When a tank containing a pressure-liquefied gas fails, one mode of failure involves the tank being propelled large distances by the released two-phase material. This mode of failure is called a tub rocket and it can pose a severe hazard to the public because of its unpredictability. Field tests were recently conducted to study the effect of explosive devices on propane tanks. The tests included tanks of various sizes up to 2000 L (500 gal).In most cases, the tests resulted in punctured tanks with transient two-phase jet releases. In some cases, the jet releases were sufficient to propel the tanks over considerable distances. In a small number of tests involving 470-L tanks, the explosive device resulted in the clean removal of a tank end, and this resulted in near-ideal launches of tub rockets. In one case, the rocket was launched vertically, and in another, the rocket was launched near 45 deg elevation angle giving a tub range of 370 m. In other cases, the explosive devices resulted in punctures, and in some of these, the resulting two-phase jet propelled the tanks over considerable distance. These examples gave a good opportunity to re-examine tub rocket models for tanks containing liquefied gases. This paper describes a theoretical model involving two-phase critical flow propulsion of cylindrical tanks. Three different critical flow models are compared, including the homogeneous equilibrium model (HEM), the homogeneous frozen model (HFM), and the Henry-Fauske model (HFK). Range predictions are compared with existing data and a model previously developed. Model predictions are calibrated to the field trial results described in the foregoing and then used to predict realistic ranges for various sizes of storage and transport tanks.

Baker, W. E., et al., Explosion Hazards and Evaluation. Elsevier Scientific Publishing Company, New York, NY, 1983.
Baum, M. R., “Disruptive Failure of Pressure Vessels: Preliminary Design Guidelines for Fragment Velocity and the Extent of The Hazard Zone,” TRANS. ASME, Vol. 110, May 1988.
Henry, R. E., “Calculational Techniques for Two-Phase Critical Flow,” Two-Phase Flow Dynamics, 1983.
R. E.
H. K.
The Two-Phase Critical Flow of One-Component Mixtures in Nozzles, Orifices, and Short Tubes
ASME Journal Heat Transfer
, Vol.
, pp.
Holden, P. L., “Assessment of Major Missile Hazards: Review of Incident Experience Relevant to Major Hazard Plant,” Report No. SRD R 477, United Kingdom Atomic Energy Authority.
Levelton, B. H., and Associates, “Summary Report On Propane Bulk Truck Rupture Near Salmon Arm, B. C.,” June 13, 1984
Mclntyre, Dale R., 1984 “Analyzing Explosions and Pressure Vessel Rupture,” ASME PVP-Vol. 76.
Pieterson, C. M., “Analysis of the LPG Incident in San Juan Ixuatepec, Mexico City, 19 November 1984,” TNO, 1985.
RPI-AAR, “Analysis Of Tank Car Tub Rocketing In Accidents,” Report No. RA-12-2-23, Dec 1972.
RPI-AAR, “Phase 01 Report on: Sequence of Events Following Crescent City Derailment.” Report No. RA-01-1-1, Aug. 1970.
RPI-AAR, “Phase 01 Report on: Summary of Ruptured Tank Cars Involved in Past Accidents,” Report No. RA-01-2-7, July 1971.
E. S.
, et al.,
. “
Expansion of a Very Low Quality Two-Phase Fluid Through a Convergent-Divergent Nozzle
ASME Journal of Basic Engineering
, Vol.
, pp.
TNO, “Calculating the Physical Effects of the Escape of Hazardous Materials (Gases and Liquids, “The Yellow Book’),” TNO Report, 1979.
This content is only available via PDF.
You do not currently have access to this content.