Numerical investigation of pyrolysis effects on heat transfer characteristics and flow resistance of n-decane under supercritical pressure  

作　　者：Zhi TAO Xizhuo HU Jianqin ZHU Hongwei WU 

机构地区：[1]National Key Laboratory of Science and Technology on Aero-thermodynamies, School of Energy and Power Engineering,Beihang University, Beijing 100083, China [2]School of Engineering and Technology, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom

出　　处：《Chinese Journal of Aeronautics》2018年第6期1249-1257,共9页中国航空学报（英文版）

基　　金：the funding support from Program for National Natural Science Foundation of China (No.51406005)

摘　　要：Pyrolysis of hydrocarbon fuel plays an important role in the regenerative cooling process. In this article, a Two-Dimensional（2D） numerical model is proposed to investigate the pyrolysis effects on the heat transfer characteristics and flow resistance of n-decane under supercritical pressure. The one-step global pyrolytic reaction mechanism consisting of 19 species is adopted to simulate the pyrolysis process of n-decane. The thermophysical and transport properties of the fluid mixture are computed and incorporated into the numerical model for simulation. Comparisons between the current predictions and the open published experimental data are carried out and good agreement is achieved. In order to better understand the complicated physicochemical process, further investigations on the turbulent flow and heat transfer coupled with pyrolysis in a tube have been performed under various operating conditions. The results indicate that the pyrolysis intensively takes place in the high fluid temperature region. The occurrence of the heat transfer deterioration would lead to increasing n-decane conversion at the beginning of the heated section. It is found that the pyrolysis could improve the heat transfer deterioration and promote the heat transfer enhancement. Meanwhile, pyrolysis gives rise to an abrupt increase of flow resistance. The mechanisms of the physicochemical phenomena are also analyzed in a systematic manner, which would be very helpful in the development of the regenerative cooling technology.Pyrolysis of hydrocarbon fuel plays an important role in the regenerative cooling process. In this article, a Two-Dimensional（2D） numerical model is proposed to investigate the pyrolysis effects on the heat transfer characteristics and flow resistance of n-decane under supercritical pressure. The one-step global pyrolytic reaction mechanism consisting of 19 species is adopted to simulate the pyrolysis process of n-decane. The thermophysical and transport properties of the fluid mixture are computed and incorporated into the numerical model for simulation. Comparisons between the current predictions and the open published experimental data are carried out and good agreement is achieved. In order to better understand the complicated physicochemical process, further investigations on the turbulent flow and heat transfer coupled with pyrolysis in a tube have been performed under various operating conditions. The results indicate that the pyrolysis intensively takes place in the high fluid temperature region. The occurrence of the heat transfer deterioration would lead to increasing n-decane conversion at the beginning of the heated section. It is found that the pyrolysis could improve the heat transfer deterioration and promote the heat transfer enhancement. Meanwhile, pyrolysis gives rise to an abrupt increase of flow resistance. The mechanisms of the physicochemical phenomena are also analyzed in a systematic manner, which would be very helpful in the development of the regenerative cooling technology.

关 键 词：N-DECANE Convective heat transfer Flow resistance PYROLYSIS Supercritical pressure 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]