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为了满足工程上对液体导热率的要求,在方阱模型基础上提出了计算液体导热率的方程。所得的导热率计算方程包括分子平动贡献项和分子内部能量贡献项。为了计算方便,根据分子模拟数据提出了计算中所需的方阱流体的径向分布函数的关联式。物质的能量参数由其临界温度估算,而硬壳体积则由基团贡献法获得。考虑到实际液体有别于方阱流体,在实际液体导热率计算中引入了一个与密度有关的校正参数。使用该文提出的方法,对液体氩及10种液态烃类物质的导热率进行了计算,其计算的平均相对误差小于5.3%。
In order to meet the engineering requirements of liquid thermal conductivity, the equation of liquid thermal conductivity is proposed based on the square-well model. The resulting thermal conductivity calculation equation includes the molecular translational contribution and the molecular energy contribution. For the convenience of calculation, the correlation of the radial distribution function of the square-well fluid required in the calculation is proposed according to the molecular simulation data. The material’s energy parameters are estimated from its critical temperature, while the hard shell volume is obtained from the group contribution method. Considering that the actual liquid is different from the square-well fluid, a density-dependent correction parameter is introduced into the actual liquid thermal conductivity calculation. Using the method proposed in this paper, the thermal conductivities of liquid argon and 10 kinds of liquid hydrocarbons are calculated. The calculated average relative error is less than 5.3%.