颗粒绕流圆管传热的数值模拟研究

摘要 干法粒化后的高炉渣颗粒余热回收工艺主要以空气为冷却介质，由于空气的比热容小从而导致热效率低，因此，提出用自流床余热锅炉来回收高温炉渣颗粒的余热.基于CFD软件，将流动的颗粒当作连续的黏性流体，建立了一个三维数学模型，对颗粒绕流圆管传热的过程进行数值模拟，并验证了模型的正确性，研究了颗粒入口速度、水入口速度以及水入口温度对余热锅炉换热效果的影响规律.数值模拟结果表明:增大颗粒和水入口速度，可提高换热效果；增大水入口温度，传热系数没有变化，但热回收率减小.
Abstract：At present， air is a commonly-used heat transfer medium to recover waste heat of slag particles in blast furnace (BF) after dry granulation， which has a low thermal efficiency owing to its low specific heat capacity. Therefore， using gravity bed waste heat boiler to recover waste heat in the high temperature BF slag particles was proposed. Considering the particles as continuous viscous flow， a three dimensional numerical model was built to simulate the heat transfer of BF slag particles flowing around tubes based on the CFD software of Fluent. The effects of the inlet velocity of particles and water， and the inlet temperature of water on the efficiency of heat exchanging in waste heat boiler were investigated. The simulation results show that the efficiency of heat transfer improves with increasing the inlet velocity of particles and water， and the heat recovery rate of the former drops. However， when the inlet temperature of water increases， the heat transfer coefficient keeps invariant and the heat recovery rate reduces.