what drives boiling in a P-v diagram?
what drives boiling in a P-v diagram?
(OP)
studying for my first paper in thermofluids, I am puzzled by how a mass of water will completely turn to vapour once it reaches saturation pressure. My textbook says during the saturated mixture phaze both temp and pressure remain constant. What drives the boiling?
To take a parallel, added heat drives boiling in a T-v diagram.
thanks
Neil.
To take a parallel, added heat drives boiling in a T-v diagram.
thanks
Neil.





RE: what drives boiling in a P-v diagram?
Hope this helps DS
RE: what drives boiling in a P-v diagram?
On the other hand if the sytem is closed and the energy in the system remains constant, a change in pressure can drive boiling, this is what happens when saturated water passes through a valve (such as a steam trap) and is discharged to a lower pressure. The boiling action results in "flash steam". It is very common in steam heating systems.
RE: what drives boiling in a P-v diagram?
Starting with a liquid as you add heat(enthalpy) the temperature increases. When the boiling point is reached and you continue to add heat to the fluid the temperature remains constant while the heat energy produces a change of phase.
Boiling is a very complex process. Depending on the temperature differance of the heating component you can have different types of boiling. From just mild surface evaporation to agated supperheated bubles froming on the heating ellement. usuall the supperheat would be given up as the bubbles travel up through the fluid to teh surface.
Knowing the enthalpy, total volume of the fluid and pressure you can deturminan howmuch is vapor and how much is liquid.
As in a previous post. Decreassing the pressure will result vaporation of some or all of the fluid.
Andy
RE: what drives boiling in a P-v diagram?
If you look at Mollier Diagram on any refrigerent you will see how the process takes place I used refrigerent because I'm familer. A diagram of water will look the same
RE: what drives boiling in a P-v diagram?
RE: what drives boiling in a P-v diagram?