| This research mainly focuses on finding and solving the inner liner crack issue which depend on the market and the company temperature change test.This paper focuses on a target of solving the inner liner crack issue.A CFD simulation model for the refrigerator heating process is established based on the theory of hydromechanics mechanics,heat transfer and finite element analysis.1.The working mechanism of refrigerator is analyzed and the refrigerator has been established according to the physical model of the refrigerator cracking phenomenon.The material parameters of the refrigerator is measured through the experiment.Refrigerating and heating environment of the refrigerator are calculated and transformed into finite element model boundary conditions and initial conditions.2.The experimental setup is built based on working environment of the refrigerator,and CFD model is built according to the experimental bench.Experiments and CFD simulations are taken simultaneously to analyze features of the refrigerator working.The axial fan working inside the refrigerator,which plays the role of increasing air circulation inside the cooling chamber.The heat transfer coefficient is calculated by simulation.3.The simulation model for steady state of refrigerator is established and the calculation is carried out.The temperature distribution is verified by the reasonable simplify of the model and a sensor is used to measure the temperature distribution of the refrigerator.The simulation results are in agreement with the theoretical calculation and the experimental results.The thermal stress of the steady state is calculated and the inner lining stress concentration points are found.4.An experiment in heating process is built and the flow field,temperature field and the structure field coupling are analyzed.The flow field and temperature field are analyzed and verified by theoretic formula of heat transfer and temperature test.The simulation result is consistency with the experiment and the error is less than 8%.The result indicates that refrigerator has no risk of crack.5.The refrigerator simulation model with oil on inner liner is built and the calculation is carried out.The simulation results show that the stress will increase with oil in the refrigerator but the stress far less than it’s yield stress.The stretching experiment with oil in inner liner show that the inner liner crack easily with oil on it.6.The crack reason of inner liner is analyzed through market and fracture mechanics principle.The inner liner is cut into pieces and observed by SEM.The crack reason of inner liner is founded.The inner liner crack easily in the thin wall and there are some cracks and holes in the corner of the refrigerator.7.The optimization suggestions are put forward.First,the hot forming process of the refrigerator is optimized through change temperature of the plate.Second,the refrigerator fillet sizes is increased to help reduce the corner stress concentration;third,the inner liner thickness is increased.The thickness of the refrigerator liner increase from 1.5mm to 1.8mm:Fourth,the location of the ribs are changed:fifth,material feeding back is changed to reduce shrinkage phenomena.Through a variety of methods the problem of refrigerator liner crack is successfully solved.This paper build the normal working,heating and cooling process models of the refrigerator through analyses of the experiment in heating process.The results of the analysis are verified by experiments.Finally,the reasons of cracking are found and the suggestions are proposed。This paper can provide reference for research on inner liner crack issue. |
