Abstract:To study the effects of hub/tip ratio on the hydraulic performance of axial-flow impeller, 4 impellers with different hub/tip ratios were optimally designed and the specific speed of these impellers is 743. The optimization design of axial-flow impeller used multidisciplinary optimization software iSIGHT, and Sequential Quadratic Programming(SQP), a gradient optimization algorithm, and meanwhile ensured a constant design flow and head, and changed cascades dense degree of each airfoil section and size of airfoil placed corner to achieve optimal efficiency. Numerical simulation Software CFX was used for multidisciplinary analysis, N-S equation based on Reynolds-averaged and the standard k-ε model were used in the optimization process to predict head, efficiency and cavitation margin va-lue required of impellers. Performance curves of impellers with different hub/tip ratios were calculated by numerical simulation, and then the effects of hub/tip ratio on the hydraulic performance of axial-flow impellers with the same specific speed were analyzed. The results show that the larger the hub/tip ratio, the higher the efficiency of impellers, and the worse the cavitation performance, but the effects on cavitation performance are more significant, the biggest difference of NPSHR is 0.9 m, in contrast, the hub/tip ratio has less effects on efficiency, the highest difference between efficiency is only around 0.3%. The larger the hub/tip ratio, the larger the slope of head performance curve; the higher the maximum head, the larger the range of head of saddle area, at the same time, with the increasing of hub/tip ratio, the range of efficient area will become narrower, and distribute to the side of a small flow.
[1]杨敬江. 轴流泵水力模型设计方法与数值模拟研究[D]. 镇江:江苏大学,2008.[2]关醒凡. 轴流泵和斜流泵水力模型设计试验及工程应用[M]. 北京:中国宇航出版社,2008.[3]韩小林, 谭梅凤, 杨洲. 轮毂比对020Q84喷水推进轴流泵性能的影响[J]. 舰船科学技术, 2010, 32(1):59-62. HAN Xiaolin,TAN Meifeng,YANG Zhou.Influence of hub ration on the performance of 020Q84 water jet axial flow pump[J].Ship science and technology, 2010, 32(1):59-62.(in Chinese)[4]万韬. 轴流泵的参数化设计及数值模拟[D]. 武汉:华中科技大学,2013.[5]石丽建, 汤方平, 谢荣盛, 等. 基于 CFD 计算的轴流泵改型设计和效果[J]. 农业工程学报, 2015, 31(4): 97-102. SHI Lijian, TANG Fangping, XIE Rongsheng, et al. Design of axial flow pump modification and its effect based on CFD calculation[J]. Transactions of the CSAE, 2015, 31(4): 97-102.(in Chinese)[6]汤方平, 周济人, 袁家博,等. 轴流泵水力模型CAD/CAM[J]. 江苏农学院学报, 1998, 19(1): 1-5. TANG Fangping,ZHOU Jiren,YUAN Jiabo,et al.CAD/CAM of the hydraulic model for axial-flow pump[J].Journal of Jiangsu agricultural college,1998,19(1):1-5.(in Chinese)[7]汤方平, 王国强, 刘超, 等. 高比转数轴流泵水力模型设计与紊流数值分析[J].机械工程学报,2005,41(1):119-123. TANG Fangping, WANG Guoqiang, LIU Chao, et al. Design and numerical analysis on an axial-flow model pump with high specific speed[J]. Journal of mechanical engineering, 2005, 41(1): 119-123.[8]周济人, 汤方平, 石丽建, 等. 基于CFD的轴流泵针对性设计与试验[J]. 农业机械学报, 2015, 46(8):42-47. ZHOU Jiren, TANG Fangping, SHI Lijian, et al. Specific design and experiment of axial-flow pump based on CFD[J]. Transactions of the CSAM, 2015, 46(8):42-47.[9]YANG Zhengjun, WANG Fujun, ZHOU Peijian. Evalua-tion of subgrid-scale models in large-eddy simulations of turbulent flow in a centrifugal pump impeller[J]. Chinese journal of mechanical engineering, 2012, 25(5): 911-918.[10]YE Liang, LIU Zhongmin. Design of implantable axial-flow blood pump and numerical studies on its performance[J]. Journal of hydrodynamics, 2009, 21(4): 445-452.[11]毛虎平. 多学科设计优化技术现状及趋势[J]. 机械管理开发, 2008, 23(5): 54-56. MAO Huping. Present situation and prospect of multidisciplinary design optimization technology[J]. Mechanical management and development, 2008, 23(5): 54-56.(in Chinese)[12]樊江, 曾维维, 王荣桥, 等. 基于iSIGHT的涡轮叶片叶冠优化设计[J]. 航空动力学报, 2011,26(4):745-751. FAN Jiang, ZENG Weiwei, WANG Rongqiao,et al.Optimization design of the turbine blade shroud based on iSIGHT software[J].Journal of aerospace power, 2011,26(4):745-751.(in Chinese)[13]谢德正.轴流泵叶片的自动优化设计研究[D].扬州:扬州大学,2010.