管道内喷雾蒸发冷却的数值模拟及优化设计

Numerical simulation and optimization of spray evaporative cooling in air duct

摘要:

为研究雾滴粒径、喷头间距、风速和喷雾比等参数的改变对管内喷雾降温蒸发效率的影响,采用DPM模型方法对送风管道内喷雾直接蒸发冷却进行数值模拟和分析．通过单因素和多因素正交试验模拟,得到各参数最佳工况．模拟结果表明:粒径、风速和喷雾比越小时,蒸发效率越高;喷头间距的最佳值,应根据饱和水气比、空气流速、喷头的喷出速度和喷射角度确定．根据模拟结果,考虑系统经济性,对雾滴粒径小于30 μm、风速1 m／s以下的工况,喷雾比下限为0.7,蒸发效率最高可达92％,饱和效率可达65％以上．

Abstract:

In order to estimate the influence of particle diameter,nozzle spacing, wind speed and the sprayed ratio on the evaporating efficiency,numerical simulation of direct evaporative cooling of spray in the air ductwas processed using discrete phase model (DPM).Through single factor analysis and multi-factors orthogonal method, the optimal operating conditionswereacquired. Simulation results showed that, the smaller diameter, wind speed and sprayed ratio generates higher evaporating efficiency. Anoptimum nozzle distance should be determined by saturated water-gas ratio, wind speed,injection velocity and injection angle. According to simulation results, considering the economyof the spray system, particlediameterunder 30 μm, wind speed under 1 m／s, sprayed ratio higher than 0.7, the evaporating efficiency could achieve 92％, with saturated efficiency higher than 65％.