Affiliation of Author(s):能源与动力学院

Journal:APPLIED THERMAL ENGINEERING

Key Words:Micro-detonation Narrow gap Flame propagation Detonation initiation distance

Abstract:Flame propagation and detonation initiation distances (DID) of the ethylene/oxygen mixture in different narrow gaps at initial operating pressure 5-50 kPa were experimentally investigated with soot track records and high-speed digital imaging. The narrow gaps were combined with some channels, the width of 1.0 mm, 2.2 mm, 2.9 mm, 4.0 mm, the height of 10 mm, 20 mm, 30 mm and the length of 1220 mm. The correlations of the DID on initial pressure and gap size were discussed. While the initial pressure was different in macro-scale tube, the effect of minimum hydraulic diameter and boundary layer on acceleration of flame during the process of deflagration-to-detonation transition (DDT) and DID in narrow gap has obviously different variation trend. Compared with large scale tube, the boundary layer plays an important role in flame acceleration process, which causes different change rule of DID in the narrow gap. The overdriven detonation waves decrease to steady detonation wave at about 2000 m/s in three kinds of gap with different height. The flame speed rose sharply from 340 m/s to 2760 m/s along approximately 30 mm distance in W = 30 mm gap, significantly higher than Chapman-Jouguet (C-J) speed 2326 m/s. The process of flame development and DDT were presented and the variation trends of DID with the height or width of gap at different initial pressure were gained. The influence of width-height ratio on DID gradually weaken with increase of the initial pressure. (C) 2016 Elsevier Ltd. All rights reserved.

ISSN No.:1359-4311

Translation or Not:no

Date of Publication:2017-01-05

Co-author:Zhang, Penggang,Yuan, Li,Pan, Zhenhua,Zhu, Yuejin

Correspondence Author:Zhang, Penggang,Li Jianzhong