Session: 03-04 Hybrid-Electric and Ammonia-Based Propulsion Concepts for Sustainable Aviation

Submission Number: 178628

Study of H2 Leak Diffusion and Concentration Measurements in a Ventilated Nacelle Volume 

The development of disruptive and innovative technologies for improvement of aircraft performances must integrate early the regulatory framework for aviation safety. For this purpose, the CONCERTO project aims to provide Means of Compliance to have a better understanding of the safety issues regarding three Proofs of Concept (PoC). One of this PoC is the use of Hydrogen in propulsion systems to drastically reduce the CO₂ emission. The path of certification for this technology goes through the fire risk assessment, and in particular the H₂ leaks and diffusion in a ventilated nacelle volume.

ONERA addresses this activity in its brand-new PyCoFiRe facility dedicated to fire extinction and composite fire resistance in two full-scale test benches, FAN and CORE. The objective is to identify the potential gas accumulation areas through a wide range of test conditions, keeping in mind the Hydrogen lower explosivity limit of 4% V/V. H₂ leakage tests are conducted in the FAN compartment, by substituting H₂ with Helium for safety reasons. ONERA developed a new system for Helium injection and concentration measurements carried out at 24 locations throughout the annular space. The positions and orientations of the injection nozzle are investigated, as well as the Helium leak mass flow rate. The environment conditions such as ventilation mass flow rate (forced ventilation and natural ventilation), flow temperature, and even the presence of obstacles, are studied to provide a better comprehension of the influence of these parameters on the diffusion of Helium in this nacelle volume.

A companion numerical model of the set-up is derived in parallel, to gain a better understanding of the flows considered, and to evaluate the ability of turbulent statistical models to represent Helium diffusion in such a complex configuration and provide quantitative agreement with experimental results.

The PyCoFiRe facility has been co-funded by the European Union, the European Regional Development Fund (ERDF) and the Occitanie / Pyrénées-Méditerranée Region. The test campaign was conducted in the CONCERTO European project (Construction Of Novel CERTification methOds and means of compliance for disruptive technologies), which is funded by the European Community’s Clean Aviation Joint Undertaking program, under Grant Agreement No 101101999.

Presenting Author: Thomas Nédélec ONERA

Presenting Author Biography: In the Multi-physics Department for Energetics , Thomas Nédélec is a test engineer working on the PyCoFiRe test facility, where he is in charge of process utilities. PyCoFiRe is composed of two full-scale benches representative of two turbofan engine compartments, aimed at simulating thermal agressions during different operating conditions. Thomas is part of a team of 5 persons in charge of the operation and maintenance of the facility.

Authors:

Thomas Nédélec ONERA
Adrien Grenouilloux ONERA
Patrick Lapeyronnie ONERA
Vanessa Delahaye ONERA
Emmanuel Laroche ONERA