Classification of Combustor–Inlet Interactions for Airbreathing Ramjet Propulsion

Cui, Tao; Wang, Yong; Liu, Kai; Jianren, Jin

doi:10.2514/1.j053378

Cited by 13 publications

(6 citation statements)

References 49 publications

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“…As a result, we proved analytically that there are mathematically 72 types of combustor-inlet interactions in a ramjet engine, 11 of which are physically existent. (29) All these studies, however, were performed in static frameworks, and can only make direct, instantaneous link between system states and external perturbations using algebraic relationships. The disadvantage of the static analysis lies in its disability in describing the time-dependent changes in the state of ramjet engine, and accordingly the main obstacle is that the algebraic equations cannot account for the dominate dynamic processes of the system, such as the unstable positivefeedback effect and the duct volume effect.…”

Section: Introductionmentioning

confidence: 99%

Combustor-inlet interactions in a low-order dynamic model of ramjet engines

Liu

Cui

2020

Aeronaut. j.

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The coexistence of multiple stable states is indicative of self-organising processes occurring in the course of the combustor-inlet interactions in a ramjet engine and give rise to the appearance of various nonlinear phenomena. This paper provides a dynamic model that can describe the multiple stable states and the corresponding nonlinear effects to further investigate the dynamic interactions between combustor and inlet in a ramjet engine. Our study shows the whole engine can display distinct dynamic behaviours ranging from irreversibility to hysteresis and to various mode transitions, depending on different physical parameters. With the model, we also illustrate the role of the instability of the normal shock wave in impacting the whole engine’s nonlinear dynamics. Additionally, we extend the previous studies of the classification of combustor-inlet interactions from a static framework to a dynamic framework, which helps to clarify the transient processes of the nonlinear interactions. This work offers a quantitative illustration of the combustor-inlet interactions in a ramjet engine by revealing its nonlinear dynamics and associated characteristics, therefore advancing our understanding of the nonlinear phenomena that exhibit in ramjet engines.

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Section: Introductionmentioning

confidence: 99%

Combustor-inlet interactions in a low-order dynamic model of ramjet engines

Liu

Cui

2020

Aeronaut. j.

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“…It is common knowledge that increasing the pressure when burning fuel in a subsonic chamber can lead to a reduction in airflow and total pressure in the air intake, which disrupts the operation mode and its thrust characteristics [1,2]. FIGURE 1.…”

Section: Introductionmentioning

confidence: 99%

The effect of backpressure on the transition to subsonic flow in the diffuser of a supersonic air intake

Gutov¹,

Звегинцев²,

Melnikov³

2017

AIP Conference Proceedings

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“…Общеиз-вестно, что повышение давления при горении топлива в дозвуковой камере сгорания передает-ся вверх против течения и может вызвать уменьшение расхода воздуха и полного давления в воздухозаборнике, что нарушает режим работы двигателя и снижает его тяговые характери-стики [1,2].…”

Section: Introductionunclassified

“…1 показана схема проточного тракта ПВРД, который включает: сверхзвуковой воздухозаборник, имеющий участок внешнего сжатия (1)(2), участок внутреннего сжатия (2-3), горло с минимальной площадью поперечного сечения (3)(4), диффузор (4)(5), камеру сгорания (5-6) и сопло с критическим сечением (6). На участках внешнего и внутреннего сжатия осуще-ствляется сжатие и торможение захватываемого сверхзвукового потока.…”

Section: Introductionunclassified

Influence of Back Pressure on the Flow in the Diffuser of a Supersonic Air Inlet

2017

PNRPU Aerospace Engineering Bulletin

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Институт теоретической и прикладной механики им. С.А. Христиановича Сибирского отделения РАН, Новосибирск, Россия ВЛИЯНИЕ ПРОТИВОДАВЛЕНИЯ НА ТЕЧЕНИЕ В ДИФФУЗОРЕ СВЕРХЗВУКОВОГО ВОЗДУХОЗАБОРНИКАПредставлены результаты численного исследования перехода от сверхзвукового течения к дозвуковому в диф-фузоре сверхзвукового воздухозаборника прямоточного воздушно-реактивного двигателя при изменении противодав-ления в камере сгорания (при дросселировании канала). Рассматривались два варианта осесимметричного диффузора с большими углами (угол раскрытия θ = 10° и θ = 90°). Получены картины течения в зависимости от геометрических па-раметров диффузора и от степени дросселирования канала. Течение в диффузоре с углом раскрытия θ = 10° соответ-ствует псевдоскачковому режиму течения с отрывными зонами в пограничном слое. Течение в диффузоре с углом рас-крытия θ = 90° соответствует струйному течению в канале. Несмотря на принципиально различные режимы течения, характеристики потока на длине более 8-10 калибров одинаковы. Проведен анализ влияния противодавления на ха-рактеристики перехода (потери полного давления, прирост статического давления, длину переходной зоны и др.). Пока-зано, что при использовании диффузора с большими углами раскрытия противодавление в камере сгорания может из-меняться в три раза, не оказывая влияния на течение в горле и, соответственно, на течение в воздухозаборнике.Ключевые слова: численное моделирование, сверхзвуковой воздухозаборник, диффузор, псевдоскачок, каме-ра сгорания, дросселирование. INFLUENCE OF BACK PRESSURE ON THE FLOW IN THE DIFFUSER OF A SUPERSONIC AIR INLETThe results of a numerical study of the transition from supersonic to subsonic flow in the diffuser of a supersonic air inlet for ramjet engine with a change in the back pressure from the combustion chamber (with channel throttling) are presented. Two variants of an axisymmetric diffuser with large opening angles were considered (angle θ = 10º and θ = 90º). Flow patterns are obtained depending on the geometric parameters of the diffuser and on the degree of channel throttling. The flow in the diffuser with the opening angle θ = 10º corresponds to the pseudo-shock flow regime with separation zones in the boundary layer. The flow in the diffuser with an opening angle θ = 90º corresponds to the jet stream in the channel. Despite the fundamentally difference in flow regimes, the flow characteristics at a length of more than 8-10 calibers are the same. The effect of back pressure on the transition characteristics (total pressure loss, static pressure increase, transition zone length, etc.) is analyzed. It is shown that when a diffusers with large opening angles are used, the back pressure in the combustion chamber can be changed by a factor of three without affecting on the flow in the throat and, accordingly, on the flow in the air inlet.Keywords: numerical simulation, supersonic air inlet, diffuser, pseudo-shock, combustion chamber, throttling. ВведениеПроблема взаимодействия воздухозаборника и камеры сгорания является одной из клю-чевых ...

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Classification of Combustor–Inlet Interactions for Airbreathing Ramjet Propulsion

Cited by 13 publications

References 49 publications

Combustor-inlet interactions in a low-order dynamic model of ramjet engines

Combustor-inlet interactions in a low-order dynamic model of ramjet engines

The effect of backpressure on the transition to subsonic flow in the diffuser of a supersonic air intake

Influence of Back Pressure on the Flow in the Diffuser of a Supersonic Air Inlet

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