三元硝酸熔盐高温粘度的计算

Calculation of viscosity of ternary nitrate salts at high temperature

三元硝酸熔盐是一种重要的传热蓄热介质,粘度物性数据对其在工业中应用非常重要。但是由于硝酸熔盐熔点高,腐蚀性强,测试条件苛刻,粘度测量结果偏差较大,故利用计算方法确定熔盐粘度。本文首先通过大量实验数据拟合了纯物质KNO_3,NaNO_3和NaNO_2的粘度,再利用Arrhenius混合规则确定的经验公式计算三元硝酸熔盐的粘度。与前人实际测量值进行比较。结果发现:利用简单经验公式估算的结果与实际测量值比较接近,表明这种熔盐热物性变化受外界影响较小,可以利用Arrhenius简单混合规则确定熔盐粘度。

Ternary nitrate salt is usually an kind of heat transfer thermal storage media, the viscosity of nitrate salt is very important for its application in industry. Measurement results of the viscosity have larger discrepancy because of high melting point, strong corrosiveness and harsh condition of test. Therefore, calculation of the viscosity of molten salt is proposed for supplementary comparison with measured values. In this paper, the viscosity data of KNO3 , NaNO3 and NaNO2 was respectively determined from a large amount of experimental data. Then, the viscosity of ternary nitrate salt is calculated by using Arrhenius mixing rule experiential formula. Compared to the previous measuring values, the results show that the calculated values from simple experiential formula well agreed with the measured values. Therefore, thermophysical properties of ternary nitrate salt is less affected by outside factors and its viscosity was determined simply by Arrhenius mixing rule.