低裂解度正癸烷物性快速计算方法

Fast Calculation Method on Physical Properties in

关键词:  正癸烷  裂解  广义对应态法则  物性  快速计算

Key words:  Decane  Cracking  Extended-corresponding-state law  Physical property  Fast calculation

摘要:

为研究正癸烷轻微裂解时物性计算方法，基于广义对应态法则建立起正癸烷裂解过程中的密度、黏度、导热系数和定压比热容的三种计算方法，包括直接计算、物性库插值计算、物性子库加权计算，在验证直接计算方法的准确度基础上，对比三种方法的计算精度、计算内存和计算时间来对其综合评估，并探究裂解度对高温物性的影响。计算温度变化范围为300 ~ 1020K，压力变化范围为1 ~ 15MPa，裂解度变化范围为0 ~ 0.25。结果表明:不同物性计算方法均能定性预测热物性的特殊变化趋势；以物性直接计算结果为基准，物性子库加权计算的误差与裂解度大小成正比；在不考虑计算内存的情况下，物性库插值计算方法能无损加速计算，低裂解度下快速工程计算可选择物性子库加权方法；裂解度对高温物性的影响显著且不可忽略。

Abstract:

In order to study the calculation methods in the mild cracking of decane，three calculation methods of density，viscosity，thermal conductivity and specific heat at constant pressure in the cracking of decane by extended corresponding state law were conducted，including direct computation，interpolation computation by physical properties library and mixing computation by physical properties sublibrary. On the basis of the accuracy of direct computation，via contrasting computation accuracy，computation memory and computation time with each other，the performances of three methods were assessed comprehensively，and the effects of the cracking degree on the physical properties at high temperature were investigated. In the computation，the temperature，pressure and cracking degree ranged from 300K to 1020K，from 1MPa to 15MPa，from 0 to 0.25，respectively. The results indicate that all computation methods could qualitatively reproduce fancy variation of physical property. Relative to the direct computation，interpolation computation by physical properties library could obtain improved computation accuracy and that the error received by mixing computation by physical properties sublibrary is proportional with the cracking degree. Provided that the computation memory，interpolation computation by physical properties library could accelerate computation without precision loss. Under mildly cracking it is advisable to use mixing computation by physical properties sublibrary for fast engineering calculation. The significant influence on the physical properties at high temperature by the cracking degree could not be neglected.