Numerical Simulation For Cabin Thermal Environment Of Capillary Radiation Heating System And Thermal Comfort Analysis

People spend more and more time in the car, which results that people pay more and more attention to the comfort of passenger compartment. Only making the in-car temperature meet the demand can not satisfy people’s more and more strict requirement for the thermal comfort of passenger compartment. The automobile air conditioning heating system mainly exchanges the heat by convective heat transfer, which may produce the phenomenon of lacking heat. So the thermal comfort of passenger compartment in winter is more unoptimistic. Besides, high levels of car ownership and the emission of high temperature exhaust gas increased the energy consumption and environment pollution. At the same time, the radiation heating device has been widely used in interior construction. This device mainly exchange heat by radiation heat transfer, and it has many advantages, such as high levels of thermal comfort, saving energy significantly, simple equipment and non-pollution. In order to improve vehicle energy saving and thermal comfort of passenger compartment, this paper try to apply the radiation heating to the car, and research the passenger compartment thermal environment under the radiation heating device and air conditioning heating respectively. It also evaluates the thermal comfort of the two thermal environments.Based on a simplified passenger compartment structure model, the heat transfer mechanism is analysed and the corresponding heat load in winter is calculated using heat transfer theory. Considering the car body’s thermal conductivity and convective heat transfer with air, it gets the heat transfer coefficient of each part of car body using the steady-state heat transfer method, then according to the energy conservation the heat load values under different operating condition are calculated. It also analyzes the influences of external temperature, speed of the car, thermal insulating layer, glass and air-gap to the heat load of passenger compartment.On the base of the above theoretical calculation, this paper puts forward a capillary radiation heating system for the car, and uses the computational fluid dynamics to research the the plow field of passenger compartment. It considered the influences of car body’s thermal conductivity, heat radiation of inside wall, the human body thermal regulation model and so on to thermal environment. The SC/Tetra software was used to generate mesh, set boundary conditions and compute flow field. The distribution of temperature, air velocity and relative humidity was obtained through numerical simulation. Based on the simulation results, it completed the analysis of passenger compartment thermal environment and evaluation of thermal comfort through the methods of theoretical analysis, data statistics and evaluation index.Through the research of numerical simulation, it obtained the radiation penal surface temperature that meets the human body thermal comfort demand, and the appropriate values of inlet air temperature and velocity. This paper provides basis for improving the passenger compartment thermal comfort, and lays the foundation for the correct application and promotion of radiation heating using in the car.