p-h热力学面上水和水蒸气热力性质快速计算

Fast Calculation of Thermodynamic Properties of Water and Steam on p-h Thermodynamic Surface

采用双网格双二次样条插值模型,建立了p-h热力学面上水和水蒸气温度和熵的样条函数T^(SPL)(p,h)和s^(SPL)(p,h)。T^(SPL)(p,h)的计算,将P-h热力学面划分为五个子区,每个子区采用均匀网格,其中两相区简化为饱和线T^(sat)(p)的计算,并采用曲面延拓的方法对饱和线附近区域进行处理,s^(SPL)(p,h)的计算无需分区,为保证全区域计算精度,采用等差和等比两种非均匀网格划分方法。计算表明,T^(SPL)(p,h)的计算速度是T^(IF97)(p.h)的18.4～23.5倍,计算精度比T^(IF97)(p,h)高3到4个数量级。

Spline function TSPL（p,h） and 8SPL（p,h） for therinodynamic properties T and s of water and steam are established based on the double-grid bi-quadratic spline interpolation model. For the calculation of TSPL（p,h）, the computational p-h region is divided into five regions on which uniform grids are established. To increase the accuracy of TSPL（p,h） in the vicinity of saturated p-h line, a surface extension method is introduced, and cMculation in the two-phase region is simplified to calculation of saturated line TSar（p）. For the calculation of sSPL（p,h）, division of computing region is not necessary, and two kinds of non-uniform grids are introduced to ensure a high accuracy in the entire computational region. Results show that the computing speed of TSpL（p,h） is 18.4-23.5 times faster than that of TIF97（p,h） with 3-4 orders of magnitude higher accuracy.