Cryogenic Sloshing in Aircraft fuel tanks

Title: Cryogenic Sloshing in Aircraft fuel tanks

Funding body: EPSRC (EP/W522223/1)
Funding period: 2021-2025

Principal researchers:

University of Plymouth: Dr Edward Ransley , Dr Yeaw Chu Lee and Professor Deborah Greaves OBE FREng
Airbus UK: Francesco Gambioli

Research student:

University of Plymouth: Mr Stuart Colville

Overview:

The aviation industry is committed to make net zero carbon aviation a reality. A promising alternative fuel for commercial aviation is liquid hydrogen (LH2). This fuel has the potential to reduce the environmental impact of the aviation sector, alongside this, the inherently high specific energy density (approximately three times that of traditional aviation fuel) makes LH2 a natural alternative fuel.

One of the technical challenges facing LH2 powered aircraft is liquid sloshing - the motion of the fluid free surface inside a partially filled container. LH2 creates a cryogenic environment, thus within an LH2 fuel tank a large temperature difference between the liquid and gas phases exists. Liquid sloshing creates mixing of these phases leading to interfacial heat and mass transfer (thermodynamic effects), this results in undesirable phenomena such as rapid pressure drops and liquid saturation.

This project focuses on physical modelling of sloshing and aims to inform understanding of sloshing regimes which will help instigate remedial measures to prevent severe thermodynamic effects which could effect fuel delivery within LH2 storage systems in next generation aircraft.

Project objectives:

The objectives of this work are described as:

Review and centralise cryogenic sloshing studies into a coherent report. Identify both the advantages and limitations of surrogate fluids in sloshing experiments for similitude with LH2 and consider a range of measurement techniques. Investigate the dependence of key parameters with a focus on the dimensionless numbers involved in the problem. Correlate the pressure evolution between a wide range of studies; including cryogenic and non-cryogenic testing, different geometries, excitations and accelerations.
Characterisation of different sloshing regimes will be explored through analysis of fluid displacements and velocities where fluids at room temperature will be tested initially.
Perform experiments on non-isothermal flows with both water and volatile liquid (HFE7000) under excitation. Quantify the pressure drop of these liquids under the different regimes. A quantitative understanding of how external excitations relate to sloshing regimes and corresponding pressure drops is important for LH2 powered aviation.