Within the framework of an ESA GSTP activity dedicated to the characterization of transient cryogenic flow phenomena in propellant-assisted shut-off valves, a high-pressure cryogenic experimental facility has recently been commissioned at the von Karman Institute for Fluid Dynamics (VKI). The installation is based on a cryogenic test bench originally developed and operated by Safran Aero Boosters (SAB), which has been transferred to VKI and upgraded with additional hardware, instrumentation and safety provisions to support research-oriented experimental campaigns.

The facility is intended for steady and transient experiments with liquid nitrogen (LN?) and gaseous nitrogen over a broad range of thermodynamic conditions, including pressure levels approaching 100 bar. The test bench combines industrial high-pressure cryogenic infrastructure with a modular experimental section allowing the integration of interchangeable geometries representative of valve internal flow restrictions. The upgraded setup includes dedicated instrumentation for pressure, temperature and mass flow measurements, enabling time-resolved characterization of cryogenic internal flows.

Particular attention has been given to the safe operation of the facility under high-pressure cryogenic conditions. The transferred bench underwent a dedicated reassessment at VKI, including mechanical verification of pressurized components through finite element analysis accounting for cryogenic material properties and conservative pressure boundary conditions. Additional safety provisions include pressure relief systems, redundant isolation devices, controlled venting and remote operation through a dedicated control architecture. These upgrades were implemented to ensure reliable operation while preserving flexibility for future cryogenic research activities.

The first experimental campaign performed on the facility focuses on the characterization of representative small orifice geometries relevant to propellant-assisted valve applications in launcher systems. The objective is to determine discharge coefficients and pressure losses under cryogenic conditions representative of realistic operating environments. Compared to existing low-pressure cryogenic databases, the present facility enables the investigation of regimes where compressibility effects, cavitation inception and phase change phenomena may influence the hydraulic response.

The test matrix spans a broad range of upstream pressures, enabling direct comparison between previously acquired low-pressure data and new high-pressure operating conditions. Although the experimental campaign is currently ongoing, preliminary measurements demonstrate the capability of the facility to provide repeatable cryogenic flow characterization with stable thermal and hydraulic conditions. First comparisons suggest that discharge coefficients remain of the same order of magnitude between low- and high-pressure conditions, while measurable deviations from conventional incompressible assumptions appear under selected operating points.

Beyond the specific application to valve modelling, the presented facility provides a versatile experimental platform for cryogenic engineering studies involving internal flows, instrumentation, and high-pressure operation with liquid nitrogen. The present work introduces the experimental setup, safety approach, hardware upgrades and first observations from the commissioning campaign, providing perspectives for future investigations relevant to cryogenic space systems and fluid components.

Keywords
cryogenic applications|valves|process control|high pressure|space