Numerical No-power LN₂ Cold Storage Technique Used In Food Preservation

Fruits and vegetables play an important role in the healthy bite and sup of human beings. For improving the quality of mess on warship, the storage of fresh vegetables is a sixty-four-dollar problem. Nowadays, the recommended and widely used means is the controlled atmosphere and cold storage of fruit and vegetable to preserving freshness technique. However, the energy sources on warship is mainly used to run it and do battle. Therefore, in this paper, according to the requirements, numerical no-power LN2 cold-storage technique has been studied, and the temperature field of cold storage system has been analyzed theoretically by finite elements method and fluid-thermal coupled analyzing theory. Meanwhile, according to the results of numerical simulation of temperature field, the cold storage system has been optimum design. Today, among the third-generation refrigerant what is called, including liquid-nitrogen, liquid carbon dioxide, dry ice, liquid-nitrogen is the best choice in the field of food industry and food carrying trade. Using liquid-nitrogen as refrigerant, the system can achieve the controlled atmosphere and cold storage of fruit and vegetable to preserving freshness technique. It is obvious that the no-power LN2 cold storage system is a new technology having strong practicability, so the value of this studying is very high.The contents and results in this paper are concluded as the following,The studying of feasibility and the design of the cold storage system. In this paper, spray style system and cold board style system are designed. The feasibility has been validated by experiment.The theoretic computation of cold load of cold storage system, and the estimation of wastage of liquid-N2.The experimental determination of the temperature-field of lab scale system. Temperature of the point corresponding to node has been measured by thermocouple. The dates have used to validate the rationality of numerical simulation method.The numerical simulation of temperature-field has done by finite element method and ANSYS 5.7.The optimization of cold storage system design. Since cold board style system is better than spray style system, optimized system is cold board style. Then some key factors was supposed, optimization project 1 and optimization project 2 have been designed. After computation and analysis, the main factors effecting temperature-field and the related reasons have been expatiated. Optimization project 3 has been get after improving the key factors logically. The results showed that the system achieved the request of the temperature condition of cold storage of the vegetable to preserve freshness.The design of cold board and the numerical simulation of temperature of the cold board, and the estimation of the characteristic parameters of food.To sum up, the studying of this technique is not only a innovation in the field of liquid-N2 cold-storage technology, but also is solution of the antinomy between cold storage and energy sources, so it is indicated that the foreground of application of the cold storage technique is very amplitude.