Communication Dans Un Congrès Année : 2024

Multi-scale analysis of textural atomization in LOx-CH4 rocket engine subcritical flames

Résumé

In cryogenic liquid rocket engines, the propellants are usually injected into the combustion chamber by a coaxial injection system. During transient or low-thrust flight regimes, the injected propellants are in a subcritical state. The oxidizer is injected as a cylindrical liquid jet and the fuel is injected as a higher-velocity annular gaseous stream surrounding the liquid. Under such conditions, the primary atomization of the liquid oxidizer plays a major role in the combustion process. The primary atomization of the liquid oxidizer refers to the production of liquid fragments and droplets from ligaments at the liquid-gas interface. These ligaments, most likely a result of turbulent fluctuations in the liquid jet, are peeled from the interface in a process referred to as textural atomization. This article proposes a multi-scale description of the liquid ligaments responsible for the primary atomization process in a liquid oxygen/methane powered subscale rocket combustor. This description relies on recently developed image processing techniques to measure the local scale distribution of the liquid ligaments, as visualized in experimental backlighting images of the atomization process. Results report an evolution of the scale distribution of textural ligaments with the distance from the injector. Three operating conditions are compared. A global trend is observed, including positions where the textural atomization process is at its most intense and where it stops. A weak dependency on chamber pressure is reported, which is in line with the turbulent fluctuation-based ligament initiation scenario proposed in the literature. The reported measurements may lead to an estimation of local drop-diameter distributions. The reported observations provide valuable insights into the primary atomization process which can be used in the development of numerical models.

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Dates et versions

hal-04650082 , version 1 (16-07-2024)

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Identifiants

  • HAL Id : hal-04650082 , version 1

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Leonardo Geiger, Nicolas Fdida, Luc-Henry Dorey, Lucien Vingert, Marie Théron, et al.. Multi-scale analysis of textural atomization in LOx-CH4 rocket engine subcritical flames. Space Propulsion 2024, May 2024, Glasgow, United Kingdom. ⟨hal-04650082⟩
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