Question about heating a fluid through a wall

[Green Zach]

Hello, I am working on a project this summer and I have run into a problem that I need a bit of help with. If I heat a fluid (water or some refrigerant) in a pipe with cross sectional area A and the fluid has a velocity V through the pipe then how long does the pipe need to be for a given heat source to heat the fluid to some desired temperature T? The fluid must also go through a phase change into a gas at some point in the heating process. No this is not a homework problem... I am going into my third year of aerospace engineering and I just don’t know much about this subject. Any help will be greatly appreciated.

 

[AlephZero]

Find the mass of fluid going throug the pipe in 1 second (volume x density).

Then find the amount of heat needed to raise the temperature of the fluid and change its phase.

That will tell you how muich power (heat energy / second) you need to put into the pipe.

Finding the temperature gradient through the pipe and into the fluid is a different question, and much harder to solve.

You might want to think about the fact that it will be relatively easy to heat the liquid but harder to heat the gas after the phase change, unless the gas is at high pressure to increase its density and reduce its flow velocity, so it stays in the heating pipe for longer.