Calculation Method of Heat-transfer Coefficient in Working Face with Auxiliary Ventilation
|School||Henan Polytechnic University|
|Keywords||Local exhaust ventilation Merry speed Numerical Simulation Heat transfer coefficient|
With the increasing depth of coal mining , the heat injury problem is getting worse . To effectively combat heat harmful necessary to accurately predict the distribution of the thermal environment of the mine , the airflow temperature distribution directly affect the heat exchange between the rock surface and the airflow and , therefore, it is necessary to calculate airflow temperature downhole Face . Heading Face the local ventilation airflow temperature calculated especially need to know the the heading face the heat transfer coefficient and the heat transfer coefficient with the airflow speed . Usually the use of computational fluid dynamics software FLUENT solver to simulate the flow field on the tunneling face , to get the the heading face the Merry velocity distribution . Analog solver heading face velocity field , the general use of the wall function method to solving the flow field near the wall , the wall function requires the first layer next to the wall of the nodes in the logarithmic . Generally the first layer meshing grid node-to- wall distance are equal , as local ventilation Heading Face wind speed distribution is very uneven , so let the first layer of nodes in for LIL layer is impossible . In this paper, the calculation of the flow field of different near-wall grid spacing to determine the distance of the first layer of mesh nodes selected , heading face flow field close to the actual situation , to get of Heading Face romantic velocity field . By wall temperature operator heading face flow field solution under isothermal conditions , the heading face temperature distribution, according to the heat of the roadway and Merry exchange theory , combined with local ventilation the heading face Merry speed distribution , heading face no distribution of the dimensionless heat transfer coefficient .