Matched Pressure Injections into a Supersonic Crossflow Through Diamond-Shaped Orifices

Tomioka, Sadatake; Izumikawa, Muneo; Kouchi, Toshinori; Masuya, Goro; Hirano, Kohshi; Matsuo, Akiko

doi:10.2514/1.35177

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…The penetration height of the stinger injector was greater than that of the circular injector below J ~ 3 and saturated with increasing J. The rapid saturation of H was caused by the axis switching of jet expansion that was the same phenomenon as observed in the experiment using the diamond-shaped orifice [23]. Figure 4 presents back views of the jet plumes through the stinger (right) and circular (left) injectors at J = 1 and J = 4 obtained by numerical simulation [25] under the same conditions as for the cold-flow experiment.…”

Section: B Stinger Injectormentioning

confidence: 54%

“…A wedge-shaped orifice [14] and a diamond-shaped orifice [15] produced better penetration than the circular injector because they reduced P b by avoiding the boundary-layer separation ahead of the injector in low J regimes. Recently, Tomioka et al attempted to further reduce P b for the diamond-shaped orifice in higher J regimes and introduced a pressurematched supersonic jet through the diamond-shaped orifice [23]. The injector was proven to achieve low jet-airflow interaction and to promote the jet penetration in a cold-flow experiment using helium injectant.…”

Section: Introductionmentioning

confidence: 99%

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Supersonic Combustion Using a Stinger-Shaped Fuel Injector

Kouchi

Masuya

Hirano³

et al. 2013

Journal of Propulsion and Power

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We developed a stinger-shaped injector (stinger injector) for supersonic combustors in cold-flow experiments. The stinger injector has a port geometry with a sharp leading edge in front of a streamwise slit. This injector produced higher jet penetration at a lower jet-tocrossflow momentum flux ratio (J) than a conventional circular injector. We applied the injector in a Mach 2.44 combustion test at a stagnation temperature of 2060 K. At a low fuel equivalence ratio (Φ) regime (i.e., low J regime), the injector produced 10% higher pressure thrust than the circular injector because of high jet penetration as expected from the coldflow experiments. Even at a moderate Φ regime, the stinger injector produced higher pressure thrust than the circular injector. At moderate Φ, the stinger injector held the flame around the injector and generated a precombustion shock wave in front of the injector. The presence of the precombustion shock wave decreased the momentum flux of the crossflow air and diminished the advantage of the injector for jet penetration. The injector, however, produced higher pressure thrust because better flame-holding produced higher pressure around the injector. At a higher Φ regime, the precombustion shock wave went upstream with both injectors. The far-upstream presence of a precombustion shock wave increased the

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Section: B Stinger Injectormentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Supersonic Combustion Using a Stinger-Shaped Fuel Injector

Kouchi

Masuya

Hirano³

et al. 2013

Journal of Propulsion and Power

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“…The decay rate of the maximum concentration was found to be nearly insensitive to the orifice shape. The same tendencies for penetration height and maximum mass fraction decay were observed in an experimental study with a Mach 2.5 crossflow, which also examined the characteristics of supersonic and subsonic injections in the matched-pressure conditions (where the fuel is injected at the effective backpressure [11]) as well as offdesign conditions [12]. A considerable advantage of a diamond orifice in penetration was also reported by Schetz et al [13], who examined the flowfields in the presence of sonic injection of helium into a Mach 3.8 airflow through circular and diamond injectors inclined at 30 deg in a combined experimental/computational approach.…”

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confidence: 53%

Mixing Characteristics of Inclined Fuel Injection via Various Geometries for Upstream-Fuel-Injected Scramjets

Ogawa

2015

Journal of Propulsion and Power

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Efficient fuel/air mixing plays a crucial role in successful operation of hypersonic airbreathing engines, particularly scramjets, where fuel must be injected into high-speed crossflow and mixed with air at an extremely short timescale. This paper presents the results of a numerical study that investigates the effects of various orifice shapes on fuel mixing characteristics into hypersonic airflow at Mach 5, aiming at the application to scramjet operation with upstream fuel injection at Mach 10. The performance of the injectors at an inclination angle of 45 deg are assessed with respect to various criteria such as the mixing efficiency, streamwise circulation, total pressure recovery, fuel penetration, and spread. Streamwise slot injectors have been found to yield higher mixing efficiency than the other injectors tested (namely, square, circular, diamond, and triangular injectors), owing to the buffering effects. Apparent higher total pressure recovery has been obtained with these rectangular injectors, but their advantages have diminished significantly with the alignment of the trailing-edge position. The highest vertical penetration has been achieved by the square injector, whereas the performances of other injectors with a sharp leading edge have been found to be affected considerably by the axis switch phenomenon due to inclined injection at higher injection pressure. A major influence of the fore and aft shapes of the orifice has been observed on the three-dimensional bow shock formation and wake recirculation, respectively. Nomenclature A = cross section at a streamwise station AR = aspect ratio (streamwise/spanwise) A j = injector area on floor, m 2 A n j = injector area normal to jet, m 2 c = mass fraction c H 2 = hydrogen mass fraction c O 2 = oxygen mass fraction c s = stoichiometric mass fraction D = effective injector diameter, m H = height of computational domain, m h f = fuel penetration height J = jet-to-freestream momentum flux ratio L = length of computational domain, m L 0 = distance to upstream end of injector, m _ m = mass flow rate, kg∕s p = static pressure, Pa p 0 = total pressure, Pa p 02 = pitot pressure, Pa U = crossflow velocity, m∕s W = domain width (injector spacing), m w f = lateral fuel spread x = streamwise direction, m y = spanwise direction, m z = vertical direction, m α j = injection angle, deg Γ = streamwise circulation γ= specific heat ratio Δp 0 = total pressure loss, Pa η m = mixing efficiency Φ = fuel/air equivalence ratio χ m = overall mesh refining factor χ m xy = refining factor in x and y directions χ m z = refining factor in z direction ω x = streamwise vorticity, ∕s Subscripts j = jet property STA = stream-thrust-averaged value ∞ = freestream property

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