Simulation Of Flow And Heat Transfer Between Air Cooling Garment And Surface Space

With the reduction of surface mineral resources and increase of mine mechanization,the mine will go deeply,and the heat damage problem will become more and more serious.Mine heat damage will become another major disaster in coal mines,which will seriously affect the working efficiency of underground workers and the operation of related equipment,thus affecting underground safety production.In order to ensure the thermal comfort of workers in mine and create a safe production environment,large-scale refrigeration equipment with individual cooling technology has received widespread attention.Individual cooling technology is to achieve the regulation of human thermal comfort by letting workers wear cooling garments.It can avoid problems such as heat stroke and shock caused by overheating in the labor process,improve work efficiency and protect workers' health.Research on the comfort of cooling garment is quite rich,and different forms of air cooling garment have corresponding working characteristics.Under the current environment of deepening reform,industrial optimization and upgrading in China,the humanized management of workers has received more and more attention from enterprises.Therefore,mining companies are in urgent need of cooling suits with stronger comfort and lower cost.The air cooling garment with compressed air as the cold source has the advantages of easy cleaning,light weight and good cooling effect.It is worth our further study.This thesis studies air cooling garment with compressed air.The contents are mainly as follows:(1)A space heat transfer model for air cooling garment was established.According to the heat transfer path in air cooling garment,the heat transfer convection,evaporation and radiation were studied based on the human body heat balance equation.At the same time,the microspace theoretical heat transfer model was established.Through the heat transfer analysis of the pipeline unit,the theoretical equations between the outlet airflow temperature and skin temperature,ambient temperature are derived.(2)A micro-space model of air cooling garment was established,and the corresponding laws of micro-space parameters and skin temperature were simulated.Studies have shown that the average temperature of the micro-space and the average skin temperature have a high correlation with the ambient temperature.The simulation results were compared with the experimental results,showing that the experimental values of the average wind speed in the front,rear and left sides are close to the simulated values.With the environmental temperature rising,the temperature difference between the inside and outside of the front,rear,left and right parts is basically declining.At the same time,the temperature of each part of the upper body trunk obtained by simulation and experiment basically increases,and the fluctuation range of both is small.Relative error is within an acceptable range.At the same time,the theoretical comparison between simulation and experimental results is carried out.The error is within 1 °C,and it is acceptable.Overall,the simulation and experiment have a good consistency.(3)The simulation was carried out on air cooling garment with micro-pore spacing of 20 mm,30 mm and 40 mm respectively.Studies have shown it should be optimal under actual conditions when the micro-pore spacing is 20 mm.At the same time,through the simulation of different branch pipes number,the 6 gas supply branches are better than 10 gas supply branches in actual situations.Based on the above results,an optimization scheme for air cooling garment is proposed.