Numerical Study On Thermal And Humid Environment Change Rule Of Excavation Face

Surrounding rock dissipation and wall moisture evaporation are the main causes of high temperature and high humidity conditions in the excavation face.The convective heat transfer and convective mass transfer between wall and airflow is the main form of heat and humidity transfer between airflow and wall.In order to study the variation law of thermal and humid environment in the excavation face and to guide the heat treatment more effectively,this thesis,based on the analysis of main heat source and influencing factors of the excavation face,uses the ?ep6aHb empirical formula and the Lewis relationship to determine the heat transfer coefficient and the mass transfer coefficient and the mathematical model of the heat and moisture exchange of the excavation face is established.The numerical simulation is used to simulate the thermal and humid environment of the excavation face.More,the influence of the main parameters on the thermal and humid environment of the working face is obtained.It is found that the heat and humidity exchange between the excavation face airflow and the surrounding rock and the heat and humidity exchange between the roadway airflow and the surrounding rock are obviously different from each other.So,in this thesis,the ventilation system is divided into "excavaion face" area and "roadway" area,and the simulation research is carried out respectively.In the area of the exavation face,the heat and humidity exchange between the airflow and the surrounding rock is limited.The climate and environment are mainly a hot and humid "small environment" created by the new wind.The heat and humidity parameters mainly depend on the outlet parameters of the air duct.The results show that in the roadway area,with the gradual increase of the return air temperature,the " air duct backheating " effect is an important factor leading to the high temperature environment of the excavation face.Finally,on the basis of simulation analysis,this thesis puts forward some suggestions on the improvement of hot and humid environment in the excavation face.