Pulse Detonation Assessment for Alternative Fuels

Muhammad Hanafi Azami,Mark Savill

doi:10.3390/en10030369

Abstract

The higher thermodynamic efficiency inherent in a detonation combustion based engine has already led to considerable interest in the development of wave rotor, pulse detonation, and rotating detonation engine configurations as alternative technologies offering improved performance for the next generation of aerospace propulsion systems, but it is now important to consider their emissions also. To assess both performance and emissions, this paper focuses on the feasibility of using alternative fuels in detonation combustion. Thus, the standard aviation fuels Jet-A, Acetylene, Jatropha Bio-synthetic Paraffinic Kerosene, Camelina Bio-synthetic Paraffinic Kerosene, Algal Biofuel, and Microalgae Biofuel are all asessed under detonation combustion conditions. An analytical model accounting for the Rankine-Hugoniot Equation, Rayleigh Line Equation, and Zel’dovich–von Neumann–Doering model, and taking into account single step chemistry and thermophysical properties for a stoichiometric mixture, is applied to a simple detonation tube test case configuration. The computed pressure rise and detonation velocity are shown to be in good agreement with published literature. Additional computations examine the effects of initial pressure, temperature, and mass flux on the physical properties of the flow. The results indicate that alternative fuels require higher initial mass flux and temperature to detonate. The benefits of alternative fuels appear significant.

Highlights

In the very early development of jet-propulsion engines, it was known from the thermodynamic analysis cycle that an engine based on a constant-volume combustion process achieves higher thermodynamic efficiency than a constant pressure engine
The same procedures have been used to evaluate other fuels by respecting the chemical relations established by the molecular formula of these fuels under stoichiometric combustion conditions
Limited data exist with which just a few comparisons can be made, and no data are available for alternative bio-fuels

Summary

Introduction

In the very early development of jet-propulsion engines, it was known from the thermodynamic analysis cycle that an engine based on a constant-volume combustion process achieves higher thermodynamic efficiency than a constant pressure engine. The earliest non-piston-engine-type prime mover employing constant volume combustion with a deflagrative and not a detonative reaction was the Holzwarth gas turbine manufactured by Brown-Boveri ( ABB) in Switzerland during the early part of the last century, but its success was limited [1]. After the work was terminated during World War II, Nicholls and co-workers reinitiated the effort in the 1950s by experimenting with a series of single- and multiple-cycle detonation experiments with different mixtures of hydrogen, oxygen, acetylene, and air in a six-foot tube. There has been a growing interest in PDEs as a propulsion technology for both air breathing and rocket systems

Methods

Results

Conclusion