• Title/Summary/Keyword: centrifugal effect

Search Result 332, Processing Time 0.034 seconds

Influence of Blade Outlet Angle and Blade Thickness on Performance and Internal Flow Conditions of Mini Centrifugal Pump

  • Shigemitsu, Toru;Fukutomi, Junichiro;Kaji, Kensuke
    • International Journal of Fluid Machinery and Systems
    • /
    • v.4 no.3
    • /
    • pp.317-323
    • /
    • 2011
  • Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices and so on. Further, the needs for mini centrifugal pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini centrifugal pump design be as simple as possible as precise manufacturing is required. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, we started research on the mini centrifugal pump for the purpose of development of high performance mini centrifugal pumps with simple structure. Three types of rotors with different outlet angles are prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on performance and internal flow condition of mini centrifugal pumps. In addition to that, the blade thickness is changed because blockage effect in the mini centrifugal pump becomes relatively larger than that of conventional pumps. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-Fluent) to investigate the internal flow condition. It is clarified from the experimental results that head of the mini centrifugal pump increases according to the increase of the blade outlet angle and the decrease of the blade thickness. In the present paper, the performance of the mini centrifugal pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle and the blade thickness on the performance are investigated and the internal flow of each type of rotor is clarified by the numerical analysis results.

Numerical studies on cavitation behavior in impeller of centrifugal pump with different blade profiles

  • Song, Pengfei;Zhang, Yongxue;Xu, Cong;Zhou, Xin;Zhang, Jinya
    • International Journal of Fluid Machinery and Systems
    • /
    • v.8 no.2
    • /
    • pp.94-101
    • /
    • 2015
  • To investigate the influence of blade profiles on cavitation behavior in impeller of centrifugal pump, a centrifugal pump with five different blade profiles impellers are studied numerically. The impellers with five different blade profiles (single arc, double arcs, triple arcs, logarithmic spiral and linear-variable angle spiral) were designed by the in-house hydraulic design code using geometric parameters of IS 150-125-125 centrifugal pump. The experiments of the centrifugal pump have been conducted to verify numerical simulation model. The numerical results show that the blade profile lines has a weak effect on cavitation inception near blade inlet edge position, however it has the key effect on the development of sheet cavitation in impeller, and also influences the distribution of sheet cavitation in impeller channels. A slight changing of blade setting angle will induce significant difference of cavitation in impeller. The sharp changing of impeller blade setting angle causes obvious cavitation region separation near the impeller inlet close to blade suction surface and much more flow loss. The centrifugal pump with blade profile of setting angle gently changing (logarithmic spiral) has the super cavitation performance, which means smaller critical cavitation number and lower vapor cavity volume fraction at the same conditions.

A Study on Production and Physical Properties of Prestressed Concrete Piles(I)-Effect of Factors on the Centrifugal Compaction of Concrte Piles (프리스트레스트 콘크리트 파일의 제조와 물성에 관한 연구(I) -콘크리트 파일의 원심 성형에 미치는 각 요인의 영향)

  • Jaung, Jae-Dong;Kim, Won-Ki;Jeong, Yong;Kim, Jin-Chul;Yoo, Taec-Jun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1992.10a
    • /
    • pp.228-233
    • /
    • 1992
  • The objective of this report is to investigate the effect of factors on the centrifugal compaction of concrete piles with design of experiments. The analysis of sludge and measurement of compressive strength of specimens compacted by centrifugal of vibration were performed. As a result, there were some effective factors like unit content of cement, high and middle centrifugal force and time. It was considered that the process of centrifugal compaction of concrete piles could be optimized with these results.

  • PDF

Analysis of Flow Characteristics on the Axial Flow Fan with Centrifugal Blade (원심형 날개를 부착한 축류홴의 유동특성 해석)

  • Choi Jung-Geun;Lee Seok-Jong;Lee Myoeng-Ho;Sung Jae-Yong
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.30 no.5
    • /
    • pp.589-596
    • /
    • 2006
  • This study aims to propose a new model axial flow fan which attachs centrifugal blades, and to investigate the effect of centrifugal blades on the performance improvement of new model axial flow fan. A numerical simulation has been conducted using STAR-CD commercial code to solve the three dimensional incompressible Navier-Stokes equation for high Reynolds number $k-{\epsilon}$ turbulent model. Numerical simulation is carried out to investigate the detail phenomenon in the flow field and performance characteristics of new model and normal model fan. Calculation results are compared with normal model's results to investigate which centrifugal blades effect on velocity profile and pressure distribution at various flow field positions. and calculation results show that new model fan can improve the performance of total pressure.

Experimental Study for the Effect of Dimensional Parameters on the Performance of Small Centrifugal Fans (소형 원심형 팬의 형상변수가 성능에 미치는 영향에 대한 실험적 연구)

  • Choi, Jong-Soo;Rhee, Wook
    • 유체기계공업학회:학술대회논문집
    • /
    • 1998.12a
    • /
    • pp.57-63
    • /
    • 1998
  • The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter to the fan performance. In this experimental study the effect of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. Total 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

  • PDF

Numerical Study on Tip Clearance Effect on Performance Characteristics of a Centrifugal Compressor for a R134a Turbo-Chiller (R134a 터보냉동기용 원심압축기의 익단간극이 성능특성에 미치는 영향에 관한 수치해석적 연구)

  • Lee, Kyoung-Yong;Choi, Young-Seok;Park, Woon-Jean
    • The KSFM Journal of Fluid Machinery
    • /
    • v.7 no.6 s.27
    • /
    • pp.38-44
    • /
    • 2004
  • In this study, the overall performance and the effect of the tip leakage flow of the centrifugal compressor with a refrigerant HFC-l34a were numerically studied using CFX-TASCflow. To study the effect of the tip leakage flow, the numerical study of the overall performance of HFC-l34a centrifugal compressor with a cascade diffuser was preceded and compared with the experimental result. Six different tip clearances were used to consider the influence of the tip clearance on the performance. The tip leakage flow was illustrated for qualitative discussion. The results obtained in this study can be applied to the determination of the cold clearance.

Numerical Study on Tip Clearance Effect on Performance Characteristics of a Centrifugal Compressor for a R134a Turbo-Chiller (R134a 터보냉동기용 원심압축기의 익단간극이 성능특성에 미치는 영향에 관한 수치해석적 연구)

  • Lee, Kyoung-Yong;Choi, Young-Seok;Park, Woon-Jean
    • 유체기계공업학회:학술대회논문집
    • /
    • 2003.12a
    • /
    • pp.451-456
    • /
    • 2003
  • In this study, the overall performance and the effect of the tip leakage flow of the centrifugal compressor with the refrigerant HFC-l34a were numerically studied using CFX-TASCflow. To study the effect of a tip leakage flow, the numerical study of the overall performance of HFC-l34a centrifugal compressor with a cascade diffuser was preceded and compared with experimental result. Six different tip clearances were used to consider the influence of a tip clearance on performance. The tip leakage flow was illustrated for qualitative discussion. The results obtained in this study can be applied to the determination of the cold clearance.

  • PDF

An Analysis of the Flow Field and Radiation Acoustic Field of Centrifugal Fan with Wedge -The Prediction of the Scattered Sound Field- (웨지가 있는 원심 임펠러의 유동장 및 방사 음향장 해석(II) -원심홴의 산란 음향장 예측-)

  • Lee, Deok-Ju;Jeon, Wan-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.25 no.9
    • /
    • pp.1165-1174
    • /
    • 2001
  • The objective of this study is to understand the generation mechanism of sound and to develop a prediction method for the acoustic pressure field of a centrifugal fan. If the fan is operating at the free field without the casing, the acoustic analogy is a good method to predict the acoustic of the fan. But, the casing gives a dominant effect to the radiated sound field and the scattering effect of casing should be considered. So, in this paper the Kirchhoff-BEM is developed, which can consider the scattering effect of the rigid body. In order to consider the scattering and diffraction effects owing to the casing, BEM is introduced. The source of BEM is newly developed, so the sound field of the centrifugal fan can be obtained. In order to compare the predicted one with experimental data, a centrifugal impeller and a wedge are used in the numerical calculation and the results are compared with the experimental data. Reasonable results are obtained not only for the peak frequencies but also for the amplitudes of the tonal sound. The radiated acoustic field shows the diffraction and scattering effects of the wedge clearly.

A Study on the Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump (극저비속도 원심펌프의 성능과 내부유동특성에 관한 연구)

  • Kurokawa Junichi;Lee Young-Ho;Choi Young-Do
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.7 s.238
    • /
    • pp.784-794
    • /
    • 2005
  • In the very low specific speed range ($n_s=0.24$ < 0.25, non-dimensional), the efficiency of centrifugal pump designed by a conventional method is very low in common. Therefore, positive-displacement pumps have long been used widely. Recently, since the centrifugal pumps are becoming higher in rotational speed and smaller in size, there expects to develop a new centrifugal pump with a high performance to replace the positive-displacement pumps. The purpose of this study is to investigate the internal flow characteristics of a very low specific speed centrifugal pump and to examine the effect of internal flow pattern on pump performance. The results show that the theoretical head definition of semi-open impeller should be revised by the consideration of high slip factor in the semi-open impeller, and the leakage flow through the tip clearance results in a large effect on the impeller internal flow. Strong reverse flow at the outlet of semi-open impeller reduces the absolute tangential velocity considerably, and the decreased absolute tangential velocity increasese the slip factor with the reduction of theoretical head.

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.