Effect of swirl on shock structure in underexpanded supersonic airflow

A. Abdelhafez; A. K. Gupta

doi:10.2514/1.45716

Effect of swirl on shock structure in underexpanded supersonic airflow

A. Abdelhafez^*, A. K. Gupta

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

This study examines the effect of imparting swirl to underexpanded supersonic-nozzle airflow on shock structure under matched mass flow conditions. A convergent nozzle with swirling capabilities is used to generate the underexpanded airflow. Fuel is injected coaxially at the nozzle throat. Nonreacting conditions are considered, wherein fuel is simulated by mixtures of helium, argon, and krypton inert gases. It was found that the effects of swirl and nozzle reservoir pressure interfere destructively from the point of view of shock-structure axial compactness. Increasing reservoir pressure stretches the shock structure axially, whereas swirl shrinks it. On the other hand, constructive interference was observed from the point of view of radial jet expansion; both result in greater jet diameter. The application of swirl was found to weaken the shock structure at matched reservoir pressure but to strengthen it at matched mass flow. It was also found that fuel injected at low subsonic Mach numbers into the supersonic airflow has to propagate initially with a negative shear angle; i.e., the cross-sectional area of fuel-rich core flow converges first, before this core flow reaches a throat after which it propagates supersonically. This behavior was found to be advantageous, as it results in reduced shock-structure strength.

Original language	English
Pages (from-to)	215-229
Number of pages	15
Journal	Journal of Propulsion and Power
Volume	26
Issue number	2
DOIs	https://doi.org/10.2514/1.45716
State	Published - 2010
Externally published	Yes

Bibliographical note

Funding Information:
This work was supported by the Space Vehicle Technology Institute, jointly funded by NASA, U.S. Department of Defense, and U.S. Air Force within the NASA Constellation University Institutes Project (CUIP), with Claudia Meyer as the Project Manager. This support is gratefully acknowledged. The simulation package CFD-GEOM, CFD-FASTRAN, and CFD-VIEW was provided by ESI-Group and CFD Research Corporation. This support is gratefully acknowledged. Assistance provided by Adam Kareem in data acquisition and analysis is much appreciated.

ASJC Scopus subject areas

Aerospace Engineering
Fuel Technology
Mechanical Engineering
Space and Planetary Science

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Cite this

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title = "Effect of swirl on shock structure in underexpanded supersonic airflow",

abstract = "This study examines the effect of imparting swirl to underexpanded supersonic-nozzle airflow on shock structure under matched mass flow conditions. A convergent nozzle with swirling capabilities is used to generate the underexpanded airflow. Fuel is injected coaxially at the nozzle throat. Nonreacting conditions are considered, wherein fuel is simulated by mixtures of helium, argon, and krypton inert gases. It was found that the effects of swirl and nozzle reservoir pressure interfere destructively from the point of view of shock-structure axial compactness. Increasing reservoir pressure stretches the shock structure axially, whereas swirl shrinks it. On the other hand, constructive interference was observed from the point of view of radial jet expansion; both result in greater jet diameter. The application of swirl was found to weaken the shock structure at matched reservoir pressure but to strengthen it at matched mass flow. It was also found that fuel injected at low subsonic Mach numbers into the supersonic airflow has to propagate initially with a negative shear angle; i.e., the cross-sectional area of fuel-rich core flow converges first, before this core flow reaches a throat after which it propagates supersonically. This behavior was found to be advantageous, as it results in reduced shock-structure strength.",

author = "A. Abdelhafez and Gupta, \{A. K.\}",

note = "Funding Information: This work was supported by the Space Vehicle Technology Institute, jointly funded by NASA, U.S. Department of Defense, and U.S. Air Force within the NASA Constellation University Institutes Project (CUIP), with Claudia Meyer as the Project Manager. This support is gratefully acknowledged. The simulation package CFD-GEOM, CFD-FASTRAN, and CFD-VIEW was provided by ESI-Group and CFD Research Corporation. This support is gratefully acknowledged. Assistance provided by Adam Kareem in data acquisition and analysis is much appreciated.",

year = "2010",

doi = "10.2514/1.45716",

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AU - Abdelhafez, A.

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PY - 2010

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N2 - This study examines the effect of imparting swirl to underexpanded supersonic-nozzle airflow on shock structure under matched mass flow conditions. A convergent nozzle with swirling capabilities is used to generate the underexpanded airflow. Fuel is injected coaxially at the nozzle throat. Nonreacting conditions are considered, wherein fuel is simulated by mixtures of helium, argon, and krypton inert gases. It was found that the effects of swirl and nozzle reservoir pressure interfere destructively from the point of view of shock-structure axial compactness. Increasing reservoir pressure stretches the shock structure axially, whereas swirl shrinks it. On the other hand, constructive interference was observed from the point of view of radial jet expansion; both result in greater jet diameter. The application of swirl was found to weaken the shock structure at matched reservoir pressure but to strengthen it at matched mass flow. It was also found that fuel injected at low subsonic Mach numbers into the supersonic airflow has to propagate initially with a negative shear angle; i.e., the cross-sectional area of fuel-rich core flow converges first, before this core flow reaches a throat after which it propagates supersonically. This behavior was found to be advantageous, as it results in reduced shock-structure strength.

AB - This study examines the effect of imparting swirl to underexpanded supersonic-nozzle airflow on shock structure under matched mass flow conditions. A convergent nozzle with swirling capabilities is used to generate the underexpanded airflow. Fuel is injected coaxially at the nozzle throat. Nonreacting conditions are considered, wherein fuel is simulated by mixtures of helium, argon, and krypton inert gases. It was found that the effects of swirl and nozzle reservoir pressure interfere destructively from the point of view of shock-structure axial compactness. Increasing reservoir pressure stretches the shock structure axially, whereas swirl shrinks it. On the other hand, constructive interference was observed from the point of view of radial jet expansion; both result in greater jet diameter. The application of swirl was found to weaken the shock structure at matched reservoir pressure but to strengthen it at matched mass flow. It was also found that fuel injected at low subsonic Mach numbers into the supersonic airflow has to propagate initially with a negative shear angle; i.e., the cross-sectional area of fuel-rich core flow converges first, before this core flow reaches a throat after which it propagates supersonically. This behavior was found to be advantageous, as it results in reduced shock-structure strength.

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Effect of swirl on shock structure in underexpanded supersonic airflow

Abstract

Bibliographical note

ASJC Scopus subject areas

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