Design of a Mach 2 shape transition nozzle for lab-scale direct-connect supersonic combustor

Sung, Bu-Kyeng; Choi, Jeong-Yeol

doi:10.1016/j.ast.2021.106906

Cited by 13 publications

(4 citation statements)

References 12 publications

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“…Leveraging cross-sectional data derived from the two-dimensional axisymmetric Method of Characteristics (MOC) design, the 3D CRST nozzle was developed by integrating the shape transition function, accounting for the cross-sectional shift from circular to square. The three-dimensional steady-state numerical analysis results validated the achievement of a homogenous Mach number distribution and the development of a homogenous boundary layer in the CRST nozzle exit region [58].…”

Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 57%

“…Consequently, when the high-enthalpy flow is channeled from the VAH to the isolator, a non-uniform flow and boundary layer may be formed. To mitigate this, CRST nozzles were conceived to suppress flow inhomogeneity and generate an optimal boundary layer [58]. Leveraging cross- The VAH's cross-section is circular, while the isolator section of the supersonic combustor has a square cross-section with an edge length of 2.0 mm.…”

Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 99%

“…Consequently, when the high-enthalpy flow is channeled from the VAH to the isolator, a non-uniform flow and boundary layer may be formed. To mitigate this, CRST nozzles were conceived to suppress flow inhomogeneity and generate an optimal boundary layer [58]. Leveraging cross-sectional data derived from the two-dimensional axisymmetric Method of Characteristics (MOC) design, the 3D CRST nozzle was developed by integrating the shape transition function, accounting for the cross-sectional shift from circular to square.…”

Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 99%

See 2 more Smart Citations

Reactive Flow Dynamics of Low-Frequency Instability in a Scramjet Combustor

Jeong,

Han,

Sung

et al. 2023

Aerospace

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This study numerically investigated the combustion instability and characteristics of a laboratory-scale gaseous hydrogen-fueled scramjet combustor. For this purpose, a numerical simulation with an improved detached eddy simulation and a detailed hydrogen/oxygen reaction mechanism was performed. The numerical framework used high-resolution schemes with high-order accuracy to ensure high resolution and fidelity. A total of five fuel injection pressures were considered to characterize the combustion instability as a function of the equivalence ratio. A sampling time of up to 100 ms was considered to sufficiently accumulate several cycles of low-frequency combustion instability dynamics with a period in the order of 100 Hz. Numerical results revealed the repetitive formation/dissipation dynamics of the upstream-traveling shock wave, and it acts as a key factor of combustion instability. The period and derived principal frequency of these upstream-traveling shock waves is several ms. The frequency analysis showed that the instability frequency increased in the low-frequency range as the combustion mode transitioned from the cavity shear-layer to the jet-wake type. This characteristic was derived from the transition in combustion mode at the same equivalence ratio. Therefore, it suggests that the instability frequency shifting is governed by the combustion mode rather than the equivalence ratio. These comprehensive numerical results demonstrated not only the effect of the equivalence ratio but also the important role of the combustion mode on the low-frequency combustion instability.

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Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 57%

Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 99%

“…Consequently, when the high-enthalpy flow is channeled from the VAH to the isolator, a non-uniform flow and boundary layer may be formed. To mitigate this, CRST nozzles were conceived to suppress flow inhomogeneity and generate an optimal boundary layer [58]. Leveraging cross-sectional data derived from the two-dimensional axisymmetric Method of Characteristics (MOC) design, the 3D CRST nozzle was developed by integrating the shape transition function, accounting for the cross-sectional shift from circular to square.…”

Section: Model Supersonic Combustor and Operating Conditionmentioning

confidence: 99%

See 1 more Smart Citation

Reactive Flow Dynamics of Low-Frequency Instability in a Scramjet Combustor

Jeong,

Han,

Sung

et al. 2023

Aerospace

Self Cite

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“…Therefore, as shown in Figure 4 and Table 2, the geometric design variables of the upstream section of the nozzle throat were defined and designed. The design process was covered in detail in a study by Sung et al [21,22]. The nozzle has a 130 mm length, a Ø 40 mm inlet, and a 20 × 20 mm rectangular outlet.…”

Section: Vitiation-air-heater Experimental Modelmentioning

confidence: 99%

A Study on a Vitiated Air Heater for a Direct-Connect Scramjet Combustor and Preliminary Test on the Scramjet Combustor Ignition

Lee

Han

et al. 2023

Aerospace

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Vitiation air heater (VAH) combustion characteristics for a direct-connect scramjet combustor (DCSC) were experimentally studied. The VAH consists of a head, modular chamber, and circular-to-rectangular shape transition (CRST) nozzle. The CRST nozzle transforms the circular cross-sectioned rocket-type VAH into a rectangular cross-sectioned scramjet combustor. The CRST nozzle exit Mach numbers at the top, middle, and bottom were measured using a tungsten wedge. The oblique shock formed by the wedge was captured using Schlieren visualization and recorded with a high-speed camera. The θ-β-M relation showed that the exit Mach number was 2.04 ± 0.04 with a chamber pressure of 1.685 ± 0.07 MPa. With the VAH design point verified, preliminary scramjet combustor ignition tests were conducted. As the fuel was not auto-ignited by the vitiated air, the forced ignition method, in which VAH ignition flame ignites the scramjet fuel, was used. The Schlieren images showed that a cavity shear layer combustion mode was formed and also showed that the forced ignition method could be used as a reference model for the ignitor-ignition method.

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