The tip leakage flow has an important influence on the performance of transonic com- pressor. Blade tip winglet has been proved to be an effective method to control the tip leakage flow in compressor, while the physic...The tip leakage flow has an important influence on the performance of transonic com- pressor. Blade tip winglet has been proved to be an effective method to control the tip leakage flow in compressor, while the physical mechanisms of blade tip winglet have been poorly understood. A numerical study for a highly loaded transonic compressor rotor has been conducted to understand the effect of varying the location of blade tip wing]et on the performance of the rotor. Two kinds of tip winglet were designed and investigated. The effects of blade tip winglet on the compressor over- all performance, stability and tip flow structure were presented and discussed, It is found that the interaction of the tip winglet with the flow in the tip region is different when the winglet is located at suction-side or pressure-side of the blade tip. Results indicate that the suction-side winglet （SW） is ineffective to improve the performance of compressor rotor. In addition, a significant stall range extension equivalent to 33.74% with a very small penalty in efficiency can be obtained by the pressure-side winglet （PW）. An attempt has been made to explain the fundamental mechanisms of blade tip winglet in detail.展开更多
Accurate and efficient prediction of the aerodynamic performance and flow details of axial-flow com-pressors is of great engineering application value for the aerodynamic design and flow control of axial-flow compres-...Accurate and efficient prediction of the aerodynamic performance and flow details of axial-flow com-pressors is of great engineering application value for the aerodynamic design and flow control of axial-flow compres-sors.In this work,a delayed detached eddy simulation method is developed and applied to numerically simulate the tur-bulent channel flow and the aerodynamic performance of NASA Rotor 35.Several acceleration techniques including parallel implementation are also used to speed up the iteration convergence.The mean velocity distribution and Reyn-olds stress distribution in the boundary layer of turbulent channel flow and the aerodynamic performance curve of NASA Rotor 35 are predicted.The good agreement between the present delayed detached eddy simulation results and the available direct numerical simulation results or experimental data confirms the effectiveness of the developed meth-od in the accurate and efficient prediction of complex flow in turbomachinery.展开更多
This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools.It describes the details of lobe shape specification,and focuses on a new lobe profile,which yields...This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools.It describes the details of lobe shape specification,and focuses on a new lobe profile,which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed.A well proven mathematical model was used to determine the optimum profile,compressor housing size,and compressor ports to achieve the superior compressors.展开更多
Upstream blade wake turbulence fluctuation may affect compressor blade forced response caused by wake sweeping.In order to investigate the effect of wake turbulence fluctuation and predict the blade vibration more acc...Upstream blade wake turbulence fluctuation may affect compressor blade forced response caused by wake sweeping.In order to investigate the effect of wake turbulence fluctuation and predict the blade vibration more accurately,this paper proposes a forced response calculation model that considers the excitation of upstream blade wake turbulence fluctuation on the basis of the conventional forced response calculation method.Using a three-stage axial compressor as the research subject,a quasi-three-dimensional large eddy simulation is conducted using the blade profile at 77.8%of the span of the inlet guide vane.Analysis of the flow field around the inlet guide vane indicates noticeable total pressure fluctuation in the wake of the inlet guide vane.The influence of upstream wake turbulence fluctuation is incorporated into the forced response calculation model in the form of total pressure fluctuation to obtain more accurate excitation forces.Specifically,the relationship between the amplitude of total pressure fluctuation and total pressure loss is established according to the results of large eddy simulation,and different formulas are set according to the position zoning of suction surface and pressure surface.Computational results show that,if only wake sweeping is considered,the maximum amplitude is 27%lower than the test result.However,when wake sweeping and wake fluctuation are considered,the calculated result better matches the test result,with only a 6%reduction compared to the test result.The results confirm the effectiveness of the proposed model.展开更多
The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor...The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor compressor.The first part of the present study is concerning the sweep effect with straight leading edge.In this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards axially.The second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading edge.Its adiabatic efficiency is a little bit greater than that of the reference un-swept rotor.展开更多
The unsteady 3D flow fields in a single-stage transonic compressor under designed conditions are simulated numerically to investigate the effects of the curved rotors on the stage performance and the aerodynamic inter...The unsteady 3D flow fields in a single-stage transonic compressor under designed conditions are simulated numerically to investigate the effects of the curved rotors on the stage performance and the aerodynamic interaction between the blade rows. The results show that, compared to the compressor with unurved rotors, the compressor under scrutiny acquires remarkable increases in efficiency with significantly reduced amplitudes of the time-dependent fluctuation. The amplitude of the pressure fluctuation around the stator leading edge decreases at both endwalls, but increases at the mid-span in the curved rotors. The pressure fluctuation near the stator leading edge, therefore, becomes more uniform in the radial direction of this compressor. Except for the leading edge area, the pressure fluctuatinn amplitude declines remarkably in the tip region of stator surface downstream of the curved rotor, but hardly changes in the middle and at the hub.展开更多
Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows tha...Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows that the variation will change the relative position ofupstream rotor wake to the downstream rotor as well as the periodic and turbulent velocityfluctuations on the airfoils. When the upstream rotor wake impinges upon the leading edge of thedownstream rotor, the corresponding stage efficiency will be higher; when the upstream wake istransferred into the mid-passage of the downstream rotor, the corresponding stage efficiency will belower. The proper configuration of the relative position of rotors will cause obvious reduction inthe unsteady aerodynamic effect on the second rotor airfoils and improve the aerodynamic performanceof blades.展开更多
The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of th...The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.展开更多
Numerical investigation of the unsteady flow variability driven by rotorstator interaction in a transonic axial compressor is performed. Two models with close and far axial gap between rotor and stator rows are studie...Numerical investigation of the unsteady flow variability driven by rotorstator interaction in a transonic axial compressor is performed. Two models with close and far axial gap between rotor and stator rows are studied in the simulation. Particular attention is attached to the analysis of mechanisms involved in driving rotor wake oscillation, rotor wake skewing and flow angle fluctuation at rotor exit. The results show that smaller axial gap is favorable to enhance the interaction in the region between two adjacent rows, and the fluctuation of the static pressure difference between two sides of rotor wake is improved by potential field from down stator, which is the driving force for rotor wake oscillation. The interaction between rotor and stator is weakened by increasing axial distance, rotor wake shifts to suction side of rotor blade with 5%-10% of rotor pitch, the absolute value of flow angle at rotor exit is less than that in the case of close interspace for every time step, and the fluctuation amplitude is also decreased.展开更多
The compressor of composite gear teeth is a new type of rotor compressor withpartial built-in compression process. Analysis of its thermodynamic process indicates that thebuilt-in process is incomplete. The thermodyna...The compressor of composite gear teeth is a new type of rotor compressor withpartial built-in compression process. Analysis of its thermodynamic process indicates that thebuilt-in process is incomplete. The thermodynamic process of the compressor of composite gear teethcan be considered as five processes; the suction process, the isometric process, the compressionprocess, the pressure-balance process at high pressure and low pressure gas, and discharge process.Here, it is necessary to explain further the pressure-balance process. The pressure-balance processis isometric process. It is found that the isometric process of gas in chamber A whose capacity is83 percent of total work volume can be eliminated basically through extending the discharge port toconnect early the discharge port with the chamber B. By the above-mentioned method, the loss ofenergy will be reduced.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.51436002,51406021)the Scientific Research Fund of Education Department of Liaoning Province(No.L2014197)+1 种基金the Program for Liaoning Innovative Research Team in University(No.LT2015004)the Fundamental Research Funds for the Central Universities(Nos.3132016014,3132014319)
文摘The tip leakage flow has an important influence on the performance of transonic com- pressor. Blade tip winglet has been proved to be an effective method to control the tip leakage flow in compressor, while the physical mechanisms of blade tip winglet have been poorly understood. A numerical study for a highly loaded transonic compressor rotor has been conducted to understand the effect of varying the location of blade tip wing]et on the performance of the rotor. Two kinds of tip winglet were designed and investigated. The effects of blade tip winglet on the compressor over- all performance, stability and tip flow structure were presented and discussed, It is found that the interaction of the tip winglet with the flow in the tip region is different when the winglet is located at suction-side or pressure-side of the blade tip. Results indicate that the suction-side winglet （SW） is ineffective to improve the performance of compressor rotor. In addition, a significant stall range extension equivalent to 33.74% with a very small penalty in efficiency can be obtained by the pressure-side winglet （PW）. An attempt has been made to explain the fundamental mechanisms of blade tip winglet in detail.
基金National Science and Technology Major Project of China(No.2017-II 0006-0020)National Key Research and Development Project of China(2016YFB0200901)National Natural Science Foundation of China(51776154)。
文摘Accurate and efficient prediction of the aerodynamic performance and flow details of axial-flow com-pressors is of great engineering application value for the aerodynamic design and flow control of axial-flow compres-sors.In this work,a delayed detached eddy simulation method is developed and applied to numerically simulate the tur-bulent channel flow and the aerodynamic performance of NASA Rotor 35.Several acceleration techniques including parallel implementation are also used to speed up the iteration convergence.The mean velocity distribution and Reyn-olds stress distribution in the boundary layer of turbulent channel flow and the aerodynamic performance curve of NASA Rotor 35 are predicted.The good agreement between the present delayed detached eddy simulation results and the available direct numerical simulation results or experimental data confirms the effectiveness of the developed meth-od in the accurate and efficient prediction of complex flow in turbomachinery.
文摘This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools.It describes the details of lobe shape specification,and focuses on a new lobe profile,which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed.A well proven mathematical model was used to determine the optimum profile,compressor housing size,and compressor ports to achieve the superior compressors.
基金supported by the National Science and Technology Major Project of China(J2019-II-0005-0025)。
文摘Upstream blade wake turbulence fluctuation may affect compressor blade forced response caused by wake sweeping.In order to investigate the effect of wake turbulence fluctuation and predict the blade vibration more accurately,this paper proposes a forced response calculation model that considers the excitation of upstream blade wake turbulence fluctuation on the basis of the conventional forced response calculation method.Using a three-stage axial compressor as the research subject,a quasi-three-dimensional large eddy simulation is conducted using the blade profile at 77.8%of the span of the inlet guide vane.Analysis of the flow field around the inlet guide vane indicates noticeable total pressure fluctuation in the wake of the inlet guide vane.The influence of upstream wake turbulence fluctuation is incorporated into the forced response calculation model in the form of total pressure fluctuation to obtain more accurate excitation forces.Specifically,the relationship between the amplitude of total pressure fluctuation and total pressure loss is established according to the results of large eddy simulation,and different formulas are set according to the position zoning of suction surface and pressure surface.Computational results show that,if only wake sweeping is considered,the maximum amplitude is 27%lower than the test result.However,when wake sweeping and wake fluctuation are considered,the calculated result better matches the test result,with only a 6%reduction compared to the test result.The results confirm the effectiveness of the proposed model.
基金supported by National Natural Science Foundation of China with project No.50736007National Basic Research Program of China numbered 2007CB210103
文摘The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor compressor.The first part of the present study is concerning the sweep effect with straight leading edge.In this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards axially.The second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading edge.Its adiabatic efficiency is a little bit greater than that of the reference un-swept rotor.
基金National Natural Science Foundation of China (506460210) Chinese Specialized Research Fund for the Doctoral Program of Higher Education (20060213007)Development Program for Outstanding Young Teachers in Harbin Institute of Technology (HITQNJS.2006.046)
文摘The unsteady 3D flow fields in a single-stage transonic compressor under designed conditions are simulated numerically to investigate the effects of the curved rotors on the stage performance and the aerodynamic interaction between the blade rows. The results show that, compared to the compressor with unurved rotors, the compressor under scrutiny acquires remarkable increases in efficiency with significantly reduced amplitudes of the time-dependent fluctuation. The amplitude of the pressure fluctuation around the stator leading edge decreases at both endwalls, but increases at the mid-span in the curved rotors. The pressure fluctuation near the stator leading edge, therefore, becomes more uniform in the radial direction of this compressor. Except for the leading edge area, the pressure fluctuatinn amplitude declines remarkably in the tip region of stator surface downstream of the curved rotor, but hardly changes in the middle and at the hub.
基金Natural Science Foundation of China( 5 0 10 60 0 2 ) 973 Project( G19990 2 2 3 0 7)
文摘Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows that the variation will change the relative position ofupstream rotor wake to the downstream rotor as well as the periodic and turbulent velocityfluctuations on the airfoils. When the upstream rotor wake impinges upon the leading edge of thedownstream rotor, the corresponding stage efficiency will be higher; when the upstream wake istransferred into the mid-passage of the downstream rotor, the corresponding stage efficiency will belower. The proper configuration of the relative position of rotors will cause obvious reduction inthe unsteady aerodynamic effect on the second rotor airfoils and improve the aerodynamic performanceof blades.
基金National Natural Science Foundation of China (50646021)Chinese Specialized Research Fund for the Doctoral Pro-gram of Higher Education (20060213007)
文摘The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.
基金National Natural Science Foundation of China (51176013)Ph.D. Programs Foundation of Ministry of Education of China (20091101110014)National High-tech Research and Development Program of China (2007AA050502)
文摘Numerical investigation of the unsteady flow variability driven by rotorstator interaction in a transonic axial compressor is performed. Two models with close and far axial gap between rotor and stator rows are studied in the simulation. Particular attention is attached to the analysis of mechanisms involved in driving rotor wake oscillation, rotor wake skewing and flow angle fluctuation at rotor exit. The results show that smaller axial gap is favorable to enhance the interaction in the region between two adjacent rows, and the fluctuation of the static pressure difference between two sides of rotor wake is improved by potential field from down stator, which is the driving force for rotor wake oscillation. The interaction between rotor and stator is weakened by increasing axial distance, rotor wake shifts to suction side of rotor blade with 5%-10% of rotor pitch, the absolute value of flow angle at rotor exit is less than that in the case of close interspace for every time step, and the fluctuation amplitude is also decreased.
文摘The compressor of composite gear teeth is a new type of rotor compressor withpartial built-in compression process. Analysis of its thermodynamic process indicates that thebuilt-in process is incomplete. The thermodynamic process of the compressor of composite gear teethcan be considered as five processes; the suction process, the isometric process, the compressionprocess, the pressure-balance process at high pressure and low pressure gas, and discharge process.Here, it is necessary to explain further the pressure-balance process. The pressure-balance processis isometric process. It is found that the isometric process of gas in chamber A whose capacity is83 percent of total work volume can be eliminated basically through extending the discharge port toconnect early the discharge port with the chamber B. By the above-mentioned method, the loss ofenergy will be reduced.
