基于空化时空分布特征的调节阀空蚀风险预测  

Prediction of cavitation erosion risk in regulating valve based on space-time distribution characteristics of cavitation

作　　者：张雨佳 刘秀梅[1] 李贝贝[1] 刘申 ZHANG Yujia;LIU Xiumei;LI Beibei;LIU Shen(School of Mechatronic Engineering,China University of Mining and Technology,Xuzhou 221116,Jiangsu China)

机构地区：[1]中国矿业大学机电工程学院,江苏徐州221116

出　　处：《华中科技大学学报（自然科学版）》2024年第6期71-79,共9页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51875559);江苏省优势学科平台资助项目。

摘　　要：针对煤液化工程中的关键设备高压差调节阀耐空蚀能力差、使用寿命短的问题,利用高速相机拍摄获取调节阀空化流场图像,提出空隙率λ表征气相体积分数、空隙率变化速率β表征空蚀风险指标,实现了调节阀空蚀破坏的准确预测.结果表明:空隙率数值与气相体积分数正相关;随着入口压力的增大,阀芯头部和喉部对应空隙率数值增大,空化得到充分发展向扩张段延伸并溃灭,调节阀内空化呈初生、发展、脱落和溃灭的周期性变化趋势.当空隙率变化速率β<0时,表示空泡处于溃灭状态,据此可以判断该处存在空蚀风险;随着入口压力的增加,附着型空泡溃灭位置较为固定在调节阀头部,是阀芯发生空蚀破坏的主要原因.游离型空化损伤区域随着入口压力增加逐渐向调节阀下游延伸,调节阀流道上方和下方空化损伤区域为非对称结构,下方的空化损伤区域整体超前于上方.Aiming at the problem of poor cavitation resistance and short service life in the regulating valve of the key equipment in coal liquefaction engineering,these images of cavitation flow field in a regulating valve were captured by a high-speed camera,the characteristic parameter void fractionλwas proposed for quantitative analysis of a gas-phase volume fraction,and the change rate of void fractionβwas also employed as the cavitation erosion risk to predict the cavitation damage on the regulating valve accurately.Results show that there is a positive correlation between the void fraction and the gas volume fraction.With the increase of inlet pressure,the void fraction at the spool head,the throat and the expansion section increase,cavitation develops fully and extends to the expansion section and then collapses.The cavitation in the regulating valve presents a periodic trend as birth,development,shedding and collapse.Furthermore,if the change rate of void fractionβ<0,it represents the collapse of cavitation.Therefore,the change rate of void fraction could be used to judge whether there is a risk of cavitation erosion.With the increase of inlet pressure,the attached cavitation is fixed at the spool head,which is the main reason for the cavitation damage of the spool.While the free cavitation damage area gradually extends downstream with the increase of inlet pressure.The cavitation damage area at the top and bottom part of the flow channel is asymmetric,and the cavitation damage area in the bottom part is overall ahead of it at the top part.

关 键 词：空化 调节阀 空隙率 空蚀破坏 风险预测 

分 类 号：TH137[机械工程—机械制造及自动化] O35[理学—流体力学]