Cryogenic sloshing in aircraft fuel tanks

已知低温罐中的燃料晃动对缺量空间中的热力学具有重要影响，潜在地导致显著的压力下降并且因此不能从罐中提取燃料。由于低温环境，旋转机械，如泵是复杂的安装和可靠的操作，因此，自由表面晃动的特性是非常重要的液氢（LH 2）存储系统的有效设计在下一代民用飞机的应用。几个非侵入式测量技术存在的多相（液体/气体）的流动状态的特性在管道/通道。这些方法基于通过安装在管道外壁上的标准传感器获得的各种测量值（加速度计、应变仪、麦克风或光学传感器）;先进的信号处理技术，如小波分析;以及基于图像分析和粒子速度测量的流态知识。在本项目中，这些技术将进一步发展，空中客车公司的ZEROe混合氢概念飞机上的低温贮箱内的晃动流（和液体自由表面的结构）。由于晃动（第一近似值）与液舱内液体密度和压力无关，因此将首先在室温下（可目视观察自由表面）对液/气系统进行实验室测试，通过目视分析和粒子测速法对这些方法进行校准。

Fuel sloshing in cryogenic tanks is known to have important effects on the thermodynamics in the ullage space, potentially leading to significant pressure drops and consequent inability to extract the fuel from the tank. Due to the cryogenic environment, rotating machinery such as pumps are complex to install and operate reliably, therefore the characterisation of free surface sloshing is of paramount importance for the effective design of liquid hydrogen (LH2) storage systems in next-generation civil aircraft applications.Several non-intrusive measurement techniques exist for the characterization of multiple phase (liquid/gas) flow regimes in pipes/channels. These methods are based on a variety of measurements acquired via standard sensors mounted on the outside wall of the pipe (accelerometers, strain gauges, microphones or optical sensors); advanced signal processing techniques, such as wavelet analysis; and knowledge of the flow regime based on image analysis and particle velocimetry.In this project, these techniques will be developed further to measure, and characterise, the sloshing flow (and the configuration of the liquid free surface) within cryogenic tanks on-board Airbus' ZEROe hybrid-hydrogen concept aircraft. Since the sloshing (to first approximation) is independent of liquid density and the pressure in the tank, the methods will first be calibrated via visual analysis and particle velocimetry in laboratory tests on liquid/gas systems at room temperature (where visual access to the free surface is attainable).