Research On Heat Resistance Of Ventilation With Heat And Moisture Exchange

With the gradual depletion of shallow resources,the number of deep mines in my country will increase.With the continuous increase of mining depth,the temperature of the original rock will continue to rise,and the problem of thermal damage will become more and more serious.Problems such as difficulty in ventilation caused by heat damage will become more and more obvious.In this thsis,the ventilation and thermal resistance caused by heat damage was studied.This thsis studies the thermal resistance during the normal ventilation period caused by heat damage,in order to clarify the generation mechanism,influencing factors and changing laws of the ventilation thermal resistance under the influence of the heat and humidity environment during the normal ventilation period,CFD software was used to analyze the gap between the roadway wall and the airflow during the normal ventilation period of the well under the basic ventilation parameters that the air velocity is 2m/s,the air flow temperature is 20°C,the roadway wall temperature is 35 °C,the air flow humidity is 80%,and the roadway wall humidity is 99%,the existing heat and moisture exchange phenomenon is simulated and studied.The thermal resistance and wind flow of horizontal roadway under the influence of 5 different ventilation parameters and 3 different roadway parameters are simulated and calculated.The result shows:When there is a temperature gradient or a humidity gradient between the wind flow and the roadway wall,the ventilation heat resistance will be generated.Both temperature gradient and humidity gradient are sufficient but not necessary conditions for thermal resistance.Compared with the dry ventilation environment,the high humidity environment will increase the thermal resistance by about 67% during the normal underground ventilation period.In the process of heat and moisture exchange between the air flow of the roadway and the wall of the roadway,the change of the direction of moisture transfer will not affect the wind velocity and temperature of the air flow at the outlet of the roadway heating area.Affected by the humid environment,when the temperature difference between the wind flow and the roadway wall is reduced from 35°C to 10°C,the thermal resistance will decrease by 3-4Pa.When the moisture transfer direction is that the roadway wall faces the wind and the humidity difference between the wind flow and the roadway wall is reduced from 90% to 10%,the thermal resistance will be reduced by 1.6Pa.When the moisture transfer direction is the wind flow to the roadway wall,and the humidity difference between the wind flow and the roadway wall is reduced from60% to 10%,the thermal resistance will increase by 1.8Pa.When the roadway friction resistance coefficient and roadway cross-sectional area change,the change of thermal resistance is less than1 Pa.During the normal ventilation period,the direction of moisture transfer between the air flow of the roadway and the wall of the roadway changes,which will affect the air flow in the roadway by about 10%.Under the condition that the heat and moisture exchange phenomenon is relatively stable,the roughness of the roadway wall and the change of the cross-sectional area will not have a significant impact on the air flow in the roadway.The thsis has 33 figures,36 tables,and 82 references.