What kind of expansion is this?

[HydroVapor]

I take a container full of water and drop a hot 350C slab of steel into it so that its heat transfers to it causing the water to vaporize to steam while at the same time the slab cools down over the course of 1 minute or so from 350C to 150C. The steam is allowed to develop pressure and expand to do work during this time. Neglecting any external heat losses, what type of expansion can the steam be categorized as if its heat source rapidly cools as stated above while the steam's pressure and temperature obviously decreases with it? Would this be considered adiabatic with the steel slab representing internal steam energy, or would it be something else?

Thanks

 

[member 553083]

for your question. This type of expansion is generally classified as an isenthalpic expansion. Isenthalpic expansions involve the transfer of energy from one form to another, in this case from the hot steel slab to the steam. The steam is still expanding and doing work, but its pressure and temperature are changing as the energy from the steel slab is transferred to it.