Experimental Investigation On Heat Transfer Performance Of High Temperature Molten Salt Heating High Pressure Steam

Solar energy is a kind of clean and renewable energy,its development prospects are widely concerned at home and abroad.Scientists have begun to study the collection,conversion,storage and transportation of solar energy from the aspects of scientific and technological,and have made significant progress.High temperature heat transfer and storage technology is one of the core technologies of solar thermal power generation.The high temperature regenerative working fluid is the key factor affecting the efficiency of the solar thermal power generation system.At present,molten salt is the best option in the regenerative heat transfer and thermal starage media.It has the advantages of wide use of temperature range,high heat transfer capacity,good thermal stability,low cost and so on.At present,the researches on the heat transfer characteristics of molten salt are seldom,especially for the actual application conditions.Therefore,we conducted the research on the heat exchange of the molten salt for the thermal storage.The system design,test platform construction,and heat transfer experiments were carried out.The aim is to provide the support of the experimental data which is effective for the application of molten salt in the field of heat storage.In this dissertation,an experimental scheme is designed to study the convection heat transfer between molten salt and high temperature high pressure steam.During the design process,the molten salt corrosion and solidification problems,and the methods to prevent have been considered.The working fluid is solar salt,a mixture with themass fraction of 60% NaNO3 and 40% KNO3.The heat transfer characteristics of solar salt were studied experimentally,which was cooled by high temperature high pressure steam(14 MPa/17 MPa).Good agreement was observed between the experimental data of solar salt and some classical and new correlations.Conversely,other correlations over predicted the heat transfer performance of solar salt.Finally,a fitted forced convective heat transfer correlation of solar salt was obtained by using multiple linear regressions within a deviation of ±10%,which can be used to design the steam generator heated by molten salt in solar thermal power plant.