Numerical Simulation And Performance Prediction Of Air Curtain Of A Cold Store

With the requirement of energy-saving and ejection-decreasing, more and more attention is taken to the issue of energy saving of cold stores. The cold store building is featured with cold inside environment and warm outside environment. When the cold store is open, the strong exchange of heat and mass takes place owing to the wind pressure and thermal pressure between the inside and outside of a cold store, leading to the increase in cold load. So air curtain is usually installed at the entrance in order to save energy.A steady model was proposed for the springhouse, the air curtain and the outside environment of a cold store based on CFD. The performances of air curtain of a cold store were tested on site. The CFD model was validated and inproved by comparing the CFD predictions and the test results. The simulation results show that the mumerical model can be applied to predict the performance of air curtain.The following researchs were carried out with the CFD technique. (1) The air flow field in springhouse was numerically studied. The research results can be helped to the design of cold a store. (2) The air infiltration is successfully predicted for the case when the cold store entrance is open but the air curtain dose not work. The analytical models of Gosney, Fritzsch and Tamm modified were comparied and the results of Goseny model provided closest comparison with the CFD predictions. It's showed that the three analytical models can be used to predict the infiltration through the cold store entrance. (3) As the cold storage entrance is open and the air curtain works at the same time, the air curtain performances, with different structure parameters, were simulated and predicted comprehensively. The changes of air curtain effectiveness were analyzed when the outlet is 0.03m, 0.05m and 0.1m, respectively. A narrow outlet is proved to be favorable to the design and installation. Furthermore, the effectiveness changes with different jet velocities were analyzed. It is found that the effectiveness of the air curtain is dependant on the jet velocity and an optimal value of the jet velocity exists. Furthermore, the effect of jet angle on the effectiveness of the air curtain was also numerically predicted. The effectiveness is better at the jet of 15°than at jet angle of 0°and 30°.