[adilsyyed]

In ANSYS CFX documentation, wall boiling model is explained but only subcooled boiling is mentioned.

I want to model a double pipe counter flow heat-exchanger with hot pressurized water in the outer shell/tube and cool water in the inner tube. The cool water is supposed to start subcooled boiling in the mid section, however, at the end of the pipe, this water boils and even reaches super heated temperatures. The outer hot water shell/tube sub-cooled because of its high pressure.

My question is; can i use wall boiling model? What are its limitations? And does it super heat the liquid or just assumes the vapor at saturation temperature?

[adilsyyed]

Originally Posted by adilsyyed

In ANSYS CFX documentation, wall boiling model is explained but only subcooled boiling is mentioned.

I want to model a double pipe counter flow heat-exchanger with hot pressurized water in the outer shell/tube and cool water in the inner tube. The cool water is supposed to start subcooled boiling in the mid section, however, at the end of the pipe, this water boils and even reaches super heated temperatures. The outer hot water shell/tube sub-cooled because of its high pressure.

My question is; can i use wall boiling model? What are its limitations? And does it super heat the liquid or just assumes the vapor at saturation temperature?

I found my answer. Actually the wall boiling model of CFX assumes all vapor to be saturated. It does not superheat the vapor. The heat given to the fluid is divided into two parts; i.e. to heat the subcooled liquid to its saturation temperature and to provide latent heat of vaporization to the saturated liquid.