Numerical Simulation And Experimental Study On The Performance Of Air Cycle Refrigeration

The adiabatic expansion is used in the air refrigeration system to obtain low temperature.The centrifugal compressor connected with the turbo-expander coaxially,recover the expansion power,which can reduce the power consumption of the system,so as to increase the coefficient of performance of the air refrigeration system.In addition,air is the most environmentally friendly refrigerant.Therefore,to carry out the air refrigeration cycle has important theoretical significance and practical value.In this paper,the low temperature air refrigeration system was established.The lumped parameter model of the experimental air refrigeration system was presented and programmed in Matlab software.On the basis the performance of the refrigeration system was simulated.The simulation results indicate that the compressor inlet pressure is the main factors that affect the refrigeration capacity of the system and the turbo-expander outlet temperature.The Turbo-expander outlet temperature can be reduced significantly,so the cooling capacity of the system is increased by adding a regenerator to the system.When the compressor inlet pressure is 200kpa,the turbo-expander outlet temperature is able to achieve-45? in the system with the regenerator and the cooling capacity is about 7.6kw.In order to study the dynamic performance of the air cooling system,a series of experiments of the low temperature air refrigeration system,under different working conditions including the different refrigeration system inlet pressure,as well as the cold side air flow rate in the of the gas cooler were carried out.The dynamic performance of the air refrigeration system under different working conditions was analyzed and the experimental data were compared with the simulation results.The experimental results show that the turbine outlet temperature is reduced with the increase in the compressor inlet pressure and the cold-side air flow rate of the gas cooler.When the compressor inlet pressure is 200kpa and the cold-side air flow rate of the gas cooler is 48kg/min,the turbine outlet temperature can achieve about-50?.Comparing the performance of the air refrigeration system with regenerator to that of the system without the regenerator,it is found that under the same conditions of the compressor inlet pressure,the flow resistance through the system with regenerator is increased,resulting in lower system mass flow rate and the turbine outlet temperature.Therefore,cooling capacity of system with the regenerator is greater than that of the system without the regenerator.When the compressor inlet pressure is 200kpa,the cooling capacity of regenerator system is increased by about 8.6%compared to the non-regenerator system.The simulation results of the turbine outlet temperature and cooling capacity are consistent with the experimental results.It shows that the lumped-parameter mathematical model and the simulation method are feasible.