A Study On The Heat Transfer And The Intensity Of Q475 Engine Body

The engine body is the main part of engine which stands the great thermal load, andthe thermal load and thermal intensity have greatly affected the durability, reliability andeconomy of the engine. On abroad the study on thermal load has stepped into the domainon lubrication and deposit, which also affect the thermal load and thermal intensity ofengine as the rotary speed and gas temperature. The work has begun later in China. Thestudy about engine body and water jacket is much less, while more about cylinder liner,which is often simplified, especially the heat transfer between water jacket and cylinderliner. The heat transfer is often simplified to a single convection coefficient. But, in fact,the convection coefficients in the water jacket are not the same due to the velocitydifference in the water jacket. At the same time, the water flow in the water jacket willaffect the temperature distribution of engine body and water jacket, and the temperaturedistribution will also affect the water flow, that is to say, the water flow and heat transferare coupled.The engine body and water jacket model of Q475 engine is built in this paper. Thewater flow in the water jacket and heat transfer between engine body and water jacket areanalyzed by the FEA method. The velocity distribution in the water jacket andtemperature distribution of engine body and water jacket are got. Based on the result, thispaper discusses how the water flow affects the temperature distribution of engine bodyand water jacket.The mechanical intensity and distortion of the engine in two extreme working stationare calculated, so are the engine's thermal intensity and distortion with temperature load,and the results are reasonable. This paper has investigated the mechanism of the stressand distortion that the engine withstands both the mechanical load and temperature load,and made the numerical simulation. The result reveals that the thermal stress anddistortion is prominent in the engine body, and the mechanical stress is added to the bodyin some region.Based on the way that the water flow affects the temperature distribution of enginebody and water jacket, some changes are made to the engine body and water jacketstructure. The water flow and heat transfer are analyzed, too. The analysis result revealsthat the temperature distribution of engine body and water jacket is more helpful to theengine.