Research On Coupled Ventilation System Of Fine Water Mist Spray Cooling In High Temperature Mines

The trend of mine mining is gradually developing to the deep,and the problem of high heat in deep Wells is increasingly serious,which has affected the safe and efficient production of mining areas.Under the condition of high temperature,the function is affected,the human metabolism will be disturbed,the human system will lose a lot of water due to high temperature,illness and even death,and the problem of heat damage seriously threatens the underground safe operation.Water spray cooling technology is economical,efficient,energy saving and environmental protection.Combined with underground ventilation system and refrigeration,it can be used for temperature regulation of underground roadway working surface.Aiming at the key issues of gas-liquid coupling cooling,this paper conducts theoretical analysis of gas-liquid two-phase flow coupling cooling,systematic experimental research and numerical simulation,and main research results are as follows:(1)The cooling mechanism of gas-liquid coupling flow is theoretically studied.The process of droplet diffusion coupled with air flow in the environment was studied,a gas-liquid coupled air flow model was built in a high-temperature mine,and the atomization mechanism of gas-liquid two-phase flow and the heat and mass transfer phenomenon of spray evaporation in the roadway were analyzed.Through the analysis of the droplet evaporation heat dissipation model,the deformation of droplet in different airflow and the rule of droplet evaporation with time were obtained.(2)An experimental system of gas-liquid coupling cooling was constructed,and the cooling effect of fine water spray coupling ventilation on high temperature environment was experimentally studied.The coupled cooling experiment system includes ventilation cooling system,spray cooling control system and related measuring device.Experimental parameters are selected to study the influence of different ventilation and spraying conditions on environmental cooling effect.The experiment shows that the introduction of water mist device under natural ventilation,reasonable droplet size and spray flow parameters can effectively improve the ambient temperature.(3)Study on the influence law of gas-liquid coupling cooling system in mine roadway.In order to improve the experimental research results and establish a three-dimensional model of the horizontal roadway in high temperature mine,the Fluent software is used to numerically simulate the gas-liquid two-phase flow field in the roadway in high temperature environment.The influences of different spray and ventilation parameters and coupling effects on the temperature,velocity and humidity field are analyzed and compared with the experimental results.The optimal parameters are selected to make the temperature and humidity of the mine cooling area within the reasonable range.The research shows that the conditions of wind temperature 298.15 K and wind speed 3m/s are the most suitable ventilation parameters.A fine water mist with a flow rate of 0.075kg/s is introduced under the ventilation condition,and the humidity increase can be controlled within the thermal comfort range of human body.Using a nozzle with small atomizing particle size can better improve the thermal damage environment,but the droplet temperature has no obvious effect on the spray cooling effect.(4)Based on the high temperature thermal damage of JC nickel mine as the research background,the coupled cooling scheme is implemented in the horizontal mine roadway.Field measurement and fuzzy analytic Hierarchy process(AHP)-information entropy method combined weighting method were used to analyze the effect of environmental cooling and human thermal comfort evaluation.The measurement results showed that the overall climate environment of the working face was significantly improved,and the temperature of the return air roadway could be controlled to 303.75 K,which was 5K lower than before the implementation of the cooling program.The evaluation results showed that the thermal comfort evaluation grade was comfortable.The goal of improving the working environment of high temperature mine and using the coupled ventilation system of fine water mist to prevent and control the heat damage is realized.