Simulation of Thermal Environmental Conditions in Heading Face with Forcing Auxiliary Ventilation. Control of thermal environmental conditions in locally ventilated working place. 1st Report.

Abstract

Numerous studies have been made to control the climate conditions in underground mines, but most of them are concentrated on a single roadway with through airflow, and those on the simulation of heat problems in developing roadway with local ventilation are very few. Therefore it is necessary to establish a proper method to simulate the thermal environmental conditions within the working face with auxiliary ventilation for controlling the thermal climate there effectively.As a basic study on control of the thermal environment in working face with auxiliary ventilation, the CFD method is employed to simulate the transfer of heat and moisture between rock surface and the airflow at a heading face with forcing auxiliary ventilation. Based on the simulation results, the distribution of local heat-transfer coefficient and its relationship with airflow rate, variation of heat transfer flux from the strata to the ventilation air with time and wetness fraction, the distribution of rock temperature and its variation with time elapse are discussed in the paper.The study provides an important basis for establishing a proper method to predict the thermal environment conditions on locally ventilated working places.

In Situ Measurements and CFD Numerical Simulations of Thermal Environment in Blind Headings of Underground Mines

“…Numerous studies have been carried out on the correlation between heat-transfer coefficient and the Reynolds number in a straight pipe with through airflow. Gao et al recommended the following Equation (6) to calculate the heat transfer coefficient [13]:…”

“…The local heat transfer coefficient varies with location in a wide range. Gao et al suggested that the dimensionless heat transfer coefficients (h/h 0 ) of roof, side wall, floor and mining face were 9.7, 5.1, 3.5, and 6.8, respectively, with the average of 5.6 [13]. Hence, the heat transfer coefficient can be determined at 4.5 W/(m 2 •K).…”

“…Gao et al employed the finite volume method for simulating the airflow velocity and temperature fields in a heading face. They obtained the distribution of heat transfer coefficient in the heading face [13]. Sasmito et al developed a three-dimensional blind heading model for studying the effects of the ventilation flow rate, cooling load, virgin rock temperature, and the heat rejection from mining Traditionally, researchers mainly adopt the following three methods for examining the thermal environment in blind headings: in situ measurement, laboratory experiment and numerical simulation [8].…”

Prediction of Climatic Conditions in Developing Roadway with Forcing Auxiliary Ventilation System. Control of thermal environmental conditions in locally ventilated working place. (2nd Report).

“…The method to determine the heat transfer coefficient on smooth rock surface in working face by CFD simulation was developed in the first report (Gao et al, 2002a). Because the surface of the roadway is usually not smooth or roughened with supports, it is necessary to determine the magnitude and distribution of local heat transfer coefficient on rough surface of working face.…”

“…As a basic study on the control of the thermal environmental conditions in working face with auxiliary ventilation, CFD method was used to simulate the transfer of heat and moisture between rock surface and the airflow in a heading face with forcing auxiliary ventilation in the first report of the authors (Gao et al, 2002a). On the basis of the developed model, the distribution of local heat transfer coefficients in working face had been elucidated.…”