Temperature Field Analysis Of Automobile Passenger Compartment Based On Heat Balance Model

With the development of economy and society, the automobile is gradually becoming the most convenient and common mode of transportation in daily life. As drivers and occupants, people spend considerable amount of time per day in automobiles, and they desire the thermal environment of automobile passenger compartment to be more comfortable. Meanwhile, the automotive companies devote more funds and energy to the research on optimizing passenger comfort. One approach to optimize this process is by using numerical methods, as Computational Fluid Dynamics (CFD) and Computational Heat Transfer (CHT). By this means, thermal environment of passenger compartment could be predicted quickly and efficiently. Recently, more and more scholars devote themselves to the field. However, there are still many problems to be solved because of the complicated structure of passenger compartment, such as setting proper boundary conditions for solar radiation, establishing human thermoregulation model, calculating the heat load of inner cabin. In order to prompt the study, this paper makes an attempt at calculation of heat load of inner cabin and establishment of heat balance model of passenger compartment.Firstly, the heat environment of passenger compartment has been introduced systemically. The calculation of heat load has been analyzed in theory from two aspects which include the method of heat exchange between passenger compartment and external environment, and the mechanics of heat transfer. At present, the heat transfer through wall of car body is considered as conforming multi-layer for the purpose of simplified calculation during the progress of calculating heat load. This method of simplifying model results in several problems although. The wall of car body except windows and doors consists of outside plate, thermal insulating layer, inside veneer. In these solid layers, thermal is transferred in the way of heat conduction. However, there is air layer existing inside the wall of car body, namely, airspace. Inside the airspace, heat conduction, radiation recuperation and heat convection are all present. Therefore, it is not exact enough to calculate the heat load as before. During the process of calculating heat load in this thesis, computational heat transfer has been introduced to analyze the mechanics of heat transfer. Besides, the heat conduction, radiation recuperation and heat convection present inside the airspace are added to the simulation model. So that the heat load of inner cabin can be calculated accurately.Secondly, CFD and CHT are introduced to simulate the flow field of inner passenger compartment. Add the heat load calculated above to the simulation model, and then run the iterative computation. So that, the temperature field and air-flow organization of inner passenger compartment can be worked out. Finally, various kinds of tools are adopted such as theoretical analysis, sampling and statistical analysis to deal with the result gained from calculation. It is shown that the result is more reliable and accurate.