摘要
为了提高鱼友好型设计造成的轴流泵汽蚀性能下降,通过实验对比验证了采用ANSYS CFX数值预测原型泵及鱼友好型泵汽蚀性能的可行性,得到经过鱼友好型设计后,原型泵许用空化余量(性能参数下降3%)数值计算结果由3.5 m增加到9 m,难以满足使用要求。通过分析鱼友好型泵的内部流场特性,揭示了轮毂处涡旋的产生机理以及叶片进口冲角过大的原因,由此设计出抑制涡旋产生、更加符合流动特性的叶片截面翼型,并修正部分设计参数。数值计算结果表明:优化后泵内部流场流动平稳,翼型头部液流过渡良好,没有局部速度增量产生,轮毂侧流动贴合叶片表面,在吸力面也没有产生涡旋,鱼友好型泵的装置许用空化余量预测值降低到3 m左右,完全满足原型泵的使用要求。
Fish-friendly designs were done on a traditional pump which was effective for reducing fish mortality during passage through the pumping station. However,optimization designs which were good for fish-friendliness had disadvantageous effect on pump cavitation performance. With the aim of improving the cavitation performance of fish-friendly axial-flow pump,a commercial computational fluid dynamic software ANSYS CFX,which showed a fair agreement with the experimental results,was used to predict the cavitation performance. The predicted NPSHr,3%of original pump was increased from about 3. 5 m to9 m after fish-friendly designs were done,which was unacceptable for pump running. Therefore,the inner flow field characteristics were numerically analyzed and the result indicated that there was vortex generated next to the hub and the inlet angle of attack was unsuitable,which was the primary reason for cavitation inception. The vortex formation mechanism was discussed and the airfoil section near the hub was redesigned to restrain the vortex generation. Furthermore,the design parameters of other airfoil sections were corrected to make streamlines smooth and fit the profile of blades. The optimization and numerical simulation results showed that the flow field was stable and flow transition around the head of airfoil section was smooth without velocity increment. The streamlines near the blade suction side fit the surface and there was no vortex generated. By reducing the inlet pressure,the predicted NPSHr,3%value of optimized fish-friendly axial-flow pump was reduced to about 3 m,which was absolutely enough for pump running. The research result provided a complete design method for fish-friendliness andoptimization of hydrodynamic performance for axial-flow pump.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第4期15-21,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51479083)
江苏省产学研前瞻性联合研究项目(BY2015064-08)
江苏省高校优势学科项目1033000008(PAPD)
关键词
泵站
鱼友好型轴流泵
汽蚀性能
涡旋生成
数值分析
pumping station
fish-friendly axial-flow pump
cavitation performance
vortex generation
numerical analysis
