颗粒帘换热器中气粒两相换热特性实验研究

Experimental Investigation on Heat Exchange Characteristics Between Gas andParticle in a Particle-Curtain Heat Exchanger

根据某1 t/h燃煤工业锅炉空气预热器的热力参数,设计并搭建了一套颗粒帘空气预热器模拟实验系统,研究了不同进气温度Tg0(150~300℃)、进气速度Vg0(0.9~1.5m/s)、颗粒帘进口厚度b0 (60~180 mm)、颗粒粒径dp(150~212μm)以及不同颗粒质量流量ms (550~2150 g/s)工况条件下热空气与进口温度tp0=20℃的硅砂颗粒帘间的换热特性。结果表明:影响颗粒帘换热器中气粒两相换热特性因素的重要性次序为进气温度、进气速度、颗粒质量流量、颗粒粒径、颗粒帘进口厚度;换热端差最低可至4.5℃,最大可达87℃;颗粒帘及颗粒帘出口气流的温度沿颗粒下落方向在前期上升迅速(186~475℃/m)而后期上升比较缓慢(60~108℃/m),并且在0~0.5 m和0.5~1.0 m的高度范围可分别用线性和对数方程来描述。

A particle-curtain-based air heater experimental modeling device is designed and built based on an air heater of a 1 t/h coal fired industrial boiler,and on this device,heat exchange characteristics between hot air and silicon sand particle of 20℃at inlet of the curtain are investigated under different conditions such as inlet air temperatures Tg0(150~300℃),inlet air velocity V0(0.9~1.5 m/s),particle-curtain’s inlet thickness b0(60~180 mm),particle diameter dp(150~212μm)and particle mass flow ms(550~2150 g/s)and the results show that:the sequence of factors according the importance influencing heat transfer between particle and air in the curtain are inlet air temperature,inlet air velocity,particle mass flow,particle diameter and inlet thickness of particle curtain;and the temperature between air at the inlet and particle at the outlet range from 4.5℃to87℃,and temperature of particles and that of air at outlet of the curtain increase promptly(186~475℃/m) but slowly(60.23~108.43℃/m)at the initial and later stage of falling curtain,respectively,and these temperatures can be described with linear and logarithm equations between the height of0~0.5 m and 0.5~1.0 m of the curtain,respectively.