so here's a thought experiment let's say that I have water in a cylinder and above it a massless, frictionless piston. if I were to pull the piston so that the pressure would go from p1 to 0, instantly.
what would happen to the water? what would the final phase be? what will the phase transition be like? and is it accurate to say that this process is a free expansion of a liquid?
and I would appreciate it if you would add references to your answers
edit: originally, the problem I was reading about was water hammering which is a sudden reduction/increase in pressure due sudden shutting of a valve. which got me to think about what happens when the water pressure is suddenly reduced to zero. so I know that the initial state is p1 and t1, and the final phase depends on thermodynamic state which is p2=0 and t2. the phase transition depends on the thermodynamic process. so I assumed different scenarios,
1)closed system/isothermal process,
2) isolated system/isentropic process,
3) and closed system/sudden pressure reduction(free expansion) according to the phase diagram, if we assume that we start at standard pressure and temperature http://www1.lsbu.ac.uk/water/water_phase_diagram.html
1) the water boils, the final phase is vapor.
2) the isentropic process causes temperature drop, and depending on t2 the final state would be vapor or crystals. the phase transition could be liquid -> vapor -> liquid -> solid, liquid -> solid, or liquid -> vapor -> solid.
3) the last scenario is water free expansion, in this scenario the water would behave as 2) at first, then the surround would heat it, so the final phase will always be vapor.
the problems are: a) I am not sure if that's what really happens because I couldn't find any references or experiments
b) I am not sure if the term "free expansion" applies to liquids and was wondering if there is an accurate descrition for this process