Analysis On Internal Flow Characteristics And Heat Dissipation Performance Of The Engine Cab Of An Extended-Range Middle Bus

In this paper, the inner and outer field coupled computational method of CFDsoftware is used to simulate the inner flow field of engine cabin of an extended-rangemiddle bus which is newly developed by some company. On this basis, the inner flowfield characteristics and heat dissipation performance of engine cabin are analyzed andsome structural improvements are put forward to achieve good results.Besides of the engine, the engine radiator, the intercooler, wheels and girders, theengine cabin model of extended-range middle bus contains a generator, a generatorradiator and various controllers. There are two cooling systems in the engine cabin ofthe middle bus studied in this paper. The generator located behind the engine is nearthe high-temperature engine and exhaust pipe. By removing the small thin tubes andwire harness, the geometric model is reasonably simplified. In order to make the finiteelement model and the actual model coincident, the finite element model is built by thesimplified geometric model in the pre-processing software Hypermesh.The finite element model is solved by the software FLUENT. The heat dissipationperformance of generator radiator has some risks in conditions of10km/h uniformclimbing and60km/h uniform driving. There are local hot air reflux problems andmutual influence between the engine radiator and the generator radiator in the enginecabin. The influence of high temperature exhaust pipe is especially serious forgenerator. For the problems identified, some structural improvements on theunderhood air-inlet grill, the position and shape of bumper beam and the frontmudguard are made. The air inlet hole is opened upon the foglight and the air damskirt is added to proper position. The simulation analysis is made for the improvedmodel. The results show that the improvement scheme obtains the expected effects inconditions of idle speed, uniform climbing and uniform driving. And both the internalflow field and heat dissipation performance of engine cabin can meet the designrequirements.