Numerical Simulation Study On Thermal Performance Of Stirling Engine Tubular Heater

The dish-type Stirling solar thermal power generation technology is a potential application method in the development and utilization of renewable energy.The efficiency of its thermal power generation system was closely related to the light-heat conversion process of Stirling engine,which include the most important heat exchanger tube heater.Therefore,according to the analysis of the temperature and pressure distribution characteristics of the tube heater.U-shaped heating tube structural optimization was an effective way to improve the thermal performance of the heater and the efficiency of the disc solar thermal power generation system.In summary,a multi-objective genetic algorithm was used to obtain the Pareto solution set of the heater structure and operating parameters,which were construct a 1 k W U-shaped heating tube simulation heater models.The heat transfer and resistance properties of the structure were analyzed with the help of software platforms such as Matlab and Fluent.The specific research process is as follows:The structure and operating parameters of the U-tube heater of the β-type Stirling engine has been analyzed,according to calculate the influence of two coupling parameters for heater tube heat exchange efficiency and heat transfer coefficient.At the same time,there are some various losses exist in heater,mainly including flow resistance loss,heat conduction loss,cavity reflection heat loss and convection heat loss.Among the parameters that affect heat transfer efficiency,heat transfer coefficient and flow resistance loss,independent parameters are selected as decision variables,heat transfer efficiency,heat transfer coefficient and flow resistance loss are the objective functions,and the Pareto solution set is sorted using the TOPSIS method obtain the optimal ideal solution.In order to analyze the heat transfer and resistance performance of the Stirling engine heater,the non-uniform flow steady-state boundary conditions were adopted for the heating tube wall of the U-shaped heater to simulate the tube heating under the spot focus of the disc condenser heat exchange process.Investigate the effect of different inlet temperature,inlet velocity and working fluid on the average temperature and inlet and outlet pressure drop at different cross-sections of uniform and non-uniform flow tube heaters.To study the dimensionless parameters Re,Nu and Eu of steady-state heat transfer,the fitting correlations are Nu=6.6107 Re^0.0124 and Eu=76183.6 Re^-0.868.Enhance the heat transfer capacity of the Stirling engine heater by adding rectangular micro-ribs inside the U-shaped heating tube of the heater,UDF is used to compile the boundary conditions of the sine velocity inlet and cosine pressure outlet.Simulate and calculate the alternating flow state of the working fluid inside the heating tube,explore the effects of different fin length L^* and different fin height H on the micro-fin tube Nu,heat transfer coefficient h,resistance coefficient f and thermal performance ratio j The effect of the optimal micro-rib structure parameters on the heat transfer enhancement of the heating tube.