Hydrocarbons play an important role in lots of industrial processes. Thermal conductivity is an important thermophysical property of fluids in energy conversion process, such as the design of the heat transfer system and the evaluation of thermodynamic cycle. Thus, it is of great significance to acquire solid experimental data and develop reliable models for achieving accurate thermal conductivity of hydrocarbons. In this work, thermal conductivity of two common fuels, n-octane and n-decane, were studied by combining experimental and theoretical methods. Using the transient hot wire method, the thermal conductivity is measured with temperature ranging from 303 to 523 K and pressures ranging from 0.1 to 15 MPa. Excellent agreement is achieved by comparing our experimental results with literatures. Furthermore, the mechanism for the influence of temperature and pressure on thermal conductivity of liquid n-octane and n-decane was explored preliminarily based on Bridgman's theory. In addition, we proposed a modified model considering the critical thermal conductivity enhancement, with which the average absolute deviations are 0.49% and 0.43% for n-octane and n-decane, respectively. It is shown that our proposed model has better predictive ability for representing thermal conductivity than the four traditional theoretical models (Assael model, Sun and Teja model, Huber and Perkins model, Liu model), especially at the vicinity of the critical point. The achievements in the present study are not only useful for relevant industrial application but also helpful for understanding the thermal conductivity critical enhancement when approaching the liquid-gas critical point for n-alkanes.

碳氢化合物在许多工业过程中起着重要作用。导热系数是能量转换过程中流体的重要热物理性质，例如传热系统的设计和热力学循环的评估。因此，获得可靠的实验数据并建立可靠的模型以实现准确的碳氢化合物导热系数具有重要意义。在这项工作中，结合实验和理论方法研究了两种常用燃料正辛烷和正癸烷的热导率。使用瞬态热线法，可在303至523 K的温度和0.1至15 MPa的压力范围内测量热导率。通过将我们的实验结果与文献进行比较，可以达到极好的一致性。此外，基于布里奇曼理论，初步探讨了温度和压力对液态正辛烷和正癸烷导热系数的影响机理。此外，我们提出了一种考虑到临界导热系数提高的改进模型，正辛烷和正癸烷的平均绝对偏差分别为0.49％和0.43％。结果表明，相对于四个传统的理论模型（Assael模型，Sun和Teja模型，Huber和Perkins模型，Liu模型），我们提出的模型具有更好的表示导热系数的预测能力，尤其是在临界点附近。