Highly Enhanced Piston Oscillation Cooling And Temperature Field Analysis

With the continuous improvement of engine power density and enhancement,the heat load on the piston is also increasing,and excessive heat load will reduce the reliability and stability of the piston,when serious,it will cause a series of problems.So,it is very important to reduce the thermal load of the piston,oscillation cooling is the most important way of piston cooling is widely used in piston cooling,therefore,it is very important for the cooling and design of the piston to study the flow and heat transfer characteristics of the piston during the oscillation cooling process.This article takes the elliptical cooling oil cavity of a high-strength diesel engine piston as the object,firstly analyzed the flow and heat transfer characteristics of the oil in the cooling oil chamber of the piston at the rated speed;then analyzed the heat transfer effect of the cooling oil cavity during the oscillation cooling process under different influencing factors;Finally,analyzed the results of the oscillation cooling of the cooling oil chamber are applied to the analysis of the piston temperature field.The main contents of this article are as follows:(1)Using a dynamic grid model and a dynamic boundary that converts the fixed oil inlet boundary conditions in the dynamic grid model into boundary conditions that vary with the crankshaft angle to compare the oil flow and heat transfer characteristics in the cooling oil chamber during the oscillation cooling process,and verify the feasibility of the moving boundary model from the calculation accuracy and calculation cost(2)Using three turbulence models to analyze the flow and heat transfer characteristics of the oil in the cooling oil cavity during the oscillation cooling process,and through a comprehensive comparison of calculation accuracy and calculation cost,select SST k-? model as the turbulence model used in this calculation.(3)Using dynamic grid model,respectively analyze the flow and heat transfer characteristics of the oil in the cooling oil chamber during the oscillation cooling process at different oil injection speeds and crankshaft speeds,and get the changes of the oil filling rate and the average heat transfer coefficient of the wall with the engine crank angle under various influencing factors.(4)Apply the above decomposition results to the temperature field analysis of the piston by coupling,and observe the effect of the oscillating cooling of the piston cooling oil chamber and the influence of different influencing factors on the piston temperature field by comparison.