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Title: CFD modelling of water scavege jet pump
Author: Le Fur, Pierre
ISNI:       0000 0004 2745 1821
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2012
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This study describes the application of Large Eddy Simulation (LES) in combination with a Volume-of-Fluid method (VOF) for the simulation of water scavenge jet pumps (WSJP) of the kind used in aircraft fuel tanks. The WSJP is operated with fuel as the primary motive fluid to pump sump water and offers a very complex flow difficult to investigate experimentally due to the opaqueness of the dense two-phase mixture. In an attempt to address this issue, a computational LES- VOF approach is used to investigate in detail the working of the WSJP. As part of this investigation, the current work aims to contribute to the understanding of liquid-liquid atomisation, lesser known than more common liquid-gas atomisation. In addition to providing a more accurate physical pic- ture, this work serves as a test of the LES- VOF methodology and its limitations. The LES- VOF calculations over a range of flow ratios presented confirm that for the stan- dard operational flow ratio, a mixture of fuel droplets into water is produced at the exit, contrary to the desired result of water drops in fuel dispersion. The occurrence of the water-in-fuel dispersion is shown to be more likely to occur at lower inlet flow rate ra- tios, through phase inversion. The turbulent break-up of the central fuel jet show clearly the important overlapping effects of small and large scale instabilities in the fragmen- tation process. Additionally, Direct Numerical Simulations (DNS) are performed using the same interface-capturing methodology in order to gain insight into the dynamics of a single fuel droplet decelerating through stagnant water, with a view towards better un- derstanding of the liquid-liquid dynamics involved in the jet pump computations, and especially the effect of grid resolution on the quality of the results. The computations provide valuable information on the physics of the process, but mostly help confirm the validity of the LES-VOF results.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available