Combined Effects of Vortex Flow and the Shchelkin Spiral Dimensions on Characteristics of Deflagration-to-Detonation Transition

Introduction

A key problem for a pulse detonation engine (PDE) application is to achieve reliable and repeatable detonations in the shortest distance possible to minimize the system weight. A predetonator was used in these studies to achieve the shortest distance of deflagration-to-detonation transition (DDT) [1]. However, the advantages of PDEs, such as their simplicity and low weight, are lost if devices such as a predetonator and an igniter are added. To control the DDT distance without additional ignition energy and sophisticated, heavy structures such as predetonators, efforts have been undertaken to apply the vortex flow (VF) injection concept to the injection part of a PDE, because the flame can propagate very quickly in a VF, depending on the rotating velocity [2,3]. Turbulence in a vortex flow promotes flame acceleration and shortens the DDT distance [4,5]. In this study, a rotating flow field of the mixture was established in the detonation tube, and the turbulence was promoted by the Shchelkin spiral; thus and the combined effects of vortex flow and dimensions of the Shchelkin spiral on the characteristics of DDT could be examined.