新型气溶性射流喷嘴设计与数值模拟

Design and Numerical Simulation of Novel Aerosol Jets Nozzle

针对传统高压水射流清洗耗水量大,能耗和运营费用高、清洗后的废液需要处理才能达到环保要求的缺陷,提出了新型射流清洗方式—气溶性射流.对新型气溶性射流喷嘴进行了结构设计,得到了喷嘴混合室直径、喉部直径、出口直径、收缩段长度以及扩张段长度等关键参数,并对新型喷嘴内外气液二相流场进行了深入计算与分析.结果表明,气液二相流雾滴在喷嘴轴线上速率随气流入口压力增大而增大,在喷嘴喉部速率变化率最大,在喷嘴出口处速率达到最大;当扩散角为10°时,射流扩散较慢,内部扰动和摩擦损失较小;当收缩角为30°时,气液二相流流动性较好,能量损失较小;粒径较小雾滴沿轴线方向速率变化较大,当喷射距离为35mm时,气液二相流雾滴速率达到最大值.

A new type of aerosol jets cleaning was proposed for the many defects of traditional high- pressure water jets cleaning, such as high water consumption and energy consumption, high operating costs, the waste liquid need to be treated after cleaning in order to meet environmental requirements. The structure of the novel aerosol jets nozzle was designed, and the diameter of the nozzle mixing chamber, the throat segment, the outlet, the length of the contraction and the length of the expansion segment and other key parameters of the nozzle were obtained, at the same time the gas-liquid two phase flow fields inside and outside of the novel nozzle were calculated and analyzed deeply. The results showed that, the speed of the gas-liquid two phase flow The droplets changed on the jets axis of the nozzle was increasing by the growth of the air inlet pressure. rate of the jets speed was the largest at the throat segment and the jets speed reached the maximum on the outlet of the nozzle. When the nozzle convergent angle was 10°, the jets diffusion was relatively slow, and it had less disturbance and friction losses;When the nozzle divergent angle was 30°, the gas-liquid two phase flow had good fluidity and small energy loss. The speed of smaller particle size droplets along the jets axis changed greatly. The speed of gas- liquid two phase flow reached its maximum when the jets distance was 35mm.