Test rig for the determination of leakage flow rate (Bild: VDMA Fluidtechnik)

31.10.2025 Influence of bio-hybrid fuels on seat valves

Simulative Prediction of Leakage

von Marius Hofmeister (RWTH Aachen University, Institut für fluidtechnische Antriebe und Systeme (ifas)), Dr.-Ing. Katharina Schmitz (RWTH Aachen University, Lehrstuhl für Wärme- und Stoffübertragung (WSA)), Felix Fischer (RWTH Aachen University, Institut für fluidtechnische Antriebe und Systeme (ifas)), Lukas Boden (RWTH Aachen University, Institut für fluidtechnische Antriebe und Systeme (ifas))

Seat valves play a critical role in various technical applications, such as automotive injectors. Here, predicting leakage is vital, as it can lead to poor combustion behavior or complete system failure. To address this, a simulation model originally designed for predicting leakage of air in ball seat valves was adapted for the use with bio-hybrid fuels. Since many bio-hybrid fuels differ significantly in their fluid-mechanical properties from conventional fuels and gases like air, the simulation model cannot be used for these liquids without any adjustments. For this reason, additional experiments and simulations have been conducted for various bio-hybrid fuels. The corresponding results are compared and discussed in this study.

Bio-hybrid fuels are produced based on renewable energy and non-fossil carbon sources. This way a closed carbon loop and CO2 neutral combustion is feasible. Therefore, bio-hybrid fuels are a promising alternative to other green energy carriers such as electric batteries and hydrogen. Within the excellence cluster „The fuel science center“, biohybrid fuels are investigated at a holistic level, with the aim of developing methods that can predict the properties of a fuel based solely on its molecular structure. This includes the prediction of combustion related properties like ignition delay, spray propagation and soot formation. Ultimately, these methods can be used to perfectly design a fuel to meet specific technical, economic, and ecological boundary conditions.