基于多相流数值模拟的环卫车集污罐结构优化

摘要

罐式环卫车罐体结构及流场特性是决定车辆作业性能的关键,某罐式环卫车气力输送系统壁面区域不合理结构无法提供有效扰流增加稀疏悬浮多相流能量耗散,导致不合理的内流场难以改善尘粒平衡特性实现重力沉降.借助CATIA与ANSYS-FLUENT工作平台建立集成气路管道和集污罐系统于一体的CFD仿真模型,分析不同结构形式降尘挡板对气路系统集污罐内流场分布的影响;为了分析罐体内颗粒运动轨迹及集污效果,基于DPM离散相模型进行了多相流分析,实现同时对气体及尘粒两相流体轨迹追踪.另外,引入逃逸率这一新指标定量评价集尘罐系统沉降特性.结果表明,未优化前35.1%的逃逸率减少至2.7%,沉降性能提高了32.4%.%The tank structure and flow field characteristics are the key factors to determine the performance of the road sweeper.The unreasonable structure of the wall area of a tank type sanitation truck pneumatic conveying system cannot provide effective spoiler to increase the energy dissipation of the sparse suspended multiphase flow, resulting in unreasonable internal flow field that is difficult to improve the dust particle balance characteristic to realize gravity sedimentation.To solve this problem, CATIA and ANSYS-FLUENT are used to build the tank Gas pipeline and dust collector system, and the influences of different structure types of dust baffles on the flow field distribution in the tank of the gas system are analyzed.In order to analyze the particle trajectory and effect of pollutant accumulation in the tank, based on the CFD simulation model, DPM discrete phase model is used to analyze the two-phase flow trajectory of gas and dust particles.In addition, the new index of escape rate is introduced to quantitatively evaluate the settling characteristics of the dust collector system.The results show that the rate of escape is reduced to 2.7%, while the rate of escape before optimization is 35.1%.In addition, the settlement performance is improved by 32.4%.