Modeling And Optimal Design Of Thermoacoustic Refrigerator Based On The Weakly Nonlinearly Theory

Thermoacoustic refrigerator is a new type of refrigerator with great potential for research and development.It has many advantages such as high reliability,no pollution to the air and long service life and can be drove by low grade energy.The stack is an important component of the refrigerator and the stack parameters directly affect the heat transfer efficiency.The numerical calculation and optimization design are presented for performance index of stack in the thermoacoustic refrigerator.Firstly,the limits of the computing method based on the short-stack approximation method is analyzed,the simultaneous iteration is constructed to solve refrigeration capacity,pressure,volume flow rate,average temperature and gradient of temperature and so on,and the numerical computation method of stack performance index is solved.Then,the relationship between the stack performance index and the length,width,position,block ratio and temperature difference of the thermoacoustic stack are discussed based on the iterative algorithm.Finally,the stack of standing wave thermoacoustic refrigerator is optimized by using genetic algorithm and the optimization variable are length,width,position and block ratio of stack and the optimization objective is stack performance index.Compared with the short-stack approximation method,the numerical method presented in the work is more accurate and the optimized results are more acceptable.Therefore,this article main research work is as follows:?1?The calculation method of weak thermoacoustic theory is proposed,iterative method is constructed to solve the refrigeration capacity,pressure,volume flow rate,average temperature and temperature gradient simultaneously,an ordinary differential equations is solved in each iteration solution to calculate the performance index COPs of the stack.?2?Compared with the approximation method of short stack,the method can predict the performance index,cooling capacity and power consumption more accurately of the stack because of the presented method takes consideration in the variable transformation about location of actual viscosity,pressure drop,temperature gradient,temperature and pressure,volume flow rate and so on.At the same time,the methods are accuracy and reliability compared with the results of Delta EC software.?3?The genetic algorithm is used to achieve the optimization design of the stack length,position,width and blocking rate.The optimal results are the x_cn=0.0532,l_sn=0.0106,d_kn=0.587,Br=0.9442,which is consistent with the results of the literature relating to expectations.?4?This paper mainly discussed the calculation and optimization of the performance index of the standing wave thermoacoustic refrigerator.Although this paper only analyzes and optimizes the stack parameters,the proposed method can be applied to the analysis and optimization design of the whole standing wave thermoacoustic refrigerator.