Experimental Study for Development of Thermal Cracking Reaction Model of exo-THDCPD under Supercritical Condition

Active regeneration cooling is one of the key technologies used to solve the high-temperature heating issues of hypersonic vehicles by utilizing hydrocarbon aviation fuel as a coolant.In the regenerative cooling system, the fuel flows through the cooling channels and is heated to a supercritical state, absorbing a large amount of heat and undergoing endothermic decomposition.The fuel decomposed in this way significantly impacts both the cooling characteristics of the hypersonic vehicle and the combustion performance of the scramjet engine.Therefore, in this study, a batch reactor experimental device was used to investigate the pyrolysis characteristics of exo-THDCPD (C 10 H 16 , exo-tetrahydrodicyclopentadiene), the main component of high-density hydrocarbon jet fuel JP-10.Specifically, experiments were conducted to induce pyrolysis under conditions where the fuel is maintained in a supercritical state, with an initial pressure at 4 MPa, temperatures ranging from 550-630C, and reaction times between 50 and 280 seconds.Under these reaction conditions, the maximum fuel conversion rate and gas production rate were found to be approximately 77% and 48%, respectively.Analysis of the pyrolysis products using GC-MS, GC-FID, and GC-TCD systems revealed that the main gaseous products were hydrogen, methane, ethylene, ethane, propylene, and propane.Meanwhile, liquid products were detected in quantities ranging from several dozen to over a hundred species, depending on the fuel conversion rate, and these were classified and analyzed based on their parent molecular structure.Based on these experimental data, a global one-step reaction PPD (Proportional Product Distribution) model for exo-THDCPD was developed, and computational fluid dynamics (CFD) simulations were performed to verify the model.The results from the numerical analysis under various heat flux conditions, represented by the fuel temperature and conversion rate at the microchannel exit, were found to match very well with existing experimental data obtained from the authors' research group as well as with data from the open literature.The PPD model for exo-THDCPD developed in this study is expected to be useful for the design and analysis of regenerative cooling systems for hypersonic cruise vehicles.