PARACHUTE

Liquid hydrogen is characterized by several important limitations restricting its current use. Main problems are the Cryogenic boiling losses which can consume up to 40% of its available combustion energy and change the allotropic composition of the dihydrogen. Molecular hydrogen exists in two allotropic forms, ortho-hydrogen and para-hydrogen, differentiated by the nuclear spin state of the protons in each hydrogen atom. For a given temperature, the equilibrium ratio of ortho to para can be calculated. However, without a suitable catalyst, conversion kinetics may require days or weeks to reach equilibrium. A lack of accurate portable mean to characterize chemical nuclear spin composition of the cooled hydrogen is currently deplored. To make up for this lack, we aim to develop a portable sensor to characterize this nuclear spin composition. The ortho-para ratio affects the magnetic, optical, volumetric and thermal properties of dihydrogen. Possible sensor’s transducer element should, then, be based on the measurement of such properties. In the project, we will exploit the difference of thermal conductivity of ortho and para hydrogen to estimate the ortho/para ratio. To reach this goal, we chose a multidisciplinary approach linking areas like thermal transfers, metrology & instrumentation, measurement statistics and regulation. To identify the fluid characteristics, a source of heating is used and the way the heat propagates through the fluid is linked to its thermal conductivity. Compared to literature data, in this project the aims will be to develop a sensing portable solution but also to develop an optimized measurement methodology that will combine specific heat transfer models, “regulation” system identification and results of tests performed in different conditions. Potential applications of the project are the ones requiring the use of liquid hydrogen. Targeted sectors are nuclear facilities, aerospatial, storage in “Power to X”, chemical engineering.