Abstract
Slush hydrogen is a mixture of solid hydrogen particles and liquid hydrogen. The flow characteristics of slush hydrogen in two types of cryogenic valves (i.e., vertical- and horizontal-moving piston valves) were investigated by visualization of its flow and measurement of pressure loss. In a preliminary ice/water flow test, circulation flow was observed in a vertical-moving piston valve, and this caused the accumulation of ice particles in the flow path. Based on the preliminary test results about particle behavior in the valve, a horizontal-moving piston valve was improved, and it was observed that slush hydrogen flows smoothly and the pressure loss of slush hydrogen is only slightly larger compared to liquid hydrogen flow. These test results show that a horizontal-moving piston valve is more suitable for slush hydrogen compared to the vertical-moving piston valve, and that an appropriate flow path design leads a smooth flow of slush hydrogen at the same level as liquid hydrogen.
