Numerical Simulation And Experimental Study Of Multi-layer Gas Cooling Structure Based On Fluent

Because of the large scale,complex function and structure of highrise buildings,it is very difficult to extinguish and escape after a fire,and it is very easy to cause mass casualties and injuries.Therefore,developing safe and efficient escape equipment as soon as possible is an urgent problem to be solved in the field of high-rise building escape.As a shelter for trapped people,the fire rescue cabin of high-rise buildings can effectively meet the needs of trapped people to escape.The thermal insulation performance of the cabin structure is the key technology in the development of the fire rescue cabin.In this paper,a multi-layer gas cooling structure based on metal foil,insulating material and multi-layer copper tube is designed and fabricated by studying the mechanism of multi-layer heat insulation and heat transfer and combining with passive gas cooling technology.Its innovation lies in the application of multi-layer thermal insulation structure in the field of aerospace and Aeronautics in the thermal insulation layer of fire rescue cabin.Considering that the fire rescue cabin needs a long time in the high temperature environment,passive refrigeration technology is used to cool the thermal insulation layer by using low temperature gas,so as to prolong the effective thermal insulation time and ensure the safety of the cabin personnel.In order to study the thermal insulation effect of multi-layer gas insulation structure at high temperature,a high temperature test platform for thermal insulation performance was built.The cooling efficiency of each layer before and after adding aluminum foil and stainless steel foil at high temperature was tested,and the effect of low temperature gas on the temperature of each layer at different inner temperature was also tested.The simulation results were simulated by Fluent software,and the simulation results and test results were added into the test results.In addition,the effects of gas flow rate,temperature and ambient temperature on gas cooling effect under real fire conditions were simulated.The results show that adding aluminium foil can effectively improve the insulation efficiency of the insulation structure.The higher the heating temperature,the better the insulation efficiency.When the heating temperature is 800 C,the insulation efficiency can reach 55%.At the same heating temperature,the insulation efficiency of the insulation structure with stainless steel foil is lower than that of aluminium foil;the test results are basically consistent with the simulation temperature changes,and the numerical model It can truly reflect the complex process of fluid cooling,and provide theoretical basis for the design and improvement of thermal insulation structure;multi-layer gas structure can effectively reduce the temperature of thermal insulation layer;the faster and lower the gas flow rate,the lower the temperature of the inner layer of thermal insulation layer,the longer the low temperature can be maintained;at the same time,the faster the gas flow rate is,the slower the temperature rise rate of the outer layer is,and the temperature of the gas flow is outside.The higher the heating temperature of the outer layer,the faster the heating rate of the outer layer,but the smaller the cooling effect of the inner layer.