• Title/Summary/Keyword: Casing Groove

Search Result 9, Processing Time 0.022 seconds

Performance Enhancement of a Low Speed Axial Compressor Utilizing Simultaneous Tip Injection and Casing Treatment of Groove Type

  • Taghavi-Zenouz, Reza;Behbahani, Mohammad Hosein Ababaf
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.18 no.1
    • /
    • pp.91-98
    • /
    • 2017
  • Performance of a low speed axial compressor is enhanced through a proper configuration of blade row tip injection and casing treatment of groove type. Air injectors were mounted evenly spaced upstream of the blade row within the casing groove and were all aligned parallel to the compressor axis. The groove, which covers all the blade tip chord length, extends all-round the casing circumference. Method of investigation is based on solution of the unsteady form of the Navier-Stokes equations utilizing $k-{\omega}$ SST turbulence model. Extensive parametric studies have been carried out to explore effects of injectors' flow momentums and yaw angles on compressor performance, while being run at different throttle valve setting. Emphasis has been focused on situations near to stall condition. Unsteady numerical analyses for untreated casing and no-injection case for near stall condition provided to discover two well-known criteria for spike stall inception, i.e., blade leading edge spillage and trailing edge back-flow. Final results showed that with only 6 injectors mounted axially in the casing groove and at yaw angle of 15 degrees opposite the direction of the blade row rotation, with a total mass flow rate of only 0.5% of the compressor main flow, surprisingly, the stall margin improves by 15.5%.

A Study on Performance Characteristics of an Axial Compressor with the Casing Groove (케이싱 그루브가 존재하는 축류압축기의 성능특성 연구)

  • Choi, Kwang-Jin;Kim, Jin-Hyuk;Kim, Kwang-Yong
    • The KSFM Journal of Fluid Machinery
    • /
    • v.13 no.2
    • /
    • pp.24-29
    • /
    • 2010
  • This paper presents a study on the performance of NASA Rotor 37 with the casing grooves based on three-dimensional numerical analysis. Reynolds-averaged Navier-Stokes equations are solved on a hexahedral grid with the shear stress transport model as a turbulence closure model. The governing equations are discretized by a finite volume method. The validation of the numerical results is performed through experimental data for the total pressure ratio and the adiabatic efficiency. The investigation for an axial compressor with a smooth casing and the casing grooves is carried out to compare the performance parameters, for example, surge margin and efficiency, etc. The surge margin is improved in the case of the casing grooves while remarkable improvement of the efficiency is not produced. The result shows that the casing groove is beneficial to expand the operating range of NASA Rotor 37.

Improvement of Pump Performance and Suppression of Cavitation in a Centrifugal Pump (원심펌프의 성능개선과 캐비테이션 억제에 관한 연구)

  • Choi, Young-Do;Kurokawa, Junichi
    • The KSFM Journal of Fluid Machinery
    • /
    • v.11 no.1
    • /
    • pp.18-25
    • /
    • 2008
  • Recent trends of a centrifugal pump are high speed in rotation and high pressure in head with high efficiency to meet the demands of industries. However, the newly developed pumps make trouble of pressure pulsation in the pumping system by performance instability of the pump. Moreover, cavitation, which is a main obstacle of high rotational speed in the pump, occurring in an impeller gives serious damages to the impeller and casing wall. The purpose of present study is not only to develop a simple method to improve pump performance but also to suppress the occurrence of cavitation in the centrifugal pump by use of J-Groove. J-Groove is a shallow groove installed on the casing wall in the meridional direction. The application of J-Groove to a centrifugal pump with a new type impeller of "semi-closed impeller" has proved its effectiveness as a useful countermeasure of the unstable pump performance and cavitation. The results show that the combination of semi-closed impeller and J-Groove can be applied successfully and improves both the pump performance and suction performance.

Numerical Investigation of Ring Groove Effect in a Centrifugal Compressor (원심압축기의 링 그루브 효과에 관한 수치해석적 연구)

  • Park, Chi-Yong;Choi, Young-Seok;Lee, Kyoung-Yong;Yoon, Joon-Yong
    • The KSFM Journal of Fluid Machinery
    • /
    • v.14 no.2
    • /
    • pp.11-16
    • /
    • 2011
  • This paper presents a numerical study of casing treatments on a centrifugal compressor stage to improve stability and the surge margin. High efficiency, a high pressure ratio, and a wide operating range are required for a high performance centrifugal compressor. In the present study, a ring groove arrangement was applied to the transonic centrifugal compressor. According to the numerical analysis using a commercial code ANSYS-CFX, the unstable phenomena limiting the range of the centrifugal compressors were compared with and without a ring groove. Although the ring groove decreased the efficiency, but increased the operating range by suppressing a flow separation at the leading-edge of the impeller especially near shroud part. Newly designed ring groove arrangement improved the compressor performance and increased the operating range of the compressor.

Improvement of Pump Performance and Suction Performance of a Very Low Specific Speed Centrifugal Pump (극저비속도 원심펌프의 펌프성능 및 흡입성능 향상)

  • Choi Young-Do;Kurokawa Junichi
    • The KSFM Journal of Fluid Machinery
    • /
    • v.9 no.3 s.36
    • /
    • pp.29-35
    • /
    • 2006
  • There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.

Suppression of Cavitation in Inducer by J-Groove (J-그루브에 의한 인듀서의 캐비테이션 억제)

  • Kurokawa, Junichi;Choi, Young-Do
    • 유체기계공업학회:학술대회논문집
    • /
    • 2005.12a
    • /
    • pp.776-781
    • /
    • 2005
  • Cavitation is the most serious problem caused in developing high-speed turbopump, and use of an inducer is often made to avoid cavitation in main impeller. Thus, the inducer always operates under the worst condition of cavitation. If it could be possible to control and suppress cavitation in the inducer by some new device, it would also be possible to suppress cavitation occurring in all types of pumps. The purpose of our present study is to develop a new effective method of controlling and suppressing cavitation in an inducer using shallow grooves, named as "J-Groove", J-Groove is installed on the casing wall near the blade tip to use the pressure difference between high pressure region and low pressure region in the axial direction at the inlet of the inducer. The results show that proper combination of backward-swept inducer with J-Groove improves suction performance of turbopump remarkably in the range of partial flow rate as well as designed flow rate. The rotating backflow cavitation occurring in the range of low flow rate and the cavitation surge occurring in the vicinity of the best efficiency point can be almost fully suppressed by installing J-Groove.

  • PDF

A Study on the Suppression of Cavitation in Inducer by J-Groove (J-그루브를 이용한 인듀서의 캐비테이션 억제에 관한 연구)

  • Choi, Young-Do;Kurokawa, Junichi
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.11 s.242
    • /
    • pp.1239-1247
    • /
    • 2005
  • Cavitation is the most serious problem in developing high-speed turbopump, and inducer is often used to avoid cavitation in main impeller. Thus, inducer is always operating in the worst .cavitation condition. If it is possible to control and suppress cavitation in inducer by some new device, it might be possible to suppress cavitation occurring in any type of pumps. The purpose of present study is to develop a new effective method of controlling and suppressing cavitation in inducer using shallow grooves, which is named 'J-Groove'. J-Groove is installed on the casing wall near the blade tip to use the pressure difference between high pressure region and low pressure region of the inducer in an axial direction. The results show that proper combination of backward-swept inducer with J-Groove improves suction performance of turbopump remarkably in the range of partial flow rate as well as designed flow rate. The rotating backflow cavitation occurring in the range of low flow rate and the cavitation surge occurring in the vicinity of the best efficiency point can be almost suppressed by installing J-Groove.

Investigation on Aerodynamic Performance of a Highly-Loaded Axial Fan with Active/Passive Flow Control Using FSI Analysis (유체-구조 연성해석을 이용한 능동/수동 유동제어방식이 결합된 고하중 축류 팬의 성능특성 연구)

  • Ma, Sang-Bum;Kim, Kwang-Yong;Choi, Jaeho;Lee, Wonsuk
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.28 no.1
    • /
    • pp.113-119
    • /
    • 2017
  • An investigation on aerodynamic performance of a highly-loaded axial fan has been conducted to find the effects of tip injection and casing groove on aerodynamic performance in this study. Three-dimensional Reynolds-averaged Navier-Stokes equations with $k-{\varepsilon}$ turbulence model were used to analyze the fluid flow in the fan with Fluid-Structure Interaction (FSI) analysis. The hexahedral grid was used to construct computational domain, and the grid dependency test drew the optimal grid system. FSI analysis was also carried out to predict the deformation of rotor and stator blades, and the effect of deformation on the aerodynamic performance of axial fan was analyzed compared to the performance predicted without FSI analysis.

A Method of Axial Thrust Control in Centrifugal Pump (원심펌프의 축추력 제어법에 관한 연구)

  • Choi, Young-Do;Kurokawa, Junichi
    • The KSFM Journal of Fluid Machinery
    • /
    • v.10 no.4
    • /
    • pp.15-20
    • /
    • 2007
  • In order to control and balance axial thrust of turbo machine, many types of balancing devices are used but most of them are complicated and sometimes cause troubles. In this study, a very simple device of using shallow grooves mounted on a casing wall, known as "J-Groove", is proposed and studied experimentally and theoretically. The result shows that 70% of axial thrust in an industrial 4-stage centrifugal pump can be reduced at the best efficiency point. Moreover, the analytical method of "interfered gap flow" is established and a simple formula which can determine the optimum dimension of groove and its location is proposed.