Experiments On Natural Convection Heat Transfer From Fine Horizontal Cylinders To Molten Salt

Solar thermal power generation is one of the most promising power generationways in renewable energy scale power generation, as its technology continue tomature and its power scale continue to increase, solar thermal power generationtechnology is attracting more and more countries in the world, with good prospectsfor development. As molten salt has a wide range of operating temperature, low vaporpressure, large heat capacity, low viscosity, good stability, low costs and many otherfeatures, it had become the most potential heat transfer and storage medium in solarthermal power generation system. In this system, the law of heat transfer by naturalconvection with molten salt is very important for the design of accumulators and otherkey equipments. But until now, the study of the law of heat transfer by naturalconvection with molten salt is still blank.In order to understand the law of heat transfer by natural convection with moltensalt and the theory of natural convection with middle Pr number medium, anexperimental system has been built to understand the law of heat transfer by naturalconvection around horizontal fine mental wires with molten salt by Joule heatingmethod.Firstly, verifying the accuracy of experimental method and reliability ofexperimental system with water and ethanol and improved them. On this basis, thestudy of the law of heat transfer by natural convection around horizontal fine mentalwires with LiNO3molten salt is taken. The experimental results of water and ethanolshow good agreement with Richard relation(0.6＜Ra＜100), and preliminary resultsof molten salt also show that Richard relation forecasts well(10＜Ra＜32). But inlarge temperature difference(ΔT＞46℃), Richard relation doesn’t forecast very well.More study is still needed on the law of natural convection in large temperaturedifference with molten salt in the future.