水下自激吸气式喷嘴脉冲射流的机理研究

项目名称： 水下自激吸气式喷嘴脉冲射流的机理研究

项目编号： No.51309099

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 水利工程

项目作者： 刘新阳

作者单位： 华北水利水电大学

项目金额： 25万元

中文摘要： 针对黄河调水调沙过程中的水库泥沙扰动问题，申请者提出了一种新型低压大流量射流喷嘴-水下自激吸气式喷嘴，通过在腔体周围布置吸气孔，实现喷嘴自吸气，达到提高冲击性能的目的。本项目以水下自激吸气式喷嘴为研究对象，采用数值模拟、试验和时频分析相结合的手段对其脉冲射流机理进行研究。建立气液两相流双流体数学模型，研究喷嘴内水气两相的三维非定常流动特性，包括射流剪切层内大尺涡结构的演化过程，水气两相流速、压力、能量和气相含气率的时空分布，监测点压力数值信号；开展水下射流冲击试验，测取吸气量和冲击信号，根据流动图像分析喷嘴内水气混合过程、气相运动过程和含气率；运用时频分析技术提取喷嘴冲击信号与压力数值信号的时频特征，分析信号时频分布与能量分布以及气相对射流剪切层不稳定过程的影响；建立喷嘴系统模型并分析喷嘴内部流动规律与冲击信号时频分布规律之间的关系，揭示喷嘴脉冲射流的机理，为喷嘴的进一步研究提供理论基础。

中文关键词： 水下；自激吸气；喷嘴；脉冲射流；机理

英文摘要： Aiming at the problem of sediment perturbation during water and silt regulation of Yellow River, the applicant puts forward a new jet nozzle with low pressure and mass flow,namely underwater self-excited suction nozzle. The nozzle realizes the automatic suction through the arrangement of the suction hole around the cavity,and reaches the purpose of improving the impact properties.The project regards nozzle as research object,the method of combining test research, numerical simulation and time-frequency analysis will be adopted to study the generation mechanism. The two-fluid mathematical model of gas-liquid two-phase flow will be adopted to study the unsteady flow characteristics for water-air two-phase in the nozzle, including the evolution of the large-scale vortex structures in jet shear layer, the spatial-temporal distribution of velocity,pressure,energy and air rate for the water-air two-phase flow,and the pressure numerical signal of internal monitoring points. The underwater jet impact test will be carried out, suction capacity and impact signal is got. The mixing process of water and air, air phase motion process and air rate are analyzed according to the flow images.The time-frequency analysis method will be adopted to extract time-frequency feature of the impact signal and pressure numerical signal of

英文关键词： underwater；self-excited suction；nozzle；pulsed jet；mechanism