Numerical Simulation And Experimental Study Of Solid Interface Thermal Contact Resistance At High Temperature

Thermal contact resistance is one of the important indicators to measure the heat transfer efficiency between contact interfaces.It is defined as the temperature difference at the contact interface divided by the heat flow at the contact interface.Scholars at home and abroad have carried out a large number of theoretical analysis and experimental research on thermal contact resistance,but most of the research work is based on the low and medium temperature environment,but there are few reports on the thermal contact resistance under high temperature environment.However,the high-temperature interface contact heat transfer phenomenon widely exists in aerospace,energy power,steel metallurgy,chemical industry and other fields,such as space vehicles,nuclear reactors,internal combustion engines,gasification reactors and other high-temperature equipment.Therefore,the research of thermal contact resistance in high temperature environment is of great significance to scientific fields such as national defense,energy and materials.Due to the complex heat transfer mechanism of the interface contact heat transfer problem,the interface thermal contact resistance is affected by many factors,such as contact pressure,interface temperature,contact surface morphology,contact material properties,and contact loading process.In this paper,the method of combining numerical simulation and experimental research is used to conduct an in-depth study on the thermal contact resistance of the solid interface under high temperature conditions.First,based on the high-temperature alloy GH4169 material,the mechanical and heat transfer numerical models of the contact interface under high temperature conditions were established,and the influence of radiative heat transfer on the contact interface under high temperature conditions was considered in the heat transfer analysis.Then using ANSYS software,based on the actual surface morphology and contour data of superalloy GH4169,a real contact model of rough surface was constructed,and the thermal contact resistance under high temperature conditions was simulated,and the contact pressure,interface temperature,The influence of surface emissivity and surface roughness on the thermal contact resistance at high temperature interface.Finally,the experimental scheme of thermal contact resistance under high temperature conditions was designed.Using the high temperature thermal contact resistance test system,the commonly used thermal contact resistance of high temperature alloy GH4169 and C/C composite materials was tested.According to the experimental test results,the numerical simulation results of superalloy GH4169 are compared,and the effects of contact pressure and interface temperature on high-temperature thermal contact resistance during loading and unloading are studied.The numerical simulation results show that the high-temperature thermal contact resistance decreases with the increase of contact pressure and interface temperature,and as the interface temperature increases,the effect of contact pressure on high-temperature thermal contact resistance gradually decreases.Under high temperature conditions,the thermal contact resistance decreases with the increase of the emissivity of the contact surface,but it does not change significantly at low temperatures.The high-temperature thermal contact resistance increases with the increase of surface roughness.Under the same conditions,the greater the surface roughness,the more obvious the thermal contact resistance is affected by the contact pressure and interface temperature.The experimental results show that the experimental test results are in good agreement with the numerical simulation results,the relative error between the two is less than 14%,and there is a tendency to gradually decrease as the contact pressure increases.During the loading and unloading of contact pressure and interface temperature,high temperature thermal contact resistance will have hysteresis effect.The amount of change in thermal contact resistance caused by hysteresis is related to the interface temperature and the mechanical properties of the contact material.