Structure of Shock Waves in Cylindrical Ducts

Waltrup, P. J.; Billig, F. S.

doi:10.2514/3.50600

Cited by 271 publications

(69 citation statements)

References 4 publications

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“…This combustion mode is typical of engines designed for flight Mach numbers less than 6 (Billig et al, 1990;Heiser and Pratt, 1994;Kobayashi et al, 2006;Waltrup and Billig, 1973). Turner and Smart (2013) recently documented the occurance of dual-mode combustion in a rest scramjet designed for flight at Mach 8.…”

Section: Fuel-off Datamentioning

confidence: 99%

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

Doherty¹

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The University of Queensland in 2014 school of mechanical and mining engineering centre for hypersonics abstract Realisation of the dream of airbreathing access-to-space requires the development of a scramjet engine that produces sufficient net thrust to enable acceleration over a wide Mach number range. With engines that are highly integrated with the airframe, the net performance of a scramjet powered vehicle is closely coupled with the vehicle attitude and is difficult to determine only from component level studies. This work investigates the influence of airframe integration on the performance of an airframe integrated scramjet through the measurement of internal pressure distribution and the direct measurement of the net lift, thrust and pitching moment using a three-component stress wave force balance. The engine chosen as the basis for this study was the Mach 12 rectangularto-elliptical shape-transition (m12rest) scramjet that was developed by Suraweera and Smart (2009) as a research engine for access-to-space applications. The inlet and combustor flowpath were integrated with a slender 6°wedge forebody, streamlined external geometry and three dimensional thrust nozzle. The scale of the engine was chosen so that the entire engine would fit within the core-flow diamond (bi-conic) produced by a Mach 10 facility nozzle. The Mach 10b facility nozzle was chosen because it is the largest nozzle current in use with the t4 Stalker Tube and because the offdesign performance of a scramjet engine is of interest for access-to-space vehicles that must accelerate over a range of Mach numbers.Freejet experiments were conducted within the t4 Stalker Tube. Two trueflight Mach 10 test conditions were used: a high pressure test condition that replicated flight at a dynamic pressure of 48 kPa and a low pressure test condition that replicated flight at a dynamic pressure of 28 kPa. Scaling of the test conditions according to the established binary scaling law was not completed due to facility operational limits.The engine featured two fuel injection stations from which gaseous hydrogen was injected. The first injection station was partway along the length of the inlet while the second injection station was at the start of the combustor behind a rearward facing circumferential step. In addition to investigating inlet-only and step-only injection, a combined scheme where 68 % of the fuel was injected from the step station and 32 % from the inlet station was also investigated.To support the analysis of the experimental results, numerical simulations of the engine with no fuel injection were conducted using the nasa code vulcan. Analysis of the simulations show that the mass capture ratio with respect to the projected inlet area is approximately 60 % at each test condition. The simulations also show that spillage of flow from the slender forebody accounts for just 12 % of the flow through the projected iii inlet area, a small but non-negligible fraction. By integrating the engine surface forces, the drag coefficient with respect ...

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Section: Fuel-off Datamentioning

confidence: 99%

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

Doherty¹

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“…Variations of entrance configuration and inlet position reveal different effects on performances [8] and studies at the position of the inlet diffuser were carried out to avoid flow separation [9,10]. Other studies included unstart criteria and inlet buzzing [11,12], which must be prevented [13] to ensure the functionality of the ramjet and prevent destruction of the structure of inflowing and the inlet unstart [14,15]. One technique is to control the inlet normal shock by adjusting internal parts of the inlet [16,17].…”

Section: Introductionmentioning

confidence: 99%

Research of Unsteady Flow Regimes in Channel of Hypersonic Inlet

Федорова¹,

Goldfeld²

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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“…The length of the pseudo-shock was attained from analysis of the flow structure in the pseudo-shock in these models. Empirical universal equations have been presented for a straight cylindrical duct 10 and a rectangular straight duct.…”

Section: Introductionmentioning

confidence: 99%

Momentum Balance Model of Flow Field with Pseudo-Shock

Kanda

Tani

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The length of a pseudo-shock was estimated with a new momentum balance model. In this simple model, it is presumed that there is no wall friction in the region of the pseudo-shock. Inflow conditions are specified at a boundary sufficiently upstream of the pseudo-shock. The outflow boundary condition is applied with, for example, specified pressure or choking. The outflow impulse function is balanced with the inflow impulse function, the wall friction upstream of the pseudo-shock, and the reaction force from the wall. The starting position of the pseudo-shock is determined through balance of the forces in this model, and the length of the pseudo-shock is also determined. The model was applied to several kinds of flow fields, for example, straight ducts with and without a backward-facing step, and divergent ducts. The model was also applied to the diffuser of an ejector-jet, in which two gases flowed in parallel. The calculated results reasonably agreed with the experimental results within the scope of preliminary application. The starting position of the pseudo-shock was primarily dominated by the reaction force in the divergent duct. Several features of the pseudo-shock were discussed with the present model. (7) and (17) a = papameter of Eq. (7) B = parameter of Eqs. (7) and (17) 2 JAXA Research and Development Report JAXA-RR-06-037E e = outflow f = friction i = inflow p = pseudo-shock, state at the exit of pseudo-shock r = reaction step = step t = total th = throat w = wall 1 = upstream of pseudo-shock, entrance, primary flow 1b = after bleeding and upstream of pseudoshock 2 = downstream of pseudo-shock, secondary flow

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Structure of Shock Waves in Cylindrical Ducts

Cited by 271 publications

References 4 publications

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

Research of Unsteady Flow Regimes in Channel of Hypersonic Inlet

Momentum Balance Model of Flow Field with Pseudo-Shock

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