Temperature Field Of Heat Regulating Zone In Surrounding Rock Of The High Geothermal Roadway And Heat-regulating&Cooling Mechanism Of Heat-insulating Support Structure

Nowadays,with the normalization of deep coal,high temperature thermal hazards in mines have become inevitable natural disasters in deep mining.In the face of increasingly severe high temperature prevention and control work,the use of thermal insulation support structure to assist cooling technology emerged as the times require.However,the technical and theoretical systems of heat transfer model,influencing factors analysis,thermal insulation scheme design and so on are not yet perfect,and the popularization of thermal insulation support structure technology has been restricted.Based on the energy theory,thermodynamics and fluid mechanics analysis of the heat transfer model of the surrounding rock-insulation support system,the finite difference equation of the surrounding rock-support system under one-dimensional unsteady state is established.Based on physical model test and numerical simulation,the influence of ventilation time,thermal conductivity coefficient,temperature difference,thickness of thermal insulation layer and thermal conductivity coefficient on the temperature field of surrounding rock thermostat is discussed.The main conclusions are as follows:(1)Based on the similarity theory,the model test of surrounding rock temperature field in deep mine is constructed,and the distribution and evolution law of surrounding rock temperature field in deep mine are explored.After roadway ventilation,the heat regulating circle of surrounding rock extends from shallow to deep,and finally tends to be stable;dimensionless parameters ? and Fo decrease logarithmically,dimensionless parameters ? and R increase exponentially.(2)Based on the numerical simulation and analysis of the evolution law of surrounding rock temperature field under different factors,it is found that the thermal insulation effect of insulation structure is to delay the heat transfer from surrounding rock to roadway by reducing the sudden change of surrounding rock temperature gradient.It is found that the radius of heat regulating circle is positively correlated with ventilation time,thermal conductivity coefficient of surrounding rock and roadway section,but not with temperature difference.Temperature gradient is negatively correlated with ventilation time and thermal conductivity coefficient of surrounding rock,and positively correlated with temperature difference.(3)Based on the numerical simulation of the evolution law of the temperature field of the heat-regulating ring in surrounding rock under different parameters of the thermal insulation support structure,the results show that the radius of the heat-regulating ring is inverselyproportional to the thickness of the thermal insulation layer and the thermal conductivity is proportional,and the thicker the thermal insulation layer,the more obvious the cooling and thermal insulation effect is,but the thermal insulation capacity tends to be saturated with the increase of the thickness.Through cost analysis,it is determined that long-term use of thermal insulation support can greatly save costs.