtain information about the boundary-layer state on the suction surface of the blade as it evolved in time. Measurements were taken at a Reynolds numbers ranging between 100,000 and 210,000. Two types of ultra high lift profile were investigated; ultra high lift and extended ultra high lift, where the latter has 25% greater back surface diffusion as well as a 12% increase in lift compared to the former. Results revealed that distributed roughness reduced the size of the separation bubble with steady flow. When wakes were present, the distributed roughness amplified disturbances in the boundary layer allowing for more rapid wake induced transition to take place, which tended to eliminate the separation bubble under the wake. The extended ultra high lift profile generated only slightly higher losses than the original ultra high lift profile, but more importantly it generated 12% greater lift.
11
Hodson, H. P., and W. N. Dawes. "On the Interpretation of Measured Profile Losses in Unsteady Wake–Turbine Blade Interaction Studies." Journal of Turbomachinery 120, no. 2 (April 1, 1998): 276–84. http://dx.doi.org/10.1115/1.2841403.
Full textAbstract:
The interaction of wakes shed by a moving blade row with a downstream blade row causes unsteady flow. The meaning of the free-stream stagnation pressure and stagnation enthalpy in these circumstances has been examined using simple analyses, measurements, and CFD. The unsteady flow in question arises from the behavior of the wakes as so-called negative jets. The interactions of the negative jets with the downstream blades lead to fluctuations in static pressure, which in turn generate fluctuations in the stagnation pressure and stagnation enthalpy. It is shown that the fluctuations of the stagnation quantities created by unsteady effects within the blade row are far greater than those within the incoming wake. The time-mean exit profiles of the stagnation pressure and stagnation enthalpy are affected by these large fluctuations. This phenomenon of energy separation is much more significant than the distortion of the time-mean exit profiles that is caused directly by the cross-passage transport associated with the negative jet, as described by Kerrebrock and Mikolajczak. Finally, it is shown that if only time-averaged values of loss are required across a blade row, it is nevertheless sufficient to determine the time-mean exit stagnation pressure.
12
Chen, Ming Xin, Ling Feng Tang, Ge Zhou, Zhong Ying Dou, Xiao Li Yang, and Xiao Yang Du. "Design and Study on Mortar Pump's Impeller Based on Bezier and Mechanical Mechanics." Applied Mechanics and Materials 327 (June 2013): 215–21. http://dx.doi.org/10.4028/www.scientific.net/amm.327.215.
Full textAbstract:
This article determined the blade profile by using the Bezier Curve.Start with ensuring the blade Angle and the blade profile , this paper designed a new impeller, avoided the appearance of the "S" shape of the blade profile, it ensured the smoothness of the blade profile. Compared with the traditional design of the impeller,Combined with mechanical mechanics software CFX, this article took a numerical calculation and simulation about the impeller and the hydrographic basin , compared the two impeller's residuals, velocity vector,pressure distribution and pressure water room's static pressure distribution,analysed and evaluated the performance of the pump.
13
Pascu, M., M. Miclea, P. Epple, A. Delgado, and F. Durst. "Analytical and numerical investigation of the optimum pressure distribution along a low-pressure axial fan blade." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 3 (December 1, 2008): 643–57. http://dx.doi.org/10.1243/09544062jmes1023.
Full textAbstract:
In the field of axial flow turbomachines, the two-dimensional cascade model is often used experimentally or numerically to investigate fundamental flow characteristics and overall performance of the impeller. The core of the present work is a design method for axial fan cascades aiming to derive inversely the optimum blade shape based on the requirements of the impeller and not using any predefined aerofoil profiles. While most design strategies based on the aerofoil theory assume constant total pressure at all streamlines, i.e. free-vortex flow, this paper investigates the possibility of varying the total pressure along the blade and based on that, an analytical expression of the outlet blade angle is determined. When computing the blade profile at a specified radius, critical parameters reflecting on the flow characteristics are observed and adjusted (i.e. sufficient lift and controlled deceleration of the flow on the contour) so that the resulting profile is derived for minimum losses. The validation of this design strategy is given by the numerical results obtained when employed as an optimization tool for an industrial fan: 10–20 per cent absolute increase in the static efficiency of the optimized impeller.
14
Mailach, Ronald, Lutz Mu¨ller, and Konrad Vogeler. "Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor—Part II: Unsteady Aerodynamic Forces of Rotor and Stator Blades." Journal of Turbomachinery 126, no. 4 (October 1, 2004): 519–26. http://dx.doi.org/10.1115/1.1791642.
Full textAbstract:
This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage low-speed research compressor of Dresden. In Part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are determined from the measured profile pressure distributions. A method to calculate the aerodynamic blade forces on the basis of the experimental data is presented. The resulting aerodynamic blade forces are discussed for the rotor and stator blade rows of the first stage and the third stage of the compressor. Different operating points between design point and stability limit of the compressor were chosen to investigate the influence of loading on the aerodynamic force excitation. The time traces and the frequency contents of the unsteady aerodynamic blade force are discussed. Strong periodic influences of the incoming wakes and of potential effects of downstream blade rows can be observed. The amplitude and shape of the unsteady aerodynamic blade force depend on the interaction of the superimposed influences of the blade rows.
15
Jiang, J., and T. Dang. "Design Method for Turbomachine Blades With Finite Thickness by the Circulation Method." Journal of Turbomachinery 119, no. 3 (July 1, 1997): 539–43. http://dx.doi.org/10.1115/1.2841155.
Full textAbstract:
This paper presents a procedure to extend a recently developed three-dimensional inverse method for infinitely thin blades to handle blades with finite thickness. In this inverse method, the prescribed quantities are the blade pressure loading and the blade thickness distributions, and the calculated quantity is the blade mean camber line. The method is formulated in the fully inverse mode whereby the blade shape is determined iteratively using the flow-tangency condition along the blade surfaces. Design calculations are presented for an inlet guide vane, an impulse turbine blade, and a compressor blade in the two-dimensional inviscid- and incompressible-flow limit. Consistency checks are carried out for these design calculations using a panel analysis method and the analytical solution for the Gostelow profile.
16
Pouagare, M., J. M. Galmes, and B. Lakshminarayana. "An Experimental Study of the Compressor Rotor Blade Boundary Layer." Journal of Engineering for Gas Turbines and Power 107, no. 2 (April 1, 1985): 364–72. http://dx.doi.org/10.1115/1.3239731.
Full textAbstract:
The three-dimensional turbulent boundary layer developing on a rotor blade of an axial flow compressor was measured using a minature “x” configuration hot-wire probe. The measurements were carried out at nine radial locations on both surfaces of the blade at various chordwise locations. The data derived includes streamwise and radial mean velocities and turbulence intensities. The validity of conventional velocity profiles such as the “power law profile” for the streamwise profile, and Mager and Eichelbrenner’s for the radial profile, is examined. A modification to Mager’s crossflow profile is proposed. Away from the blade tip, the streamwise component of the blade boundary layer seems to be mainly influenced by the streamwise pressure gradient. Near the tip of the blade, the behavior of the blade boundary layer is affected by the tip leakage flow and the annulus wall boundary layer. The “tangential blockage” due to the blade boundary layer is derived from the data. The profile losses are found to be less than that of an equivalent cascade, except in the tip region of the blade.
17
Mai, Thanh Dam, and Jaiyoung Ryu. "Effects of Leading-Edge Modification in Damaged Rotor Blades on Aerodynamic Characteristics of High-Pressure Gas Turbine." Mathematics 8, no. 12 (December 9, 2020): 2191. http://dx.doi.org/10.3390/math8122191.
Full textAbstract:
The flow and heat-transfer attributes of gas turbines significantly affect the output power and overall efficiency of combined-cycle power plants. However, the high-temperature and high-pressure environment can damage the turbine blade surface, potentially resulting in failure of the power plant. Because of the elevated cost of replacing turbine blades, damaged blades are usually repaired through modification of their profile around the damage location. This study compared the effects of modifying various damage locations along the leading edge of a rotor blade on the performance of the gas turbine. We simulated five rotor blades—an undamaged blade (reference) and blades damaged on the pressure and suction sides at the top and middle. The Reynolds-averaged Navier–Stokes equation was used to investigate the compressible flow in a GE-E3 gas turbine. The results showed that the temperatures of the blade and vane surfaces with damages at the middle increased by about 0.8% and 1.2%, respectively. This causes a sudden increase in the heat transfer and thermal stress on the blade and vane surfaces, especially around the damage location. Compared with the reference case, modifications to the top-damaged blades produced a slight increase in efficiency about 2.6%, while those to the middle-damaged blades reduced the efficiency by approximately 2.2%.
18
Egorov, Sergey, Alexey Kapitanov, Dmitriy Loktev, Sergey Fedorov, and Tatiana Egorova. "The Problems of Measuring Profile and Roughness of Turbine Blades." Applied Mechanics and Materials 876 (February 2018): 110–16. http://dx.doi.org/10.4028/www.scientific.net/amm.876.110.
Full textAbstract:
The article presents a study of a turbine blade profile and roughness measurement processes - the task facing any manufacturer of this part. The blade is one of the most complex regarding parts manufacture because of its complex profile. This profile should be measured in several sections on the feather on all profile elements - the suction side, pressure surface, leading and trailing edge of a blade. If the blade has a shroud platform, its profile should be also measured (and possibly the gland packing profile). It is also necessary to measure the feather end and base of blade profile. Finally, a separate independent task is the blade tang profile measurement.
19
Boldyrev, Aleksei V., Sergei V. Boldyrev, and Dmitrii L. Karelin. "THE EFFECT OF BLADE PROFILE ON THE PERFORMANCE OF A SIDE CHANNEL PUMP." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 6, no. 3 (2020): 23–37. http://dx.doi.org/10.21684/2411-7978-2020-6-3-23-37.
Full textAbstract:
This article presents the results of a numerical modeling of a steady turbulent flow of an incompressible fluid in an open-type vortex pump with an open side channel, comparing the generalized simulation results with the existing experimental data. The mathematical model is based on the Reynolds-averaged Navier — Stokes and continuity equations, as well as on the equations of the two-layer Realizable k-ε turbulence model that accounts for the curvature of streamlines. The authors have estimated the grid independence of the solution and studied the influence of 14 blade profiles on the head and efficiency of the vortex pump. The solution of the model equations was achieved by the finite volume method using a sequential algorithm in three calculation areas (“feeder channel”, “blade wheel”, “open hull side channel and diverter channel”) with the evaluation of grid independence of the solution. The result of the solution between the calculated areas was transmitted at the corresponding points of the interface surfaces. The authors have studied the influence of 14 profiles of a blade on pressure and efficiency of the vortex pump: the initial profile of the blade with the installation in the wheel coaxial shaft of the ring plate of different width, the initial profile of the blade with a bevel on the discharge side, a profile in the form of an isosceles triangle, a profile in the form of a quadrangle, the initial profile with a rounded blade on the suction side, and a profile in the form of a rectangular triangle with a rounded blade on the suction side, among others. The simulation results have aided in proposing the blade profiles: in the form of a rectangle with a convex rounding of the blade on the suction side with a 10 mm radius and a right-angled triangle with a concave rounding of the blade on the suction side with a 52 mm radius and without rounding, giving a significant increase in pressure — more than 20%. Nevertheless, none of the considered cases have revealed any significant increase in the vortex pump hydraulic efficiency.
20
Schwarzbach, Felix, Dajan Mimic, and Florian Herbst. "Profile Aerodynamics of an Oscillating Low-Pressure–Turbine Blade." International Journal of Gas Turbine, Propulsion and Power Systems 11, no. 4 (2020): 68–75. http://dx.doi.org/10.38036/jgpp.11.4_68.
Full text
21
Yang, Xiaopei, Boyan Jiang, Jun Wang, Yougen Huang, Weigang Yang, Kemin Yuan, and Xuna Shi. "Multi-objective optimization of dual-arc blades in a squirrel-cage fan using modified non-dominated sorting genetic algorithm." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 8 (January 21, 2020): 1053–68. http://dx.doi.org/10.1177/0957650919898983.
Full textAbstract:
In this study, a dual-arc profile parameterized by four geometric variables was designed to replace the original single-arc profile of a squirrel-cage fan used in a range hood, in order to improve the efficiency of the entire machine and the fan pressure. A modified Non-dominated Sorting Genetic algorithm coupled with a three-dimensional Reynolds-averaged Navier–Stokes computation is applied to search the optimum blade shape. Moreover, a relatively coarse but proven reliable grid model is employed to accelerate the optimization process, and a dynamic crowding distance is applied to improve the broad diversity of the Pareto front. The optimization results show that the optimal dual-arc blades are formed by a leading arc with a relatively smaller curvature and a trailing arc with a larger curvature, and the shape of the leading arc dominates the aerodynamic performance of the dual-arc blade. The blade schemes at two end of the Pareto front have increased the fan pressure and efficiency at the optimization point by 5.3% and 1.5%, respectively, but also result in a decline in another performance indicator. The best compromised solution in the middle of the Pareto front has improved the pressure by 2.6% without reducing the efficiency in the numerical calculation. Compared with the single-arc blade with the same inlet and outlet angle, the dual-arc blade has a higher fan pressure, but at the same time, the efficiency is negatively affected. Finally, the new impeller with optimized dual-arc blades is manufactured and tested, and the experimental results show an increment exceeds 2% in pressure and an unexpected slightly improvement in fan efficiency.
22
HUYNH, THANH NGOC, TOẢN QUỐC TRẦN, and QUYẾT THÀNH PHẠM. "Research on aerodynamic characteristics through airflow clearances in compressor blades of gas turbine engine." Science & Technology Development Journal - Engineering and Technology 3, SI3 (December 27, 2020): first. http://dx.doi.org/10.32508/stdjet.v3isi3.640.
Full textAbstract:
Reducing the loss in the airflow clearance among the compressor blades of the rotor disk and stationary blades (guide vanes) is an urgent issue. Furthermore, additional losses of airflow through the clearances among the blades and airfoil losses are the main cause of reducing the efficiency of an axial flow compressor, especially the blade height is small. With a view towards the efficiency improvement of a multistage axial compressor with a high-pressure ratio, it is necessary to manufacture a highly economical compressor with a variety of compression stages. Airflow in the circulation clearances alternating among compressor blades has viscosity, unstable compression, and quite complex flow structure. This needs to be researched into the design with the assistance of modern software (ANSYS CFX, FlowER, etc.). Although this is an important step in the current design orientation, it requires additional practical elements to perform, especially the problem of optimizing the outer rim, the level, and the number of compression stages in the whole compressor. In this paper, authors have used the method of creating three-dimensional (3D) models for blade profiles in a compressor based on analyzing the flow in three-dimensional form and studying their parameters. This paper deals with the geometry problems of the row of rotating blades (cascade) by proposing the structural arrangement of stacking blades in the circular direction and the blade profile formed the S-shape. Investigating and calculating the aerodynamic properties of the airflow through clearances of compressor blades by using ANSYS is one of the new methods. The researched result showed the dependence between the camber angle as the rotating blade formed an S-shape profile rotates regarding the stagger angle of the airfoil and the incident angle of airflow. Some characteristics of aerodynamic properties are distributed according to the blade height in conducting with different curved profiles of the rotating blades on the rotor disk and stationary blades.
23
Howell, R. J., O. N. Ramesh, H. P. Hodson, N. W. Harvey, and V. Schulte. "High Lift and Aft-Loaded Profiles for Low-Pressure Turbines." Journal of Turbomachinery 123, no. 2 (February 1, 2000): 181–88. http://dx.doi.org/10.1115/1.1350409.
Full textAbstract:
This paper shows how it is possible to reduce the number of blades in LP turbines by approximately 15 percent relative to the first generation of high lift blading employed in the very latest engines. This is achieved through an understanding of the behavior of the boundary layers on high lift and ultra-high lift profiles subjected to incoming wakes. Initial development of the new profiles was carried out by attaching a flap to the trailing edge of one blade in a linear cascade. The test facility allows for the simulation of upstream wakes by using a moving bar system. Hot wire measurements were made to obtain boundary layer losses and surface-mounted hot films were used to observe the changes in boundary layer state. Measurements were taken at a Reynolds number between 100,000 and 210,000. The effect of increased lift above the datum profile was investigated first with steady and then with unsteady inflow (i.e., with wakes present). For the same profile, the losses generated with wakes present were below those generated by the profile with no wakes present. The boundary layer behavior on these very high lift pressure distributions suggested that aft loading the profiles would further reduce the profile loss. Finally, two very highly loaded and aft loaded LP turbine profiles were designed and then tested in cascade. The new profiles produced losses only slightly higher than those for the datum profile with unsteady inflow, but generated 15 percent greater lift.
24
Dang, T. Q. "A Fully Three-Dimensional Inverse Method for Turbomachinery Blading in Transonic Flows." Journal of Turbomachinery 115, no. 2 (April 1, 1993): 354–61. http://dx.doi.org/10.1115/1.2929241.
Full textAbstract:
This paper presents a procedure to extend a recently developed fully three-dimensional inverse method for highly loaded turbomachine blades into the transonic-flow regime. In this inverse method, the required three-dimensional blade profile to produce a prescribed swirl schedule is determined iteratively using the blade boundary conditions. In the present implementation, the flow is assumed to be inviscid and the blades are assumed to be infinitely thin. The relevant equations are solved in the conservative forms and are discretized in all three directions using a finite-volume technique. Calculations are carried out for the design of high-pressure axial- and centrifugal-compressor rotors. These examples include prescribed swirl schedules corresponding to blade designs that are shock-free and blade designs that have rapid compression regions in the blade passage.
25
Azad, Gm S., Je-Chin Han, Shuye Teng, and Robert J. Boyle. "Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip." Journal of Turbomachinery 122, no. 4 (February 1, 2000): 717–24. http://dx.doi.org/10.1115/1.1308567.
Full textAbstract:
Heat transfer coefficient and static pressure distributions are experimentally investigated on a gas turbine blade tip in a five-bladed stationary linear cascade. The blade is a two-dimensional model of a first-stage gas turbine rotor blade with a blade tip profile of a GE-E3 aircraft gas turbine engine rotor blade. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial chord of 1.1×106. The middle 3-blade has a variable tip gap clearance. All measurements are made at three different tip gap clearances of about 1, 1.5, and 2.5 percent of the blade span. Heat transfer measurements are also made at two different turbulence intensity levels of 6.1 and 9.7 percent at the cascade inlet. Static pressure measurements are made in the midspan and the near-tip regions as well as on the shroud surface, opposite the blade tip surface. Detailed heat transfer coefficient distributions on the plane tip surface are measured using a transient liquid crystal technique. Results show various regions of high and low heat transfer coefficient on the tip surface. Tip clearance has a significant influence on local tip heat transfer coefficient distribution. Heat transfer coefficient also increases about 15–20 percent along the leakage flow path at higher turbulence intensity level of 9.7 over 6.1 percent. [S0889-504X(00)00404-9]
26
Bogdanovic, Bozidar, Zivan Spasic, and Jasmina Bogdanovic-Jovanovic. "Low-pressure reversible axial fan designed with different specific work of elementary stages." Thermal Science 16, suppl. 2 (2012): 605–15. http://dx.doi.org/10.2298/tsci120503195b.
Full textAbstract:
Low-pressure axial fan impellers designed according to the principle of equal specific work of all elementary stages have blades whose profile near the fan hub is under a significantly larger inclination angle than at the impeller periphery. In order to minimize the spatial curvature of the fan blades and the fan hub length, impeller blades of low-pressure axial fans can be designed with different specific work of elementary stages, so that the specific work of elementary stages is smaller at the hub than at the periphery. This paper presents the operating characteristics of a low-pressure reversible axial fan with straight blade profiles, designed with different specific work of elementary stages. The fan was tested on a standard test rig, with air intake loading on the suction side of the fan.
27
Cho, C.-H., S.-Y. Cho, K.-Y. Ahn, and Y.-C. Kim. "Study of an axial-type fan design technique using an optimization method." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 3 (June 2, 2009): 101–11. http://dx.doi.org/10.1243/09544089jpme254.
Full textAbstract:
A robust axial-type fan design technique is developed by using an optimization method based on the gradient method. A three-dimensional fan blade was initially designed by stacking several two-dimensional (2D) blade profiles along the spanwise direction. These 2D blade profiles were designed using the free-vortex method and profile parameters such as the incidence, deviation, camber, and so on. The initial fan blade adopts 13 design variables to improve the target value of the fan efficiency or the total pressure. These design variables are used to control the rotor and stator profile for obtaining a better target value. In this study, fan efficiency is chosen as a target objective variable to be maximized, and the total and static pressure on the design point are applied as constraints. These procedures are applied to the design of an axial-type fan that must operate at a mass flowrate of 8.37 kg/s with a minimum total pressure rise of 670 Pa. The optimized fan not only increases the efficiency by 2.9 per cent but also satisfies the required total and static pressure conditions compared with the initially designed fan performance. The optimized fan performance agrees with the experimental results; therefore, this fan design technique can be applied to improve the efficiency and the operating pressure of axial-type fans.
28
Huang, Bin, Guitao Zeng, Bo Qian, Peng Wu, Peili Shi, and Dongqing Qian. "Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification." Processes 9, no. 8 (August 15, 2021): 1408. http://dx.doi.org/10.3390/pr9081408.
Full textAbstract:
The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.
29
Togh, Reza Aghaei, and Mohammad Mahdi Karimi. "Finding an optimal blade-profile to improving the performance of partially admitted turbines." Aircraft Engineering and Aerospace Technology 92, no. 6 (May 1, 2020): 863–77. http://dx.doi.org/10.1108/aeat-06-2019-0132.
Full textAbstract:
Purpose This paper aims to present the designing and investigating various types of impulse blade profiles to find the optimal profile that has better performance than the first or original blade. The studied model is a turbine with an output power below 1 MW and a large pressure ratio up to 20, which is used to gain relatively high specific work output. As a result of its low mass flow rate, the turbine is used under partial-admission conditions. The turbine’s stator is a group of convergence–divergence nozzles that provide supersonic flow. Design/methodology/approach More than 10 types of two-dimensional blade profiles were designed using the developed preliminary design calculations and numerical analysis. The numerical results are validated using the existing experimental results. Finally, the case with improved performance is introduced as the final optimum case. Findings It was found that the performance parameters such as efficiency, power and torque are increased by more than 8% in the selected best model, in comparison with the original model. Moreover, the total pressure loss is 12% decreased for the selected model. Finally, the selected profile with superior performance is proposed. Originality/value Simultaneous numerical tests are conducted to examine the interaction of different supersonic blade profiles with the partially injected flow to the rotor.
30
Tao, Yuan, Yifei Wu, Xianjun Yu, and Baojie Liu. "Analysis of Flow Characteristic of Transonic Tandem Rotor Airfoil and Its Optimization." Applied Sciences 10, no. 16 (August 12, 2020): 5569. http://dx.doi.org/10.3390/app10165569.
Full textAbstract:
Tandem blade technology has become an effective method to break the load limit of conventional aerodynamic configurations. To expand the application range of tandem blades, the supersonic tandem blade flow characteristic was studied and an optimal design was conducted by using a computational fluid dynamics (CFD) solver, with an inflow Mach number of 1.2. The main conclusions follow: (1) the tandem blade loss is difficult to control because of the complicated flow structures with supersonic inflow; (2) the forward blade loss dominates the tandem blade overall loss in the whole operating conditions; and (3) the tandem blade profile was optimized by considering the aerodynamic interaction between forward and aft blade. The numerical simulation results show that the total pressure loss declines by 20% at the design point, and the incidence range increases by about 0.5°.
31
Zhang, Xue Feng, Maria Vera, Howard Hodson, and Neil Harvey. "Separation and Transition Control on an Aft-Loaded Ultra-High-Lift LP Turbine Blade at Low Reynolds Numbers: Low-Speed Investigation." Journal of Turbomachinery 128, no. 3 (February 1, 2005): 517–27. http://dx.doi.org/10.1115/1.2187524.
Full textAbstract:
An experimental study was conducted to improve the performance of an aft-loaded ultra-high-lift low-pressure turbine blade known as U2 at low Reynolds numbers. This was achieved by manipulation of the laminar-turbulent transition process on the suction surface. The U2 profile was designed to meet the targets of reduced cost, weight and fuel burn of aircraft engines. The studies were conducted on both low-speed and high-speed experimental facilities under the unsteady flow conditions with upstream passing wakes. The current paper presents the low-speed investigation results. On the smooth suction surface, the incoming wakes are not strong enough to suppress the separation bubble due to the strong adverse pressure gradient on the suction surface and the low wake passing frequency, which allows the separation between the wakes more time to re-establish. Therefore, the profile losses of this ultra-high-lift blade are not as low as conventional or high-lift blades at low Reynolds numbers even in unsteady flows. Two different types of passive separation control devices, i.e., surface trips and air jets, were investigated to further improve the blade performance. The measurement results show that the profile losses can be further reduced to the levels similar to those of the high-lift and conventional blades due to the aft-loaded nature of this ultra-high-lift blade. Detailed surveys of the blade surface boundary layer developments showed that the loss reduction was due to the suppression of the separation underneath the wakes, the effect of the strengthened calmed region and the smaller separation bubble between wakes.
32
Qin, Sheng, Shuyue Wang, Liyue Wang, Cong Wang, Gang Sun, and Yongjian Zhong. "Multi-Objective Optimization of Cascade Blade Profile Based on Reinforcement Learning." Applied Sciences 11, no. 1 (December 24, 2020): 106. http://dx.doi.org/10.3390/app11010106.
Full textAbstract:
The multi-objective optimization of compressor cascade rotor blade is important for aero engine design. Many conventional approaches are thus proposed; however, they lack a methodology for utilizing existing design data/experiences to guide actual design. Therefore, the conventional methods require and consume large computational resources due to their need for large numbers of stochastic cases for determining optimization direction in the design space of problem. This paper proposed a Reinforcement Learning method as a new approach for compressor blade multi-objective optimization. By using Deep Deterministic Policy Gradient (DDPG), the approach modifies the blade profile as an intelligent designer according to the design policy: it learns the design experience of cascade blade as accumulated knowledge from interaction with the computation-based environment; the design policy can thus be updated. The accumulated computational data is therefore transformed into design experience and policies, which are directly applied to the cascade optimization, and the good-performance profiles can be thus approached. In a case study provided in this paper, the proposed approach is applied on a blade profile, which is thus optimized in terms of total pressure loss and laminar flow area. Compared with the initial profile, the total pressure loss coefficient is reduced by 3.59%, and the relative laminar flow area at the suction surface is improved by 25.4%.
33
Li, Linling, and Qibai Huang. "Research on the Mechanism of Fan Blade Shape Effect on its Noise." Journal of Low Frequency Noise, Vibration and Active Control 24, no. 1 (March 2005): 59–69. http://dx.doi.org/10.1260/0263092054037720.
Full textAbstract:
The fan blade configuration affects its efficiency and sound pressure level—(SPL). This paper analyzes the fan blade noise components and studies the aerodynamic characteristics of fan blades. The bar theory and moving soundfield characteristics are used in the theoretical analysis. Nonlinear aerodynamics theory is used to analyze the blade force. A mathematical model of fan blade noise is developed and simulated by the precision Gauss-Legendre method. The model simulation and the experiment results are analyzed in the frequency domain. The simulation results are in reasonable agreement with the measured data. Our model and the Fukano model are compared for different rotational speeds of the fan. This paper then studies the change of SPL when the blade parameters (number of blades, rotation speed of fan, chord of fan, and blade profile etc.) vary. The major factors affecting the fan noise are analyzed. Our model is derived from the viewpoint of blade design, so the result can be used to study the aerodynamic characteristics of fan blades quantitatively. The study is considered as a prerequisite to designing fans of high quality, since it provides a theoretical basis for noise prediction and noise control.
34
Lakshminarayana, B., N. Sitaram, and J. Zhang. "End-Wall and Profile Losses in a Low-Speed Axial Flow Compressor Rotor." Journal of Engineering for Gas Turbines and Power 108, no. 1 (January 1, 1986): 22–31. http://dx.doi.org/10.1115/1.3239880.
Full textAbstract:
The blade-to-blade variation of relative stagnation pressure losses in the tip region inside the rotor of a single-stage, axial-flow compressor is presented and interpreted in this paper. The losses are measured at two flow coefficients (one at the design point and the other at the near peak pressure rise point) to discern the effect of blade loading on the end-wall losses. The tip clearance losses are found to increase with an increase in the pressure rise coefficient. The losses away from the tip region and near the hub regions are measured downstream. The losses are integrated and interpreted in this paper.
35
Young, J. B., and K. K. Yau. "The Inertial Deposition of Fog Droplets on Steam Turbine Blades." Journal of Turbomachinery 110, no. 2 (April 1, 1988): 155–62. http://dx.doi.org/10.1115/1.3262175.
Full textAbstract:
A theoretical approach for calculating the rate of deposition of fog droplets on steam turbine blades by inertial impaction is described. Deposition rates are computed by tracking a number of droplet path lines through a specified blade-to-blade vapor flowfield and identifying the limiting trajectories that just intersect the blade surface. A new technique for performing the calculations efficiently has been developed whereby the mathematical stiffness of the governing equations is removed, thus allowing the numerical integration to proceed stably with comparatively large time increments. For high accuracy, the vapor flowfield is specified by a quasi-three-dimensional flow calculation involving both meridional and blade-to-blade plane calculations. Results are presented for two representative “test cases,” namely the final stage blading of the low-pressure cylinder of a 500 MW turbine and a typical stage in a high-pressure wet steam turbine. The effect on the deposition rate of fog droplet size and blade profile geometry is investigated for both on- and off-design flowfields. Comparisons are made with the predictions of a simplified theory for inertial deposition and the effect of blade rotation in flows with high pitch angles is discussed.
36
de Vito, L., R. A. Van den Braembussche, and H. Deconinck. "A Novel Two-Dimensional Viscous Inverse Design Method for Turbomachinery Blading." Journal of Turbomachinery 125, no. 2 (April 1, 2003): 310–16. http://dx.doi.org/10.1115/1.1545765.
Full textAbstract:
This paper presents a novel iterative viscous inverse design method for turbomachinery blading. It is made up of two steps: the first one consists of an analysis by means of a Navier-Stokes solver; the second one is an inverse design by means of an Euler solver. The inverse design resorts to the concept of permeable wall, and recycles the ingredients of Demeulenaere’s inviscid inverse design method that was proven fast and robust. The re-design of the LS89 turbine nozzle blade, starting from different arbitrary profiles at subsonic and transonic flow regimes, demonstrates the merits of this approach. The method may result in more than one blade profile that meets the objective, i.e., that produces the viscous target pressure distribution. To select one particular solution among all candidates, a target mass flow is enforced by adjusting the outlet static pressure. The resulting profiles are smooth (oscillation-free). The design of turbine blades with arbitrary pressure distribution at transonic and supersonic outflow illustrates the correct behavior of the method for a large range of applications. The approach is flexible because only the pitch chord ratio is fixed and no limitations are imposed on the stagger angle.
37
Nosov, Nicolay V. "Study of surface quality using quasi-optimal correlation algorithms." MATEC Web of Conferences 224 (2018): 01077. http://dx.doi.org/10.1051/matecconf/201822401077.
Full textAbstract:
The article proposes a new approach for evaluating roughness of the profile surface of gas turbine engine blade airfoils after vibratory polishing. An optical electronic unit was used to study microgeometry of blade suction and pressure sides: video imagery of the surface was processed using computer methods to obtain the average amplitude of the autocorrelation function variable component. The applied optical electronic method of evaluating microgeometry of compressor/turbine blades allows obtaining fields of surface roughness and tension concentration coefficients as well as analyzing the finish machining technology to a greater depth.
38
Laumert, Bjo¨rn, Hans Ma˚rtensson, and Torsten H. Fransson. "Investigation of Unsteady Aerodynamic Blade Excitation Mechanisms in a Transonic Turbine Stage—Part II: Analytical Description and Quantification." Journal of Turbomachinery 124, no. 3 (July 1, 2002): 419–28. http://dx.doi.org/10.1115/1.1458579.
Full textAbstract:
This paper presents a study of the blade pressure perturbation levels and the resulting blade forces in a high-pressure transonic turbine stage based on 3-D time dependent viscous computations. Globally, the blade pressure unsteadiness is quantified with the RMS of the pressure perturbations integrated in both time and along the blade surface. Operation point as well as spanwise variations are addressed. Locally, the relative strength of the pressure perturbation events on the vane and rotor blade surface is investigated. To obtain information about the relative strength of events related to the blade passing frequency and higher harmonics, the pressure field is Fourier decomposed in time at different radial positions along the blade arc-length. The amplitude peaks are then related to the pressure events in space-time maps. With the help of the observations and results from the blade pressure study, the radial variations of the unsteady blade force and torque acting on a constant span blade profile section are investigated. The connection between the first and second vane passing frequency pressure amplitudes on the rotor blade surface and the resulting force and the torque amplitudes for three selected blade modes was investigated in detail. In this investigation the pressure was integrated over defined rotor blade regions to quantify local force contributions. Spanwise as well as operation point variations are addressed.
39
Mamaev, Vladimir K., Leonid V. Vinogradov, and Petr P. Oschepkov. "Modeling the set of blade profiles of a gas turbine engine." RUDN Journal of Engineering Researches 20, no. 2 (December 15, 2019): 140–46. http://dx.doi.org/10.22363/2312-8143-2019-20-2-140-146.
Full textAbstract:
In the development of gas turbine engines (GTE) it is necessary to simulate the flow section of blade machines (turbines, compressors). At the same time, it is rational to use previously designed profiles and set of profiles with high aerodynamic and efficient performance. This is due to the fact that the process of creating profiles of a nozzle and moving blades set requires the participation of a large team and considerable labor and time costs. Many sets were created for the graphic-analytical design method, which leads to an increase in the development time and a decrease in the universality in terms of the use of programming languages and digital technologies. The article presents the design scheme of the nozzle profile sets of type С8626, the main fragments of the mathematical model of the sets, the results of the design of the original profile С8626 and the sets, comparison of the geometric parameters of the source and built profiles. The contours of the initial profile are approximated by second-order Bezier curves, and the leading and trailing edges are circular arcs. The coordinates of the points of conjugation of the circles of the leading and trailing edges with convex (suction side) and concave (pressure side) profile surfaces are determined. After approximation of the contours of the initial profile, an integral system of equations of the original C8626 turbine profile was obtained. The proposed mathematical model can be considered as independent, it can be a subsystem (software module) of CAD, to represent the shearer of the electronic atlas of profiles and etc.
40
Kwak, Jae Su, and Je-Chin Han. "Heat Transfer Coefficients on the Squealer Tip and Near Squealer Tip Regions of a Gas Turbine Blade." Journal of Heat Transfer 125, no. 4 (July 17, 2003): 669–77. http://dx.doi.org/10.1115/1.1571849.
Full textAbstract:
Detailed heat transfer coefficient distributions on a squealer tip of a gas turbine blade were measured using a hue detection based transient liquid crystals technique. The heat transfer coefficients on the shroud and near tip regions of the pressure and suction sides of a blade were also measured. Tests were performed on a five-bladed linear cascade with a blow-down facility. The blade was a two-dimensional model of a first stage gas turbine rotor blade with a profile of a GE-E3 aircraft gas turbine engine rotor blade. The Reynolds number based on the cascade exit velocity and axial chord length of a blade was 1.1×106 and the total turning angle of the blade was 97.7 deg. The overall pressure ratio was 1.2 and the inlet and exit Mach number were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7 percent. The heat transfer measurements were taken at the three different tip gap clearances of 1.0 percent, 1.5 percent, and 2.5 percent of blade span. Results showed that the overall heat transfer coefficients on the squealer tip were higher than that on the shroud surface and the near tip regions of the pressure and suction sides. Results also showed that the heat transfer coefficients on the squealer tip and its shroud were lower than that on the plane tip and shroud. However, the reductions of heat transfer coefficients near the tip regions of the pressure and suction sides were not remarkable.
41
Venkiteswaran, Vinod Kumar, Syaida Hazira Ramli, and Vijay R. Raghavan. "CFD Simulation of Air Flow through the Annular Distributor of a Swirling Fluidized Bed." Applied Mechanics and Materials 700 (December 2014): 619–25. http://dx.doi.org/10.4028/www.scientific.net/amm.700.619.
Full textAbstract:
Fluidized beds are widely used in a variety of industrial processes. The air distributor being an integral part of the fluidized bed, the air flow characteristic through it is of great importance as far as the design and working of it is concerned. Inappropriate design will lead to an incomplete fluidization and improper mixing of the air and bed particles. The current study was carried out to investigate the flow characteristics and predict non-uniformity in flow through the annular distributor of a Swirling Fluidized Bed and its variation with various aspects of the distributor like blade overlap angle and blade inclination. In this study, the commercial CFD package FLUENT 6.3 was used for analysis. The velocity and pressure profiles for various blade designs were investigated at the distributor outlet based on several operating variables including air inlet velocities, blade overlap angles (9o, 12o, 15o, and 18o), blade inclinations (10oand 15o), along with variations in the opening between the distributor blades. The most significant finding of this work is that the fluid tends to flow through a path with least resistance. The flow path with the largest cross section area and shortest path length has been identified and explains the velocity profile at blade exit.
42
Tao, Yi, Shouqi Yuan, Jianrui Liu, Fan Zhang, and Jianping Tao. "The influence of the blade thickness on the pressure pulsations in a ceramic centrifugal slurry pump with annular volute." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, no. 5 (May 8, 2017): 415–31. http://dx.doi.org/10.1177/0957650917708495.
Full textAbstract:
Due to the serious abrasion caused by the existence of solid phase in slurry, the slurry pumps usually adopt thick impeller blades to prolong its service life. In this paper, the influence of the blade thickness on the transient characteristics, the vibration, and the solid–liquid two-phase flow in a ceramic centrifugal pump with annular volute was investigated by the numerical method. And the experimental test was also conducted for computational fluid dynamics validation. The static pressure, the velocity, the force, and the solid fraction within the impeller passage and the volute casing have been discussed in detail. The results show that the influence of the blade thickness variation on the pressure fluctuation intensity is larger at the impeller inlet than that at the impeller exit and is larger at the pressure sides than that at the suction sides. The pressure fluctuation intensity decreases at the regions close to the volute tongue with the increase in the blade thickness. However, it increases at the regions, which are away from the volute tongue as the blade thickness increases. Moreover, the torque on the impeller, the radial force, and the axial force decreases with the increase in the blade thickness. Meanwhile, increasing the blade thickness will disperse the solid fraction at the impeller back shroud and make the regions with high solid fraction on pressure sides offset towards the impeller exit with a larger blade thickness, thus prolonging the service life of the impeller. However, the best efficiency point offsets to a low flow rate condition. The results are expected to pave the way for further optimization of impeller blade profile.
43
Brear, Michael J., Howard P. Hodson, and Neil W. Harvey. "Pressure Surface Separations in Low-Pressure Turbines—Part 1: Midspan Behavior." Journal of Turbomachinery 124, no. 3 (July 1, 2002): 393–401. http://dx.doi.org/10.1115/1.1450764.
Full textAbstract:
This paper describes an investigation into the behavior of the pressure surface separation at midspan in a linear cascade. It is found that the pressure surface separation can be a significant contributor to the profile loss of a thin, solid, low-pressure turbine blade that is typical of current engine designs. Numerical predictions are first used to study the inviscid behavior of the blade. These show a strong incidence dependence around the leading edge of the profile. Experiments then show clearly that all characteristics of the pressure surface separation are controlled primarily by the incidence. It is also shown that the effects of wake passing, freestream turbulence and Reynolds number are of secondary importance. A simple two-part model of the pressure surface flow is then proposed. This model suggests that the pressure surface separation is highly dissipative through the action of its strong turbulent shear. As the incidence is reduced, the increasing blockage of the pressure surface separation then raises the velocity in the separated shear layer to levels at which the separation can create significant loss.
44
Bakhtar, F., Z. A. Mamat, O. C. Jadayel, and M. R. Mahpeykar. "On the performance of a cascade of improved turbine nozzle blades in nucleating steam. Part 1: Surface pressure distributions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 8 (April 2, 2009): 1903–14. http://dx.doi.org/10.1243/09544062jmes1255.
Full textAbstract:
This article is the first of a set and describes the results of surface pressure measurements and flow visualizations in a cascade of improved steam turbine nozzle blade profiles. In the course of expansion of steam in turbines, the state path crosses the saturation line and the fluid nucleates to become a two-phase mixture. Formation and subsequent behaviour of the liquid lowers the performance of turbine wet stages. Turbine two-phase flow conditions can be reproduced satisfactorily under blow-down conditions for systematic study. Following earlier studies of some typical profiles the performance of a new design of blades is presented. A substantially improved aerodynamic performance has been achieved by the new profile.
45
Yu, Xianjun, Mingzhi Li, Guangfeng An, and Baojie Liu. "A Coupled Effect Model of Two-Position Local Geometric Deviations on Subsonic Blade Aerodynamic Performance." Applied Sciences 10, no. 24 (December 16, 2020): 8976. http://dx.doi.org/10.3390/app10248976.
Full textAbstract:
The coupled aerodynamic performance influence of multiple deviations in the blade profile is a complex phenomena. In this paper, a high-pressure compressor rotor blade mid-span profile is studied with the design of experiments (DOE), numerical simulation and surrogate model to analyze the influence of the deviations on the blade aerodynamic performance. The purpose of this work is to provide a new rapid evaluation approach for the blade aerodynamic performance under multiple geometric deviations influence. First, the Hicks-Henne function was used to model the local geometric deviations of the blade profile, and the blade aerodynamic performance was calculated by using the computational fluid dynamics tools. By analyzing the calculation results, the momentum thickness of the boundary layer, the deviations height and the distance between the deviations are combined into a coupled effect model. Then, the coupled effect model was used to rapidly evaluate the blade aerodynamic performance when the two-position local geometric deviations exist on the blade surface. Finally, the evaluated performance were compared with the results predicted by a high-precision surrogate model, which verifies the high accuracy of the coupled effect model in evaluating the positive incidence range of the blade profile.
46
Deutsch, S., and W. C. Zierke. "The Measurement of Boundary Layers on a Compressor Blade in Cascade: Part 1—A Unique Experimental Facility." Journal of Turbomachinery 109, no. 4 (October 1, 1987): 520–26. http://dx.doi.org/10.1115/1.3262142.
Full textAbstract:
A unique cascade facility is described which permits the use of laser-Doppler velocimetry (LDV) to measure blade boundary layer profiles. Because of the need for a laser access window, the facility cannot reply on continuous blade pack suction to achieve two-dimensional, periodic flow. Instead, a strong suction upstream of the blade pack is used in combination with tailboards to control the flow field. The distribution of the upstream suction is controlled through a complex baffling system. A periodic, two–dimensional flow field is achieved at a chord Reynolds number of 500,000 and an incidence angle of 5 deg on a highly loaded, double circular arc, compressor blade. Inlet and outlet flow profiles, taken using five-hole probes, and the blade static-pressure distribution are used to document the flow field for use with the LDV measurements (see Parts 2 and 3). Inlet turbulence intensity is measured, using a hot wire, to be 0.18 percent. The static-pressure distribution suggests both separated flow near the trailing edge of the suction surface and an initially laminar boundary layer profile near the leading edge of the pressure surface. Probe measurements are supplemented by sublimation surface visualization studies. The sublimation studies place boundary layer transition at 64.2 ± 3.9 percent chord on the pressure surface, and indicate separation on the suction surface at 65.6 percent ± 3.5 percent chord.
47
Taylor, R. P. "Surface Roughness Measurements on Gas Turbine Blades." Journal of Turbomachinery 112, no. 2 (April 1, 1990): 175–80. http://dx.doi.org/10.1115/1.2927630.
Full textAbstract:
Results are presented from profilometer measurements of the surface roughness on in-service turbine engine blades from F-100 and TF-39 aeroengines. On each blade, one roughness profile is taken in the region of the leading edge, the midchord and the trailing edge on both the pressure and suction sides for a total of six profiles. Thirty first-stage turbine blades are measured from each engine. Statistical computations are performed on these profiles and the root mean square height, skewness and kurtosis of the roughness height distribution are presented along with the correlation length of the autocorrelation function. The purpose of this work is to provide insight into the nature of surface roughness characteristics of in-service turbine blades which can be used in the development of scaled laboratory experiments of boundary layer flow and heat transfer on turbine engine blades.
48
Adhikary, Anik, Md Quamrul Islam, and Mohammad Ali. "PERFORMANCE OF A STATIONARY SAVONIUS ROTOR WITH CIRCULAR ARC BLADE PROFILE." Journal of Mechanical Engineering 43, no. 2 (February 1, 2014): 77–81. http://dx.doi.org/10.3329/jme.v43i2.17830.
Full textAbstract:
Static torque and drag coefficients of a stationary Savonius rotor with circular arc blade profile havebeen investigated by measuring the pressure distribution on the blade surfaces for different rotor angles.Experiments have been performed at a Reynolds Number 1.8×105 with rotors having no overlap. Resultsindicate that static torque coefficients vary considerably with the rotor angle.DOI: http://dx.doi.org/10.3329/jme.v43i2.17830
49
de la Blanco, E. Rosa, H. P. Hodson, R. Vazquez, and D. Torre. "Influence of the state of the inlet endwall boundary layer on the interaction between pressure surface separation and endwall flows." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 217, no. 4 (January 1, 2003): 433–41. http://dx.doi.org/10.1243/095765003322315496.
Full textAbstract:
This paper describes the effect of the state of the inlet boundary layer (laminar or turbulent) on the structure of the endwall flow on two different profiles of low-pressure (LP) turbine blades (solid thin and hollow thick). At present the state of the endwall boundary layer at the inlet of a real LP turbine is not known. The intention of this paper is to show that, for different designs of LP turbine, the state of the inlet boundary layer affects the performance of the blade in very different ways. The testing was completed at low speed in a linear cascade using area traversing, flow visualization and static pressure measurements. The paper shows that, for a laminar inlet boundary layer the two profiles have a similar loss distribution and structure of endwall flow. However, for a turbulent inlet boundary layer the two profiles are shown to differ significantly in both the total loss and endwall flow structure. The pressure side separation bubble on the solid thin profile is shown to interact with the passage vortex, causing a higher endwall loss than that measured on the hollow thick profile.
50
Corriveau, D., and S. A. Sjolander. "Influence of Loading Distribution on the Performance of Transonic High Pressure Turbine Blades." Journal of Turbomachinery 126, no. 2 (April 1, 2004): 288–96. http://dx.doi.org/10.1115/1.1645534.
Full textAbstract:
Midspan measurements were made in a transonic wind tunnel for three high pressure turbine blade cascades at design incidence. The baseline profile is the midspan section of a high pressure turbine blade of fairly recent design. It is considered mid-loaded. To gain a better understanding of blade loading limits and the influence of loading distributions, the profile of the baseline airfoil was modified to create two new airfoils having aft-loaded and front-loaded pressure distributions. Tests were performed for exit Mach numbers between 0.6 and 1.2. In addition, measurements were made for an extended range of Reynolds numbers for constant Mach numbers of 0.6, 0.85, 0.95, and 1.05. At the design exit Mach number of 1.05, the aft-loaded airfoil showed a reduction of almost 20% in the total pressure losses compared with the baseline airfoil. However, it was also found that for Mach numbers higher than the design value the performance of the aft-loaded blade deteriorated rapidly. The front-loaded airfoil showed generally inferior performance compared with the baseline airfoil.