Effect of swept blade on hump and cavitation characteristics of axial flow pump
LIU Zhu-Qing1, XIAO Ruo-Fu1, Lv Teng-Fei 1, LI Shu-Lin2
(1. College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083,China; 2. Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration,Nanjing, Jiangsu 211106, China)
A swept blade was designed based on changing the stacking line in the meridional plane of an axial flow pump impeller. The high speed fuel axial flow pumps, with swept blades and datum blades respectively, were simulated in the overall operation by the code of computational fluid dynamics (CFD) and the overall efficiency and pump head performance curves were obtained. Using the full cavitation model, the cavitation performances of pumps were predicted under the designed point condition and near stall point condition to investigate the effects of swept blade on the cavitation performance and distribution of pressure on blade surfaces of an axial flow pump. According to the numerical results, the swept blade changes the hump characteristic of the axial flow pump, controls the onset and growth of the secondary flows, and recovers the lowenergy fluid on the endwalls. Therefore, the stability of operation in the hump zones is improved. Near stall point condition, the swept blade improves the cavitation characteristic of the pump, changes the pressure distribution on the impeller inlet, and avoids the separated flow on the endwalls. While under the design point condition, the swept blade reduces the cavitation characteristic, the blade surface pressure distribution also presents the pressure difference of the datum blade is higher than the swept blade, resulting in the ability of doing work of the former is better than the latter.
Yang Zhengjun, Wang Fujun, Liu Zhuqing, et al. Prediction of cavitation performance of axialflow pump based on CFD[J]. Journal of Drainage and Irrigation Machinery Engineering, 2011,29(1):11-15. (in Chinese)
Mao Mingming, Song Yanping, Wang Zhongqi. Effect of bowed and swept rotors on unsteady aerodynamic loading in a transonic compressor[J]. Journal of Engineering Thermophysics, 2010, 31(10):1663-1666. (in Chinese)
McNulty G Scott, Decker John J, Beacher Brent F, et al. The impact of forward swept rotors on tip clearance flows in subsonic axial compressors[J]. Journal of Turbomachinery, 2004,126(4): 445-454.
Yang Minguan, Ji Kai, Li Zhong. Numerical calculation of cavitating flow in impeller of axialflow pump[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010,41 (S1):10-14. (in Chinese)
Okita K, Ugajin H, Matsumoto Y. Numerical analysis of the influence of the tip clearance flows on the unsteady cavitating flows in a threedimensional inducer[J]. Journal of Hydrodynamics, Ser B, 2009,21(1): 34-40.