Influence of Axial Position of Self-Circulating Casing Treatment on the Performances of a Centrifugal Pump at Low Mass Flow Conditions

Document Type : Regular Article


1 Marin Engineering College, Dalian Maritime University, Dalian 116026, China

2 Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.

3 Naval Architecture & Ocean Engineering College, Dalian Maritime University, Dalian 116026, China

4 Jiangsu Haiming Medical Equipment Co., Ltd, Yangzhou, 225101, China

5 Danai Pumps Co. Ltd, Dalian 116630, China



Centrifugal pumps often deviate from its design condi-tion during its operation and work at low mass flow conditions. Under such circumstances, unstable flow phenomena may be generated, affecting the efficient and stable operation of pumps. In this paper, a self-circulating casing treatment in U-tube shape is employed on a centrifugal pump to study its effects on the pump’s performance by computational and experi-mental studies. CFD results show that as the flow rate decreases, the back-flow in the inlet pipe of the studied pump without casing treatment increases in intensity and spreads over an growing distance, interfering with the main flow. CFD results also reveal that the casing treatment has a sucking function to the back-flow due to the blade loading of the pump, and when the inlet bleed of the U-tube is placed above (in front of) the leading edge of the blades, the sucking is the strongest, and the control of the back-flow and the improvement to the head coefficient under low mass flow conditions is the best, as the vortex blockage caused by the sucked back-flow in the U-tube is the smallest; when the bleed is under (after) the leading edge of the blades, the effect of the casing treatment is the second best; and when the bleed is across the leading edge of the blades, the blockage in the U-tube is most severe, and the sucking function is the weakest, so there is little improvement to the back-flow and head coefficient. Finally, the relia-bility of this study was demonstrated employing an open pump experimental system with the original pump and the same pump with the casing treatment whose bleed is located above the leading edge of the impeller.


Chen, H. and V. M. Lei (2013). Casing treatment & inlet swirl of centrifugal compressors. Journal of Turbomachinery 135(04), 1-8.##
Cheng, Q., W. M. Feng and L. C. Zhou (2016). Effect of front guide vane on the return vortex characteristics of axial flow pump saddle area operating conditions. Journal of Agricultural Machinery 47(4), 8-14.##
Cooper, P., D. P. Sloteman and J. L. Dussourd (1984). Stabilization of the off-design behavior of centrifugal pumps and inducers. Proceedings of the second European congress on fluid machinery for the oil, petrochemical and related industries.##
Feng, J. J., K. F. Yang, G. J. Zhu, X. Q. Luo and W. F. Li (2018). Axial grooving of inlet pipe wall surface to eliminate the characteristic curve hump of axial flow pump. Journal of Agricultural Engineering 34(13), 105-112.##
Fraser, H. (1981). Flow recirculation in centrifugal pumps. US: ASME meeting.##
Gonzalez, J., J. Fernandez, E. Blanco and C. Santolaria (2002). Numerical Simulation of the Dynamic Effects Due to Impeller-Volute Interaction in a Centrifugal Pump. Journal of Fluids Engineering 124(2).##
Guo, L. (2019). Study on the effect of leakage flow from the lobe top gap of semi-open centrifugal pumps on stall characteristics. Shaanxi: Xi'an University of Technology.##
Ito, Y., A. Tsunoda and Y. Kurishita (2015). Experimental Visualization of Cryogenic Back-flow Vortex Cavitation with Thermodynamic Effects. Journal of Propulsion and Power 32(01), 1-12.##
Li, G., Y. Wang and P. Cao (2014). Numerical analysis of transient flow in centrifugal pump at off-design conditions. US: 6th International Symposium on Fluid Machinery and Fluid Engineering.## 
Li, J. Q., W. W. Song, L. J. Wan and C. F.  Shi (2019). Study on the mechanism of roughness on centrifugal pump inlet flow under multiple working conditions. Thermal Power Engineering 34(10), 63-70.##
Li, Y., H. Chen, X. J. Li, M. H. Jiang and G. N. Wang (2020). The influence of casing treatment on the performance of a centrifugal pump. USA: 18th ISROMAC.##
Li, Y., H. Chen, X. J. Li, M. H. Jiang and G. N. Wang (2021). Influence of U-tube type casing treatment on pressure fluctuations of a centrifugal pump at low flow conditions. Modern Physics Letters B, 35(12).##
Oshima, M. (1967). A study on suction performance of a centrifugal pump with an inducer [J]. JSME 10: 959–965.##
Schiavelo, B. and M. Sen (1983). Performance prediction of centrifugal pump and compressors. US: ASME 22nd Ann Fluids Engineering Conference.##
Si, Q., S. Yuan and J. Yuan (2013). Investigation on Flow-Induced Noise due to Back-flow in Low Specific Speed Centrifugal Pumps. Advances in Mechanical Engineering 109(5), 48-53.##
Stepanoff, A. J. (1998). Centrifugal and Axial Flow Pumps: Theory, Design, and Application. Vienna: Springer.##
Toyokura, T. and A. Kubota (1969). Studies on back-flow to the suction side of mixed-flow impeller blades. JSME;##
Tsujimoto, Y. (1997). Observations of Oscillating Cavitation of an Inducer. Journal of Fluids Engineering 119(4), 775-781.##
Tsujimoto, Y. (2007). Fluid Dynamics of Cavitation and Cavitating Turbo pumps. Vienna: Springer.##
Tsujimoto, Y. (2013). Cavitation instabilities in hydraulic machines. IOP Conference Series: Materials Science and Engineering 52(1),169-190.##
Tsujimoto, Y. and Y. Semenvo (2002). New types of cavitation instabilities in inducers. Belgium: 4th International Symposium on Launcher Technology.## 
Yamamoto, K. and Y. Sujimoto (2009). Backflow Vortex Cavitation and Its Effects on  Cavitation Instabilities. International Journal of Fluid Machinery & Systems 2(01), 40-54.##
Yuan, J. P., J. S. Hou, Y. X. Fu, J. W. Hu, H. Y. Zhang and C. D. Shen (2018). Study on the unsteady characteristics of back-flow vortex cavitation in a centrifugal pump. Vibration and Shock 37(16), 24-30.##
Zhang, J. F., Y. Liang, J. P. Yuan and S. Q. Yuan (2012). Numerical simulation of recirculation control at centrifugal pump inlet. Jiangsu University 33, 402-407.##