The impacts of the cavity leakage flow on the shrouded stator aerodynamic performance were investigated by modelling the annular cascade mainstream with the seal cavity flow path based on the validated numerical metho...The impacts of the cavity leakage flow on the shrouded stator aerodynamic performance were investigated by modelling the annular cascade mainstream with the seal cavity flow path based on the validated numerical method.Meanwhile,the interactions between the cavity leakage and the mainstream were also determined in the current study.The development of hub corner separation under the action of leakage was discussed and the total pressure loss coefficient as well as the entropy-based loss coefficient was employed to evaluate the performance changes at different seal clearances and cavity rotational speeds.The results show that the cavity leakage flow induces a new vortex near the blade leading edge and plays an important role in the development of passage vortex and the size of concentrated shedding vortex.By increasing the seal clearance with more cavity leakage flow rate,an increase in the pitchwise extent of the separation region under 15%span is significant and the total pressure loss in the separation core increases.In addition,with the increase of cavity rotating speed,the starting point of corner separation moves backward,reducing the size and depth of the hub corner separation.The mainstream loss reduction in combination with the entropy increase in the seal cavity causes the entropy-based loss coefficient to perform a trend of decreasing first and then increasing with the cavity speed.展开更多
The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize it...The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.展开更多
With the aim of deepening the understanding of high-speed compressor cascade flow,this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow.With the increase of passage p...With the aim of deepening the understanding of high-speed compressor cascade flow,this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow.With the increase of passage pressurizing ability, endwall boundary layer behavior is deteriorated, and the transition zone is extended from suction surface to the endwall as the adverse pressure gradient increases.Cross flow from endwall to midspan, mixing of corner boundary layer and the main stream, and reversal flow on the suction surface are caused by corner separation vortex structures.Passage vortex is the main corner separation vortex.During its movement downstream, the size grows bigger while the rotating direction changes, forming a limiting circle.With higher incidence, corner separation is further deteriorated, leading to higher flow loss.Meanwhile, corner separation structure, flow mixing characteristics and flow loss distribution vary a lot with the change of incidence.Compared with low aspect-ratio model, corner separation of high aspect-ratio model moves away from the endwall and is more sufficiently developed downstream the cascade.Results obtained present details of high-speed compressor cascade flow,which is rare in the relating research fields and is beneficial to mechanism analysis, aerodynamic optimization and flow control design.展开更多
For the compressor with shrouded stator blades,the stator well is a rotor-stator space between the rotating drum and the stationary shroud.Due to the pressure difference,a reverse leakage flow would travel through the...For the compressor with shrouded stator blades,the stator well is a rotor-stator space between the rotating drum and the stationary shroud.Due to the pressure difference,a reverse leakage flow would travel through the stator well and inject into the main flow path.Although,the labyrinth seal is commonly placed under the shroud,the rotation effect and seal clearance variation in actual operation process have great impact on the characteristics of this inter-stage leakage,as well as the compressor performance.In this paper,experiments were conducted at a compressor inter-stage seal test rig.The leakage flow rates,total temperatures and swirl ratios were obtained at different speeds and working clearances.The proportions of rotation effect and the clearance reduction effect were analyzed by data processing.Comparisons indicate that the working clearance and leakage flow reduce about 43%and 50%respectively,when the rotational speedω=8100 r/min.The proportion of reduction caused by the rotation effect is around 15%,while the influence of working clearance variation is much greater,accounting for about 35%.The windage heating coefficient and swirl ratio in the outlet cavity are almost in exponential relationship with the rotor speed.The increases in total temperature and swirl ratio generated by the rotation effect are found to be about 80%.In addition,the swirl and radial velocity profiles in the cavities were discussed by validated numerical simulations to reveal the typical flow characteristics.The data presented can provide guidance for better leakage conditions prediction as well as the inter-stage seal design enhancement.展开更多
基金supported by the National Natural Science Foundation of China(No.52006021,No.52106040)China Postdoctoral Science Foundation(No.2021M690498,No.2021M700648)+3 种基金Natural Science Foundation of Liaoning Province(No.2020-BS-069)Dalian Science and Technology Innovation Fund(No.2021JJ12GX030)the Fundamental Research Funds for the Central Universities(No.3132022210)National Research Center for International Subsea and Engineering Technology and Equipment(No.3132022349)。
文摘The impacts of the cavity leakage flow on the shrouded stator aerodynamic performance were investigated by modelling the annular cascade mainstream with the seal cavity flow path based on the validated numerical method.Meanwhile,the interactions between the cavity leakage and the mainstream were also determined in the current study.The development of hub corner separation under the action of leakage was discussed and the total pressure loss coefficient as well as the entropy-based loss coefficient was employed to evaluate the performance changes at different seal clearances and cavity rotational speeds.The results show that the cavity leakage flow induces a new vortex near the blade leading edge and plays an important role in the development of passage vortex and the size of concentrated shedding vortex.By increasing the seal clearance with more cavity leakage flow rate,an increase in the pitchwise extent of the separation region under 15%span is significant and the total pressure loss in the separation core increases.In addition,with the increase of cavity rotating speed,the starting point of corner separation moves backward,reducing the size and depth of the hub corner separation.The mainstream loss reduction in combination with the entropy increase in the seal cavity causes the entropy-based loss coefficient to perform a trend of decreasing first and then increasing with the cavity speed.
基金the National Natural Science Foundation of China(Grant No.:51076018)the Fundamental Research Funds for the Central UniversitiesSpecialized Research Fund for the Doctoral Program of Higher Education
文摘The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.
基金supported by the National Natural Science Foundation of China (Nos.51336011, 50906100)the Science Foundation for the Author of National Excellent Doctoral Dissertation of China (No.201172)China Scholarship Council
文摘With the aim of deepening the understanding of high-speed compressor cascade flow,this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow.With the increase of passage pressurizing ability, endwall boundary layer behavior is deteriorated, and the transition zone is extended from suction surface to the endwall as the adverse pressure gradient increases.Cross flow from endwall to midspan, mixing of corner boundary layer and the main stream, and reversal flow on the suction surface are caused by corner separation vortex structures.Passage vortex is the main corner separation vortex.During its movement downstream, the size grows bigger while the rotating direction changes, forming a limiting circle.With higher incidence, corner separation is further deteriorated, leading to higher flow loss.Meanwhile, corner separation structure, flow mixing characteristics and flow loss distribution vary a lot with the change of incidence.Compared with low aspect-ratio model, corner separation of high aspect-ratio model moves away from the endwall and is more sufficiently developed downstream the cascade.Results obtained present details of high-speed compressor cascade flow,which is rare in the relating research fields and is beneficial to mechanism analysis, aerodynamic optimization and flow control design.
基金supported by the Fundamental Research Funds for the Central Universities(No.3132020121,No.3132020192)Natural Science Foundation of Liaoning Province(No.2020-BS-069),which are gratefully acknowledged。
文摘For the compressor with shrouded stator blades,the stator well is a rotor-stator space between the rotating drum and the stationary shroud.Due to the pressure difference,a reverse leakage flow would travel through the stator well and inject into the main flow path.Although,the labyrinth seal is commonly placed under the shroud,the rotation effect and seal clearance variation in actual operation process have great impact on the characteristics of this inter-stage leakage,as well as the compressor performance.In this paper,experiments were conducted at a compressor inter-stage seal test rig.The leakage flow rates,total temperatures and swirl ratios were obtained at different speeds and working clearances.The proportions of rotation effect and the clearance reduction effect were analyzed by data processing.Comparisons indicate that the working clearance and leakage flow reduce about 43%and 50%respectively,when the rotational speedω=8100 r/min.The proportion of reduction caused by the rotation effect is around 15%,while the influence of working clearance variation is much greater,accounting for about 35%.The windage heating coefficient and swirl ratio in the outlet cavity are almost in exponential relationship with the rotor speed.The increases in total temperature and swirl ratio generated by the rotation effect are found to be about 80%.In addition,the swirl and radial velocity profiles in the cavities were discussed by validated numerical simulations to reveal the typical flow characteristics.The data presented can provide guidance for better leakage conditions prediction as well as the inter-stage seal design enhancement.