Experimental investigation on the thermo-hydraulic characteristics and occurrence boundary of geyser in a cryogenic pipe

Abstract

• The essential characters are summarized for the effective recognition of geyser in cryogenic engineering. • The tank pressure and liquid level have an effective suppression effect on geyser. • The occurrence and transition boundary of geyser is divided by a new dimensionless parameter Ae . • The geyser might occur when Ae is larger than 2, and a strong geyser might occur when Ae is larger than 4. In the present study the thermo-hydraulic characteristics of geyser in the cryogenic fuel transportation pipe of a liquid rocket is experimentally investigated using liquid nitrogen. The typical thermo-hydraulic appearances are characterized and analyzed in the geyser process to effectively recognize the occurrence of geyser in practical engineering. The effect of interfering factors such as heat flux, liquid level and tank ullage pressure on geyser are explored. Moreover, based on the new proposed dimensionless parameter of the maximum energy storage ability ( Ae ), the occurrence boundary of geyser is divided. It could be concluded from the results that a clear periodic pressure and temperature change accompanied by periodic plenty vapor ventilation could serve as an indication for geyser’s occurrence, and the eruption of cryogenic geyser has a similar appearance as that in the geothermal field. It is found that a higher tank ullage pressure and liquid level could reduce the geyser’s intensity, and a violent boiling will occur instead of geyser when the heat flux is extremely high. It is a feasible way to eliminate geyser in the cryogenic pipe by increasing the pressure inside the pipe via increasing the tank ullage pressure or liquid level in the tank. Moreover, it is found that a weak geyser would occur in LN 2 and LO 2 when Ae exceeds 2, and then as Ae being larger than 4, a strong geyser might occur with a noticeable pressure peak.