Measurement of Sound Speed in High Pressure Hydrogen with a Spherical Acoustic Resonator

Abstract

A spherical acoustic resonator was adopted to measure the sound speed in hydrogen to evaluate the derived properties calculated from an equation of state (EOS). The EOS was developed mainly based on experimental PVT properties because of a lack of the other properties data. The resonator has a 40 mm radius, and the inside of it is processed very smoothly with a surface roughness of Ra0.01μm. The present apparatus is available at room temperature and at pressures up to 15 MPa. The sound speed is determined from the resonance frequency in the radial mode, and the latest EOS shows good agreement with the present data within 0.2 %.