以水为介质阻尼孔气穴流动理论和试验研究

针对水的汽化压力高、容易发生气穴的特点,应用气穴模型理论对阻尼小孔中以水作为工作介质时的流动特性进行理论分析.在此基础上,用可视化方法对阻尼小孔中的气穴流动特性进行试验,研究阻尼孔中的气穴发生过程,分析阻尼孔内径和长径比对气穴的影响.研究结果表明阻尼孔的气穴首先在进口部位产生,并随着两端压差的增大向出口推移.大长径比的阻尼孔相对小长径比的阻尼孔而言不容易发生气穴.在相同长径比的情况下,孔径大的阻尼孔相对孔径小的阻尼孔更容易发生气穴.研究结果对阻尼小孔的选择设计具有一定的参考意义.

THEORETICAL AND EXPERIMENTAL RESEARCH ON CAVITATON FLOW OF ORIFICES USING WATER AS WORKING MEDIA

Aiming at the high vaporous pressure and easy cavitation occurrence of water, the cavitation flow in orifices using water as working media is analysed theoretically by applying cavitation model. At the same time, the cavitation flow in the orifices is experimented with visualization method. Based on these, the growing processes of cavitation in the orifices are introduced and the influences of diameter and the ratio of length and diameter of orifices are analysed. The research results show that cavitation occurs firstly at the inlet of orifice and is gradually pushed to the outlet with the increasing of pressure drop across the orifice. Cavitation is more likely to happen in the orifice with larger ratio of length and diameter when the diameter is the same and with larger diameter when the ratio of length and diameter is the same.