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Experiments in Fluids

, Volume 53, Issue 6, pp 1895–1913 | Cite as

Shadowgraph, Schlieren and interferometry in a 2D cavitating channel flow

  • Cyril Mauger
  • Loïc Méès
  • Marc Michard
  • Alexandre Azouzi
  • Stéphane Valette
Research Article

Abstract

Cavitation plays an important role in fuel atomization mechanisms, but the physics of cavitation and its impact on spray formation and injector efficiency are not well documented yet. Experimental investigations are required to support the development and the validation of numerical models and the design of tomorrow’s injectors, in the context of pollutant and fuel consumption reduction. The complexity of modern injectors and the extreme conditions of injection do not facilitate experimental investigations. In this paper, experiments are conducted in a simplified geometry. The model nozzle consists of a transparent 2D micro-channel supplied with a test oil (ISO 4113). Three different optical techniques are proposed to investigate the channel flow, with the pressure drop between upstream and downstream chambers as a parameter. A shadowgraph-like imaging technique allows the observation of cavitation inception and vapor cavities development throughout the channel. The technique also reveals the presence of density gradients (pressure or temperature) in the channel flow. However, this additional information is balanced by difficulties in image interpretation, which are discussed in the paper. In addition, a combination of Schlieren technique and interferometric imaging is used to measure the density fields inside the channel. The three techniques results are carefully analyzed and confronted. These results reveal a wealth of information on the flow, with pressure waves generated by bubble collapses, turbulence in the wake of vapor cavities and bubble survival in flow regions of high pressure. Our results also show that cavitation inception is located in the shear layers between the recirculation zones and the main flow, relatively far from the inlet corner, where the pressure is minimum in average. To explain this behavior, we propose a scenario of cavitation inception based on the occurrence and the growing of instabilities in the shear layers.

Keywords

Cavitation Pressure Drop Shear Layer Recirculation Zone Channel Inlet 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

This work takes place in the French collaborative program NADIA-bio (New Advance Diesel Injection Diagnosis for bio fuels). This program is supported by the French Automotive Cluster Mov’eo and funded by the DGCIS (Direction Générale de la Compétitivité, de l’Industrie et des Services), the Région Haute Normandie and the Conseil Général des Yvelines.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Cyril Mauger
    • 1
  • Loïc Méès
    • 1
  • Marc Michard
    • 1
  • Alexandre Azouzi
    • 1
  • Stéphane Valette
    • 2
  1. 1.Laboratoire de Mécanique des Fluides et d’Acoustique (LMFA), CNRS UMR5509, Ecole Centrale de Lyon, INSA de LyonUniversité Claude Bernard Lyon 1EcullyFrance
  2. 2.Laboratoire de Tribologie et Dynamique des Systèmes (LTDS), CNRS UMR5513, Ecole Centrale de LyonEcole Nationale d’Ingénieurs de Saint EtienneSaint-ÉtienneFrance

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