Analysis And Design Of Reciprocating Cylindrical Thermoelectric Conversion Device

In the context of promoting the use of clean energy,solar thermal power generation technology has developed rapidly.Among them,the dish-type solar power generation technology with independent power generation and flexible layout is very suitable for utilization in areas with abundant solar energy resources in China.However,due to technical deficiencies,it has not been widely applied.This paper is aimed at a new type of low-power light-weight thermoelectric conversion device suitable for dish-type systems.Based on its working principle,the structure of the scheme is designed and analyzed in detail,and the structural form of some parts is optimized,to achieve the purpose of reducing the complexity of the mechanism and testing the performance of the device.In this paper,based on the external combustion Stirling micro-generator model,combined with the structural characteristics of the device,the flywheel structure is optimized.For the crank structure in the device,the crank is optimized with a new structural form to meet the required working strength of the device and reduce the complexity of the structure.In addition,the structure of the scavenging valve has been optimized and improved,which not only satisfies the stable compression ratio of the system,but also increases the cross-sectional area displacement ratio of the scavenging valve by more than 10 times,which greatly reduces the resistance of the cavity to entry the working medium into the heat collection during the preheating process.Furthermore,the connecting rod of the device is optimized,and the strength of the connecting rod is checked in combination with the specific force conditions during the working process.The results show that under the two combined conditions,the dangerous nodes are at the small end of the connecting rod and the joint between the small end hole and the shaft.The design parameters of the small end hole and the connection with the shaft are adjusted to improve the safety factor.All components are reassembled.On this basis,the motion simulation of the transmission mechanism of the device is carried out to verify that the optimized device can meet the stable operation requirements.Finally,through the establishment of the fluid model in each process chamber,the commercial field software is used to simulate the flow field problems involved in the compression stroke,preheating process and expansion stroke.The results show that in the working environment with solar radiation intensity of 300W/m~2,the temperature of the aluminum alloy base plate of the collector is maintained at about 700K,and the temperature of the air layer in the heat collecting chamber can reach about 500K before the preheating process.At the end of the compression process,the working pressure in the compression chamber is about 0.22 MPa.At the end of the preheating process,the temperature of the working fluid entering the expansion chamber is 395K,and the pressure is about 0.177 MPa.At the end of the expansion stroke,the working fluid temperature in the expansion chamber is about 308K,and the pressure value drops to the atmospheric pressure level.According to the calculation results,the cycle thermal efficiency of the light device is 18.7%.The work of this paper has certain significance for the physicalization of light solar thermoelectric conversion devices.