Numerical modelling of cryogenic chilldown of transfer lines using liquid hydrogen in simulink

Conference item

Abstract To prevent combustion instabilities in future liquid hydrogen (LH2) aircrafts, it is important to chill down cryogenic fuel transfer lines before useful LH2 can be introduced for combustion. Efficient strategies to minimize the chilldown mass and time required, warrant thorough experimental investigation. However, we also need to develop tools that can guide designers towards favorable configurations. Thus, it is desirable to build computational frameworks for the design and prediction of chill-down of LH2 transfer lines. To date, published numerical models are commonly built on the proprietary Generalized Fluid System Simulation Program (GFSSP) developed by NASA. Moreover, some models employ Heat Transfer Coefficient (HTC) correlations which are either not suitable for cryogenic conditions or developed on datasets of other cryogens like liquid nitrogen. In this study, we review existing numerical models and present a computational framework in Simulink to model turbulent pipe chilldown experiments previously conducted at NASA. Since transients are sensitive to HTC, we modify the built-in two-phase pipe correlations in Simscape and implement HTC correlations developed using the LH2 chilldown dataset. This model accounts for different two-phase regimes that hydrogen passes through as a result of heat transfer from the pipe. Results from both trickle and pulse chilldown cases are presented and compared against transient data at four locations along the transfer line. Compared to the previous GFSSP simulations during the transients, the new method shows better agreement with the experimental temperature transients, with an overall improvement in between 20% and 38% in mean absolute error in temperature. The new computational framework thus offers a simple and accurate approach to predicting chilldown. Furthermore, as future datasets become available on LH2 chilldown, the framework can be readily adapted to develop and test new HTC correlations.

Authors: Sharma, V; Coull, J; Ireland, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: ASME International
• Host title: ASME 2025 Fluids Engineering Division Summer Meeting
• Volume: 2
• Article number: FEDSM2025-158030, V002T07A015
• Publication date: 2025-09-23
• Acceptance date: 2025-07-27
• Event title: ASME Fluids Engineering Division Summer Meeting (FEDSM 2025)
• Event location: Philadelphia, Pennsylvania, USA
• Event website: https://event.asme.org/FEDSM-2025
• Event start date: 2025-07-27
• Event end date: 2025-07-30
• DOI: 10.1115/fedsm2025-158030
• ISSN: 0888-8116
• EISBN: 9780791889008
• Language: English
• Keywords: cryogenic chilldown; liquid hydrogen propulsion