| In order to solve the heat stress under hot environment and alleviate the tense energy situation caused by the overuse of air conditioners,the liquid cooling garments emerged and gradually transferred to civil use from the special fields such as aerospace.The liquid cooling garment is mainly composed of two parts,one is the basic clothing with liquid cooling pipelines,the other is the cooling source system.This paper conducted theoretical research on the basic clothing of liquid cooling suits,explored methods to improve the performance of liquid cooling garments,and optimized the design of cooling source system to extend the working time of liquid cooling garments,then optimized the overall system and made them into products.Details are shown below:Theoretical heat transfer model of body-liquid cooling garment-environment was established.Heat loss of liquid cooling garment is related to the coolant flow rate,inlet water temperature,the length of the cooling pipeline,the number of tube channels,the physical parameters of the coolant,the thermal resistance of outside garment,and the contact ratio between tube and body surface.Cooling characteristics of liquid cooling garment were verified by three-dimensional simulation of body-liquid cooling garment-environment.The simulation also analyzed the influence of the number of tube channels on the average surface temperature and standard deviation of the body surface temperature.Designed orthogonal experiments with constant temperature water tank to explore the relationship between inlet water temperature,water flow rate,pipeline layout of the liquid cooling garment and the heat dissipation,heat dissipation efficiency and average surface temperature.The results showed that the inlet water temperature and tube spacing had a greater impact on the heat dissipation and average surface temperature,the water flow rate had a greater impact on heat dissipation efficiency.According to different environmental conditions,we could roughly adjusted the inlet water temperature and fine-tuned the water flow rate to improve the performance of liquid cooling garments.Considering the garment processing technology,it is suitable to adjust the distance between liquid cooling garment pipelines for 25 mm,the pipe length is about 14.4m,the coolant flow rate is 800 ml /min,and the inlet water temperature can be determined by the specific environmental conditions.Designed the experiment with ice to explore the influence of cold source inside the fanny pack and the heat insulation layer outside the basic clothing on the reference working time of the liquid cooling garments.The results showed that compared with the ice,the blue ice in the same mass as the cold source could extend the reference working time of the liquid cooling garment by 20%,and the silver fiber heat insulation layer could extend the reference working time of the liquid cooling garment by 42%.The material of the fanny pack is nano aerogel,which greatly improves the thermal insulation performance and effectively prevents the users from feeling uncomfortable when the ice melts and wets the fanny pack.Complete sets of real liquid cooling garments were established.The pipe length is14.4m,the pipe spacing is 25 mm,the outer diameter of the tube is 5mm,the inner diameter of the tube is 3mm,the water flow rate is 800ml/min,and the silver fiber insulation layer was added.Person wore liquid cooling garments and measure the temperature changes with infrared thermal imager.The results showed that the liquid cooling garment with 200 g ice can work continuously for 75 min. |
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