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1
Lim, Choon Peng. "Experimental investigation of vortex shedding in high Reynolds number flow over compressor blades in cascade." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FLim.pdf.
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Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, March 2003.Thesis advisor(s): Garth V. Hobson, Raymond P. Shreeve. Includes bibliographical references (p. 81-82). Also available online.
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Intaratep, Nanyaporn. "Formation and Development of the Tip Leakage Vortex in a Simulated Axial Compressor with Unsteady Inflow." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26771.
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The interaction between rotor blade tip leakage vortex and inflow disturbances, such as encountered in shrouded marine propulsors, was simulated in the Virginia Tech Linear Cascade Wind Tunnel equipped with a moving endwall system. Upstream of the blade row, idealized periodic inflow unsteadiness was generated using vortex generator pairs attached to the endwall at the same spacing as the blade spacing. At three tip gap settings, 1.7%c, 3.3%c and 5.7%c, the flow near the lower endwall of the center blade passage was investigated through three-component mean velocity and turbulence distributions measured by four-sensor hotwires. Besides time-averaged data, the measurements were processed for phase-locked analysis, with respect to pitchwise locations of the vortex generators relative to the blade passage. Moreover, surface pressure distributions at the blade tip were acquired at eight tip gaps from 0.87%c to 12.9%c. Measurements of pressure-velocity correlation were also performed with wall motion but without inflow disturbances.
Achieved in this study is an understanding of the characteristics and structures of the tip leakage vortex at its initial formation. The mechanism of the tip leakage vortex formation seems to be independent of the tip gap setting. The tip leakage vortex consists of a vortical structure and a region of low streamwise-momentum fluid next to the endwall. The vortical structure is initially attached to the blade tip that creates it. This structure picks up circulation shed from that blade tip, as well as those from the endwall boundary layer, and becomes stronger with downstream distance. Partially induced by the mirror images in the endwall, the vortical structure starts to move across the passage resulting in a reduction in its rotational strength as the cross sectional area of the vortex increases but little circulation is added. The larger the tip gap, the longer the vortical structure stays attached to the blade tip, and the stronger the structure when it reaches downstream of the passage.
Phased-averaged data show that the inflow disturbances cause small-scale responses and large-scale responses upstream and downstream of the vortex shedding location, respectively. This difference in scale is possibly dictated by a variation in the shedding location since the amount of circulation in the vortex is dependent on this location. The inflow disturbances possibly cause a variation in the shedding location by manipulating the separation of the tip leakage flow from the endwall and consequently the flowâ s roll-up process. Even though this manipulation only perturbs the leakage flow in a small scale, the shedding mechanism of the tip leakage vortex amplifies the outcome.Ph. D.
3
Baiense, Jr Joao C. "Vortex Generator Jet Flow Control in Highly Loaded Compressors." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/916.
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"A flow control method for minimizing losses in a highly loaded compressor blade was analyzed. Passive and active flow control experiments with vortex generator jets were conducted on a seven blade linear compressor cascade to demonstrate the potential application of passive flow control on a highly loaded blade. Passive flow control vortex generator jets use the pressure distribution generated by air flow over the blade profile to drive jets from the pressure side to the suction side. Active flow control was analyzed by pressuring the blade plenum with an auxiliary compressor unit. Active flow control decreased profile losses by approximately 37 % while passive flow control had negligible impact on the profile loss of a highly loaded blade. Passive flow control was able to achieve a jet velocity ratio, jet velocity to upstream velocity, of 0.525. The success of active flow control with a velocity ratio of 0.9 suggests there is potential for passive flow control to be effective. The research presented in this thesis is motivated by the potential savings in the applications of passive flow control in gas turbine axial compressors by increasing the aerodynamic load of each stage. Increased stage loading that is properly controlled can reduce the number of stages required to achieve the desired pressure compression ratio."
4
Lenglin, Geoffroy (Geoffroy Philippe) 1976. "Characterization of wake- and tip-vortex-induced unsteady blade response in multistage compressor environment." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/82227.
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Znidarčić, Matej. "Computational Validation of the Compressor Design Program Blade Layout Method." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1323361068.
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Семенов, Ф. Д. "Розроблення вихрового компресора для системи газодинамічних ущільнень і дослідження впливу параметрів на його ефективність." Master's thesis, Сумський державний університет, 2020. https://essuir.sumdu.edu.ua/handle/123456789/82264.
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У роботі виконано розрахунок одноступеневого та двоступеневого вихрового компресора. Виконано порівняльний аналіз розрахунків для різниці діаметрів коліс (D = 250/255/318/391) компресорів на параметри стиснення Рвх = 0,4 МПа, Рвих = 0,45 МПа, Vе = 0,006 м3/с, Т0 = 288 К, n = 3500 об/хв, середовище – аміак. В результаті визначено, що на задані значення кращим варіантом є двоступеневий компресор з діаметрами коліс D2 = 250 мм та D2 = 255 мм.В работе выполнен расчет одноступенчатого и двухступенчатого вихревого компрессора. Выполнен сравнительный анализ расчетов для разницы диаметров колес (D = 250/255/318/391) компрессоров на параметры сжатия Рвх = 0,4 МПа, Рвых = 0,45 МПа, Vе = 0,006 м3 / с, Т0 = 288 К, n = 3500 об / мин, среда - аммиак. В результате определено, что на заданные значения лучшим вариантом является двухступенчатый компрессор с диаметрами колес D2 = 250 мм и D2 = 255 мм.
The calculation of a single-stage and two-stage vortex compressor is performed in this work. A comparative analysis of calculations for the difference in wheel diameters (D = 250/255/318/391) of compressors for compression parameters Pvx = 0.4 MPa, Pvih = 0.45 MPa, Ve = 0.006 m3 / s, T0 = 288 K, n = 3500 rpm, medium - ammonia. As a result, it was determined that the best option for the set values is a two-stage compressor with wheel diameters D2 = 250 mm and D2 = 255 mm.
7
Brown, Peter J. "Experimental investigation on vortex shedding in flow over second-generation, controlled-diffusion, compressor blades in cascade." Thesis, Monterey, California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/6092.
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Approved for public release, distribution unlimitedAn investigation of vortex shedding downstream of a cascade of second-generation, controlled-diffusion, compressor stator blades, at off-design inlet-flow angles of 31, 33 and 35 degrees and Reynolds numbers, based on chord length, of 280,000, 380,000 and 640,000 is reported. The objective of the study was to characterize the flow and shedding through various complementary methods. Blade surface pressure measurements were taken from a fully instrumented blade, and distributions of pressure coefficients were determined. Five-hole probe wake surveys were performed at midspan, and the total pressure loss coefficients and axial velocity ratios were calculated. Upstream inlet-flow angle was set, and further characterized through two-component laser-Doppler velocimetry (LDV). Hot-wire anemometry measurements were performed at mid span, in the wake, and the reduced data were compared with two-component LDV surveys of the same regions. Plots of hot-wire vs. LDV turbulence data are reported in addition to power spectra documenting the shedding events. Vortex shedding was determined to be a leading edge phenomenon as periodic shedding was only detected on the pressure side of the wake. The frequency and magnitude of shedding were found to be independent of incidence angle, and to increase with Reynolds number at constant incidence angle. The Strouhal number, based on leading edge diameter, was found to be in the range of 0.23-0.26, which is comparable to that of vortex shedding behind a circular cylinder in the Reynolds number range tested.
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Langford, Matthew David. "Experimental Investigation of the Effects of a Passing Shock on Compressor Stator Flow." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32020.
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A stator cascade was developed to simulate the flow conditions within a close-stage-spacing transonic axial compressor. Experiments were conducted in a linear transonic blowdown cascade wind tunnel with an inlet Mach number of 0.65. The bow shock from the downstream rotor was simulated by a single moving normal shock generated with a shock tube. First, steady pressure data were gathered to ensure that the stator cascade operated properly without the presence of the shock. Next, the effects of the passing shock on the stator flow field were investigated using shadowgraph photography and Digital Particle Image Velocimetry (DPIV). Measurements were taken for three different shock strengths. In every case studied, a vortex formed near the stator trailing edge as the shock impacted the blade. The size of this vortex was shown to be directly related to the shock strength, and the vortex remained present in the trailing edge flow field throughout the cycle duration. Analysis of the DPIV data showed that the vortex acts as a flow blockage, with the extent of this blockage ranging from 2.9% of the passage for the weakest shock, to 14.3% of the passage for the strongest shock. The vortex was also shown to cause flow deviation up to 75° for the case with the strongest shock. Further analysis estimated that the total pressure losses due to shock-induced vorticity ranged from 46% to 113% of the steady wake losses. Finally, the total pressure loss purely due to the upstream-propagating normal shock was estimated to be roughly 0.22%.Master of Science
9
Shin, Sangmook. "Reynolds-Averaged Navier-Stokes Computation of Tip Clearance Flow in a Compressor Cascade Using an Unstructured Grid." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28947.
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A three-dimensional unstructured incompressible RANS code has been developed using artificial compressibility and Spalart-Allmaras eddy viscosity model. A node-based finite volume method is used in which all flow variables are defined at the vertices of tetrahedrons in an unstructured grid. The inviscid fluxes are computed by using the Roe's flux difference splitting method, and higher order accuracy is attained by data reconstruction based on Taylor series expansion. Gauss theorem is used to formulate necessary gradients. For time integration, an implicit scheme based on linearized Euler backward method is used.
A tetrahedral unstructured grid generation code has been also developed and applied to the tip clearance flow in a highly staggered cascade. Surface grids are first generated in the flow passage and blade tip by using several triangulation methods including Delaunay triangulation, advancing front method and advancing layer method. Then the whole computational domain including tip gap region is filled with prisms using the surface grids. Each prism is divided into three tetrahedrons. To accomplish this division in a consistent manner, connectivity pattern is assigned to each triangle in the surface grids. A new algorithm is devised to assign the connectivity pattern without reference to the particular method of triangulation. This technique offers great flexibility in surface grid generation.
The code has been validated by comparisons with available computational and experimental results for several test cases: invisicd flow around NACA section, laminar and turbulent flow over a flat plate, turbulent flow through double-circular arc cascade and laminar flow through a square duct with 90° bend. For the laminar flat plate case, the velocity profile and skin friction coefficient are in excellent agreement with Blasius solution. For the turbulent flat plate case, velocity profiles are in full agreement with the law of the wall up to Reynolds number of 1.0E8, however, the skin friction coefficient is under-predicted by about 10% in comparison with empirical formula. Blade loading for the two-dimensional circular arc cascade is also compared with experiments. The results obtained with the experimental inflow angle (51.5° ) show some discrepancies at the trailing edge and severely under-predict the suction peak at the leading edge. These discrepancies are completely remedied if the inflow angle is increased to 53.5° . The code is also capable of predicting the secondary flow in the square duct with 90° bend, and the velocity profiles are in good agreement with measurements and published Navier-Stokes computations.
Finally the code is applied to a linear cascade that has GE rotor B section with tip clearance and a high stagger angle of 56.9° . The overall structure of the tip clearance flow is well predicted. Loss of loading due to tip leakage flow and reloading due to tip leakage vortex are presented. On the end wall, separation line of the tip leakage vortex and reattachment line of passage vortex are identified. The location of the tip leakage vortex in the passage agrees very well with oil flow visualization. Separation bubble on the blade tip is also predicted. Mean streamwise velocity contours and cross sectional velocity vectors are compared with experimental results in the near wake, and good agreements are observed. It is concluded that Spalart-Allmaras turbulence model is adequate for this type of flow field except at locations where the tip leakage vortex of one blade interacts with the wake of a following blade. This situation may prevail for blades with longer span and/or in the far wake. Prediction of such an interaction presents a challenge to RANS computations.
The effects of blade span on the flow structure have been also investigated. Two cascades with blades of aspect ratios of 0.5 and 1.0 are considered. By comparing pressure distributions on the blade, it is shown that the aspect ratio has strong effects on loading distribution on the blade although the tip gap height is very small (0.016 chord). Grid convergence study has been carried out with three different grids for pressure distributions and limiting streamlines on the end wall.Ph. D.
10
Carr, M. I. "The excitation of acoustic resonances in an axial flow compressor stage by vortex shedding from aerofoil section blading." Thesis, Swansea University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636209.
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In recent years continuing development of the axial flow compressor for use in the aero-engine has increased its susceptibility to unsteady flow phenomena which can cause severe blade vibration. A source which has emerged and become of considerable importance is excitation by acoustic resonances. An experimental investigation in a single stage axial flow compressor rig has been performed to ascertain whether acoustic resonances can be excited by vortex shedding from loaded aerofoil section blades. A further experimental programme, to study further the effect of inter-row spacing, was peformed in both an open jet facility and a wind tunnel facility with a tandem plate arrangement. Results showed that acoustic resonances could be excited in a compressor stage in which there was severe blade loading. The speed range over which the resonances were excited was demonstrated to be not only a function of the degree of loading but also the inter-row spacing. Vortex shedding will drive a resonance when the shedding is correlated by the resonant acoustic field and interaction between the vortices and the acoustic field in the vicinity of the blades may result in a net positive input of acoustic energy. As a result the phase of the acoustic field as vortices pass over the trailing edge of the shedding blades and the leading and trailing edges of the downstream blades, control the energy generation. The inter-row spacing controls the phase of the downstream blade interaction and therefore is a major factor influencing the resonant acoustic amplitude. As well as the fundamental acoustic mode, a resonance can also drive significant blade vibration in two other consequential frequency bands which are: a) Sum and Difference frequency bands due to acoustic non-linearity and b) Sidebands of the fundamental modes due to spatial modulation effects caused by flow distortions.
11
Tian, Qing. "Some Features of Tip Gap Flow Fields of a Linear Compressor Cascade." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9673.
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This thesis presents some results from an experimental study of three-dimensional turbulent tip gap flows in the linear cascade wind tunnel, for two different tip gap clearances (t/c=1.65% and 3.3%). The experiments focus on near-wall flow field measurements for the stationary wall and moving wall, and static pressure measurement on the low end-wall for the stationary wall case. The representative flows were pressure driven, three-dimensional turbulent boundary layers in the linear cascade tunnel for the stationary wall case, and the combination of the pressure driven and shear driven flow for the moving wall case.
Several experimental techniques are used in the studies: a three-orthogonal-velocity-component fiber-optic laser Doppler anemometer (3D-LDA) system, surface oil flow visualization, and a scanivalve system for static pressure measurement through pressure ports on the end-wall. From the details of the oil flow visualization pattern on the end-wall, some features of the passage flow, cross flow, and the tip leakage vortex in this cascade flow were captured. Oil flow visualization on the blade surface reveals the reattachment of the tip leakage vortex on the blade surface. The static pressure results on the lower end-wall and mid-span of the blade show huge pressure drop on the lower end-wall from the pressure side to the suction side of the blade and from mid-span to the lower end wall. The end-wall skin friction velocity is calculated from near-wall LDA data and pressure gradient data using the near-wall momentum equation.
The statistics of Reynolds stresses and triple products in two-dimensional turbulent boundary layer and three-dimensional turbulent boundary layer was examined using a velocity fluctuation octant analysis in three different coordinates (the wall collateral coordinates, the mid tip gap coordinates, and the local mean flow angle coordinates). The velocity fluctuation octant analysis for the two-dimensional turbulent boundary layer reveals that ejections of the low speed streaks outward from the wall and the sweeps of high speed streaks inward toward the wall are the dominant coherent motions. The octant analysis for the three-dimensional turbulent boundary layer in the tip gap shows that the dominant octant events are partially different from those in the two-dimensional turbulent boundary layer, but ejection and sweep motions are still the dominant coherent motions. For the three-dimensional turbulent boundary layer in the moving wall flow, the near-wall shear flow reinforces the sweep motion to the moving wall and weakens the out-ward ejection motion in the shear flow dominant region. Between the passage flow and the shear flow, is the interaction region of the high speed streaks and the low speed streaks. This is the first time that the coherent structure of the three-dimensional turbulent boundary in the linear cascade tip gap has been studied.Master of Science
12
Ma, Ruolong. "Unsteady Turbulence Interaction in a Tip Leakage Flow Downstream of a Simulated Axial Compressor Rotor." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28060.
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The unsteady behavior of a tip leakage flow downstream of a simulated axial compressor rotor has been studied. The Virginia Tech low speed linear cascade wind tunnel was adapted to model the unsteady tip leakage flow produced by a rotor operating in the vortical wakes of a set of stator vanes. The cascade, consisting of 8 GE rotor B blades, has adjustable tip gap, inlet angle of 65.1 degrees, turning angle of 11.8 degrees and solidity of 1.076. The cascade Reynolds number, based on blade chord, was 393,000. A moving end wall was used to simulate the relative motion between rotor and casing, and vortex generators attached to the moving end wall were used to produce an idealized periodic unsteady vortical inflow similar to that shed by the junction of a row of inlet guide vanes.
Measurements of the vortical inflow to the cascade produced by the generators and of the mean blade loading at the mid span are presented. The periodic and aperiodic behavior of the tip leakage flow downstream of the cascade, produced by this vortical disturbance, is also presented using phase and time averaged 3-component turbulence and pressure fluctuation measurements. These measurements are made for tip gap from 0.83% to 3.3% chord and streamwise locations from 0.772% to 1.117% blade spacing axially downstream of the cascade.
The phase averaged inflow measurements reveal that the inflow produced by the vortex generators consists of a pair asymmetric counter-rotating vortices embedded in a thin (4.6% chord) endwall boundary layer. The vortices extend some 7.4% chord from the end wall. Their strength is about two orders smaller than the typical circulation of the tip leakage vortices produced by the cascade.
Phase averaged single point three component hot-wire measurements downstream of the cascade reveal that the vortical inflow is, however, capable of producing significant large scale fluctuations in the size, strength, structure and position of the tip leakage vortex. These effects increase in magnitude with increase of tip gap. For small tip gaps these effects appear to be due to simple superposition between the inflow vortices and the tip leakage vortex. However for larger tip gaps these effects appear primarily a consequence of the inflow vortices interfering with the shedding of circulation from the blade tip. The fact that the circulation fluctuation is consistent with the inviscid unsteady loading prediction suggests that the inviscid response may be a major mechanism for generating the tip leakage unsteadiness.
Although there is large periodic fluctuation in the tip leakage flow disturbed by the inflow, there is a larger aperiodic component. Two point correlation measurements and linear stochastic estimation are used to reveal the structure of this aperiodic part for a tip gap of 3.3% chord. The aperiodic fluctuation, containing most of the turbulence energy, is found appearing to be organized structures in large scale, and making the estimated instantaneous velocity field significantly different from the phase averaged periodic velocity field.
Phase averaged pressure fluctuation measurements made using a microphone in the tip leakage vortex downstream of the cascade reveal that there are significant periodic fluctuating pressure waves and intense mean square fluctuation of the aperiodic fluctuating pressure. They are consistent with the measured periodic flow and aperiodic flow field respectively. These microphone measurements are validated using fluctuating pressure gradient estimates determined from the hot-wire measurements.Ph. D.
13
Clark, Kenneth Phillip. "Numerical Analysis on the Effects of Blade Loading on Vortex Shedding and Boundary Layer Behavior in a Transonic Axial Compressor." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2652.
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Multiple high-fidelity, time-accurate computational fluid dynamics simulations were performed to investigate the effects of upstream stator loading and rotor shock strength on vortex shedding characteristics in a single stage transonic compressor. Various configurations of a transonic axial compressor stage, including three stator/rotor axial spacings of close, mid, and far in conjunction with three stator loadings of decreased, nominal, and increased were simulated in order to understand the flow physics of transonic blade-row interactions. Low-speed compressors typically have reduced stator/rotor axial spacing in order to decrease engine weight, and also because there is an increase in efficiency with reduced axial spacing. The presence of a rotor bow shock in high-speed compressors causes additional losses as the shock interacts with the upstream stator trailing edge. This research analyzes the strength of shock-induced vortices due to these unsteady blade-row interactions. The time-accurate URANS code, TURBO, was used to generate periodic, quarter annulus simulations of the Blade Row Interaction compressor rig. Both time-averaged and time-accurate results compare well with experimentally-observed trends. It was observed that vortex shedding was synchronized to the passing of a rotor bow shock. Normal and large shock-induced vortices formed on the stator trailing edge immediately after the shock passing, but the large vortices were strengthened at the trailing edge due to a low-velocity region on the suction surface. This low velocity region was generated upstream of mid-chord on the suction surface from a shock-induced thickening of the boundary layer or separation bubble, due to the rotor bow shock reflecting off the stator trailing edge and propagating upstream. The circulation of the shock-induced vortices increased with shock strength (decreased axial spacing) and stator loading. Most design tools do not directly account for unsteady effects such as blade-row interactions, so a model is developed to help designers account for shock-induced vortex strength with varying shock strength and stator loading. An understanding of the unsteady interactions associated with blade loading and rotor shock strength in transonic stages will help compressor designers account for unsteady flow physics early in the design process.
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Берніков, П. І. "Розробка вихрового компресора і дослідження впливу термодинамічних параметрів на його характеристики." Master's thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/72208.
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У роботі розроблено вихровий компресор і досліджено вплив термодинамічних парметрів на його характеристики.В работе разработаны вихревой компрессор и исследовано влияние термодинамических парметры на его характеристики.
A vortex compressor was developed and the effect of thermodynamic parameters on its characteristics was investigated.
15
Чепуренко, І. О. "Розробка та дослідження вихрового компресора продуктивністю 4 м3/хв при тиску всмоктування 100 кПа, температурі всмоктування 293 К і різних тисках нагнітання." Master's thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/72177.
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У конструкторській частині виконано термодинамічний розрахунок вихрового компресора, розрахунки оптимальних режимів при різних тисках, та при різних діаметрах робочих коліс, побудовані графіки залежності.
Були побудовані креслення вихрового компресора, кришки, робочого колеса, і системи суфлювання компресора
В розділі охорони праці проведено аналіз небезпечних та шкідливих виробничих факторів при роботі вихрового компресора, виконано розрахунок шумоглушника.В конструкторской части выполнен термодинамический расчет вихревого компрессора, расчеты оптимальных режимов при различных давлениях, и при различных диаметрах рабочих колес, построены графики зависимости. Были построены чертежи вихревого компрессора, крышки, рабочего колеса, и системы суфлирования компрессора В разделе охраны труда проведен анализ опасных и вредных производственных факторов при работе вихревого компрессора, выполнен расчет шумоглушителя.
In the design part, a thermodynamic calculation of the vortex compressor is made, the calculations of optimal modes at different pressures, and with different diameters of impellers, dependency graphs are constructed. The blueprints for the vortex compressor, the cover, the impeller, and the compressor venting system were built. In the section of labor protection, the analysis of hazardous and harmful production factors during the operation of the vortex compressor has been carried out, the calculation of the silencer has been performed.
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Tian, Qing. "Near Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Blade." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/30062.
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This dissertation presents the results from an experimental study of three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler velocimeter (LDV) system was developed to make simultaneous three-velocity-component measurements. The overall size of the probe is 24"à 37"à 24"and measurement spatial resolution is about 100 μm. With 24" optical access distance, the LDV probe allows measurements to be taken from the side of the linear cascade tunnel instead of through the bottom of the tunnel floor. The probe has been tested in a zero-pressure gradient two-dimensional turbulent boundary layer.
Experimental measurements (oil flow visualization, pressure measurement, and LDV measurement) for the stationary wall captured the major flow structures of the tip leakage flow in the linear compressor cascade, such as tip leakage vortex, tip leakage vortex separation and tip separation vortex. Large velocity gradients in the tip leakage vortex separation, tip leakage vortex, and tip separation vortex regions generate large production of the Reynolds stresses and turbulent kinetic energy. One of the most interesting features of the tip leakage flow is the bimodal velocity probability histograms of the v component due to the unsteady motion of the flow in the interaction region between the tip leakage vortex and tip leakage jet. The tip separation vortex, tip leakage vortex separation, and tip leakage vortex contain most of turbulent kinetic energy and generate the highest dissipation rate.
Relative motion of the endwall significantly affects the tip gap flow structures, especially in the near wall region. Compared to the stationary wall case, velocity gradients in the near wall region for the moving wall case are much smaller and lower velocity gradients in the near wall region cause the low production of Reynolds stresses and turbulent kinetic energy. Similar to the stationary wall case, high Reynolds stresses and turbulent kinetic energy values are mainly located in the vicinity of the tip leakage vortex and tip separation vortex region. The bimodal velocity probability histograms of the v component are also found at the same locations. The tip separation vortex with most of the turbulent kinetic energy generates the highest dissipation rate. The dissipation rate in the tip leakage vortex region is reduced with the decrease of turbulent kinetic energy under the moving wall effect.Ph. D.
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Tang, Genglin. "Measurements of the Tip-gap Turbulent Flow Structure in a Low-speed Compressor Cascade." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11178.
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This dissertation presents results from a thorough study of the tip-gap turbulent flow structure in a low-speed linear compressor cascade wind tunnel at Virginia Tech that includes a moving belt system to simulate the relative motion between the tip and the casing. The endwall pressure measurements and the surface oil flow visualizations were made on a stationary endwall to obtain the flow features and to determine the measurement profiles of interest. A custom-made miniature 3-orthogonal-velocity-component fiber-optic laser-Doppler velocimetry (LDV) system was used to measure all three components of velocity within a 50 mm spherical measurement volume within the gap between the endwall and the blade tip, mainly for the stationary wall with 1.65% and 3.30% tip gaps as well as some initial experiments for the moving wall.
Since all of the vorticity in a flow originates from the surfaces under the action of strong pressure gradient, it was very important to measure the nearest-wall flow on the endwall and around the blade tip. The surface skin friction velocity was measured by using viscous sublayer velocity profiles, which verified the presence of an intense lateral shear layer that was observed from surface oil flow visualizations. All second- and third-order turbulence quantities were measured to provide detailed data for any parallel CFD efforts.
The most complete data sets were acquired for 1.65% and 3.30% tip gap/chord ratios in a low-speed linear compressor cascade. This study found that tip gap flows are complex pressure-driven, unsteady three-dimensional turbulent flows. The crossflow velocity normal to the blade chord is nearly uniform in the mid tip-gap and changes substantially from the pressure to suction side. The crossflow velocity relies on the local tip pressure loading that is different from the mid-span pressure loading because of tip leakage vortex influence. The tip gap flow is highly skewed three-dimensional flow throughout the full gap. Normalized circulation within the tip gap is independent of the gap size. The tip gap flow interacts with the primary flow, separates from the endwall, and rolls up on the suction side to form the tip leakage vortex. The tip leakage vortex is unsteady from the observation of the TKE transport vector and oil flow visualizations. The reattachment of tip separation vortex on the pressure side strongly depends on the blade thickness-to-gap height ratio after the origin of tip leakage vortex but is weakly related to it before the origin of tip leakage vortex for a moderate tip gap. Other than the nearest endwall and blade tip regions, the TKE does not vary much in tip gap. The tip leakage vortex produces high turbulence intensities. The tip gap flow correlations of streamwise and wall normal velocity fluctuations decrease significantly from the leading edge to the trailing edge of the blade due to flow skewing. The tip gap flow is a strongly anisotropic turbulent flow. Rapid distortion ideas can not apply to it. A turbulence model based on stress transport equations and experimental data is necessary to reflect the tip gap flow physics. For the moving endwall, relative motion skews the inner region flow and is decorrelated with the outer layer flow. Hence, the TKE and correlations of streamwise and wall normal velocity fluctuations decrease.Ph. D.
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Lee, Daniel H. "Numerical Investigation on the Effects of Self-Excited Tip Flow Unsteadiness and Blade Row Interactions on the Performance Predictions of Low Speed and Transonic Compressor Rotors." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1380620247.
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Le, Sausse Paul. "Contribution à la modélisation de l’écoulement dans un compresseur centrifuge et développement de critères d’optimisation." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0105.
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Cette thèse est le fruit d’un partenariat entre la société Johnson Controls et l’université Bordeaux1. L’objectif s’inscrit dans le cadre d’un projet de développement de pompe à chaleur innovante et est de développer un compresseur centrifuge à haute compression. Pour ce faire, un modèle numérique a été créé afin de simuler l’écoulement dans ce type de compresseur. Afin de respecter des impératifs industriels, une première géométrie a été établie par modifications itératives de divers paramètres et analyse des performances induites. L’écoulement a ensuite été étudié plus précisément, particulièrement pour mieux comprendre l’apparition des décollements. Enfin, une étude instationnaire de l’écoulement dans le diffuseur a été effectuée. Au delà des phénomènes physiques étudiés et appréhendés au cours de ce processus, c’est avant tout une méthodologie qui valorise ce travailThis thesis is the result of a partnership between the company Johnson Controls and the university Bordeaux1. The objective is part of a project to develop innovative heat pump and involves the design of a high head centrifugal compressor. To do this, a numerical model is created to simulate the flow in this kind of compressor. To observe industriel deadlines, a first geometry was established by iterative changes of various parameters in analysing induced effiencies. The flow was then studied further, especially to better understand the onset of flow separation. Finally, a study of unsteady flow in the diffuser was performed. Beyond the physical phenomena investigated and comprehended during this process, it is firstly a methodology that values this work
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Fournis, Camille. "Study of tip clearance flows." Thesis, KTH, Flygdynamik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-244423.
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The tip leakage vortex is responsible for the generation of stagnation pressure losses inside the compressor along with the outbreak of rotating stall and surge. The current paper analytically proved that a part of the losses is proportional to the vortex circulation squared. The evolution of this circulation has been investigated as part of a parametric study which tested several clearance heights. The work consists in adopting a simplified single blade configuration to study the physics of the flow by means of wind tunnel experiments and numerical calculations. Upon visualising the main features of the flow, a model based on the study of jet in crossflows was implemented to describe the tip clearance flow for small gap sizes. For big gaps, the flow is assumed to behave as an isolated wing tip vortex which circulation is easily computed by the so called lifting line theory. The main vortical structures highlighted by the topology of the flow justified the use of the model of a jet in crossflow for small gap sizes. This model was challenged by experimental and numerical data and proved to well predict the evolution of the clearance vortex circulation for an increasing clearance height although some numerical results remain further away from the model.Gapvirveln är ansvarig för lufttryckförluster i motorn av ett flygplan och kan orsaka utbrottet av kompressorstall och pumpning. Artikeln bevisade matematiskt att en del av de här förlusterna är proportionell mot gapvirvelncirkulationen upphöjd. Utvecklingen av den där cirkulationen undersöktes med hjälp av en parametrisk studie som provkörde flera gapstorlekar. Arbetet bestå av att adoptera en förenklad enda blad konfiguration för att studera flödes fysik med vindtunnel experiment och flödesberäkningar. Efter att man analyserar flödes viktigaste egenskaper genomfördes en modell baserad på studien av en jet i ett korsflöde. Den här modellen används för att beskriva flödet för små gapstorlekar. För stora gap antar man att flödet beter sig som en vingspetsvirvel som cirkulationen kan beräknas utan svårighet med hjälp av lyftledningsteorin. Flödes topologi visualiserades tack vare numeriska beräkningar och legitimerade användningen av modellen av en jet i ett korsflöde för små gapstorlekar. Teoretiska, experimentella och numeriska resultat jämfördes och bevisade att modellen väl förutsäger utvecklingen av gapvirvelncirkulationen mot gapstorlek även om några numeriska resultat är långt från modellen.
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Радченко, В. С. "Розроблення вихрового компресора і дослідження впливу продуктивності на його параметри." Master's thesis, Сумський державний університет, 2019. http://essuir.sumdu.edu.ua/handle/123456789/76518.
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В дослідницькій частині досліджено вплив продуктивності вихрового компресора на ККД компресора, потужність компресора, температуру газу на виході з компресора, геометричний комплекс.
Спроектовано вихровий компресор на параметри: робоче тіло - повітря; об'ємна продуктивність - Й, - 20 м'/хв; тиск всмоктування ро-100 кПа і нагнітання р, - 115 кПа; температура початкова Т; - 293 К; частота обертання ротора приводу п - 2950 об/мин.
Розглянуті питання регулювання вихрових компресорів.
В розділі охорона праці виконаний аналіз небезпечних та шкідливих промислових факторів, виконаний розрахунок шумоглушнику.В исследовательской части исследовано влияние производительности вихревого компрессора на КПД компрессора, мощность компрессора, температуру газа на выходе из компрессора, геометрический комплекс. Спроектирован вихревой компрессор на параметры: рабочее тело - воздух; объемная производительность - И - 20 м '/ мин; давление всасывания ро-100 кПа и нагнетания г. - 115 кПа; температура начальная Т; - 293 К; частота вращения ротора поводу п - 2950 об / мин. Рассмотрены вопросы регулирования вихревых компрессоров. В разделе охрана труда выполнен анализ опасных и вредных промышленных факторов, выполненный расчет шумоглушителю.
In the research part, the effect of vortex compressor performance on compressor efficiency, compressor power, gas temperature at the outlet of the compressor, and the geometric complex is studied. The vortex compressor was designed for the following parameters: working medium - air; volumetric productivity - And - 20 m '/ min; suction pressure of ro-100 kPa and forcing city - 115 kPa; initial temperature T; - 293 K; frequency rotor rotation about p - 2950 rpm. The issues of regulation of vortex compressors are considered. In the section on labor protection, an analysis of hazardous and harmful industrial factors, a calculation of the silencer is performed.
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Белява, К. Р. "Розробка та дослідження вихрового компресора продуктивністю 5 м3/хв при тиску всмоктування 100 кПа, тиску нагнітання 120 кПа і різних температурах всмоктування." Master's thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/72229.
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У роботі досліджено вплив зовнішнього діаметра робочого колеса на параметри вихрового компресора, а також вплив різних температур на вході в компресора.В работе исследовано влияние внешнего диаметра рабочего колеса на параметры вихревого компрессора, а также влияние различных температур на входе в компрессора.
The work investigated the influence of the external diameter of the impeller on the parameters of the vortex compressor, as well as the effect of different temperatures at the entrance to the compressor.
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Riera, William. "Evaluation of the ZDES method on an axial compressor : analysis of the effects of upstream wake and throttle on the tip-leakage flow." Thesis, Ecully, Ecole centrale de Lyon, 2014. http://www.theses.fr/2014ECDL0030/document.
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L’écoulement de jeu dans les compresseurs axiaux est étudié à l’aide de la Zonal Detached Eddy Simulation (ZDES). L’objectif consiste à évaluer la capacité de méthodes hybrides URANS/LES à simuler l’écoulement de jeu d’un compresseur axial réaliste afin de mieux comprendre la physique de cet écoulement, notamment son comportement au vannage ainsi que l’effet de sillages venant du stator amont sur le rotor aval. Après avoir choisi la méthode hybride ZDES, un banc d’essai numérique est défini afin de simuler le premier rotor du compresseur de recherche CREATE. Ce banc a la particularité de pouvoir prendre en compte les effets instationnaires venant de la roue directrice d’entrée (RDE), notamment son sillage ainsi que les tourbillons générés en pied et en tête. Basé sur des critères de maillage ZDES, il est utilisé pour évaluer cette méthode comparativement aux méthodes classiques RANS et URANS. La ZDES est validée par étape jusqu’à une analyse spectrale de l’écoulement de jeu se basant sur des données expérimentales. Elle s’est révélée capable de capturer plus précisément l’intensité et la position des phénomènes instationnaires rencontrés en tête du rotor, notamment le tourbillon de jeu. Les densités spectrales de puissance analysées montrent que cela est dû en partie à une meilleure prise en compte du transfert d’énergie des grandes vers les petites structures de l’écoulement avant leur dissipation. De plus, l’écart entre les approches s’accentue lorsque le tourbillon de jeu traverse le choc en tête. Proche pompage, les effets d’interaction entre le choc, le tourbillon de jeu, la couche limite carter et le tourbillon venant de la tête de la RDE sont amplifiés. Le décollement de la couche limite carter s’accentue et une inversion locale de l’écoulement est observée. De plus, le tourbillon de jeu s’élargit et est dévié vers la pale adjacente, ce qui intensifie le phénomène de double écoulement de jeu. L’interaction du tourbillon venant de la tête de la RDE avec le choc et le tourbillon de jeu du rotor est ensuite étudiée au point de dessin. Un battement du tourbillon de jeu est rencontré lors de l’interaction de ce tourbillon avec le tourbillon de tête de la RDE, ce qui diminue le double écoulement de jeuThe tip-leakage flow in axial compressors is studied with the Zonal Detached Eddy Simulation (ZDES). This study aims at evaluating the capability of hybrid URANS/LES methods to simulate the tip-leakage flow within a realistic axial compressor in order to better understand the involved physics, especially the behaviour of the flow near surge and the effects of stator wakes on the downstream rotor. Once the ZDES method is chosen, a numerical test bench is defined to simulate the first rotor of the research compressor CREATE. This bench takes into account the unsteady effects of the Inlet Guide Vane (IGV), such as its wake as well as vortices generated at the IGV hub and tip. It is based upon ZDES meshing criteria and is used to evaluate this method compared to classic RANS and URANS approaches. A method validation is carried out up to a spectral analysis compared to experimental data. The ZDES is capable to capture more accurately the intensity and position of the unsteady phenomena encountered in the tip region, especially the tip-leakage vortex. The power spectral densities highlight that this partly originates from a better capture of the energy transfer from large to small structures until their dissipation. The discrepancy between the methods is accentuated as the tip-leakage vortex crosses the shock. Near the surge line, the interactions between the shock, the tip-leakage vortex, the boundary layer developing on the shroud and the vortex generated by the IGV tip are amplified. The boundary layer on the shroud separates earlier and a local flow inversion occurs. Besides, the tip-leakage vortex widens and is deflected toward the adjacent blade. This strengthens the double leakage. At the design operating point, the interaction of the IGV tip vortex with the shock and the rotor tip vortex is studied. A vortex flutter is observed as the IGV tip vortex arrives on the rotor blade and stretches the rotor tip vortex. This phenomenon decreases the double leakage
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Шаталов, Є. О. "Розроблення вихрового компресора для системи газодинамічних ущільнень." Master's thesis, Сумський державний університет, 2019. http://essuir.sumdu.edu.ua/handle/123456789/76526.
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В дослідницькій виконано розрахунок варіантів вихрового компресора, досліджено вплив товщини лопаток і частоти обертання ротора на параметри, а також характеристики компресора.
Виконано обробку і аналіз результатів випробувань. Розглянуті питання регулювання вихрових компресорів. В розділі охорона праці виконаний аналіз небезпечних та шкідливих промислових факторів, виконаний розрахунок шумоглушнику.В исследовательской выполнен расчет вариантов вихревого компрессора, исследовано влияние толщины лопаток и частоты вращения ротора на параметры, а также характеристики компрессора. Выполнено обработку и анализ результатов испытаний. Рассмотрены вопросы регулирования вихревых компрессоров. В разделе охрана труда выполнен анализ опасных и вредных промышленных факторов, выполненный расчет шумоглушителю.
In the research, the calculation of the vortex compressor options was carried out, the influence of the blade thickness and rotor speed on the parameters, as well as compressor characteristics, was studied. Processing and analysis of test results has been completed. The issues of regulation of vortex compressors are considered. In the section on labor protection, an analysis of hazardous and harmful industrial factors, a calculation of the silencer is performed.
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Margalida, Gabriel. "Analyse expérimentale et contrôle actif de l'écoulement dans un compresseur axial mono-étagée durant la transition vers le décrochage tournant." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0039.
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Durant la dernière décennie, le secteur aéronautique n’a cessé de croître et le nombre de passagers transportés a considérablement augmenté. En parallèle, des politiques de plus en plus restrictives ont été mises en place afin de diminuer notre impact environnemental notamment en réduisant les émissions de CO2. Dans cette optique, les motoristes cherchent à concevoir des moteurs plus efficaces, conduisant à l’utilisation de points de fonctionnement plus proches des limites d’opération et a un chargement des étages de compression plus important. Cependant, ces zones étant sensibles au déclenchement du décrochage tournant, les constructeurs cherchent à les éviter en fixant des marges de sécurités importantes. Deux problèmes majeurs doivent donc être traités : étendre la plage de fonctionnement du compresseur en éloignant sa limite de stabilité et être en mesure de connaître avec précision la position du point de fonctionnement de ce dernier afin de diminuer la marge de sécurité.Par ailleurs, même si le phénomène de décrochage tournant est aujourd’hui globalement bien compris, des études récentes ont mis en évidence de nouveaux processus de formation. Ainsi, afin de traiter au mieux les deux principaux enjeux liés au décrochage tournant, il est nécessaire d’approfondir les connaissances relatives à la physique de la formation du phénomène. Cette thèse s’inscrit dans cette démarche, en proposant une étude de la formation du décrochage tournant d’une part, ainsi que le développement et l’étude d’un système de détection et de contrôle actif de l’écoulement par jets continus ou pulsés, dont le rôle est de prévenir l’approche des zones à risque et d’étendre la plage de fonctionnement du compresseurOver the past decades, the aviation sector has continuously grown, and the number of passengers carried has increased considerably. At the same time, increasingly restrictive policies have been put in place to reduce our environmental impact, especially by reducing CO2 emissions. In this context, engine manufacturers try to design more efficient engines, leading to the use of operating points closer to the stability limits and to higher loading of the compressor stages. However, these regions are more sensitive to the onset of rotating stall, and manufacturers seek to avoid them by using large security margins. Two major problems must therefore be addressed, extending the operating range of the compressor by moving its stability limit and being able to know precisely the position of its operating point to reduce the security margin.Moreover, even if the phenomenon of rotating stall is now globally well understood, recent studies have highlighted new onset mechanisms. Thus, in order to correctly handle the two main challenges cited before, it is necessary to improve our knowledge of the underlying mechanisms of the phenomenon inception. This PhD thesis follows this approach by proposing a study of the rotating stall onset, and then the development and analysis of a surveillance and active flow control system, using continuous or pulsed jets, which aims at warning of the approach of sensitive areas and expanding the operating range of the compressor by preventing the onset of stall
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Kuhl, David Derieg. "Near Wall Investigation of Three Dimensional Turbulent Boundary Layers." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34676.
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This report documents the experimental study for four different three-dimensional turbulent flows. The investigation focuses on near wall measurements in these flows. Several experimental techniques are used in the studies; however, the bulk of the investigation focuses on a three-orthogonal-velocity-component fiber-optic laser Doppler anemometer (3D-LDA) system. The control volume of the 3D-LDA is on the order of 50 micro-meter in size, or a y+ distance of around 2.3 units (using average values of Uτ and ν from the experiment). An auxiliary small boundary layer wind tunnel (auxiliary tunnel) and a low speed linear compressor cascade wind tunnel (cascade tunnel) are utilized in this study. One of four flow experiments is done in the auxiliary tunnel the other three are in the cascade tunnel. The first three-dimensional turbulent flow is a vortical flow created by two half-delta wing vortex generators. Near wall secondary flow features are found. The second flow is an investigation of the first quarter chord tip gap flow in the cascade tunnel. Strong three-dimensional phenomena are found. The third flow investigated is the inflow to the compressor cascade with the moving wall. The experiment records shear layer interaction between the upstream flow and moving wall. Finally the fourth flow investigated is the inflow to the compressor cascade with the moving wall with half-delta wing vortex generators attached. Phase-averaged data reveal asymmetrical vortex structures just downstream of the vortex generators. This is the first time any near wall data has been taken on any of these flows.Master of Science
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Kníř, Jakub. "Parametrická studie vlivu tvaru štěrbiny mezi lopatkou rotoru turbíny a skříní motoru na aerodynamické vlastnosti rotoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230820.
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Tato diplomová práce otevírá otázku možnosti zlepšení vlastností kompresoru za pomoci numerické simulace proudění. Hlavním cílem je zvýšení operačního rozsahu na jednom stupni axiálního kompresoru s využitím zařízení pro pasivní kontrolu proudu umístěných ve skříni kompresoru. Prvně bylo prověřeno chování víru ve štěrbině mezi lopatkou a skříní následně celkové charakteristiky původního rotoru. Při snižování hmotnostního průtoku simulace odhalila zvýšený vliv koncového výru na hlavní proud. Navíc byl největší koncový vír v režimu blízkém odtrhávání proudění. Z tohoto důvodu byly pro kontrolu koncového víru navrženy čtyři verze drážkování implementováním sinusové úpravy geometrie. Tři ze čtyř testovaných verzí ukázaly možnost výrazného zvýšení rozsahu stabilního proudění. Nicméně prodlužení operačního rozsahu mělo za následek snížení celkové účinnosti. Na konec této práce jsou navrženy doporučení pro další výzkum.
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Гриненко, Ю. В. "Розроблення вихрового компресора при тиску всмоктування 100 кПа, температурі всмоктування 313 К, тиску нагнітання 120 кПа і дослідження впливу продуктивності на його ефективність." Master's thesis, Сумський державний університет, 2020. https://essuir.sumdu.edu.ua/handle/123456789/82902.
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В роботі виконані термогазодинамічні розрахунки для
оптимального режиму роботи при різних значеннях витрат газу на вході в
вихровий компресор. Виконано аналіз результатів розрахунків і отримано
залежності основних режимних параметрів компресора від витрат газу на
вході в компресор і виконано їх аналіз. Обрано варіант для подальшого
проектування. Спроектовано вихровий компресор з двоканальною
проточною частиною, що дозволяє розвантажити ротор компресора від
осьових зусиль. В розділі охорони праці проведено аналіз небезпечних та
шкідливих виробничих факторів при роботі вихрового компресора і
зроблений розрахунок шумоглушника.В работе выполнены термогазодинамические расчеты для оптимального режима работы при различных значениях расхода газа на входе в вихревой компрессор. Выполнен анализ результатов расчетов и получены зависимости основных режимных параметров компрессора от расхода газа на входе в компрессор и выполнен их анализ. Выбран вариант для дальнейшего проектирования. Спроектирован вихревой компрессор с двухканальной проточной частью, позволяющей разгрузить ротор компрессора от осевых усилий. В разделе охраны труда проведен анализ опасных и вредных производственных факторов при работе вихревого компрессора и произведен расчет шумоглушителя.
In this work, a thermogas-dynamic calculations for the optimal mode of operation at different values of gas flow at the inlet to the vortex compressor are performed. The analysis of the results of calculations is performed and the dependences of the main mode parameters of the compressor on the gas flow at the inlet to the compressor are obtained and their analysis is performed. An option for further design has been selected. A vortex compressor with a two-channel flow part is designed, which allows to unload the compressor rotor from axial forces. In the section of labor protection the analysis of dangerous and harmful production factors at work of the vortex compressor is carried out and the calculation of the muffler is made.
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Сорін, В. Д. "Вихровий компресор для наддуву повітря в топку згорання на ТЕЦ." Master's thesis, Сумський державний університет, 2021. https://essuir.sumdu.edu.ua/handle/123456789/86615.
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У роботі виконано розрахунок одноступеневого вихрового компресора та визначено діаметр робочого колеса. З метою зменшення габаритних розмірів виконано розрахунок двоступеневого вихрового компресора з різними діаметрами робочих коліс першого та другого ступенів. Виконано аналіз отриманих результатів та вибрано оптимальну конструкцію для пропонованих вихідних даних. У розділі охорони праці виконано аналіз шкідливих та небезпечних факторів при експлуатації вихрових компресорів та виконано розрахунок шумоглушника.В работе выполнен расчет одноступенчатого вихревого компрессора и определен диаметр рабочего колеса. С целью уменьшения габаритных размеров выполнен расчет двухступенчатого вихревого компрессора с разными диаметрами рабочих колес первой и второй ступеней. Выполнен анализ полученных результатов и выбрана оптимальная конструкция для предлагаемых исходных данных. В разделе охраны труда выполнен анализ вредных и опасных факторов при эксплуатации вихревых компрессоров и расчет шумоглушителя.
In this work, the calculation of a single-stage vortex compressor is carried out and the diameter of the impeller is determined. In order to reduce the overall dimensions, a calculation was made for a two-stage vortex compressor with different diameters of the impellers of the first and second stages. The analysis of the obtained results is carried out and the optimal design for the proposed initial data is selected. In the labor protection section, the analysis of harmful and hazardous factors during the operation of vortex compressors and the calculation of the silencer are carried out.
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Ванєєв, Сергій Михайлович, Сергей Михайлович Ванеев, Serhii Mykhailovych Vanieiev, and Д. Є. Ісаєнко. "Дослідження параметрів вихрового компресора." Thesis, Сумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/45647.
Full textAbstract:
Широке використання в газовій промисловості знаходять
газоперекачувальні агрегати з відцентровими компресорами. Ці агрегати
призначені для роботи на лінійних компресорних станціях, дожимних
компресорних станціях, станціях підземного зберігання газу, установках
збору і транспортування нафтового газу. При запуску цих агрегатів в роботу
необхідний наддув повітря у торцеві газодинамічні ущільнення і магнітні
підшипники відцентрового компресора.
У даній роботі використовується схема наддуву повітрям від
спеціального вихрового компресора, який встановлюється безпосередньо
біля відцентрового компресора.
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Heffron, Andrew P. "Rotating stall and passive flow control on blade profiles and in centrifugal compressors." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/30708.
Full textAbstract:
The operating range and efficiency of a centrifugal compressor is limited by the development of rotating stall and surge at low mass flow rates. To extend the operating range of a compressor, flow control in the compressor can be used to suppress secondary flow structures that lead to rotating stall. The presented work seeks to use the novel idea of placing passive vortex generators (VG) upstream of the impeller to suppress rotating stall, while also developing new concepts and optimization of microvortex generators (MVG). To accomplish this goal, a new SIMPLE-type algorithm for compressible flows was written in Code_Saturne along with a 2nd-order MUSCL scheme for convective terms and an AUSM+-up scheme for mass flux computation. The new algorithm was successfully validated against several widely-used test cases. The new algorithm was used to model the flow of the NASA CC3, a high-speed centrifugal compressor, from choke to rotating stall with a vaneless and vaned diffuser. The new algorithm predicted the performance of the compressor with a vaneless diffuser very well; satisfactory results were obtained for the compressor with a vaned diffuser. The full compressor with a vaned diffuser was used to model rotating stall. A complex stall cycle between the inlet of the impeller and diffuser was observed and studied. The fundament behavior of MVG, i.e. micro (sub-boundary layer) vortex generator, in a turbulent boundary layer was investigated in a channel flow with RANS and LES. Complementary wind tunnel testing was conducted to validate the computational predictions. The configuration of the MVG was studied to determine an optimal configuration and several conclusions were reached on the design of MVG. Most importantly triangle MVG were found to be the most efficient shape followed by NACA0012 and e423-type MVG, and a MVG angle of 18˚ to 20˚ was found to be optimal. Rectangle MVG were observed to suffer flow separation on the vanes which reduced their performance. The circulation and drag of a MVG was found to have a logarithmic relationship with the device's Reynolds number. These findings were incorporated in a LES study to control separated flow on the e387 airfoil and achieved an improvement in lift-to-drag ratio of 11.27%. Additional recommendations for MVG implementation were given. Combining the work on the NASA CC3 with the work on MVG, vortex generators were implemented near the inlet of the impeller. A detailed optimization study was conducted for the implementation vortex generators in the compressor. It was found vortex generators equal to the boundary layer thickness were the most efficient on controlling the downstream flow. The best configuration was implemented into the full compressor with a vaned diffuser to assess the ability of vortex generators to suppress rotating stall. The vortex generators were found to suppress rotating stall and extend the operating range of the compressor.
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Chomier, Mickael Thierry. "Effect of Vortex Roll-up and Crevice Mass Flow on Ignition in a Rapid Compression Machine." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1374666527.
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Silva, Oseas Carlos da. "Refrigerating System By Rank-Hilsch Tubes With Supply of Compressed Air Tank to Power With PV Source." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13476.
Full textAbstract:
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorA busca por novos sistemas de refrigeraÃÃo vem se tornando o alvo de estudo de diversos pesquisadores, com o objetivo de diminuir impactos ambientais referentes à destruiÃÃo da camada de ozÃnio e efeito estufa que trazem consigo diversos malefÃcios à vida no planeta. Sistemas de refrigeraÃÃo convencionais respondem por boa parte do consumo de energia elÃtrica de uma residÃncia ou uma empresa (de 20 ou atà 25%), e sÃo normalmente ligados durante o dia , quando a demanda à maior e as tarifas mais caras. Dispositivos de refrigeraÃÃo sÃo indispensÃveis nas atividades humanas, como conservaÃÃo de alimentos, medicamentos, etc. Sistemas fotovoltaicos sÃo fontes de energia elÃtrica confiÃveis e independentes. Por essas razÃes, atualmente, hà um aumento no uso de sistemas de refrigeraÃÃo acionados por energia solar fotovoltaica nas zonas rurais. Tubos de Ranque-Hilsch ou tubos de vÃrtice sÃo geralmente utilizados para refrigeraÃÃo local de baixo custo, onde hà a disponibilidade de ar comprimido. Nesse trabalho, um tubo de vÃrtice foi concebido, testado e otimizado para operaÃÃo em pressÃes inferiores Ãs convencionais, de modo a ser alimentado por um compressor acionado por mÃdulos fotovoltaicos, suprindo as necessidades de esfriamento em localidades desprovidas de energia elÃtrica. Nas mediÃÃes experimentais, foram obtidas temperaturas abaixo do ponto de congelamento da Ãgua por meio da combinaÃÃo de certos parÃmetros, possibilitando a esse sistema de climatizaÃÃo ser utilizado de maneira eficiente e racional em localidades remotas, podendo contribuir para a soluÃÃo da questÃo energÃtica e ambiental da sociedade.
The search for new refrigeration systems has become the target of various researchers. Their goal is to reduce the environment impacts resulting from the destruction of the ozone layer and the greenhouse effects that harm life in the planet Earth. Vapor-compression refrigeration systems represent a big fraction of the world energy consumption in houses and commercial stores (between 20 to 25%) and these systems usually run during the day, when the energy demand and the prices are higher. Refrigeration systems are necessary to todayâs human activities, such as food and medicament conservation, air conditioning, etc. Photovoltaic systems are reliable energy sources and they can operate separately from the distribution energy grid. For these reasons, there is an increase in the use of refrigeration systems powered by solar photovoltaic panels in rural areas. Ranque-Hilsch tubes or vorticity tubes are commonly used for low cost local refrigeration, where compressed air is available. In this study, a vortex tube was designed, tested, and optimized to operate at pressure levels lower than the conventional values. The purpose is to allow its operation by a compressor system powered by solar photovoltaic panels and, therefore, its installation in locations where there is no electrical grid. In the experimental measurements, temperatures below the water freezing point were reached due to the combination of a number of tube parameters. These low temperature values support the use of the vortex tube in air cooling applications in a more efficient and rational energy use, particularly in remote locations, and can contribute to the solution of the energy demand and environmental problems.
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Astorri, Pietro. "Prototipazione e stampa 3D degli stadi di un compressore assiale con diverso design." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
La mia tesi consiste nel prototipare e valutare lo svergolamento dei palettamenti di alcuni stadi di un compressore assiale ,progettati con diverso design, e realizzare dei modelli didattici in stampa 3D dei risultati ottenuti.
Si articola nelle seguenti fasi :
- Raccolta teorica sulle basi della progettazione di un compressore assiale
- Raccolta dati di progetto di partenza e caratteristiche Free Vortex, Exponential e Constant Reaction design
- Progettazione al raggio medio con Excel
- Elaborazione programma Matlab per il calcolo delle coordinate palari e delle curve dei palettamenti , interfaccia necessaria tra i calcoli al raggio medio e il software di modellazione SolidWorks.
Questo programma verifica anche i dati al raggio medio con una sequenza di calcoli preliminari e, grazie alle sue subroutines indipendenti, permette il calcolo progettuale di un qualsiasi compressore con un qualsiasi profilo geometrico NACA.
- Estrapolazione risultati analitici e conversione in coordinate assolute importabili su SolidWorks
- Modellazione 3D e verifica Fem su SolidWorks dei palettamenti progettati
- Modellazione 3D del primo stadio (più sollecitato) con Exponential design (meno svergolato)
- Stampa 3D dei modelli tridimensionali citati nei punti precedenti
- Confronto tra i design e conclusioni