Pulse detonation engine performance and thrust improvement using ejector

Abstract

This thesis is concerning the improvement of thrust by employing ejector at the end tube of pulse detonation engine (PDE). There are two ways of improving the thrust of PDE, one is to choose higher performance engine component and the other is in to improve the mechanism of detonation initiation. But sometimes those steps required more advanced and sometimes more complex mechanism. This thesis suggest a simpler and easier way to improve thrust in PDE by employing ejector of different geometries at the open end of detonation tube. Therefore the objective of this thesis is to improve the performance of the PDE so that stable detonation can be achieved at a reasonable repetitive rate. In this study the improvement on thrust generated by the installation of ejector is quantified. The study is conducted in High Speed Reacting Flow Laboratory (HiREF), Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. The PDE is operated with propane as fuel and oxygen as the oxidiser at the frequency of 5Hz. The four ejectors tested in this study namely straight, convergent, divergent and convergent-divergent ejectors. All ejectors have similar length and inlet diameter which are 400 mm and 130 mm respectively. The maximum augmentations for each ejector were measured using load cell. The highest improvement on thrust generated which is 12.6% higher than the baseline configuration has been achieved with the use of convergent ejector that is installed at downstream position. The study shows that the ejectors are very sensitive with its axial position to the open end of PDE.