Comparison of Supersonic Combustion Between Impulse and Vitiation-Heated Facilities

Boyce, Russell; Paull, A.; Stalker, R. J.; Wendt, M.; Chinzei, Nobuo; Matsubara, Hiroshi

doi:10.2514/2.5631

Cited by 49 publications

(9 citation statements)

References 9 publications

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“…Thermal choking occurred at lower fueling rates with dry air; consequently, higher performance was measured using vitiated air. As a follow-up to the experiments of Mitani et al [9], the performance of a scramjet combustor in a flow supplied by a combustion air preheater was compared with that for a flow supplied by a shock tunnel [10]. The pressure measurements in the combustor for the shock tunnel were found to be up to 15% higher than for the combustion air preheater experiment.…”

Section: Introductionmentioning

confidence: 96%

Test Gas Vitiation Effects in a Dual-Mode Scramjet Combustor

Goyne

McDaniel

Krauss

et al. 2007

Journal of Propulsion and Power

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Since flow at hypersonic Mach numbers (M≥5) behaves very differently from flow at subsonic or supersonic Mach numbers, the testing of hypersonic engines involves challenges not encountered in engine testing for flight in other regimes. For hypersonic Mach numbers, thermal, chemical, radiative, and ablative effects become important. Energy and heat transfer considerations make continuous-run, full scale testing at hypersonic Mach numbers difficult or impossible. While facilities have been devised specifically to study certain aspects of hypersonic flight, no single facility has the ability to simulate all the flow conditions that a hypersonic vehicle or engine may encounter. Flight can be considered the ultimate test of a hypersonic vehicle or engine because no facility effects are present. It is often the case, however, that budgetary, thermal, structural, or other logistical limitations restrict the range of diagnostics available for flight vehicle testing. Flight programs also incur significant risk that is generally not present or is significantly reduced for ground testing programs. If an unguided rocket is used to minimize cost, the likelihood that the payload will achieve the desired test conditions decreases. If a reactive control system is utilized to increase the likelihood that the payload will achieve the desired test conditions, both complexity and cost increase significantly. As such, flight programs are nearly always augmented with significant ground testing to reduce risk and confirm engine operability limits. Often a range of wind tunnels is used in order to resolve the inherent deficiencies of any one type of ground test facility. Two common shortcomings of hypersonic test facilities are the short test time associated with shock-heated facilities and the contaminated or vitiated test gas associated with combustion-heated facilities. iv Approved for public release; distribution is unlimited. AEDC PA 2012-083 This dissertation details a test program for a dual-mode scramjet which involves both ground and flight experiments in support of the Short Duration Propulsion Test and Evaluation (SDPTE) program, which aims to resolve the effects of a short test time and vitiated test medium on the operation and performance of a dual-mode scramjet (DMSJ). Included is background information related to previous scramjet test programs and their objectives, information on the design of the ground and flight tests for this program, as well as a novel rocket dispersion reduction scheme aimed at increasing the probability of a successful scramjet test flight. As part of this work, a hypersonic inlet for flight and freejet ground testing was designed and tested in an impulse facility. In these same tests, dual-mode operation of a DMSJ was demonstrated. Since only one test flight is planned for the SDPTE program and a scramjet's operation is directly influenced by the freestream conditions it encounters, a novel method was devised to reduce dispersion in test conditions seen by a scramjet flight-tested aboard a two-s...

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Section: Introductionmentioning

confidence: 96%

Test Gas Vitiation Effects in a Dual-Mode Scramjet Combustor

Goyne

McDaniel

Krauss

et al. 2007

Journal of Propulsion and Power

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“…Although scramjet development programs have a long history of using both direct-connect and freejet testing to validate engine geometry [9][10][11], often the data are only referenced in a compendium of the test campaign, or if comparisons are presented, they are generally very brief. In [12], a comparison study was performed of tests conducted on an identical flowpath in a Japan Aerospace Exploration Agency direct-connect blowdown facility and the University of Queensland T4 impulse freejet facility. Although the scramjet flowpath performed in a similar manner in the two facilities, the freejet flowpath did not use a traditional scramjet inlet.…”

Section: Introductionmentioning

confidence: 99%

Comparison of a Direct-Connect and Freejet Dual-Mode Scramjet

Steva

Goyne

Rockwell

et al. 2015

Journal of Propulsion and Power

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Testing of identical dual-mode scramjet flowpath geometries in the freejet and direct-connect configurations was conducted in two separate facilities. These tests enabled a comparison study between the two configurations, which was directed toward the determination of the effects of inlet distortion and backpressure on the performance and operability of a dual-mode scramjet. Bulk flow conditions were matched between the two facilities at the isolator entrance plane to simulate Mach 4.8 flight, and a series of metrics were established to quantify similarities and differences. The effects of flowpath backpressure in the direct-connect case were seen to be isolated to regions close to the exhaust. An approximate 10% decrease in combustor pressure rise and consequently integrated pressure force were observed in the freejet configuration; shock train length, however, remained the same. Mode transition was delayed from an equivalence ratio of ∼0.5 in the direct-connect case to ∼0.7 in the freejet configuration. Further, ignition difficulties were experienced in the freejet tests which were not encountered in those of direct-connect tests, limiting the scope of comparable test points. This work represents the first attempt at a quantitative comparison in the literature of an identical direct-connect and freejet dual-mode scramjet. Nomenclature A = cross-sectional area D = isolator duct height F = integrated pressure force H = fuel injector ramp normal height L = shock train length M 0 = freestream Mach number M u = Mach number at shock train leading edge M c = Mach number at combustor entrance _ m TBIVmc = predicted freejet flowpath mass capture _ m TBIVnom = nominal freejet facility mass flow rate _ m test = as tested facility mass flow rate (direct connect or freejet) P s = static pressure P 0 = total pressure p d ∕p u = peak static pressure/static pressure at leading edge of shock train Re u = unit Reynolds number, m −1 Re θ = Reynolds number based on boundary-layer momentum thickness T s = static temperature T 0 = total temperature x = axial distance θ = boundary-layer momentum thickness at the leading edge of shock train ϕ = angle of flowpath divergence from the horizontal φ = fuel equivalence ratio

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“…The streamlines that produced the required inlet cowl shock cancellation at the expansion into the isolator were used to form the inviscid inlet geometry. A viscous correction was applied to allow for the growing boundary layer within the inlet, using a flat plate analytical approximation [13]. If unaccounted for, a growing boundary layer will reduce the cross sectional area available to the flow, thereby increasing the pressure rise beyond the intended design value.…”

Section: Inlet Design Methodologymentioning

confidence: 99%

Hypersonic Inlet for a Laser Powered Propulsion System

Harrland¹,

Doolan²,

Wheatley³

et al. 2011

AIP Conference Proceedings

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Abstract. Propulsion within the lightcraft concept is produced via laser induced detonation of an incoming hypersonic air stream. This process requires suitable engine configurations that offer good performance over all flight speeds and angles of attack to ensure the required thrust is maintained. Stream traced hypersonic inlets have demonstrated the required performance in conventional hydrocarbon fuelled scramjet engines, and has been applied to the laser powered lightcraft vehicle. This paper will outline the current methodology employed in the inlet design, with a particular focus on the performance of the lightcraft inlet at angles of attack. Fully threedimensional turbulent computational fluid dynamics simulations have been performed on a variety of inlet configurations. The performance of the lightcraft inlets have been evaluated at differing angles of attack. An idealized laser detonation simulation has also been performed to validate that the lightcraft inlet does not unstart during the laser powered propulsion cycle.

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Comparison of Supersonic Combustion Between Impulse and Vitiation-Heated Facilities

Cited by 49 publications

References 9 publications

Test Gas Vitiation Effects in a Dual-Mode Scramjet Combustor

Test Gas Vitiation Effects in a Dual-Mode Scramjet Combustor

Comparison of a Direct-Connect and Freejet Dual-Mode Scramjet

Hypersonic Inlet for a Laser Powered Propulsion System

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