Application And Experimental Study On Singlestage Auto-cascade Refrigeration System Of Quick-freezing

In recent years many domestic colleges and research departments are studying the topic of using Single-stage auto-cascade refrigeration system to achieve -65℃refrigeration temperature, and the contents of its research mainly includes the optimization ratio of mixed refrigerants and the separation of refrigerant etc. In order to achieve the requested temperature, researchers used various computer simulations to make many kinds of small experiment devices to find out the optimum proportion of refrigerants and the way of high-purity refrigerants separating. At present the results of computer simulations show that it is theoretically feasible to achieve requested temperature; the experimental results of small experiment devices also shows it is possible to achieve requested temperature. Because of interference factors in actual application, the difference between Simulation results and experimental results are considerable. Due to the complexity of the experiment device design, some design is very difficult to achieve. During operation of the system, refrigerants thermodynamics condition is complicated and instable and it take a long time to achieve the requested temperature and the lowest temperature is not stable. Therefore simulation results and experimental results are very different from required results in practical applications. In domestic there is almost no successful Single-stage auto-cascade refrigeration system application in practice.With the use of siphon, I improved the purity of refrigerant in separation and achieved-70℃evaporation temperature. And in the experiment I found it is very important to improve the purity of refrigerant in order to achieve requested evaporation temperature and to keep the system running steady. Using the method of siphon the design of the system is simplified and the equipments of system are reduced. The whole system is relatively simple, included: compressor, condenser, evaporator, throttle valve and condenser-evaporator, liquid storage type of gas-liquid separator, it is relatively simple. The main purpose of this paper is validating the design and structure of Single-stage auto-cascade siphoning refrigeration system whether can be applied in practice. The main contents of this paper are the compare of EER among single-stage auto-cascade siphoning refrigeration system, two-stage compression refrigeration system, two-stage cascade refrigeration system. The main contents of this paper also include the perfecting of condenser-evaporator, liquid storage type of gas-liquid separator structure and the design method of Single-stage auto-cascade siphoning refrigeration system.Through home and abroad literature searching, anglicizing, I reviewed multi-dimensional mix working substance auto-cascade cycle refrigeration technology. This paper introduces auto-cascade refrigeration system at home and abroad study history and current research progress. Two-stage compression refrigeration system and auto-cascade refrigeration system were compared. And then I introduced the classification of mixed refrigerants and the calculation method of non-azeotropic refrigerant's thermo physical properties. From the perspective of single-stage auto-cascade siphoning refrigeration system refrigerants' choice I introduced the way of refrigerant choice. Then I emphatically introduced the definition of quick-frozen food and the calculation of quick-frozen time. In this paper, single-stage auto-cascade siphoning refrigeration system was designed and I design the system's condenser-evaporator and liquid storage type of gas-liquid separator and present a better method for liquid supply. I made detailed instructions of single-stage auto-cascade siphoning refrigeration system device which was used in these experiments. And finally I successfully built experiment system and made a successful experiment.Through experiment data analysis, we proof that the single-stage auto-cascade siphoning refrigeration system can be applied in practice and draw a complete design method. In this paper, we got some conclusions but at the same time we also found some deficiencies. These studies can be a very important guiding basis for this topic's studying.