Academic literature on the topic 'Inlet Swirl'
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Journal articles on the topic "Inlet Swirl"
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Fan, Yu, De Xin Liu, and Li Wang. "3D Numerical Simulation on the Variable Swirl Intake Process of Diesel Engine." Applied Mechanics and Materials 273 (January 2013): 143–47. http://dx.doi.org/10.4028/www.scientific.net/amm.273.143.
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To study the flow and swirl characteristics in the variable swirl intake system of a four-valve diesel engine, a numerical simulation with using the three dimensional CFD software AVL-FIRE, was calculated on the intake flow in three types of inlet of the engine. Two swirl-control valve plans are posed and a better plan was selected through the comparative study. The result shows that with a lager valve lift the flow characteristic of spiral inlet is better than that of tangential inlet, and in the opposite case the results are also opposite. The double inlets make the swirl torque increase. When a swirl-control valve is set in the spiral inlet, the variable swirl effect is better, and it ensures better flow capacity and larger swirl ratio range.
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Elkersh, A. M., A. H. Elgammal, and N. R. L. Maccallum. "An Experimental Investigation of the Performance of Equiangular Annular Diffusers with Swirled Flow." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 199, no. 4 (1985): 293–97. http://dx.doi.org/10.1243/pime_proc_1985_199_126_02.
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An experimental study of the influence of geometrical parameters and swirl on the performance of equiangular diffusers is presented. Three diffusers were tested over a range of inlet swirls up to 45°, the swirls being of free vortex distribution. The data presented indicate similar flow patterns for different cant angles, and show that the centrifugal forces due to swirl stabilize the flow on the outer wall, while increasing the tendency towards separation at the inner wall. Diffuser performance improves as the inlet swirl increases up to 30°, the improvement being influenced by area ratio and cant angle. A further increase of swirl causes a deterioration of performance.
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Liu, Yin Li, and Hao Tang. "Numerical Study on the Interaction Mechanism between Swirl and Reverse Flow Rate in a Twin Swirl Combustor." Advanced Materials Research 960-961 (June 2014): 341–48. http://dx.doi.org/10.4028/www.scientific.net/amr.960-961.341.
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An isothermal flow in a Twin Swirl Combustor (TSC) was simulated with the Renormalized Group (RNG) k-ε turbulence model. The swirling and recirculation intensity was studied under different structures and inlet conditions. The results confirmed that there was a significant negative correlation between the trend lines of the swirl number (S) and reversed flow rate (Xr). The gradient of reversed flow rate was larger in the front and middle parts of the combustor than that of swirl number. The end-surface-inlet structure had a better swirl and recirculation enhancement effect. With the end-surface-inlet structure, the internal swirl and reverse intensity could be flexibly adjusted by switching the swirl intensity of the primary air. Under the structure of staggered-inlet, there was a critical distance between primary and secondary air inlets. When exceeded, it would be more difficult to enhance the swirl and reverse flow effect by increasing the swirl intensity of the secondary air.
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Jiao, Yun Jing, Peng Kun Si, and Zi Li Zhang. "Optimization Design and CFD Study of Nature Gas Engine Inlet." Advanced Materials Research 655-657 (January 2013): 315–19. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.315.
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By adopting CFD numerical simulation software, the steady numerical simulation of original engine inlet is carried on. On base of the original one, two new inlets are redesigned and their velocity fields are analyzed. From the simulation of CFD, we can learn that with the different inlet, the average flow velocity increases when the swirl ratio rises in same cross-section. Then the experiment of inlets with different geometry is carried on. Considered various kinds of performance of the engine, we found that the swirl ratio which is generated by the inlet should not be too high, but it also is not good with too low swirl ratio. In this investigation, comprehensive consideration of economy and power, the no.1 inlet is selected as the best one for the next study.
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Shih, T. I.-P., and Y. L. Lin. "Controlling Secondary-Flow Structure by Leading-Edge Airfoil Fillet and Inlet Swirl to Reduce Aerodynamic Loss and Surface Heat Transfer." Journal of Turbomachinery 125, no. 1 (2003): 48–56. http://dx.doi.org/10.1115/1.1518503.
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Computations, based on the ensemble-averaged compressible Navier-Stokes equations closed by the shear-stress transport (SST) turbulence model, were performed to investigate the effects of leading-edge airfoil fillet and inlet-swirl angle on the flow and heat transfer in a turbine-nozzle guide vane. Three fillet configurations were simulated: no fillet (baseline), a fillet whose thickness fades on the airfoil, and a fillet whose thickness fades on the endwall. For both fillets, the maximum height above the endwall is positioned along the stagnation zone/line on the airfoil under the condition of no swirl. For each configuration, three inlet swirls were investigated: no swirl (baseline) and two linearly varying swirl angle from one endwall to the other (+30 to −30 deg and −30 to +30 deg). Results obtained show that both leading-edge fillet and inlet swirl can reduce aerodynamic loss and surface heat transfer. For the conditions of this study, the difference in stagnation pressure from the nozzle’s inlet to its exit were reduced by more than 40% with swirl or with fillet without swirl. Surface heat transfer was reduced by more than 10% on the airfoil and by more than 30% on the endwalls. When there is swirl, leading-edge fillets became less effective in reducing aerodynamic loss and surface heat transfer, because the fillets were not optimized for swirl angles imposed. Since the intensity and size of the cross flow were found to increase instead of decrease by inlet swirl and by the type of fillet geometries investigated, the results of this study indicate that the mechanisms responsible for aerodynamic loss and surface heat transfer are more complex than just the intensity and the magnitude of the secondary flows. This study shows their location and interaction with the main flow to be more important, and this could be exploited for positive results.
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Uy, Robert V., and Christopher E. Brennen. "Experimental Measurements of Rotordynamic Forces Caused by Front Shroud Pump Leakage." Journal of Fluids Engineering 121, no. 3 (1999): 633–37. http://dx.doi.org/10.1115/1.2823516.
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Unsteady forces generated by fluid flow through the impeller shroud leakage path of a centrifugal pump were investigated. Different pump shroud geometries were compared, and the effect of leakage path inlet swirl (pump discharge swirl) on the rotordynamic forces was examined for various ratios of fluid throughflow velocity to impeller tip speed. A short axial length leakage path reduced the measured forces, while curvature appeared to increase the destabilizing forces when inlet swirl was present. It was observed that changing the inlet swirl velocity does not appear to significantly affect the measured forces for a given leakage flow coefficient, but any nonzero inlet swirl is destabilizing when compared to cases with no inlet swirl.
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Pazur, W., and L. Fottner. "The Influence of Inlet Swirl Distortions on the Performance of a Jet Propulsion Two-Stage Axial Compressor." Journal of Turbomachinery 113, no. 2 (1991): 233–40. http://dx.doi.org/10.1115/1.2929091.
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Aeroengine intakes containing S-shaped diffusers produce different types of inlet swirl distortions and essentially a combination of a twin swirl and a bulk swirl. The main object of this investigation was to assess the influence of inlet swirl distortions on the performance of a transonic two-stage axial compressor installed in a turbo jet bypass engine Larzac 04. A typical inlet swirl distortion was simulated by a delta-wing in front of the engine. An experimental method was investigated to measure the performance map of the installed low-pressure compressor for different engine operating lines. The influence of an inlet swirl distortion with different strengths on the performance map of the compressor was investigated experimentally. It is shown that the performance parameters decrease and a temperature distortion is generated behind the compressor. As the basis of the theoretical investigations of the performance map, including inlet swirl distortions, a computing model considering four compressors working in parallel was established. The model is based on the idea that an inlet swirl distortion can be substituted by two fundamental types of swirl components, i.e., a bulk swirl corotating, and a bulk swirl counterrotating to the revolution of the compressor. Computed performance maps of the compressor will be discussed and compared with the experimental data.
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Whitfield, A., and A. H. Abdullah. "The Performance of a Centrifugal Compressor With High Inlet Prewhirl." Journal of Turbomachinery 120, no. 3 (1998): 487–93. http://dx.doi.org/10.1115/1.2841744.
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The performance requirements of centrifugal compressors usually include a broad operating range between surge and choke. This becomes increasingly difficult to achieve as increased pressure ratio is demanded. In order to suppress the tendency to surge and extend the operating range at low flow rates, inlet swirl is often considered through the application of inlet guide vanes. To generate high inlet swirl angles efficiently, an inlet volute has been applied as the swirl generator, and a variable geometry design developed in order to provide zero swirl. The variable geometry approach can be applied to increase the swirl progressively or to switch rapidly from zero swirl to maximum swirl. The variable geometry volute and the swirl conditions generated are described. The performance of a small centrifugal compressor is presented for a wide range of inlet swirl angles. In addition to the basic performance characteristics of the compressor, the onsets of flow reversals at impeller inlet are presented, together with the development of pressure pulsations, in the inlet and discharge ducts, through to full surge. The flow rate at which surge occurred was shown, by the shift of the peak pressure condition and by the measurement of the pressure pulsations, to be reduced by over 40 percent.
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Fang, Yibo, Dakun Sun, Xu Dong, and Xiaofeng Sun. "Effects of Inlet Swirl Distortion on a Multi-Stage Compressor with Inlet Guide Vanes and Stall Margin Enhancement Method." Aerospace 10, no. 2 (2023): 141. http://dx.doi.org/10.3390/aerospace10020141.
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Inlet swirl distortion is generally considered as a type of velocity distortion, and inlet guide vanes (IGVs) are widely used in the multi-stage compressor of aero-engines to eliminate the tangential velocity of the swirl flow. However, few studies have explored whether there still exists some negative influence of inlet swirl distortion on the compressor, even after the installation of IGVs. Therefore, in this study, the influence of various types of inlet swirl distortions on a multi-stage compressor with the installation of IGVs is investigated. A swirl distortion generator installed in the inlet duct was designed to produce various types of swirl flow patterns. When the distortion intensity increased to some degree, there still existed a decrease in the compressive capability and an obvious additional efficiency loss. The inlet twin swirl distortion was accompanied by total pressure distortion, so even with the installation of IGVs, there was still a significantly negative influence on the performance of the multi-stage compressor, especially the stall margin. Subsequently, to improve the stall margin under inlet swirl distortion, the stall precursor-suppressed (SPS) casing treatment was installed in the first stage of the multi-stage compressor. It could enhance the stall margin of the compressor with no obvious change in the characteristic curves and no additional efficiency loss under various types of inlet swirl distortions, and its mechanism was verified by capturing the dynamic pressure characteristics.
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Xie, Y., C. Zhong, D. F. Ruan, K. Liu, and B. Zheng. "Effect of Core Flow Inlet Swirl Angle on Performance of Lobed Mixing Exhaust System." Journal of Mechanics 32, no. 3 (2016): 325–37. http://dx.doi.org/10.1017/jmech.2016.1.
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AbstractGeometric model of a lobed mixing exhaust system is created and its flow field is simulated by using the steady Reynolds Averaged Navier-Stokes (RANS) equations under the condition of different core flow inlet swirl angles. According to the numerical simulation results, due to the guidance effect of the lobe parallel side wall, the structure and vorticity of streamwise vortices change little near the lobe exit with inlet swirl angle, and it is the same with the thermal mixing efficiency. As the flow develops, although the inlet swirl angle has limited influence on the streamwise vorticity, it greatly affects the structure of streamwise vortices. It causes the thermal mixing efficiency to increase with the swirl angle. As for the total pressure recovery coefficient, it falls slightly when the inlet swirl strengthens. At the nozzle exit, the total pressure recovery coefficient of CFISA = 30° model is 0.5% lower than CFISA = 0° model. Moreover, as the inlet swirl strengthens, the thrust fall of lobed mixing exhaust system gradually accelerates, especially when the inlet swirl angle is over 15°.
Dissertations / Theses on the topic "Inlet Swirl"
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Hoopes, Kevin M. "A New Method for Generating Swirl Inlet Distortion for Jet Engine Research." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/49545.
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Jet engines operate by ingesting incoming air, adding momentum to it, and exhausting it through a nozzle to produce thrust. Because of their reliance on an inlet stream, jet engines are very sensitive to inlet flow nonuniformities. This makes the study of the effects of inlet nonuniformities essential to improving jet engine performance. Swirl distortion is the presence of flow angle nonuniformity in the inlet stream of a jet engine. Although several attempts have been made to accurately reproduce swirl distortion profiles in a testing environment, there has yet to be a proven method to do so.<br /><br />A new method capable of recreating any arbitrary swirl distortion profile is needed in order to expand the capabilities of inlet distortion testing. This will allow designers to explore how an engine would react to a particular engine airframe combination as well as methods for creating swirl distortion tolerant engines. The following material will present such a method as well as experimental validation of its effectiveness.<br>Master of Science
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Guimaraes, Bucalo Tamara. "Fluid Dynamics of Inlet Swirl Distortions for Turbofan Engine Research." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/82921.
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Significant effort in the current technological development of aircraft is aimed at improving engine efficiency, while reducing fuel burn, emissions, and noise levels. One way to achieve these is to better integrate airframe and propulsion system. Tighter integration, however, may also cause adverse effects to the flow entering the engines, such as total pressure, total temperature, and swirl distortions. Swirl distortions are angular non-uniformities in the flow that may alter the functioning of specific components of the turbomachinery systems. To investigate the physics involved in the ingestion of swirl, pre-determined swirl distortion profiles were generated through the StreamVane method in a low-speed wind tunnel and in a full-scale turbofan research engine. Stereoscopic particle image velocimetry (PIV) was used to collect three-component velocity fields at discrete planes downstream of the generation of the distortions with two main objectives in mind: identifying the physics behind the axial development of the distorted flow; and describing the generation of the distortion by the StreamVane and its impact to the flow as a distortion generating device.
Analyses of the mean velocity, velocity gradients, and Reynolds stress tensor components in these flows provided significant insight into the driving physics. Comparisons between small-scale and full-scale results showed that swirl distortions are Mach number independent in the subsonic regime. Reynolds number independence was also verified for the studied cases. The mean secondary flow and flow angle profiles demonstrated that the axial development of swirl distortions is highly driven by two-dimensional vortex dynamics, when the flow is isolated from fan effects. As the engine fan is approached, the vortices are axially stretched and stabilized by the acceleration of the flow. The flow is highly turbulent immediately downstream of the StreamVane due to the presence of the device, but that vane-induced turbulence mixes with axial distance, so that the device effects are attenuated for distances greater than a diameter downstream, which is further confirmed by the turbulent length scales of the flow. These results provide valuable insight into the generation and development of swirl distortion for ground-testing environments, and establishes PIV as a robust tool for engine inlet investigations.<br>Ph. D.
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Frohnapfel, Dustin Joseph. "Experimental Investigation of Fan Rotor Response to Inlet Swirl Distortion." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71323.
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Next generation aircraft design focuses on highly integrated airframe/engine architectures that exploit advantages in system level efficiency and performance. One such design concept incorporates boundary layer ingestion which locates the turbofan engine inlet near enough to the lifting surface of the aircraft skin that the boundary layer is ingested and reenergized. This process reduces overall aircraft drag and associated required thrust, resulting in fuel savings and decreased emissions; however, boundary layer ingestion also creates unique challenges for the turbofan engines operating in less than optimal inlet flow conditions.
The engine inlet flow profiles predicted from boundary layer ingesting aircraft architectures contain complex distortions that affect the engine operability, durability, efficiency, and performance. One component of these complex distortion profiles is off-axial secondary flow, commonly referred to as swirl. As a means to investigate the interactions of swirl distortion with turbofan engines, an experiment was designed to measure distorted flow profiles in an operating turbofan research engine.
Three-dimensional flow properties were measured at discrete planes immediately upstream and immediately downstream of the fan rotor, isolating the component for analysis. Constant speed tests were conducted under clean and distorted test conditions. For clean tests, a straight cylindrical inlet duct was attached to the fan case; for distorted tests, a StreamVane swirl distortion generator was inserted into the inlet duct. The StreamVane was designed to induce a swirl distortion matching results of computation fluid dynamics models of a conceptual blended wing body aircraft at a plane upstream of the fan. The swirl distortion was then free to develop naturally within the inlet duct before being ingested by the engine.
Results from the investigation revealed that the generated swirl profile developed, mixed, and dissipated in the inlet duct upstream of the fan. Measurements immediately upstream of the fan rotor leading edge revealed 50% reduction in measured flow angle magnitudes along with evidence of fanwise vortex convection when compared to the StreamVane design profile. The upstream measurements also indicated large amounts of secondary flow entered the fan rotor. Measurements immediately downstream of the fan rotor trailing edge demonstrated that the fan processed the distortion and further reduced the intensity of the swirl; however, non-uniform secondary flow persisted at this plane. The downstream measurements confirmed that off-design conditions entered the fan exit guide vanes, likely contributing to cascading performance deficiencies in downstream components and reducing the performance of the propulsor system.<br>Master of Science
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Smith, Katherine Nicole. "New Methodology for the Estimation of StreamVane Design Flow Profiles." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82039.
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Inlet distortion research has become increasingly important over the past several years as demands for aircraft flight efficiency and performance has increased. To accommodate these demands, research progression has shifted the emphasis onto airframe-engine integration and improved understanding of engine operability in less than ideal conditions. Swirl distortion, which is considered a type of non-uniform inflow inlet distortion, is characterized by the presence of swirling flow in an inlet. The presence of swirling flow entering an engine can affect the compression systems performance and operability, therefore it is an area of current research.
A swirl distortion generation device created by Virginia Tech, identified as the StreamVane, has the ability to produce various swirl distortion flow profiles. In its current state, the StreamVane methodology generates a design swirl distortion at the trailing edge of the device. However, in many applications the plane at which the researcher wants a desired distortion is downstream of the StreamVane trailing edge. After the distortion is discharged from the StreamVane it develops as it moves downstream. Therefore, to more accurately replicate a desired swirl distortion at a given downstream plane, distortion development downstream of the StreamVane must be considered.
Currently Virginia Tech utilizes a numerical modeling design tool, designated StreamFlow, that generates predictions of how a StreamVane-generated distortion propagates downstream. However, due to the non-linear physics of the flow problem, StreamFlow cannot directly calculate an accurate inverse solution that can predict upstream conditions from a downstream boundary, as needed to design a StreamVane. To solve this problem, in this research, an efficient estimation process has been created, combining the use of the StreamFlow model with a Markov Chain Monte Carlo (MCMC) parameter estimation tool to estimate upstream flow profiles that will produce the desired downstream profiles. The process is designated the StreamFlow-MC2 Estimation Process.
The process was tested on four fundamental types of swirl distortions. The desired downstream distortion was input into the estimation process to predict an upstream profile that would create the desired downstream distortion. Using the estimated design profiles, 6-inch diameter StreamVanes were designed then wind tunnel tested to verify the distortion downstream. Analysis and experimental results show that using this method, the upstream distortion needed to create the desired distortion was estimated with excellent accuracy. Based on those results, the StreamFlow-MC2 Estimation Process was validated.<br>Master of Science
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Allison, Colin Bidden. "The effect of inlet swirl on knock limits in spark ignition engines." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/18604.
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An investigation was undertaken to determine the effect of swirl ratio on knock limits in spark ignition engines. Initially it was attempted to find a correlation between swirl ratio and Knock Limited Spark Advance (KLSA) for a selection of commercially available engines. A comparison of measured swirl ratios and KLSA indicated that no such correlation could be found. This was put down to the fact that other factors such as combustion chamber shape and spark plug location play a more dominant role in affecting knock limits than swirl level. Following from this, a single engine with a relatively poor swirl ratio was selected and the swirl level was altered. A novel method of increasing and decreasing the swirl level, with the same pressure drop in each case was developed, and this development is described. This method made it possible to perform dynamometer tests, measuring the KLSA timing for the cases of low and high swirl, while keeping all other parameters such as pressure, temperature, spark plug location and combustion chamber shape constant. All these factors are known to have an effect on the occurrence of knock. In this manner it was possible to determine whether swirl alone has any effect on knock limits. It was found that the high swirl case exhibited higher values of knock limited spark advance above the low swirl case although there was no significant change in torque. A comparison of rubber castings of the inlet ports of numerous engines was made, and is presented in a photographic form. This was done in order to assess how inlet port geometry affects swirl ratios. It was found that a helically shaped inlet port produced the greatest swirl ratio, non directed ports have average values and multiple inlet valve ports have very low swirl ratios. Furthermore, a comparison of swirl ratios of an inlet port with and without deposits, demonstrates that deposits have a significant effect on swirl ratios and volumetric efficiency. However, although the volumetric efficiency was reduced, the deposits enhanced the swirl ratios for this particular case. This is contrary to the general belief that deposits reduce swirl.
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Abdullah, Abu Hasan. "The application of high inlet swirl angles for broad operating range turbocharger compressor." Thesis, University of Bath, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320555.
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Wilkes, Kevin Wood. "Rotordynamic analysis of circumferentially grooved annular pump seals with turbulent flow and inlet swirl /." This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12302008-063353/.
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Defoe, Jeff (Jeffrey James). "Inlet swirl distortion effects on the generation and propagation of fan rotor shock noise." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68404.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 195-200).<br>A body-force-based fan model for the prediction of multiple-pure-tone noise generation is developed in this thesis. The model eliminates the need for a full-wheel, three-dimensional unsteady RANS simulation of the fan blade row, allowing Euler calculations to be used to capture the phenomena of interest. The Euler calculations reduce numerical wave dissipation and enable the simultaneous computation of source noise generation and propagation through the engine inlet to the far-field in non-uniform flow. The generated shock Mach numbers are in good agreement with experimental results, with the peak values predicted within 6%. An assessment of the far-field acoustics against experimental data showed agreement of 8 dB on average for the blade-passing tone. In a first-of-its-kind comparison, noise generation and propagation are computed for a fan installed in a conventional inlet and in a boundary-layer-ingesting serpentine inlet for a free-stream Mach number of 0.1. The key effect of boundary layer ingestion is the creation of streamwise vorticity which is ingested into the inlet, resulting in co- and counter-rotating streamwise vortices in the inlet. The fan sound power level increases by 38 dB due to this distortion, while the vortex whose circulation is in the same direction as the fan rotation enhances the sound power attenuation within the inlet duct such that the far-field overall sound pressure levels are increased by only 7 dB on average. The far-field spectra are altered in the following manner due to inlet distortion: (1) tones at up to 3 times the blade-passing frequency are amplified; and (2) tones above one-half of the blade-passing frequency are attenuated and appear to be cut-off. To quantify the effects of serpentine inlet duct geometry on the generation and propagation of multiple-pure-tone noise, a parametric study of inlets is conducted. The conclusions are that (1) the ingestion of streamwise vorticity alters multiple-pure-tone noise more than changes in inlet area ratio or offset ratio do; and (2) changes in the far-field spectra relative to the conventional inlet results are only weakly affected by the duct geometry changes investigated and are instead predominantly caused by flow non-uniformities. A response-surface correlation for the effects of inlet geometry on far-field noise is also developed.<br>by Jeff Defoe.<br>Ph.D.
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Wilkes, Kevin. "Rotordynamic analysis of circumferentially grooved annular pump seals with turbulent flow and inlet swirl." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/46444.
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In this thesis an analysis is developed to predict the leakage and dynamic characteristics for circumferentially grooved turbulent annular seals used in turbopumps. The flow in the groove is modelled using turbulent shear layer theory and an entrance loss model is applied at the inlet and land regions of the seal. The governing equations are derived using Hirs’ turbulent lubrication theory. The equations are expanded to yield zeroth and first order perturbation equations for small rotor displacements about a centered position. The leakage and velocity distribution is obtained from a numerical solution of the zeroth order equations. The first order equations define the dynamic pressure distribution which is integrated to yield the fluid force reactions. The model predictions are compared to test results for smooth walled and grooved seals. The model shows good qualitative agreement with experimental test results for seal leakage and rotordynamic coefficients. Actual quantitative agreement is unresolved given the high level of experimental uncertainty in the test results.<br>Master of Science
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Nelson, Michael Allan. "Stereoscopic Particle Image Velocimetry Measurements of Swirl Distortion on a Full-Scale Turbofan Engine Inlet." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64993.
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There is a present need for simulation and measuring the inlet swirl distortion generated by airframe/engine system interactions to identify potential degradation in fan performance and operability in a full-scale, ground testing environment. Efforts are described to address this need by developing and characterizing methods for complex, prescribed distortion patterns. A relevant inlet swirl distortion profile that mimics boundary layer ingesting inlets was generated by a novel new method, dubbed the StreamVane method, and measured in a sub scale tunnel using stereoscopic particle image velocimetry (SPIV) as a precursor for swirl distortion generation and characterization in an operating turbofan research engine. Diagnostic development efforts for the distortion measurements within the research engine paralleled the StreamVane characterization. The system used for research engine PIV measurements is described. Data was obtained in the wake of a total pressure distortion screen for engine conditions at idle and 80% corrected fan speed, and of full-scale StreamVane screen at 50% corrected fan speed. The StreamVane screen was designed to generate a swirl distortion that is representative for hybrid wing body applications and was made of Ultem*9085 using additive manufacturing. Additional improvements to the StreamVane method are also described. Data reduction algorithms are put forth to reduce spurious velocity vectors. Uncertainty estimations specific to the inlet distortion test rig, including bias error due to mechanical vibration, are made. Results indicate that the methods develop may be used to both generate and characterize complex distortion profiles at the aerodynamic interface plane, providing new information about airframe/engine integration.<br>Master of Science
Book chapters on the topic "Inlet Swirl"
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Wenzel, Wolfgang, U. Hanig, J. Song, B. Bareis, and M. Miclea-Bleiziffer. "Inlet swirl throttle for passenger car engines." In Proceedings. Springer Fachmedien Wiesbaden, 2016. http://dx.doi.org/10.1007/978-3-658-13255-2_71.
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Singh, Hardial, and B. B. Arora. "Optimization of Inlet Swirl for Flow Separation in Annular Diffuser." In Lecture Notes in Mechanical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5463-6_36.
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Stuart, C., S. W. Spence, S. Teichel, and A. Starke. "Design and evaluation of an active inlet swirl control device for automotive turbocharger compressors." In 14th International Conference on Turbochargers and Turbocharging. CRC Press, 2020. http://dx.doi.org/10.1201/9781003132172-01.
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Sivakumar, G., and S. Senthil Kumar. "CFD Analysis of Swirl Enhancement in a Direct Injection Diesel Engine with Vortex Generator in Inlet Manifold." In Lecture Notes in Mechanical Engineering. Springer India, 2014. http://dx.doi.org/10.1007/978-81-322-1871-5_19.
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Ghose, Prakash, and A. Datta. "Effect of Inlet Swirl and Turbulence Levels on Combustion Performance in a Model Kerosene Spray Gas Turbine Combustor." In Lecture Notes in Mechanical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7831-1_46.
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Mahottamananda, Sri Nithya, D. N. Dilli Babu, and P. N. Kadiresh. "Effect of Number of Inlet Tangential Ports and Their Angle on Spray Characteristics of Plug Type Swirl Injector." In Lecture Notes in Mechanical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6619-6_15.
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Hadjkacem, Sahar, Mohamed Ali Jemni, and Zied Driss. "Turbine Swirling Device Effect on LPG-H2 Engine In-Cylinder Flow Motion at Intake Stroke." In Mechanical Engineering Technologies and Applications: Volume 3. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815179279123030006.
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The main issue of internal combustion (IC) engines is efficiency. Engine inlet systems should be carefully designed to provide an optimum flow to the cylinder. Inlet manifold design is one of the ways to increase efficiency. This study focuses on improving the inlet system of an LPG-H2 fueled engine by adding a static inclined blade turbine. It is a horizontal rotational axis turbine with four blades evenly distributed with an angle of inclination of 35°. Computational Fluid Dynamics (CFD) simulations are used in order to capture the in-cylinder flow motion and its influence on the flow characteristics. The method is assessed by application to flow calculations in the intake manifold for 3000 rpm engine speed. The percentage of supplied Hydrogen with LPG is equal to 20% in volume. The simulation results of in-cylinder turbulence kinetic energy (TKE), velocity and swirl motion were presented and discussed. Numerical results reveal significant improvements in the in-cylinder flow velocity, in-cylinder swirl motion and turbulent characteristics using an inlet system with a static swirling turbine (SST). Hence, this research found that by using a static turbine, we can improve the in-cylinder flow characteristics of the CI engine running with the LPG-20%H2 blend.
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Harun, Zambri, Tajul Ariffin Norizan, and Wan Hanna Melini Wan Mohtar. "Application of Vortex Control Principle at Pump Intake." In Vortex Dynamics Theories and Applications. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.92853.
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Vortex flow in a pump intake could affect a pump operation significantly if not treated appropriately. Many researches have been conducted to determine the best control method for vortex flow in pump sumps so that the pump lifespan can be maximized. In this study, a vortex control principle designed to minimize the impact of submerged vortex flow in pump sump on major pump components is presented. This principle employs a device called the plate type floor splitter which serves the function of eliminating vortices formed on the sump floor and reduces the intensity of swirling motion in the intake flow. A pump sump model was built to carry out the study by installing a floor splitter plate sample under the pump suction inlet and the corresponding parameters used to quantify the swirl intensity known as the swirl angle was measured. Procedures for the measurement were conducted based on ANSI/HI 9.8-2018 standard. A numerical simulation was performed to study the flow in a full-scale pump sump. The results showed that the installation of floor splitter plate can eliminate vortices efficiently and reduce swirl angle significantly. However, optimization of floor splitter design is needed to achieve a reduction effect that can reduce swirl angles to an acceptable value of lower than 5° according to ANSI/HI 9.8-2018 standard.
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Kirk, R. G., and R. Gao. "Analysis of rotordynamic forces for high inlet pre-swirl rate labyrinth seals." In 10th International Conference on Vibrations in Rotating Machinery. Elsevier, 2012. http://dx.doi.org/10.1533/9780857094537.7.467.
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Domingues, Rafael, and Francisco Brójo. "Conversion of Gas Turbine Combustors to Operate with a Hydrogen-Air Mixture: Modifications and Pollutant Emission Analysis." In Hydrogen Energy - New Insights [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106224.
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In this work, an overview of the use of hydrogen in aviation, the modifications needed to adapt an existent gas turbine to use hydrogen, and a CFD simulation of an existent gas turbine burning hydrogen are performed. The CFD simulation was done in a CFM56-3 combustor burning hydrogen and Jet A. It was intended to evaluate the viability of conversion of existent gas turbines to hydrogen, in a combustion point of view, by analyzing the emissions while burning it through ICAO’s LTO cycle. The pollutant emissions (only NOx, since hydrogen combustion produce only water vapor and NOx) were evaluated through a detailed mechanism and the Ansys Fluent NOx model to get a better agreement with the ICAO’s values. For this assessment, several sensibility studies were made for hydrogen burn, for example, the analysis of the air flow with/without swirl in the primary zone and different inlet temperature and pressure for fuel. In the end, it was concluded that theoretically the CFM56-3 combustor can be converted to operate with hydrogen fuel with minor changes (related to injection system). The quantity of NOx produced for each power setting when burning hydrogen is expected to be almost twice the values for Jet A.
Conference papers on the topic "Inlet Swirl"
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Baba-Ahmadi, Mohammad H., and Gavin R. Tabor. "Inlet Conditions for LES of Swirl Flows." In ASME 2008 Fluids Engineering Division Summer Meeting collocated with the Heat Transfer, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/fedsm2008-55107.
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In this paper we present a novel technique for generating swirl inlets for Large Eddy Simulation (LES). The velocity a short distance downstream of the inlet to the main domain is sampled and the flow velocity data reintroduced back into the domain inlet, creating an inlet section integrated into the main domain where turbulence can develop. Additionally, variable artificial body forces and velocity corrections are imposed in this inlet section, with feedback control to force the flow towards desired swirl, mean and turbulent profiles. The method has been applied to swirling flow in a circular pipe and in an axisymmetric sudden expansion, and for the latter case compared against experimental and literature LES data, and against similar results in the literature. The method generates excellent results, and is elegant and straightforward to implement.
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Hsiao, George, and Hukam Mongia. "Swirl Cup Modeling Part 2: Inlet Conditions." In 41st Aerospace Sciences Meeting and Exhibit. American Institute of Aeronautics and Astronautics, 2003. http://dx.doi.org/10.2514/6.2003-1350.
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NEJAD, R., R. BORAY, S. AHMED, and P. BUCKLEY. "Inlet swirl effects on dump combustor flows." In 28th Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics, 1990. http://dx.doi.org/10.2514/6.1990-35.
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Frohnapfel, Dustin J., Elizabeth Mack, Alexandrina Untaroiu, Walter F. O’Brien, and K. Todd Lowe. "Turbofan Nose Cone Interactions With Inlet Swirl." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76616.
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With highly integrated airframe architectures emerging as the leading concept of next generation aviation vehicles, research is needed to understand the interactions between inlet swirl distortions and turbofan engines. To meet these research demands, a computational fluid dynamics investigation was conducted to monitor the streamwise development of a complex swirling velocity field in the inlet duct of a turbofan engine with and without the presence of the turbofan nose cone component. By modeling the two geometric setups, natural fluid development and forced fluid/nose cone interactions were distinguishable. To validate the model, computational results were compared to existing experimental data at the fan rotor inlet plane. With the nose cone included, flow angle and swirl intensity predictions from the computational approach agreed well with the experimental measurements. The computational results were expanded upstream to demonstrate the effects of the nose cone geometry on the incoming swirl distortion. Radial flow angles in the presence of the nose cone began to vary from natural swirl development at approximately 0.25 fan diameters upstream, reaching a maximum difference near the leading edge of the nose cone component. Results from this investigation provided a validated model for the prediction of swirl development in a turbofan inlet duct in the presence of a nose cone. Significant change in the swirl profile development was shown from natural vortex motion to induced fluid/solid interactions.
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Frohnapfel, Dustin J., Walter F. O’Brien, and K. Todd Lowe. "Experimental Quantification of Fan Rotor Effects on Inlet Swirl Using Swirl Distortion Descriptors." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64779.
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The prominence of highly integrated engine/airframe architectures in modern commercial aircraft design concepts has led to significant research efforts investigating the use of conventional turbofan engines in unconventional installations where severe inlet distortions can arise. In order to determine fan rotor capabilities for reducing or eliminating a complex inlet swirl distortion, an experimental investigation using a StreamVane™ swirl distortion generator was conducted in a turbofan engine research platform. Three-dimensional flow data collected at two discrete planes surrounding the fan rotor indicated that the intensity of the swirl distortion was decreased by the fan rotor; however, substantial swirl distortion effects remained in the fan exit flow. Flow angle magnitudes and swirl intensity decreased by approximately 30–40% across the fan rotor, while the presence of large-scale features within the distortion profile was nearly eliminated. Secondary flow streamlines indicated that small-scale features of the distortion were less affected by the rotating component and remained coherent at the fan rotor outlet plane. These results led to the conclusion that swirl distortion survived interactions with the fan rotor, leading to off-design conditions cascading through downstream engine components.
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Chen, Hua, and Vai-Man Lei. "Casing Treatment and Inlet Swirl of Centrifugal Compressors." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69340.
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Ported shroud is a cost effective casing treatment that can greatly improve stability of centrifugal compressors. It is widely used in turbochargers and other applications where compressors with wide flow range are required. This paper reviews the development of the ported shroud concept from its first conception in the 1980s to its current various configurations, explores the underline mechanisms that deliver the performance improvement. It is explained that by removing stagnant fluid from impeller inducer shroud end wall boundary-layer region and recirculating it to the impeller inlet, blade loading near the inducer shroud is increased with improved inlet suction. For transonic flow, ported shroud weakens the shock wave and reduces flow separation on the inducer suction surface. It is argued that the effectiveness of the ported shroud is a balance of blade loading and the flow loss inside the ported shroud cavity. The loss needs to be minimised if ported shroud is to be more effective. Blade loading may be increased by various methods such as using high inducer blade turning and using full bladed impellers. The blade loading can also be improved by removing flow swirl in ported shroud flow by vanes, or imposing negative swirl by vanes in ported shroud. Circumferential flow variation caused by volute housing can be taken into account by variable pitch vanes or by variable port position.
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Norizan, Tajul Ariffin, Zambri Harun, Wan Hanna Melini Wan Mohtar, and Shahrir Abdullah. "Characteristics of Swirl Angle in Pump Intake Flow Near the Minimum Inlet Submergence." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5053.
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Abstract Swirling flow in pump sump intake has been the subject of discussion for the past decades due to the detrimental effects brought about by its existence. Among the effects of swirling flow are reduced pump efficiency, cavitation, excessive vibration and load imbalance at the pump impeller which are caused by hydraulic problems associated to swirling flow such as swirls and vortices. One of the remedial measures for preventing such occasion is by keeping the pump inlet submerged above a defined value known as the minimum inlet submergence. It is the minimum submergence required to reduce the probability of the occurrence of free surface vortices. However, this requirement may not be fulfilled in some situations due to on site conditions or operational restrictions. In this paper, an experimental study was conducted to investigate the characteristics of swirl angle in the pump intake flow when the pump inlet is submerged near the value of minimum inlet submergence. The ratio of pump submergence to the minimum submergence was varied between 0.8 to 1.2 with constant inlet Froude Number which referred to as submergence ratio. The strength of the swirl in the intake flow was determined by measuring the swirl angle which was accomplished using a swirl meter attached in the suction pipe. Measurements using Acoustic Doppler Velocimeter (ADV) was performed to capture the velocity profile in the intake sump. The swirl angle distribution across the range of submergence ratios was dominated by a subsurface vortex formed at the sump floor. As soon as the submergence was reduced below the minimum submergence, a free surface vortex emerged near the pump inlet and brought a swirl retardation effect to the swirl meter rotation resulting in a bigger fluctuation of the swirl meter reading. An anti vortex device (AVD) called the floor splitter commonly used to reduce vorticity at pump inlet was installed and its effect on the reduction of swirls and vortices was evaluated.
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Haidari, Ahmad, Thomas Hordendorf, and John C. Bartos. "Evaluation of Compressor Inlet Flow Conditioners." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-016.
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Experimental investigations were conducted to determines: 1) the degradation of single stage centrifugal compressor performance due to induced inlet distortion and swirl, and 2) the subsequent performance recovery achievable by use of an upstream flow conditioner developed by VORTAB Incorporated. The compressor inlet flow velocity profile was distorted using out-of-plane double elbows and a specially designed swirl generator. The distorted flow was conditioned using the flow conditioner. Performance tests were conducted for baseline (no distortion), distorted flow, and conditioned flow. The results indicate that velocity profile distortion and swirl can strongly affect the compressor performance. It is additionally demonstrated that the profile correction and swirl elimination achieved with the flow conditioner recovers the compressor performance to its baseline level, with minimum device pressure loss.
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Schmid, Gregor, and Heinz-Peter Schiffer. "Numerical Investigation of Inlet Swirl in a Turbine Cascade." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69397.
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New combustion concepts towards lean burn aim at reducing peak temperatures and therefore emissions, especially nitrogen oxides. High swirl is required in order to enhance the mixing of fuel and air and thus, improve combustion and flame stability. In a numerical investigation of a turbine vane cascade the effect of such inlet swirl on aerodynamic losses, secondary flow pattern and heat transfer is investigated. The computations are conducted prior to particle image velocimetry and five-hole-probe measurements in a cascade of six vane passages and swirl generators upstream of each passage. The analysis covers three constituent parts: First, different swirl intensities are simulated which resemble the situation in a real combustion chamber. Second, different clocking positions are investigated — the swirl cores are either aligned with the vane leading edge or with midpassage — and finally, swirl orientation as clockwise, anticlockwise and counter rotating swirl is analysed. Two-dimensional inlet boundary conditions are applied to model the discrete swirl cores. Furthermore, a comparison with circumferentially averaged as well as with axial inflow conditions is made. Increasing the swirl number at the inlet boundary results in reduced heat transfer coefficient within the vane passage and higher pressure loss. Heat transfer through vanes and endwalls is maximal if the swirl generators are aligned with the vane leading edge and counter rotating swirl.
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LI, Zhenyu, Xu DONG, Dakun SUN, and Xiaofeng SUN. "Quantification of Swirl Distortions Caused by S-shape Inlet Ducts." In GPPS Xi'an21. GPPS, 2022. http://dx.doi.org/10.33737/gpps21-tc-38.
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The S-shape inlet is generally the main reason for the occurrence of swirl inlet distortion that is seriously concerned by the manufactures of fighters. The non-uniform inlet combined with large-scale bulk swirl, small-scale tight-wound swirl, or both of them may greatly impact the performance of aero-engines. Focusing on the swirl patterns and the effects of swirl flow on the compression system, many attempts have been carried out. However, there is still no general and quantitative criterion for assessing the swirl pattern and intensity to serve the further performance or stability analysis. In this paper, a vorticity-based method was used to quantify the swirl inlet distortion caused by different S-inlet ducts. Three series of S-ducts with different offset distances and different lengths were designed. Numerical investigations on the intensity and form of swirl distortion were carried out to achieve quantitative results.