矿井巷道对流换热系数的现场测定

In-situ Measurement of Convective Heat Transfer Coefficient on Underground Airway Surface

对流换热系数是计算围岩壁面与风流之间热交换量的重要参数。根据矿井风流与围岩热湿交换理论,提出测算井下巷道平均对流换热系数的方法。并在现场进行实测,通过对实测结果的回归分析,得出U型钢支护、断面形状为半圆拱以及工字钢支护、断面形状为梯形的巷道平均对流换热系数的简化计算式。并且当风速一定时,U型钢支护、断面形状为半圆拱的巷道平均对流换热系数值比工字钢支护、断面形状为梯形的要小;在这两种巷道条件下,其平均对流换热系数都随平均风速的增加而增大。

Convective heat transfer coefficient is an important parameter for calculation of the heat transfer from surrounding rock to airflow.Based on the fundamental principle of heat transfer between airflow and surrounding rock,a method to measure and calculate the average convective heat-transfer coefficient on roadway surface is put forward and in-situ measurement was carried out at several coal mines.Simple formulas to calculate the heat transfer coefficient of U-steel support semicircle-arch shaped airway and I-beam support trapezoidal roadway are separately established based on the field test data.At the same air velocity,the convective heat-transfer coefficient of U-steel support semicircle-arch shaped airway is less than that of I-beam support trapezoidal roadway.But both of them increase with the increase of airflow speed.