scholarly journals Influence of Blade Lean on Performance and Shock Wave/Tip Leakage Flow Interaction in a Transonic Compressor Rotor

2022 ◽  
Vol 15 (1) ◽  
Keyword(s):  
Shock Wave ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Flow Interaction

scholarly journals Effects of Tip Leakage Flow on the Aerodynamic Performance and Stability of an Axial-Flow Transonic Compressor Stage

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4168
Author(s):  
Botao Zhang ◽  
Xiaochen Mao ◽  
Xiaoxiong Wu ◽  
Bo Liu
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Transonic Compressor

To explain the effect of tip leakage flow on the performance of an axial-flow transonic compressor, the compressors with different rotor tip clearances were studied numerically. The results show that as the rotor tip clearance increases, the leakage flow intensity is increased, the shock wave position is moved backward, and the interaction between the tip leakage vortex and shock wave is intensified, while that between the boundary layer and shock wave is weakened. Most of all, the stall mechanisms of the compressors with varying rotor tip clearances are different. The clearance leakage flow is the main cause of the rotating stall under large rotor tip clearance. However, the stall form for the compressor with half of the designed tip clearance is caused by the joint action of the rotor tip stall caused by the leakage flow spillage at the blade leading edge and the whole blade span stall caused by the separation of the boundary layer of the rotor and the stator passage. Within the investigated varied range, when the rotor tip clearance size is half of the design, the compressor performance is improved best, and the peak efficiency and stall margin are increased by 0.2% and 3.5%, respectively.

scholarly journals Unsteadiness of Tip Leakage Flow in the Detached-Eddy Simulation on a Transonic Rotor with Vortex Breakdown Phenomenon

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 954 ◽  
Author(s):  
Xiangyu Su ◽  
Xiaodong Ren ◽  
Xuesong Li ◽  
Chunwei Gu
Keyword(s):  
Vortex Breakdown ◽  
Leakage Flow ◽  
Angle Distribution ◽  
Detached Eddy Simulation ◽  
Tip Leakage Flow ◽  
Flow Angle ◽  
Tip Leakage ◽  
Transonic Compressor ◽  
Eddy Simulation ◽  
Compressor Rotor

Tip leakage vortex (TLV) in a transonic compressor rotor was investigated numerically using detached-eddy simulation (DES) method at different working conditions. Strong unsteadiness was found at the tip region, causing a considerable fluctuation in total pressure distribution and flow angle distribution above 80% span. The unsteadiness at near choke point and peak efficiency point is not obvious. DES method can resolve more detailed flow patterns than RANS (Reynolds-averaged Navier–Stokes) results, and detailed structures of the tip leakage flow were captured. A spiral-type breakdown structure of the TLV was successfully observed at the near stall point when the TLV passed through the bow shock. The breakdown of TLV contributed to the unsteadiness and the blockage effect at the tip region.

Study of the Standard k-ε Model for Tip Leakage Flow in an Axial Compressor Rotor

2016 ◽  
Vol 33 (4) ◽  
Author(s):  
Yanfei Gao ◽  
Yangwei Liu ◽  
Luyang Zhong ◽  
Jiexuan Hou ◽  
Lipeng Lu
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Turbulent Viscosity ◽  
Axial Compressor ◽  
Leakage Flow ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor

AbstractThe standard k-ε model (SKE) and the Reynolds stress model (RSM) are employed to predict the tip leakage flow (TLF) in a low-speed large-scale axial compressor rotor. Then, a new research method is adopted to “freeze” the turbulent kinetic energy and dissipation rate of the flow field derived from the RSM, and obtain the turbulent viscosity using the Boussinesq hypothesis. The Reynolds stresses and mean flow field computed on the basis of the frozen viscosity are compared with the results of the SKE and the RSM. The flow field in the tip region based on the frozen viscosity is more similar to the results of the RSM than those of the SKE, although certain differences can be observed. This finding indicates that the non-equilibrium turbulence transport nature plays an important role in predicting the TLF, as well as the turbulence anisotropy.

Effect of Airfoil Vortex Generator on the Performance and Stability of a Transonic Axial Compressor

2021 ◽  
Author(s):  
Subbaramu Shivaramaiah ◽  
Mahesh K. Varpe
Keyword(s):  
Pressure Ratio ◽  
Research Work ◽  
Vortex Generator ◽  
Leading Edge ◽  
Leakage Flow ◽  
Compressor Stage ◽  
Tip Leakage Flow ◽  
Stall Margin ◽  
Tip Leakage ◽  
Transonic Compressor

Abstract In the present research work, effect of airfoil vortex generator on performance and stability of transonic compressor stage is investigated through CFD simulations. In turbomachines vortex generators are used to energize boundary and generated vortex is made to interact with tip leakage flow and secondary flow vortices formed in rotor and stator blade passage. In the present numerical investigation symmetrical airfoil vortex generator is placed on rotor casing surface close to leading edge, anticipating that vortex generated will be able to disturb tip leakage flow and its interaction with rotor passage core flow. Six different vortex generator configuration are investigated by varying distance between vortex generator trailing edge and rotor leading edge. Particular vortex generator configuration shows maximum improvement of stall margin and operating range by 5.5% and 76.75% respectively. Presence of vortex generator alters flow blockage by modifying flow field in rotor tip region and hence contributes to enhancement of stall margin. As a negative effect, interaction of vortex generator vortices and casing causes surface friction and high entropy generation. As a result compressor stage pressure ratio and efficiency decreases.

Application of Detached Eddy Simulation to a Subsonic Compressor Rotor

2008 ◽  
Author(s):  
Chunwei Gu ◽  
Fan Feng ◽  
Xuesong Li ◽  
Meilan Chen
Keyword(s):  
Wake Flow ◽  
Leakage Flow ◽  
Separation Region ◽  
Detached Eddy Simulation ◽  
Tip Leakage Flow ◽  
Blade Loading ◽  
Tip Leakage ◽  
Eddy Simulation ◽  
Compressor Rotor ◽  
Des Model

An attempt is made in the present paper to apply DES (Detached Eddy Simulation), which is based on S-A model of RANS, for investigating the flow field around a subsonic compressor rotor with a tip clearance of 2% blade height. Comparison of the results by DES and S-A model shows that DES model can capture more intensive vortex flow, such as tip leakage flow, double leakage flow, as well as interaction between the leakage flow and wake flow downstream of the rotor passage. DES model predicts more complicated flow at the separation region near the hub. DES simulation for different operation conditions also reveals interesting details. The shedding angle and strength of the tip leakage flow changes with the blade loading. The starting point of the leakage vortex moves towards the leading edge when the blade loading increases. Double leakage is observed only at the design and higher loading conditions, and is not at a lower loading condition. The tip leakage vortex splits into two branches downstream of the rotor blade due to interaction with the wake flow. Instantaneous results show unsteadiness of the tip leakage vortex. Alternating regions of higher and lower loss is found along the time-averaged leakage vortex trajectory. Obvious is also the unsteadiness in the separation region near the hub.

Circumferential Propagation Characteristic of Unsteady Flow in a Subsonic Axial Flow Compressor Rotor at Different Reynolds Numbers

2019 ◽  
Author(s):  
Zhiyang Chen ◽  
Yanhui Wu ◽  
Yanwen Zhang ◽  
Junwen Gan ◽  
Jinhuaiyuan An
Keyword(s):  
Unsteady Flow ◽  
Frequency Band ◽  
Radial Flow ◽  
Propagation Characteristic ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Characteristic Frequencies ◽  
Tip Leakage ◽  
Flow Unsteadiness ◽  
Compressor Rotor

Abstract This paper studies the circumferential propagation characteristic of unsteady flow that occurs close to stall in a subsonic axial compressor rotor at different Reynolds number (Re). Experimental measurements are first conducted at high Re on the ground, and numerical investigations are carried out at two altitudes to explore the mechanism of circumferential propagation characteristic at different Re. The stability operating range of the compressor rotor gets small with the decrease of Re. Rotating instability (RI) is observed in the blade passage near the stall limit of the test rotor at high Re on the ground, which is characterized by a hump frequency band in the spectrum. Characteristic frequencies of numerical pressure signals at fixed frame are limited in the frequency band of RI at high Re. The cross power spectrums of numerical pressure signals detected in the neighboring passages suggest that circumferential disturbances rotates in the flow fields at different Re. Characteristic frequencies of the flow unsteadiness change with the decrease of Re. At high Re, the circumferential propagation of tip leakage flow unsteadiness is controlled by the interaction of the tip leakage flow and incoming flow, which is linked to RI. When the Re is reduced, the tip leakage flow gets weak and the radial flow from the hub to tip induced by the suction surface flow separation is dominant in the tip region. Thereafter, both the tip leakage flow and radial flow are associated with the blade tip loading, which changes the flow mechanism of RI.

Stall Inception and Development Process Due to Tip Leakage Flow in Axial Compressor Rotor Blades Row

2014 ◽  
Vol 30 (3) ◽  
pp. 307-313 ◽  
Author(s):  
R. Taghavi-Zenou ◽  
S. Abbasi ◽  
S. Eslami
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotor Blades ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor

ABSTRACTThis paper deals with tip leakage flow structure in subsonic axial compressor rotor blades row under different operating conditions. Analyses are based on flow simulation utilizing computational fluid dynamic technique. Three different circumstances at near stall condition are considered in this respect. Tip leakage flow frequency spectrum was studied through surveying instantaneous static pressure signals imposed on blades surfaces. Results at the highest flow rate, close to the stall condition, showed that the tip vortex flow fluctuates with a frequency close to the blade passing frequency. In addition, pressure signals remained unchanged with time. Moreover, equal pressure fluctuations at different passages guaranteed no peripheral disturbances. Tip leakage flow frequency decreased with reduction of the mass flow rate and its structure was changing with time. Spillage of the tip leakage flow from the blade leading edge occurred without any backflow in the trailing edge region. Consequently, various flow structures were observed within every passage between two adjacent blades. Further decrease in the mass flow rate provided conditions where the spilled flow ahead of the blade leading edge together with trailing edge backflow caused spike stall to occur. This latter phenomenon was accompanied by lower frequencies and higher amplitudes of the pressure signals. Further revolution of the rotor blade row caused the spike stall to eventuate to larger stall cells, which may be led to fully developed rotating stall.

Behavior of Tip Leakage Flow in an Axial Flow Compressor Rotor

2006 ◽  
Author(s):  
Yanhui Wu ◽  
Wuli Chu ◽  
Xingen Lu ◽  
Junqiang Zhu
Keyword(s):  
Boundary Layer ◽  
Vortex Breakdown ◽  
Axial Flow ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Pressure Side ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Flow Compressor

The current paper reports on investigations with an aim to advance the understanding of the flow field near the casing of a small-scale high-speed axial flow compressor rotor. Steady three dimensional viscous flow calculations are applied to obtain flow fields at various operating conditions. To demonstrate the validity of the computation, the numerical results are first compared with available measured data. Then, the numerically obtained flow fields are analyzed to identify the behavior of tip leakage flow, and the mechanism of blockage generation arising from flow interactions between the tip clearance flow, the blade/casing wall boundary layers, and non-uniform main flow. The current investigation indicates that the “breakdown” of the tip leakage vortex occurs inside the rotor passage at the near stall condition. The vortex “breakdown” results in the low-energy fluid accumulating on the casing wall spreads out remarkably, which causes a sudden growth of the casing wall boundary layer having a large blockage effect. A low-velocity region develops along the tip clearance vortex at the near stall condition due to the vortex “breakdown”. As the mass flow rate is further decreased, this area builds up rapidly and moves upstream. This area prevents incoming flow from passing through the pressure side of the passage and forces the tip leakage flow to spill into the adjacent blade passage from the pressure side at the leading edge. It is found that the tip leakage flow exerts little influence on the development of the blade suction surface boundary layer even at the near stall condition.

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