The Study Of Heat And Mass Transfer Theory And Cooling Technology In The Shaft And Tunnel That In The High-Temperature Mine

With the development of mineral resources in the shallow depleted, mining has gradually developed to the deep. The phenomenon of high temperature of the ground, coal face and roadway head is inevitable. And mine heat-harm will be the sixth-largest disaster following the top five disasters as roof, gas, water, fire and dust. Moreover, the harm would exceed them. Therefore, research about the control theory and technology on high-temperature heat-harm mine is of great significance.In this paper, the theory about heat and mass exchange in high temperature roadway and the cooling techniques about coal face and roadway head were studied. The specific contents of the study and obtained research results are as follows:1. Contents of the study:Simplified the calculation methods of convection heat transfer about wet roadway surface. The methods about predicting airflow state parameters in high temperature mine. The calculation methods of mining face cooling load. Find the export wind parameters of the air cooler and the method used for installing the air cooler to ensure the cooling effect of the coal face and roadway head. The research and development of large enthalpy drop and large temperature drop mine air coolers.2. Methods of the study:Combining theoretical analysis and field test, analyzing the test data using MATLAB software.3. Main results of the study:(1) Through the introduction of Lewis relationship, linear representation of the partial pressure of water vapor and the latent heat of water, latent heat ratio coefficient and the roadway surface moisture coefficient, and do a reasonable simplification, put the convection heat transfer of wet-wall tunnel and airflow as the research object, get the simplified calculation formula of latent heat exchange and wet exchange capacity between the wet roadway and airflow in theory. And analysis obtained:at the standard atmospheric pressure, the latent heat exchange capacity is about 3.935 times than sensible heat exchange capacity in completely wet surface; in partial wet roadway surface the latent heat exchange capacity is related to degree of wetness, and it's about 0.2-1.57 times the sensible heat exchange capacity.(2) According to the shortcomings of that most of the existing prediction method on thermal parameters of mine air heating is integration of multiple factors and highly summarized into a single mathematical expression home and abroad, proposed a predict method using multiple associated mathematical models. The new established model's expression is simple and reliable and can be calculated by hand or be completed by calculation software with simple program.(3) Based on the problems that previously determining methods of mining face cooling load takes many complex factors into account and "the land area where the original rock temperature above 31℃is designated as first heat-damaged area, the land area which is higher than 37℃is designated as second heat-damaged area", proposed the simple calculation method "only calculation the surrounding rock and water body's emit heat where the original rock temperature exceeds 30℃as the heat cooling load of working surface".(4) Proposed the viewpoint that installed capacity of terminal air cooler should include three parts "inlet airflow cooling load, working space cooling load and transmission cold loss", established calculation model that calculation the inlet airflow cooling load and cold loss along the roadway, discussed a determine method about the states parameters of the air cooler exports and the air cooler installation position.(5) Demonstrated "put an end to the cold airflow's temperature rise in the course of transmission is impossible, but it is possible that put an end to the cold airflow's moisture absorption in the course of transmission, the loss of cold 1 gram water vapor was absorbed by per kg cold airflow is 2.5 time the loss of the per kg airflow's self temperature rise 1℃", come to a conclusion "reducing access to cold airflow in the amount of water vapor is more conducive to keep cold". So, we proposed a "isolate wet so to keep cold" new idea here, apply this concept to achieve the cold's long-distance transmission in the case of cold tube without insulation.(6) Design and developed the large temperature drop, large enthalpy drop, larger wind volume, strong drying ability spray chamber which can handling the air on the ground of 35-39℃high temperature to about 5-10℃, the temperature drop rate up to about 30℃, and the air enthalpy drop in the 90kJ/kg around, each spray chamber could condensate 1180kg of water from the airflow per hour (the treated flow rate of 700m3/min).(7) Developed one of the thermal damage control techniques that apply to the shaft in the mine construction period and long distance roadway heading face.4. The principal innovations of this paper:(1) Proposed a new method that represent the latent heat exchange capacity of water evaporation and wet exchange capacity in the roadway surface with airflow temperature and temperature difference, and through the introduction of the concept of coefficient latent heat, represent the wet roadway surface latent heat exchange capacity to multiples of sensible heat for the heat, all this simplified the existing complex calculation of roadway surface convection heat transfer and wet exchange capacity of the complex calculation.(2) Based on the principle of division about first heat-damaged mine and second heat-damaged mine, demonstrated that the coal face and roadway head where mine original rock temperature is below 30℃would not appear high-temperature behavior. Proposed following new method to simplify the calculation "only calculation the surrounding rock and water body's emit heat where the original rock temperature exceeds 30℃as the heat cooling load of working surface. "(3) Demonstrated "put an end to the cold airflow's temperature rise in the course of transmission is impossible, but it is possible that put an end to the cold airflow's moisture absorption in the course of transmission, the loss of cold 1 gram water vapor was absorbed by cold airflow is 2.5 time the loss of the airflow's self temperature rises 1℃", come to a conclusion "reducing access to cold airflow in the amount of water vapor, more conducive to cold". So, we proposed a "isolate wet so to keep cold" new idea here, apply this concept to achieve the cold's long-distance transmission in case of cold tube without insulation. (4) Connection the "isolate wet so to keep cold" concept, proposed that put evaporative cooling technology as auxiliary cooling measures in mine cooling system's cold long-distance transmission, so to achieve the secondary cooling of cold wind.