风琴管空化喷嘴流场数值模拟

 风琴管空化喷嘴是一种常见的空化射流喷嘴,利用喷嘴内部特殊结构形成产生空化效应,从而提高射流的打击效果,因此,研究空化喷嘴内部结构对形成的空化效应影响,有利于提高喷嘴的工作性能。本文利用多相流模型研究风琴管空化喷嘴,在出口压力为2MPa工况下,对不同入口压力下喷嘴的内流场进行了数值计算。结果表明,在正常工作压力8MPa情况下,喷嘴喉道位置出现局部低速区和低压区域,且空化位置出现在喉道截面突变位置。同时,研究了喷嘴喉道长径比和存在圆角情况下内部空化情况,发现增大喷嘴喉道长径比实际相当于增加了低压区域,有利于空化的产生;喷嘴喉道变径区域存在圆角会严重影响空化喷嘴的空化性能,且圆角半径越大,临界空化压力越大。

Numerical Simulation of Flow Field for Organ-pipe Cavitation Jet Nozzle

Organ-pipe cavitation jet nozzle is a common nozzle for cavitation jet, by using its internal special structure; the nozzle generates the cavitation effect in order to improve the percussion effect of jet. Therefore, the research on the structure inside of cavitation nozzle is able improve the nozzle performance. By using multi-phase flow model to study organ-pipe cavitation nozzle, on the conditions of the outlet pressure of 2MPa, for the different inlet pressure, nozzle inner flow field is numerically calculated. The results indicate that with the normal working pressure of 8MPa, nozzle throat position locates at local low speed zone and low pressure area, and cavitation position appears at the position of throat section mutation. At the same time, in the case of the nozzle throat long diameter ratio and existing corner, the internal cavitation is studied; the following conclusions are drawn: The increase of nozzle throat long diameter larger than it is actually is equivalent to increase the low pressure area, and is helpful for the generation of cavitation; that nozzle throat reducer area exists corner would seriously affect the cavitation performance of cavitation nozzle, and the larger radius is, the bigger the critical cavitation pressure is.