Over-expanded liquid

The momentum of the water as it moves outward causes the gas bubble to over-expand so that its pressure drops below the hydrostatic pressure, and then to collapse as liquid flows back in. The return flow also overshoots the gas pressure rises again, but to nowhere near the detonation pressure. However, the bubble expands again in rebound, behaving in effect as a second explosion. Several successive rebounds may occur, each becoming weaker. To evaluate the total damage, both the shock wave and the subsequent bubble pulses must be considered... 

The portion VN corresponds to a supersaturated vapour, which may exist but is metastable and disappears spontaneously if condensation nuclei are introduced into the system. Similarly ML corresponds to an over-expanded liquid, which again is a metastable state. The points M and N are thus boundary points between metastable and unstable states of the system. 

Over the years, there are many other reports of steam explosions involving hot oil unintentionally coming in contact with water. Water is unique in that many organic chemical liquids will expand 200-300 times when vaporized from a liquid to a vapor at atmospheric pressure. Amazingly, water will expand 1570 times in volume from water to steam at atmospheric conditions. These expansion and condensation properties makes it an ideal working fluid for steam boiler, steam engines, and steam turbines, but those same properties can destroy reputations, equipment, and lives (see Fig. 3.13). 

Cp = dHjdT, than in simpler liquids. An expanded scale of the specific heat of water versus temperature is shown over the liquid range. Source D Eisenberg and W Kauzmann, The Structure and Properties of Water, Oxford University Press, New York,... 

If high wellhead pressures are available over long periods, cooling can be achieved by expanding gas through a valve, a process known as Joule Thomson (JT) throttling. The valve is normally used in combination with a liquid gas separator and a heat exchanger, and inhibition measures must be taken to avoid hydrate formation. The whole process is often termed low temperature separation (LTS). 

The sample solution is pumped (e.g., from the end of a liquid chromatographic column) through a capillary tube, near the end of which it is heated strongly. Over a short length of tube, some of the solvent is vaporized and expands rapidly. The remaining liquid and the expanding vapor mix and spray out the end of the tube as an aerosol. A flow of argon carries the aerosol into the plasma flame. 

As liquid flowrate inereases beyond the minimum required to suspend the partieles, the bed expands. Unfortunately, however, the expansion index n is not eonstant over all flow regimes but is a funetion of the flow. Thus... 

The combustion process is carried out in a thrust chamber or a motor case, and the reaction products are momentarily contained therein. The newly formed species are heterogeneous in composition and involve a wide variety of low molecular weight products. The temperature of these products is generally high, and it ranges from about 2,000°F (1,100°C) in gas generators to well over 8,000°F in advanced liquid propellant engines. The combustion products leave the chamber and are directed and expanded in a nozzle to obtain velocities from about 5,000 to 14,000 ft/sec. 

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