Thermal Comfort Analysis Of Microbus Passenger Compartment Based On CFD

With the continuous development of the automotive industry, vehicle isbecoming an important part of people’s normal life. An increasingly high requirementfor the quality of the car riding thermal comfort is demanded. However, the methodsof traditional improving air conditioning power or other measures to increase the airconditioning output don’t have much sense for the increasingly nervous energyproblem. In order to maximize the saving energy consumption in summerair-conditioning cooling and winter heating, on the premise of guaranteeing the cabincompartment occupant thermal comfort, there must be an optimization on the designof the crew cabin decorated structure, air conditioning ducts and vent grille structure.So as to be able to provide effective guidance for the optimal design quickly, theremust be an appropriate evaluation criterion of passenger compartment thermalcomfort. It has very real sense for deep researching on the heat transfer mechanism ofCrew wall surface and the effective evaluation of thermal comfort.This paper firstly introduces the basic principle of the numerical simulation ofthe flow field, which includes CFD (Computational Fluid Dynamic) turbulence model,boundary treatment model and the buoyancy force. Then，selected the appropriatetemperature field analysis model for thermal comfort of the passenger compartment.Have being had a good understanding of the heat transfer process of thepassenger compartment temperature field, which includes the wall heat transfer theoryand the thermal resistance of heat transfer calculation. Taking into account thewindow frames, doors, pillars and other metal surface those extend directly to thecrew compartment internal，which called the penetration phenomenon of thermalbridges. Calculated the thermal resistance of each cabin wall by different wall heattransfer condition, this make it more precision and accuracy for the calculation ofthermal resistance and temperature field.As the automobile passenger compartment heat temperature field is combinedwith conduction, convection, radiation, forced convection and natural convection ofhighly complex flow field, moreover, the lack of traditional thermal comfortevaluation criterion exist, such as much more parameters, the complex calculateprocess and the narrow applicable range. With the basis of thermal balance theory andthe indoor-related evaluation of existing buildings, this paper has been Constructed a new evaluation of the cabin compartment thermal comfort standards, which is calledthe ACS-DR criterion. This method has less calculable parameters, the simplecalculate process and widely application range. According to this research, it has beenproved that the new standards could match the experimental thermal comfortevaluation of microbus very well. Moreover, the new evaluation criterion has beenproved to be better and more applicable to the highly inhomogeneous transienttemperature field than the traditional evaluation criterion such as Fanger’s thermalbalanced theory, which is called the PMV-PPD criterion.Finally, by integrating the new evaluation criterion theories with the practicalvehicle thermal comfort development, and apply the new evaluation criterion to amicrobus passenger compartment thermal comfortable model, which is beingdeveloped. The results show that it makes greatly advantage to the cabin compartmentheat temperature field by using the new evaluation criterion, which can provideengineering advice for rapid geometric optimal design of the air conditioning systempiping, grilles institutions and the trim of cabin. All of these can greatly saving thedevelopment time for cars, furthermore, this can provide a kind of guidance directionfor reducing energy consumption on cabin development.