Numerical prediction of thermal environmental conditions in locally ventilated working places

摘要

This paper describes the construction of a mathematical model to predict thermal environmental conditions in a developing roadway with auxiliary ventilation. A 3-dimensional K — S turbulent flow model is used to simulate the airflow and the simultaneous transfer of heat and mass between the rock surfaces and the airflow in locally ventilated working places. A method is also developed to estimate the local heat transfer coefficients at the wall surface of the working face. A Finite Difference Method is applied to simulate climatic conditions in development roadway with a forcing auxiliary ventilation system. In the model simulations, the 3-dimesional heat conduction in surrounding strata rock, the heat and mass transfer at the airway walls, the heat and mass transfer between the airflow in the ventilation duct and that in the development roadway, and air leakage from the duct and the advancement of the working face are taken into consideration. The developed modeling algorithms and program are verified through the comparison of the simulated results with data obtained from in-situ measurements. The program can be used to predict the thermal environmental conditions in a working face during the design stage with satisfactory accuracy. It can also be used to evaluate the effectiveness of the measures taken to solve possible environmental problems prior to the start of development.