Cocentration Characteristic Of Solar Multi–dishes Concentrator System And Ray Thermal Structrual Characteristic Of Solar Receiver

Solar dynamic power generation system is a clean power generation system with manyadvantages, such as: without using fossil fuel and zero pollutant emission, etc. The solarradiation intensity received by the earth is affected no only by diurnal variation, season,latitude and other regular factors, but also by clouds, rain, snow and other random factors, aswell as by heterogeneous heat flux transmission of the collector subsystem. Therefore, the solarthermal utilization has severe intermittence and heterogeneity, which can cause the receiver toendure repeated high–temperature differential thermal shock cycles and subjected to highthermal stress till bending deformation and receiver failure.Based on the background of high–temperature conversion and utilization of solar energyas well as the requirement of applied technology development of high effective and low costsolar energy utilization, this dissertation will research on the concentration and transmission ofsolar rays, absorption and conversion of energy, reliability of receiver and other key scientifictechnologies of solar dynamic power generation system. The main researches of thisdissertation include the following four aspects.1．Heat flux distribution on the focal plane of the biaxial tracking multi–dishesconcentrator system set up in Harbin Institute of Technology is measured by direct heat fluxdistribution measurement system. A program for solving concentration and transmissionproblem of solar radiation is compiled based on the Monte Carlo method. In order to seek theoptimal parameter combination for numerical calculation, the dimensionless heat fluxdistribution calculated by numerical method is compared with that measured by direct heatflux distribution measurement system. Besides, the variations of dimensionless heat fluxdistribution on the focal plane of multi–dishes concentrator system with the increase of dishesand change of reflectivity are also studied in this dissertation.2．Based on the directional characteristic analysis of concentrated heat flux distributionon the focal plane of hemispherical cavity receiver and the redistribution effect of opticalwindow, a cavity receiver with internal convex optical window is proposed. The effects ofeffective error variation, characteristic parameters variation and absorptivity variation ofreceiver surface on the heat flux distribution of the hemispherical cavity receiver with internalconvex optical window are analyzed. Besides, the thermal efficiency of cavity receiver withinternal convex optical window is also investigated. The researches on conical cavity receiver are carried out from the perspective of optical efficiency of receiver, and the irradiativetransfer properties variation of conical receiver with the change of aperture radius and relativeaperture is analyzed.3．In order to solve the problem that the bottom surface of conical cavity receiver can notbe completely covered with coiled metal tube and to improve the optical efficiency, two newtypes of cavity receiver with bottom surface convex are put forward in this dissertation. Theeffects of dimensionless bottom surface convex height variation, absorptivity variation ofreceiver surface, pointing error variation and alignment error variation on the optical efficiencyof cavity receiver with bottom surface convex are analyzed.4．The researches on the temperature field, thermal stress field and strain field of tubereceiver are carried out by adopting Monte Carlo and Finite Element combined method, andthe results calculated by Monte Carlo and Finite Element combined method are compared withthe results calculated with simplified heat flux distribution boundary condition. In view ofsolving the deformation problem of stainless steel tube receiver occurred during applicationand experiment in the National University of Mexico solar dynamic power station by usingcopper tube receiver, the effects of material selection on the thermal stress field and strain fieldare investigated. The eccentric tube receiver is put forward in this dissertation to decrease thethermal stress and total strain of tube receiver, and the effects of oriented angle and eccentricityvariation on the thermal stress field and strain field of eccentric tube receiver are alsoinvestigated.