Supersonic spray combustion subject to scramjets: Progress and challenges

Ren, Zhaoxin; Wang, Bing; Xiang, Gaoming; Zhao, Dan; Zheng, Longxi

doi:10.1016/j.paerosci.2018.12.002

Cited by 110 publications

(25 citation statements)

References 146 publications

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“…The fuel and air are also assumed to be well premixed at the inlet and the effect of injection is not considered. In fact, the injection of fuel in the supersonic inflow can lead to complicated cases (Ren et al 2019a), and this process determining whether the mixture could be well premixed could affect significantly the ODW initiation. Since the flow of the incoming air is supersonic, efficient premixing with fuel in the inlet is inevitably difficult to achieve, resulting in an inhomogeneous mixture (Iwata, Nakaya & Tsue 2017).…”

Section: Physical Model and Computational Methodsmentioning

confidence: 99%

Morphology of oblique detonation waves in a stoichiometric hydrogen–air mixture

et al. 2021

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Section: Physical Model and Computational Methodsmentioning

confidence: 99%

Morphology of oblique detonation waves in a stoichiometric hydrogen–air mixture

et al. 2021

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“…The smooth transition can only be achieved by a mixture with very low temperature sensitivity (or equivalently a small E a ). [36,40,64], the transition is characterized by a smoothly curved shock at M0 = 12.5, while at low Mach number, the transition is given by the classical abrupt structure. For the case with M0 = 10, the multi-wave point connecting the deflagration wave, induction OSW, ODW, and transverse compression waves can be clearly seen.…”

Section: Resultsmentioning

confidence: 99%

“…To this end, the dynamics of ODW formation has recently drawn significant research attention.With the advance in scientific computing using parallel Central Processing Units (CPUs) and Graphics Processing Units (GPUs) computing technology [32][33][34], there has been significant advance in investigating in detail the unsteady oblique detonation waves. Using high-resolution numerical simulations, various formation structures of wedge-induced oblique detonation waves, i.e., the transition from the oblique shock wave (OSW) to the oblique detonation wave (ODW), have been revealed in recent investigations, e.g., References [35][36][37][38][39][40]. Hysteresis phenomenon of the ODW structure related to initial condition and ODW responses subject to inflow non-uniformities and turbulences have also been investigated [41][42][43][44][45].…”

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confidence: 99%

The Effect of Chemical Reactivity on the Formation of Gaseous Oblique Detonation Waves

Yan

Teng

et al. 2019

Aerospace

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High-fidelity numerical simulations using a Graphics Processing Unit (GPU)-based solver are performed to investigate oblique detonations induced by a two-dimensional, semi-infinite wedge using an idealized model with the reactive Euler equations coupled with one-step Arrhenius or two-step induction-reaction kinetics. The novelty of this work lies in the analysis of chemical reaction sensitivity (characterized by the activation energy E a and heat release rate constant k R ) on the two types of oblique detonation formation, namely, the abrupt onset with a multi-wave point and a smooth transition with a curved shock. Scenarios with various inflow Mach number regimes M 0 and wedge angles θ are considered. The conditions for these two formation types are described quantitatively by the obtained boundary curves in M 0 -E a and M 0 -k R spaces. At a low M 0 , the critical E a,cr and k R,cr for the transition are essentially independent of the wedge angle. At a high flow Mach number regime with M 0 above approximately 9.0, the boundary curves for the three wedge angles deviate substantially from each other. The overdrive effect induced by the wedge becomes the dominant factor on the transition type. In the limit of large E a , the flow in the vicinity of the initiation region exhibits more complex features. The effects of the features on the unstable oblique detonation surface are discussed.Aerospace 2019, 6, 62 2 of 17 the conditions and interpret the observed flow field regimes in terms of competing reactions and flow-quenching effects.Alternatively, an oblique detonation wave can be induced by a wedge in an incoming reactive flow [20][21][22]. A standing oblique detonation wave attached to the wedge tip presents a more practical configuration for engine operation [23][24][25]. There has been indeed a remarkable progress in understanding the fundamental aspects of oblique detonation waves induced by a semi-infinite, two-dimensional wedge. Analytical solutions such as wave angles and steady structures as the basic foundation were sought in a number of pioneering works using detonation polar analysis by approximating the ODW as an oblique shock wave (OSW) coupled with an instantaneous post-shock heat release [26][27][28][29]. In later studies, it has been demonstrated that the ODW formation structure induced by the wedge is more complex. In many cases, an oblique shock wave first forms upon the flow interaction with the wedge igniting the combustible flow mixture, and subsequently transits into an oblique detonation wave [30]. Due to the strong coupling sensitivity between fluid dynamics and chemical reactions, as well as the inherent unstable nature of detonation waves [31], it remains technically challenging to establish steady oblique detonations in high-speed combustible mixtures for practical propulsion applications, and such success requires fundamental understanding of the initiation structure of oblique detonation waves. To this end, the dynamics of ODW formation has recently drawn significant research attention...

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“…As mentioned in the Section 2.3, there is little literature on air assisted atomisation in ICEs and typically they have been at low air injection pressures (<1.0 MPa). Air blast atomisation and crossflow atomisation at high pressures (>1.0 MPa) have seen wider experimentation in literature associated with applications such as rockets, ramjet, scramjet, and gas turbine combustors [44][45][46][47][48][49][50]. Generally higher pressure and velocity conditions have demonstrated enhanced mixing, with high velocity subsonic and supersonic crossflow conditions producing rapid mixing in comparison to coaxial jet injection [44].…”

Section: Hypothesis 2 Increased Mixing Driven By Impinging Jet Airblast and Crossflow Atomisationmentioning

confidence: 99%

“…Both primarily utilised relative velocity and density as a route to increased mixing. However, as the high-pressure research has typically been focussed on rocket and ramjet applications, the experiments involved an open volume and have had difficulties in combustion stability and performance in the past, with the physiochemical mechanisms at supersonic conditions still not well understood [50].…”

Section: Hypothesis 2 Increased Mixing Driven By Impinging Jet Airblast and Crossflow Atomisationmentioning

confidence: 99%

Starting to Unpick the Unique Air–Fuel Mixing Dynamics in the Recuperated Split Cycle Engine

et al. 2021

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In this work air fuel mixing and combustion dynamics in the recuperated split cycle engine (RSCE) are investigated through new theoretical analysis and complementary optical experiments of the flow field. First, a brief introduction to the basic working principles of the RSCE cycle will be presented, followed by recent test bed results relevant to pressure traces and soot emissions. These results prompted fundamental questioning of the air-fuel mixing and combustion dynamics taking place. Hypotheses of the mixing process are then presented, with differences to that of a conventional Diesel engine highlighted. Moreover, the links of the reduced emissions, air transfer processes and enhanced atomisation are explored. Initial experimental results and Schlieren images of the air flow through the poppet valves in a flow rig are reported. The Schlieren images display shockwave and Mach disk phenomena. Demonstrating supersonic air flow in the chamber is consistent with complementary CFD work. The results from the initial experiment alone are inconclusive to suggest which of the three suggested mixing mechanism hypotheses are dominating the air–fuel dynamics in the RSCE. However, one major conclusion of this work is the proof for the presence of shockwave phenomena which are atypical of conventional engines.

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Supersonic spray combustion subject to scramjets: Progress and challenges

Cited by 110 publications

References 146 publications

Morphology of oblique detonation waves in a stoichiometric hydrogen–air mixture

Morphology of oblique detonation waves in a stoichiometric hydrogen–air mixture

The Effect of Chemical Reactivity on the Formation of Gaseous Oblique Detonation Waves

Starting to Unpick the Unique Air–Fuel Mixing Dynamics in the Recuperated Split Cycle Engine

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