Vapor Nucleation in a Cryogenic-Fluid-Dissovled-Nitrogen Mixture During Rapid Depressurization.
Vapor Nucleation in a Cryogenic-Fluid-Dissovled-Nitrogen
Mixture During Rapid Depressurization.
Yang, J. C.; Cleary, T. G.; Huber, M. L.; Grosshandler,
Royal Society of London Proceedings. Vol. 455. Series
A. 1999, 1717-1738 pp, 1999.
depressurization; cryogenic fluids; fire suppression;
pressure reduction; thermodynamics; nucleation; nitrogen
The behaviour of four cryogenic-fluid-dissolved-nitrogen
mixtures inside a pressure vessel during rapid
depressurization was investigated through experiment.
The four fluids studied were CF3I, FC-218 (C3F8),
HFC-125 (C2HF5), and CF3Br. Depressurization was
achieved by discharging the liquid mixture through a
solenoid valve at room temperature. Two initial total
vessel pressures were used: (1) ca.2.8 MPa and (2)
ca.4.2 MPa. Based on the experimental observations
obtained by using a high-speed movie camera, the
evolution of dissolved nitrogen was suggested for
FC-218, HFC-125 and CF3Br in the cases of initial total
pressures of ca.4.2 MPa. For initial vessel pressures of
ca.2.8 MPa, vapour nucleation was not observed for any
of the four fluid-dissolved-nitrogen mixtures. No
degassing was observed for CF3I irrespective of the two
initial total pressures. The predicted nucleation
pressures based on the classical homogeneous nucleation
theory for a binary-component mixture provided
qualitative agreement with the observed vapour
nucleation inside the vessel.