If you had to pressurize a pressure vessel in testing, would you rather pressurize with liquid or gas and why?

Mechanical Engineering Mechanical Design
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1

If you had to pressurize a pressure vessel in testing, would you rather pressurize with liquid or gas and why?

2

It’d be better to pressure test with a liquid because it’s safer. The bulk modulus of water is ~300 ksi while the bulk modulus of air is 0.02 ksi, so water’s volume will change significantly less as a result of increased pressure.

So, if you’re testing a pressure vessel and it fails, the released gas has the potential to be much more dangerous to people/surroundings where as liquid will expand less significantly for a given change in pressure.