The impact of liquefied natural gas (LNG) with the walls of its containing tank and the impact of droplets with very hot surfaces are two examples of liquid-solid impacts in which the liquid may be close to thermodynamic equilibrium with the surrounding gas/vapour. In addition to the usual violent fluid flows associated with liquid-solid impacts, significant phase change is possible in these cases. This project will seek to quantify this phase change and assess what effect it has on impact dynamics. In impacts without phase change, pre-impact gas cushioning in a narrow gas film separating the liquid and the solid has been observed. This leads to the formation of entrained pockets of gas, which have been modelled (see references).
In LNG sloshing, gas film pressure increases can lead to vapour condensation and reduced entrained gas pocket volumes. This effect is not currently included in LNG sloshing impact models, and consequently incorporating this phenomenon will improve the prediction of loads on the container wall and inform future LNG tank design.
Droplet impacts with heated surfaces are widely used as a method of reducing the temperature of very hot surfaces. Energy is transferred from the heated surface to individual droplets, leading to droplet evaporating and a net reduction in surface temperature. Evaporation from the droplet into the gas film enhances the pre-existing cushioning process. Once the surface reaches the Leidenfrost temperature the vapour cushion stabilizes and the droplet skates upon this cushion rather than impact the solid.
Using computational and analytical fluid dynamics, and mathematical modelling, this project will extend existing pre-impact gas-cushioning models by incorporating liquid boiling and condensation from the gas film. The models developed in this project will inform the thermofluid dynamics of liquid-solid impacts with phase change and improve understanding of the problems described.
Candidates should have (or expect to achieve) a UK honours degree at 2.1 or above (or equivalent) in Engineering, Applied Mathematics, Physics or a cognate discipline. Knowledge of Fluid dynamics, thermodynamics. Experience of computational methods would be beneficial.
• Apply for Degree of Doctor of Philosophy in Engineering
• State name of the lead supervisor as the Name of Proposed Supervisor
• State ‘Self-funded’ as Intended Source of Funding
• State the exact project title on the application form
When applying please ensure all required documents are attached:
• All degree certificates and transcripts (Undergraduate AND Postgraduate MSc-officially translated into English where necessary)
• Detailed CV
Informal inquiries can be made to Dr P Hicks ([email protected]
) with a copy of your curriculum vitae and cover letter. All general enquiries should be directed to the Postgraduate Research School ([email protected]
Hicks, P. D. LNG-solid impacts with gas cushioning and phase change. J. Fluid Struct., 2018, 80, 22-36.
Hicks, P. D. & Purvis, R. Air cushioning and bubble entrapment in three-dimensional droplet impacts. J. Fluid Mech., 2010, 649, 135-163.
Hicks, P. D.; Ermanyuk, E. V.; Gavrilov, N. V. & Purvis, R. Air trapping at impact of a rigid sphere onto a liquid. J. Fluid Mech., 2012, 695, 310-320.