Simulation And Analysis Of Flow And Heat Transfer In A Side-mounted Heavy Duty Diesel Engine Cabin

With the application of high power density diesel engine,the heat load of engine becomes higher as a result,which means a corresponding enhancement to the requirement of the cooling system.However,the engine compartment space has hardly changed,so the heat-dissipation problem becomes more and more prominent.In this paper,CFD is utilized to simulate the streaming and heat-dissipation of power cabin,and the heat dissipation characteristics of the engine cabin are systematically studied.Firstly,physical models and mathematical models of the radiator and intercooler of a side-mounted heavy-duty engine are established,the grid meeting the quality requirement and boundary conditions set for different conditions.Then,coupled calculation of cooling air flow and heat transfer of engine cooling module in the cabin is carried out.Meantime,effectiveness of the radiator and intercooler calculation models are verified.Secondly,this dissertation conducts the optimization of size and layout of the cooling module to improve the cooling performance under the condition of limited space.Because the original cooling system of the engine can’t meet the heat dissipation needs and cause the engine’s overheating and performance degradation,the heat dissipation area of the radiator needed for the heavy engine is first calculated based on the theory.Then,quantitative calculation of temperature field and flow field under different height of intercooler is conducted and the results show that the increase of intercooler height cannot infinitely increase the cooling effect.There exists an intercooler height corresponding to the best heat dissipation effect,which with higher heat dissipation effect can be achieved with smaller dissipation area.The heat dissipation effect of intercooler and radiator in the form of the up and down layout is better than the before and after layout structure.In the meantime,the radiator maintains the original radiating effect under the condition of about 40% reduction of the cooler and radiator material,and the cooling effect of the intercooler increases by24%.The results confirm that the upper and lower layout can effectively improve the utilization rate of materials,achieve better heat dissipation effect with smaller heat dissipation area.Lastly,this dissertation analyzes the flow characteristics of power compartment under idling,maximum torque and high speed conditions,and evaluates the heat dissipation characteristics according to temperature nephogram,3D streamlines,flow distribution and other aspects.The results find that the influence of the heat problem is mainly concentrated in the hot reflux phenomenon and flow leakage.Aiming at these problems,specific improvement scheme is put forward.