Experimental and modelling investigation of the thermal decomposition of n-dodecane

K.D Dahm,P.S Virk,R Bounaceur,F Battin-Leclerc,P.M Marquaire,R Fournet,E Daniau,M Bouchez

doi:10.1016/j.jaap.2003.11.005

Abstract

An important challenge in developing the Scramjet engine is cooling of the walls. One possibility is circulating the fuel itself through the walls of the engine, with cooling achieved through the strongly endothermic decomposition of the fuel. This paper presents an experimental and modelling study of the pyrolysis of n-dodecane, a component of some jet fuels. The experiments have been performed in a stainless steel isothermal plug flow reactor at temperatures of 950, 1000 and 1050 K and atmospheric pressure, with GC analysis of the end products, mainly methane, ethane and alkenes from C 2 to C 10. A detailed kinetic model containing 1175 reactions has been produced using EXGAS software. This model is able to represent with reasonable accuracy the experimental results presented here, both for the conversion of n-dodecane and for the formation of products, as well as literature data obtained from 623 to 823 K.

Highlights

The Scramjet engine is the key enabling technology for sustained hypersonic flight, which could be used for high-speed missiles or could power hypersonic aircraft and spacecraft into orbit
In order to study the thermal decomposition of n-dodecane at higher temperatures than the previous papers [4,8], the present paper presents measurements at 950, 1000 and 1050 K
We describe here the changes, which have been needed to obtain a satisfactory model for the thermal decomposition of n-dodecane from 400 to 1500 K

Summary

Introduction

The Scramjet engine is the key enabling technology for sustained hypersonic flight, which could be used for high-speed missiles or could power hypersonic aircraft and spacecraft into orbit. Scramjet is an acronym for Supersonic Combustion Ramjet. A ramjet has no moving parts and achieves compression of intake air by the forward speed of the vehicle. Air entering the intake of a supersonic aircraft is slowed by aerodynamic diffusion created by the inlet and diffuser. The expansion of hot gases accelerates the exhaust momentum to a velocity higher than that at the inlet and creates positive thrust. The Scramjet differs from the ramjet in that combustion takes place at supersonic air velocities through the engine and, theoretically, permits a flight speed from Mach 5 to Mach 10–12

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