摘要
离心泵运行过程中其进口来流速度随时间的波动对泵的水力性能具有不可忽略的影响,该研究采用非嵌入式多项式混沌(non-intrusive polynomial chaos, NIPC)方法对进口来流速度扰动的不确定性进行量化分析,探究其对离心泵水力性能的影响。结果表明:随机来流速度对泵的水力性能具有较大影响,且不确定度越大,其影响越大;进口来流速度扰动会引起泵叶片压力面尾缘与吸力面上压力分布及叶轮流道内流场的变化,从而造成泵的扬程及效率的波动且波动范围较大;同时,来流不确定性的影响在叶轮内流场中的传播是非对称且非均匀的。不同工况下来流速度随时间的扰动对泵性能的影响有所差异,大部分工况下来流速度扰动会造成泵性能的下降,其中不确定度为5%时,扬程最大可下降0.4 m,效率下降3%。对不同工况下泵的进口流速不确定性进行量化分析,能够对离心泵在整个运行工况下的稳健性进行综合评定,为泵稳健性设计提供一定的基础。
Centrifugal pumps have been widely used in the national economy and defense industry.Their hydraulic performance can depend mainly on the geometric parameters(such as blade angle,blade wrap angle,impeller outlet width,and blade inlet edge)and operating conditions(such as rotation speed and flow rate).Among them,the fluctuation of the inlet flow velocity over time has posed a great impact on the hydraulic performance of the centrifugal pumps during operation.This study aims to quantify the uncertain perturbation of the inlet flow velocity using the non-intrusive polynomial chaos(NIPC).A systematic investigation was implemented to explore the effect of the perturbation on the hydraulic performance of centrifugal pumps.The results show that the random inflow velocity shared a significant impact on the hydraulic performance of the pump.Specifically,the greater the uncertainty was,the greater the impact was.There was a larger difference between the mean and original pressure distribution,as the uncertainty increased,indicating a more significant impact on the pressure distribution on the blade surface.At the same time,there was a much greater distribution of pressure coefficient on the blade pressure surface under velocity disturbance deviates from the original design,as the flow rate increased.Therefore,the impact of inlet flow velocity disturbance on the blade pressure surface was significantly larger under design and high flow rate than that under the low one.Once the uncertainty was 1%and 5%,the disturbance of inlet flow velocity caused significant vibrations in the pressure and velocity near the blade suction surface,while there was a relatively small impact on the flow field near the blade pressure surface and the impeller outlet.The fluctuation range was large when the uncertainty increased to 10%.The variation of the inlet flow velocity also caused significant fluctuations in the pressure of the impeller outlet,resulting in certain variations in the pump head and efficiency.Meanwhile,there was the asymmetric and non-uniform propagation of the inflow uncertainty in the internal flow field of the impeller.There was also the variation in the impact of inflow velocity disturbance over time on pump performance under different operating conditions.In addition,the disturbance of the inflow velocity under most operating conditions caused to decrease in the pump performance.Particularly,the head and efficiency decreased by 0.4 m and 3%,respectively,when the uncertainty was 5%.There was also a decrease in the head and efficiency of the pump under design conditions,compared with the reference model.But there were relatively small decreased values and the range of variation when the uncertainty was 1%.Furthermore,the head and efficiency of the pump increased at 0.2Qd in the design condition,compared with the reference model.Both absolute values of the mean and standard deviation were larger than before.The quantitative analysis of the uncertain inlet flow velocity can evaluate the robustness of the centrifugal pump under the whole operating conditions.
作者
陈学炳
杨博文
张人会
郭广强
杨军虎
CHEN Xuebing;YANG Bowen;ZHANG Renhui;GUO Guangqiang;YANG Junhu(School of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Fluid Machinery and Systems,Gansu Province,Lanzhou 730050,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2024年第12期77-85,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
甘肃省教育厅产业支撑计划项目(2021CYZC-14)
甘肃省教育厅双一流重点项目(057047)
甘肃省重点研发计划项目(21YF5GA077)
中央引导地方科技项目(23ZYQA0320)。
关键词
离心泵
流速
水力性能
不确定性分析
非嵌入式多项式混沌
centrifugal pumps
flow velocity
hydraulic performance
uncertainty analysis
non-intrusive polynomial chaos