轮毂比对轴流式叶轮水力性能的影响
|
摘要
为了研究轮毂比对轴流式叶轮水力性能的影响,针对比转数为743的叶轮,采用4种不同的轮毂比进行优化设计,得到4副不同轮毂比的叶轮.轴流式叶轮的优化设计应用多学科优化软件i SIGHT,采用梯度优化算法的序列二次规划法SQP,改变各翼型断面的叶栅稠密度和翼型安放角的大小,保证设计流量和设计扬程不变,实现效率最优.优化过程中应用数值模拟软件CFX,采用基于雷诺平均的N-S方程和标准k-ε模型,预测叶轮的扬程、效率和必需汽蚀余量值.通过数值模拟计算得到不同轮毂比叶轮的性能曲线.分析了同一比转数下,不同轮毂比对轴流式叶轮水力性能的影响.结果表明:轮毂比越大,叶轮效率越高,汽蚀性能越差,但是轮毂比对汽蚀性能的影响比较显著,必需汽蚀余量最大差别达0.9 m,对效率的影响较小,最高效率差别只有0.3%左右;轮毂比越大,扬程性能曲线斜率越大,最大扬程越高,马鞍区扬程范围越大,同时随着轮毂比增大,高效区范围较窄,并往小流量侧分布.
To study the effects of hub/tip ratio on the hydraulic performance of axial-flow impeller,4impellers with different hub/tip ratios were optimally designed and the specific speed of these impellers are 743. The optimization design of axial-flow impeller used multidisciplinary optimization software i SIGHT,Sequential Quadratic Programming(SQP),a gradient optimization algorithm,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 standard k-ε model were used in the optimization process to predict head,efficiency and cavitation margin value 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,thehigher the efficiency of impellers,and the worse the cavitation performance. 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 for 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.
To study the effects of hub/tip ratio on the hydraulic performance of axial-flow impeller,4impellers with different hub/tip ratios were optimally designed and the specific speed of these impellers are 743. The optimization design of axial-flow impeller used multidisciplinary optimization software i SIGHT,Sequential Quadratic Programming(SQP),a gradient optimization algorithm,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 standard k-ε model were used in the optimization process to predict head,efficiency and cavitation margin value 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,thehigher the efficiency of impellers,and the worse the cavitation performance. 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 for 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.
引文
[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.(in Chinese)
[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.(in Chinese)
[9]YANG Zhengjun,WANG Fujun,ZHOU Peijian.Evaluation 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 axialflow 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i SIGHT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 i SIGHT 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.
[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.(in Chinese)
[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.(in Chinese)
[9]YANG Zhengjun,WANG Fujun,ZHOU Peijian.Evaluation 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 axialflow 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i SIGHT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 i SIGHT 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.