Cryogenic sloshing in aircraft fuel tanks

众所周知，燃料在低温储罐中的晃动对真空空间中的热力学有重要影响，可能导致显著的压力下降，从而无法从储罐中提取燃料。由于低温环境，泵等旋转机械的安装和可靠运行非常复杂，因此自由表面晃动的特征对于下一代民用飞机应用中液氢（LH2）存储系统的有效设计至关重要。存在几种非侵入式测量技术，用于表征管道/通道中的多相（液/气）流动状态。这些方法是基于通过安装在管道外壁的标准传感器（加速度计、应变计、麦克风或光学传感器）获得的各种测量结果；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测速的流态知识。在这个项目中，这些技术将进一步发展，以测量和表征空中客车零oe混合氢概念飞机上的低温储罐内的晃动流动（以及液体自由表面的配置）。由于晃动（初步近似）与液体密度和罐内压力无关，因此将首先通过室温下液体/气体系统的实验室测试中的视觉分析和粒子测速来校准这些方法（在室温下，可以直观地看到自由表面）。

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).