Study on the development of a capacitance-type flowmeter for slush hydrogen Original Research Article

Slush hydrogen is a two-phase solid–liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen, various applications for which are anticipated, including fuel for reusable space shuttles. Noting the slight fluctuation in the distribution of solid hydrogen particles in slush hydrogen, i.e., slush hydrogen density, the authors of the current study placed capacitance-type densimeters at two locations along the piped flow to measure the density and to detect density fluctuations. The flow velocity was also calculated from the densimeter distance and delay time when the cross correlation function of the two density signals was at a maximum. This capacitance-type flowmeter has no moving mechanical parts and no probe in the flow stream. This paper reports the development of a prototype slush hydrogen capacitance-type flowmeter, together with the fabrication of required test equipment, and confirmation of flowmeter accuracy.