Experimental Study On The Thermal Shock Of Diesel Piston

High-frequency and low-frequency thermal shock under different conditions, these are the main factors that lead to the thermal damage of piston. In this paper, high-frequency thermal shock of piston was studied by means of experimental way. The main research work was not focused on the theoretic way. So the new and complicated models were not developed. The main work in theoretic way was the analysis of the simulated results by means of the lumped parameter, 1 dimension plane wall and 2 dimension finite element models.In this paper, a multi-channel stored testing and measuring system (MSTMS) was established, the temperature and strain values under real operating conditions are also measured by this equipment. A laser heat thermal shock test bench was developed for the first time in China, and also the laser light beam space transform technology was used in the piston thermal shock experiment innovatively. These research works make steady base for the study of the thermal damage of the piston. The main content and conclusion in this paper were shown as following:1. In theoretic way, there are three different models: the lumped parameter model, 1 dimension plane wall model and 2 dimension model used for temperature and strain analyses of the piston. The influence of coupling factor and inertia factor in 1 dimension plane wall was also analyzed. The studies show that the simulated result of 1 dimension plane wall model with inertia factor is good agreement with the simulated result of quasi-stationary 1 dimension plane model. And the error between the classic Fourier heat conduction equation and the equation with the influence of coupling is only 1.8%. The affection of the material characteristic, load intensity, load cycle, initial temperature on the simulation results under the rectangle thermal shock model is also studied. The results shown that the load intensity is one of the most important among the parameters.2. Based on the above theory preparation, the 150 piston's dynamic thermal behavior under high-frequency thermal shock is simulated by using the three models. The simulated results show that the three models can simulate the piston's temperature variation quite well, but simulated results of the thermal stress are not agreement with the test data that gotten under the engine's operating conditions. This is due to the boundary constraint and the initial temperature of these models not agreement with the engine's operating condition. In conclusion, the boundary...