Predication Of Viscosity Of Molten Salts And Analysis Of Influence Of Properties Accuracy On Heat Transfer Performance

The solar thermal power technology has been getting more and more attention for itscleanliness, low cost, renewability, but the heat transfer and storage technology is one ofthe key technologies for the solar thermal power. Feature by wide temperature applicationrange, large heat capacity, cheapness, the molten salts have been considered to be the mostpotential heat transfer and storage medium. The thermal properties of molten salts haveclosely relation with the process of heat transfer and storage, so it has considerableimportance to deeply study the thermal properties of molten salts.First of all, according to the classic heat transfer formula based on different heattransfer conditions, this paper respectively calculated deviation value of every thermalproperties which impact on heat transfer performance with+10%and-10%by thefunction error theory, and then combined with a number of data error analysis of thermalproperties to determine the influence degree of the thermal properties data on the heattransfer performance calculation, after summarized the published thermal properties dataof molten salts in present literature. The results showed that, compared to the density andheat capacity, viscosity and thermal conductivity data had the more influence to the heattransfer performance calculation. This conclusion pointed out the direction for thefollowing research.Based on the above conclusions, this paper successfully applied the correspondingstates principle with shape factor on the viscosity estimation in the inorganic molten salt.Through to calculate the reference fluid and conformal parameters, the viscosityestimation model of pure molten halide salts has been established. With this model, thepaper estimated the viscosity of eight kinds of pure molten halide salts, which allowed thetemperature range from melting point upto150K-300K. The work achieved satisfactoryresults, in which the maximum deviation between estimation value and reference valuewas not more than13.8%while the average deviation was less than6.7%.The paper also carried out the smooth hard sphere theory to establish viscositypredication model of pure molten salts. Based on the principle of molecular dynamics, apure chloride salt viscosity predication model has been established with smooth hardsphere theory. With this model, the paper predicated the viscosity of six kinds of puremolten chloride salts in a large temperature range, and achieved satisfactory results, inwhich the maximum deviation between reckoned value and reference value was17.945%while the average deviation was less than12%.The resulting thermal properties data obtained from up research would providepowerful theoretical support of basic physical properties for the heat transfer research ofmolten salts.