Transient combustion in hybrid rockets

Karabeyoğlu, M. Arif; Altman, David; Bershader, D.

doi:10.2514/6.1995-2691

Cited by 27 publications

(27 citation statements)

References 5 publications

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“…Paraffin-based fuels, tested at Stanford University, show a 3-5 times higher regression rate at similar mass fluxes compared to polymers , Karabeyoglu, 1998. This is achieved by a different combustion mechanism.…”

Section: Introductionmentioning

confidence: 99%

Evaluation techniques for optical analysis of hybrid rocket propulsion

Petrarolo

Kobald

2016

JFST

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This article summarizes recent results of data evaluation techniques obtained with optical investigations on the combustion behavior of hybrid rocket fuels. Tests are performed in a 2D slab burner configuration with windows on two sides. Liquefying paraffin-based fuels are tested in combination with gaseous oxygen (GOX). High speed videos of combustion tests are recorded in order to investigate the combustion phenomena of this kind of fuels. Hybrid combustion of liquefying fuels is dominated by transient flow dynamics like Kelvin-Helmholtz instability and vortex shedding, also due to the characteristic turbulent diffusion flame. In order to better evaluate these flow phenomena, characteristic frequencies and wavelengths of the main structures of the flow field and of the combustion flame appearing in the video data have to be found. In this work, a spatial and temporal analysis of these structures is carried out by using two different techniques, applied within an automated video evaluation routine. First of all, the Proper Orthogonal Decomposition (POD) technique is used. Its results deliver linearly uncorrelated variables, which are the principal components of the flow field. This method enables to recognize the main structures of the flow field and the combustion flame appearing in the video data. Secondly, the Independent Component Analysis (ICA) technique is applied to the same data. It is able to search for statistically independent, or as independent as possible, structures hidden in the data. It increases the independence to higher statistical orders with respect to POD. The basis functions found with the ICA are expected to describe the essential structure of the data and to resemble some physical processes involved in the combustion. With both methods it is possible to compute spatial and temporal coefficients, which can be later analyzed by applying a Power Spectral Density (PSD) in order to obtain the excited frequencies and wavelengths during the combustion. Finally, the results of the two methods are compared in order to better understand and interpret them. The results collected so far and the comparison of both techniques show that their application is consistent and useful for the automated evaluation of combustion data. Petrarolo and Kobald, Journal of Fluid Science and Technology, Vol.11, No.4 (2016) fuel grains for high thrust applications. The multiport design increases the residual mass of unburnt fuel and thereby decreases the delivered specific impulse. Instabilities are also more likely with this type of design.Liquefying hybrid rocket fuels were only found recently. Cryogenic solid n-pentane showed regression rates 5-10 times higher than polymeric hybrid fuels (Carrick and Larson, 1995, Larson et al., 1996, DeRose et al., 1997.Paraffin-based fuels, tested at Stanford University, show a 3-5 times higher regression rate at similar mass fluxes compared to polymers , Karabeyoglu, 1998. This is achieved by a different combustion mechanism. Paraffin fuels form a liquid layer on the...

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Section: Introductionmentioning

confidence: 99%

Evaluation techniques for optical analysis of hybrid rocket propulsion

Petrarolo

Kobald

2016

JFST

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“…Karabeyoglu found that the calculation accuracy of the velocity distribution obtained by Marxman et al becomes worse with comparison to Eq. (11) as the blowing from the fuel surface becomes stronger (13) . We therefore used this velocity distribution in order to obtain a theoretical regression rate for hybrid rocket combustion.…”

Section: Solid-fuel Regression Ratementioning

confidence: 99%

Solid-Fuel Regression Rate for Standard-Flow Hybrid Rocket Motors

Morita

Yuasa

Yamaguchi

et al. 2012

JTST

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Marxman's diffusion-limited analysis of hybrid rocket combustion has been often used to investigate various combustion problems in hybrid rocket motors. This analysis was developed on the basis of the Reynolds analogy in turbulent boundary layers. This analogy assumes that both molecular and turbulent Prandtl numbers are equal to one. In the present study, a semi-empirical correlation between the Stanton number and the skin-friction coefficient in a turbulent boundary layer was obtained. This is applicable to hybrid rocket combustion, and also includes the effects of the Prandtl numbers variation. Using this correlation, a fuel regression rate equation for standard-flow hybrid rocket motors was obtained, and its characteristics were examined. In addition, the calculated regression rate characteristics were compared with the experimental data from the laboratory-scale hybrid rocket motors that used gaseous oxygen (GOX) as oxidizer and polymethylmethacrylate (PMMA) as fuel.

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“…It takes a different expression from the transfer function derived by Karabeyoglu (2) . When the polytropic exponent of the combustion product gas is equal to one, it is equivalent to that derived by Karabeyoglu.…”

Section: ( )mentioning

confidence: 99%

“…Many studies were done on the theoretical treatment of feed system coupled combustion instabilities in hybrid rocket motors using the assumption that various physical quantities in a combustion chamber change in bulk mode (1)(2)(3) . However, the axial variation of various physical quantities in large L/D motors cannot be ignored.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it is necessary to incorporate the spatial non-uniformities into the transfer function of chamber gas dynamics in hybrid rocket motors. In order to examine the low-frequency combustion instabilities of large L/D motors, the transfer function of a liquid-fed system was coupled with that of the full thermal-combustion-gasdynamic (TCG) coupled system, which was obtained based on the method developed by Karabeyoglu (2) . Moreover, considering the effect of heat loss on a combustion chamber wall, gas temperature is assumed to change in a polytropic process.…”

Section: Introductionmentioning

confidence: 99%

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Low-Frequency Feed-System-Coupled Combustion Instability in Hybrid Rocket Motors

Morita

Yuasa

Kitagawa

et al. 2013

JTST

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The low-frequency unstable combustion of hybrid rocket motors was investigated using the transfer function of the full thermal-combustion-gasdynamic coupled system that was coupled with a liquid oxidizer feed system. This transfer function was obtained based on the method developed by Karabeyoglu et al. The transfer function is applicable to the motors that have a long fuel port length. The linear stability limits and the frequencies of pressure oscillations in hybrid rocket motors were obtained theoretically using the transfer function. In addition, we compared these results with the results obtained under the assumption that various physical quantities change in bulk mode.

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Transient combustion in hybrid rockets

Cited by 27 publications

References 5 publications

Evaluation techniques for optical analysis of hybrid rocket propulsion

Evaluation techniques for optical analysis of hybrid rocket propulsion

Solid-Fuel Regression Rate for Standard-Flow Hybrid Rocket Motors

Low-Frequency Feed-System-Coupled Combustion Instability in Hybrid Rocket Motors

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