Petrarolo, Anna and Kobald, Mario and Schlechtriem, S. (2018) Understanding Kelvin-Helmholtz Instability in Paraffin-Based Hybrid Rocket Fuels. Experiments in Fluids, 59 (4), p. 62. Springer. doi: 10.1007/s00348-018-2516-1. ISSN 0723-4864.
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Official URL: https://link.springer.com/article/10.1007%2Fs00348-018-2516-1
Abstract
Liquefying fuels show higher regression rates than the classical polymeric ones. They are able to form, along their burning surface, a low viscosity and surface tension liquid layer, which can become unstable (Kelvin--Helmholtz instability) due to the high velocity gas flow in the fuel port. This causes entrainment of liquid droplets from the fuel surface into the oxidizer gas flow. To better understand the droplets entrainment mechanism, optical investigations on the combustion behaviour of paraffin-based hybrid rocket fuels in combination with gaseous oxygen have been conducted in the framework of this research. Combustion tests were performed in a 2D single-slab burner at atmospheric conditions. High speed videos were recorded and analysed with two decomposition techniques. Proper orthogonal decomposition (POD) and independent component analysis (ICA) were applied to the scalar field of the flame luminosity. The most excited frequencies and wavelengths of the wave-like structures characterizing the liquid melt layer were computed. The fuel slab viscosity and the oxidizer mass flow were varied to study their influence on the liquid layer instability process. The combustion is dominated by periodic, wave-like structures for all the analysed fuels. Frequencies and wavelengths characterizing the liquid melt layer depend on the fuel viscosity and oxidizer mass flow. Moreover, for very low mass flows, no wavelength peaks are detected for the higher viscosity fuels. This is important to better understand and predict the onset and development of the entrainment process, which is connected to the amplification of the longitudinal waves.
Item URL in elib: | https://elib.dlr.de/119134/ | ||||||||||||
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Document Type: | Article | ||||||||||||
Title: | Understanding Kelvin-Helmholtz Instability in Paraffin-Based Hybrid Rocket Fuels | ||||||||||||
Authors: |
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Date: | 5 March 2018 | ||||||||||||
Journal or Publication Title: | Experiments in Fluids | ||||||||||||
Refereed publication: | Yes | ||||||||||||
Open Access: | Yes | ||||||||||||
Gold Open Access: | No | ||||||||||||
In SCOPUS: | Yes | ||||||||||||
In ISI Web of Science: | Yes | ||||||||||||
Volume: | 59 | ||||||||||||
DOI: | 10.1007/s00348-018-2516-1 | ||||||||||||
Page Range: | p. 62 | ||||||||||||
Publisher: | Springer | ||||||||||||
ISSN: | 0723-4864 | ||||||||||||
Status: | Published | ||||||||||||
Keywords: | Paraffin fuels, hybrid Propulsion, optical Investigation, POD, ICA, Oxygen, liquefying fuel | ||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||
HGF - Program: | Space | ||||||||||||
HGF - Program Themes: | Space Transportation | ||||||||||||
DLR - Research area: | Raumfahrt | ||||||||||||
DLR - Program: | R RP - Space Transportation | ||||||||||||
DLR - Research theme (Project): | R - Antriebsystemtechnik - Raketenantriebtests (old) | ||||||||||||
Location: | Lampoldshausen | ||||||||||||
Institutes and Institutions: | Institute of Space Propulsion > Propellants | ||||||||||||
Deposited By: | Kobald, Dr. Mario | ||||||||||||
Deposited On: | 06 Mar 2018 07:55 | ||||||||||||
Last Modified: | 06 Sep 2019 15:25 |
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