Numerical investigation of jet-wedge combinatorial initiation for oblique detonation wave in supersonic premixed mixture

Abstract

The jet-wedge combinatorial initiation (JWCI) is a novel functional form for initiating an oblique detonation wave (ODW) with reduced total drag within the oblique detonation combustor under the conditions of a low Mach number and low static pressure inflow. It can suppress the instability of the detached ODW. The evolution of the combustion wave during combinatorial initiation is dominated by the intersection between the bow shock wave (BSW) and the oblique shock wave (OSW), and consists of four stages: the shock-induced combustion stage, the shock-deflagration coupling stage, the hybrid combustion stage, and the oblique detonation stage. Three combustion regimes can be formed by using the JWCI: the shock-induced combustion regime, the hybrid combustion regime, and the oblique detonation combustion regime. These regimes have distinct characteristics of combustion and of flow structure that can be controlled by changing two non-dimensional variables: the ratio of momentum flux ( J) and the penetration ratio (PR). This is significant as it can facilitate the application of different combustion regimes under a variety of realistic flight conditions. In this study, the criterion for the transformation of the combustion regime is quantitatively investigated, and show that the structure of the combustion wave does not transform until both non-dimensional variables have reached their respective thresholds. J is crucial for determining the combustion regime and facilitating its transformation but the PR accounts only for the height of the combustion wave structure. The work is beneficial for research on the initiation of the ODW in applications of oblique detonation engines.

Numerical Investigation of Transverse-Jet-Assisted Initiation of Oblique Detonation Waves in a Combustor

“…Hydrogen is used as the fuel, and its combustion is modeled by a modified Jachimowski's reaction model [51] involving 19 reversible elementary reactions among 8 species: H 2 , H, O 2 , O, OH, HO 2 , H 2 O 2 and H 2 O and with N 2 serving as the bathing species. This detailed chemistry mechanism for H 2 /air combustion was proved to well predict the ignition delay time [52] and has been widely used in numerical simulations of unsteady shock-induced combustion phenomena [48,53,54] scramjets [55,56], ODWs [45], and ODEs [48,57]. More details regarding the mathematical modeling are available in Zhang et al [47].…”

“…Since the effectiveness of a transverse jet in assisting oblique detonation initiation is the main focus of this study, complex 3-D effects of the flow field, such as 3-D wave structures and boundary layers over the combustor's side walls, are neglected for simplicity [43][44][45], which is believed to have limited impact on the conclusions. Hence, the flow field in the ODE combustor is governed by the 2-D multispecies reactive Reynolds-averaged Navier-Stokes (RANS) equations.…”

“…The formation process of a detonation wave initiated by a hot transverse jet was numerically investigated by Cai et al [43,44], and the role of a contracting flow channel formed by the hot jet on the propagation of the detonation wave was analyzed. The initiation characteristics of ODWs via a combination of a jet and a wedge were studied numerically by Yao & Lin [45], and the transformations of different combustion regimes controlled by two nondimensional parameters (i.e., the momentum flux ratio and the penetration ratio) were thus revealed.…”

Effects of Fuel Concentration Gradient on Stabilization of Oblique Detonation Waves in Kerosene–Air Mixtures

“…This combustion organization method can be harnessed to be promising for the future high-speed propulsion system due to the intrinsic pressure gain features and fast burning rate. The research on oblique detonation wave engines (ODWE) using ODW to produce thrust has grown over the past few decades (Desai et al 2023;Yao and Lin 2023;Zhang et al 2022;Bachman and Goodwin 2021). However, the organization of the well-stabilized ODW in engineering applications is still challenging.…”