Thermal cracking of aviation kerosene for scramjet applications

Abstract

Thermal cracking of China No.3 aviation kerosene was studied experimentally and analytically under supercritical conditions relevant to regenerative cooling system for Mach-6 scramjet applications. A two-stage heated tube system with cracked products collection/analysis was used and it can achieve a fuel temperature range of 700-1100 K, a pressure range of 3.5-4.5 MPa and a residence time of approximately 0.5-1.3 s. Compositions of the cracked gaseous products and mass flow rate of the kerosene flow at varied temperatures and pressures were obtained experimentally. A one-step lumped model was developed with the cracked mixtures grouped into three categories: unreacted kerosene, gaseous products and residuals including liquid products and carbon deposits. Based on the model, fuel conversion on the mass basis, the reaction rate and the residence time were estimated as functions of temperature. Meanwhile, a sonic nozzle was used for the control of the mass flow rate of the cracked kerosene, and correlation of the mass flow rate gives a good agreement with the measurements.thermal cracking, aviation kerosene, lumped model, scramjet applications

Characteristics of compressible flow of supercritical kerosene

“…The fuel mass flow rate was calibrated and measured using a fuel collection system. Details of the fuel heating, control and collection system were described in our previous work [6,7,12].…”

“…During fuel injection, the supercritical fuel can be directly transformed to the gaseous state without atomization and vaporization processes. When the fuel temperature is sufficiently high, the fuel pyrolysis occurs as well [7]. Experimental results [6,8] demonstrated that the overall burning intensity as well as the combustion efficiency improved with supercritical/cracked kerosene injection.…”

Three-Dimensional Heat Transfer Analysis and Optimized Design of Actively Cooled Strut for Scramjet Applications

“…The one-dimensional mass, momentum and energy equation with a 10-species surrogate for China No.3 aviation kerosene [3,7] are solved to obtained the flow properties of the kerosene along the cooling path. The convective heat transfer of the coolant is determined with correlation formulas based on the experimental results of heated kerosene flow at supercritical pressures [7,9] . The 3-dimensonal heat conduction equation is solved to obtain the distribution of wall temperature and heat flux of the strut with cooling effect.…”

Numerical Simulation of the Conjugate Heat Transfer in the Cooling System of the Combustion Chambers of the Aviation Ramjet on the Endothermic Fuels

“…Instead of real EF, the model uses some fictitious substance that decomposes without any intermediate reactions (so-called one-step pyrolytic mechanism) [5,6]. Empirical constants and functions described the fictitious substance decomposition are chosen for obtaining good agreement between computed and experimental data for real EF [7,8].…”