水利水电技术（中英文）

三河口水利枢纽供水阀采用DN2000-16活塞式调流调压阀。为保证流量符合设计要求、阀门不发生气蚀振动破坏,确保工程安全,针对水头高、流量变幅大、工作条件复杂的问题,进行了调流调压阀的流场仿真分析计算和试验研究。首先建立三维仿真模型,选择合适的计算软件,根据设计流量率定流阻系数后,选择前半段开小孔、后半段开大孔的活塞开孔型式,进行流态仿真计算,包括流场分析、气蚀和振动分析计算。其次,按线性缩尺1∶5设计1台DN400模型机,分析论证模型机与真机的相似性。最后,按照计算参数设计加工一台DN400的模型机,通过试验验证其关键参数和流量特性与计算值的符合性,测量模型机上下游压力、流量等参数,测算其流阻系数、流量系数和流量-压力-开度曲线。结果显示:压力-开度-流量关系符合设计要求,流量/开度比呈直线分布,压力值相等情况下流量比与模型比呈平方关系;DN400模型机仿真分析计算结果与DN2000调流调压阀计算结果比较,流阻系数、流量系数比误差基本≤5%,基本达到相似性要求;与DN400模型机CFD计算结果对比后误差≤5%,试验和计算结果基本吻合,气蚀判定后没有气蚀发生,噪音小于95分贝。结果表明:流场分析计算所用软件是可靠的,DN2000调流调压阀具有良好的抗气蚀性能。通过试验和研究后,研究制定了"模型试验内容及验收标准"和"DN2000-1.6 MPa调流调压阀验收标准",为我国《调流调压阀设计导则》的制定奠定了坚实基础。

In Sanhekou Water Control Project, the DN2000 Piston Flow/Pressure Regulating Valve is adopted. In order to ensure that the flow rate is accord with the design requirement and the valve is not to be damaged by cavitation vibration for guaranteeing the safety of the project, the simulative analysis and the experimental study on the flow field of the flow/pressure regulating valve are carried out for the problems of high water head, large flow variation amplitude and complicated working condition. Firstly, a 3-D simulation model is established and appropriate calculation software is selected, and then a flow pattern simulative calculation, including flow pattern analysis, cavitation and vibration analysis and calculation, is carried out by means of selecting the hole-opening pattern of small holes for the front half of piston and large holes for the rear half of piston after calibrating the flow resistance coefficient in accordance with the design flow rate. Secondly, a DN400 model machine is designed with the linear scale of 1∶5 for analyzing and demonstrating the similarity between both the model machine and the real machine. Finally, a DN400 model machine is designed and manufactured according to the design parameters, and then the conformities between its key parameters and flow rate characteristics and their calculation values are verified through the relevant experiment for measuring the parameters of both the upstream and downstream pressures, flow rate, etc. of the model machine and calculating its flow resistance coefficient, flow rate coefficient and flow rate-pressure-opening curve. The result shows that the relationship among the flow rate-pressure-opening complies with the design requirement with the straight line distribution of flow rate/opening ratio, while the flow rate ratio and the model ratio exhibit square relations under the condition of the same pressure values. The calculation results from the simulative analysis made on the DN400 model machine are compared with the results from the calculation made on the DN2000 Piston Flow/Pressure Regulating Valve, from which the errors from the flow resistance coefficients and the flow rate coefficients are basically≤5%, and then the relevant similarity requirements are reached, while the errors after comparing with the results from the CFD calculation made on the DN400 model machine are≤5%, thus the results from both the experiment and the calculation are basically coincided and the noise is less than 95 dB without occurrence of cavitation after the relevant judgment. The study result shows that the software adopted for the calculation of flow field is reliable and the DN2000 Piston Flow/Pressure Regulating Valve has a better cavitation-resistant performance. Through the experiment and study, the relevant "Model Experiment Content and Acceptance Standards" and "DN2000-1.6 MPa Piston Flow/Pressure Regulating Valve Acceptance Standards" are established, which lay solid foundations for formulating the "Design Guidelines of Piston Flow/Pressure Regulating Valve" in China