Research On Thermal Insulation And Application Simulation Of High Temperature Vacuum Insulation Panel

Vacuum Insulation Panel(VIP)is a kind of super insulation material.Due to the extremely high vacuum degree in the insulation panel and the filling of loose and porous core material,it has a very low thermal conductivity,and the thermal insulation performance is far better than traditional insulation material.But the temperature aimed at the high temperature pipe outlet is higher and more obvious,the environment of interface is very bad,it often need to remove the maintenance,resistance to high temperature is put forward for pipe interface thermal insulation material,good heat preservation performance,high mechanical properties,wear resistance,long service life,convenient and simple multiple demands disassembly,the traditional VIP can't meet its application environment.Through exploring the preparation process,heat insulation performance and application performance of the high temperature VIP,it can effectively make up for the defects of the traditional VIP,improving its comprehensive performance,and broaden its application scope,especially in the heat insulation application of high temperature pipe joints.The heat insulation performance of high temperature VIP not only depends on the composition,morphology,fiber diameter and single layer thickness of the ceramic fiber cotton paper core material itself,but also the type,thickness,size of the film material,as well as the choice of packaging technology and parameters.This topic is based on the insulation performance study of ceramic fiber cotton paper core material,by changing the membrane material type,thickness,size and packaging process of preparation of different high temperature VIP,and tested coefficient of thermal conductivity,analyzing these factors on the properties of high temperature VIP to insulation effect,optimizing preparation process and parameters optimization of high temperature VIP,and put forward experiment guidance and theoretical support for high temperature VIP design development and practical application,then by using COMSOL software to analogue simulate application of VIP insulation cover in high temperature heat pipe joint,evaluating the effect of heat insulation,Some constructive suggestions on the application of high temperature VIP were put forward.The main research works and results of this paper are as follows:(1)Optimized the core material composition of ceramic fiber paper.The heat insulation property of ceramic fiber paper core material was studied,and the influence of fiber diameter,surface density and adhesive content on the heat insulation properties of ceramic fiber paper core material were analyzed.When fiber diameter is 1?m,surface density is 70g/m~2,glue content is 30%,the thermal insulation performance of ceramic fiber paper is the best,it can be optimized as core material for high temperature VIP.(2)The preparation process of high temperature vacuum insulation plate was optimized.This paper analyzed the influence mechanism of film material's gas release and barrier,type,thickness and size on thermal conductivity of high-temperature VIP,studied the influence of packaging technology on long-term thermal insulation performance of high-temperature VIP,and explored the influence law of core material thickness on high-temperature VIP insulation performance.Results show that the membrane material with thickness of 1mm austenitic stainless steel,the core material selects 40 single layer thickness of 0.25mm ceramic fiber paper,selection of high temperature VIP size 400mm×400mm,selection of laser welding power 2.8 kW,vacuum 0.1 Pa,high temperature VIP insulation performance is optimal,450?heat conductivity is 0.042 W/(m·K).(3)COMSOL software was used to simulate the structure of VIP for high-temperature pipe joints in combination with engineering practice,For common conditions,the temperature is 450?,sodium velocity of 2.5 m/s fluid medium of high temperature pipe,to observe the heat flux distribution and temperature of the heat pipe thermal module numerical,learn that this topic developed high temperature vacuum insulation panel can be used for the preparation of high temperature pipe joints with thermal insulation structure,good heat insulation effect,it can be widely used in engineering practice.