Unformatted text preview: ntil the final temperatures of the two bodies Tf become m, C
QH HE W QL m, C
T2 FIGURE P7–151
7–152 The explosion of a hot-water tank in a school in
Spencer, Oklahoma, in 1982 killed 7 people while injuring
33 others. Although the number of such explosions has decreased dramatically since the development of the ASME Pressure Vessel Code, which requires the tanks to be designed to
withstand four times the normal operating pressures, they still
occur as a result of the failure of the pressure relief valves and
thermostats. When a tank filled with a high-pressure and hightemperature liquid ruptures, the sudden drop of the pressure of
the liquid to the atmospheric level causes part of the liquid to
flash into vapor, and thus to experience a huge rise in its volume. The resulting pressure wave that propagates rapidly can
cause considerable damage.
Considering that the pressurized liquid in the tank eventually reaches equilibrium with its surroundings shortly after
the explosion, the wo...
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