| At present,the number of deep well mining in China is gradually increasing,and the problem of high temperature heat damage in the underground is also becoming increasingly prominent.Aiming at mine heat damage control,and combining cooling principle of air source heat pump and underground environmental conditions,a set of downhole air source heat pump cooling system was constructed by theoretical calculation and numerical simulation method.The air temperature change of the roadway before and after the system cooling and the cooling effect of the system were studied.The heat transfer coefficient of surrounding rock and airflow in different periods of roadway was analyzed by using the relevant theory of heat transfer in surrounding rock.According to the theory of heat balance,the air temperature curve of the roadway mainly under the influence of heat release from surrounding rock was obtained.According to the arrangement of the air source heat pump cooling system in the roadway and the cooling characteristics of the air source heat pump,the variation formula of the wind temperature after the system is cooled was analyzed and derived.The variation law of the air temperature curve under different air source heat pump cooling capacity,wind speed of roadway inlet and wall temperature of surrounding rock was analyzed.The influence of three factors on the cooling distance of the system was obtained: the larger the cooling capacity of the air source heat pump,the lower the wind speed of the inlet and the wall temperature of the surrounding rock,the longer cooling distance of the system;the influence degree of the three factors on the cooling distance is: air source heat pump cooling capacity > wall temperature of the surrounding rock > wind speed of the roadway inlet;when the air source heat pump cooling capacity is 54 640 W,the inlet airflow speed of the roadway is 1.42m/s,and the wall temperature of surrounding rock is 30°C,the maximum cooling distance of the system reaches 212.48 m.Through the numerical simulation by Fluent,the roadway ventilation model before and after the system cooling were established,and the influence of the air source heat pump cooling capacity,the air blowing angle of the air source heat pump outlet and the size of the air outlet on the cooling effect of the system was analyzed.The simulation results show that: the air temperature curve obtained before the cooling is in good agreement with the theoretical results and the cooling distance obtained after cooling is basically consistent with the theoretical results.In addition,the mixing process of the cold and hot airflow during the cooling process was supplemented in the simulation;it is concluded that the air blowing angle of the air source heat pump outlet is inclined downward by about 15° along the air inlet direction of the roadway,the larger the air source heat pump outlet,the greater the decrease in air temperature,the longer the cooling distance of the system. |
PDF Full Text Request