Fluid Dynamic Sizing and Structural Optimization of Pressurized Fuel Lines for a Hydrogen-Powered Aircraft

Kurzfassung

This research paper, conducted as part of the D-LIGHT+ project, addresses the sizing of hydrogen pipelines while taking into account different materials. The primary objective of this work is to develop a weight-efficient overall solution based on the selected material and one of three routing options. The Darcy-Weisbach equation is applied to determine the inner diameter of various pipe sizes, also considering additional pressure losses caused by fittings. A key advantage of this method is that it includes material-dependent surface roughness. Based on the calculated inner diameter, the required wall thickness is than determined. For isotropic materials, this is done in accordance with an ASME standard. The selection of pipe dimensions for both stainless steel and aluminum is made in regard to ASME standard. In the case of filament wound fiber-reinforced tubes, the wall thickness is initially established in accordance with a constant winding angle, as documented in extant literature. Subsequently, the potential for weight reduction through variation of the winding angle is investigated. Increasing the winding angle form the inner to the outer layers improves stress distribution and enhances resistance to inter fiber failure, as the results show. This enables a reduction in the required wall thickness. These findings are further supported by a mechanical derivation. In the specific context of pipeline optimization, the developed optimization method offers only limited advantages. Nevertheless, it provides valuable insights into the design of filament winding. Subsequent studies may consider the implementation of this method for applications such as hydrogen tanks and pipeline systems of greater diameter. In addition, the specific scope of application should be further defined. Following the sizing analysis, a preselection of suitable materials and a suitable routing option can be made. In the further course of the project, the focus should be particularly on optimizing the selection of valves with a view to further reducing total weight, given that these account for a significant contribution of the total weight of the piping system.