| Improving the design and analysis efficiency of refrigerator, and reducing the energy consumption are important subjects in refrigerator industry. Aiming at the two points, following research work is conducted.Firstly, dynamic simulation model is built according to single-system direct cooling refrigerator with three departments, simulation software is developed to calculate refrigerator performance (energy consumption, operating rates, temperatures in compartments). This software can be used in performance evaluation for existing refrigerators or design optimization for new refrigerators.Next, to get steady state natural convection flow field and temperature field in freezer compartment, numerical simulation model is built. With this model, optimized design is proposed to reduce temperature nonuniformity in freezer compartment.Next, tests are done to verify the optimal design. It shows that through simple optimization design of evaporator structure and area distribution of each layer, the temperature nonuniformity decreases from5.7℃to3.8℃, proving that the simulation method can be applied in the optimization of temperature nonuniformity.Finally, three-dimensional numerical simulation with transient evaporating temperature boundary condition is performed to calculate temperature nonuniformity in freezer compartment. The result shows that transient simulation is more accurate than steady simulation.To clarify, calculation accuracy of the refrigerator system dynamic simulation software developed in this article not only depends on the model, but also on the empirical data. How to improve the model and find more proper correlation technique to improve calculation accuracy is to be further studied. Although numerical simulation method developed in this thesis can be used qualitatively in optimization of temperature nonuniformity in the freezer compartment, but the prediction accuracy needs to be improved quantitatively. |
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