Numerical Study of N-Decane Convective Heat Transfer with Endothermic Pyrolytic Reaction under a Constant Wall Temperature and Supercritical Pressures

摘要

A numerical study was conducted on the turbulent convective heat transfer of n-decane in a mini tube with endothermic pyrolytic reaction under a constant wall temperature and supercritical pressures. A onestep pyrolytic reaction mechanism of n-decane was employed. Numerical results with and without pyrolysis were compared and discussed. Effects of the inlet velocity and pressure on heat transfer processes were investigated. It is found that the wall heat flux at the thermal exit can be increased by more than 280% due to the pyrolytic reaction under certain operation conditions. Furthermore, the flow velocity increases significantly as n-decane is thermally decomposed to low-molecular-weight components. Heat absorption from the endothermic pyrolytic reaction dictates the convective heat transfer process in the high temperature region toward the thermal exit. This effect weakens as the inlet velocity increases. The pressure effect on heat absorption from pyrolysis is quite weak under the tested operation conditions.