heat transfer coefficent
heat transfer coefficent
(OP)
hi,
i'm currently trying to spec a heat exchanger for a cooling system as part of the calcs i have to work out the overall heat transfer coefficient using 1/U = 1/h1 + b/k = 1/h2 where h is the local heat transfer coefficient b is the breadth and k is the thermal conductivity of the material.
my question is how do i calculate the local heat transfer coefficient?
can anybody help?
i'm currently trying to spec a heat exchanger for a cooling system as part of the calcs i have to work out the overall heat transfer coefficient using 1/U = 1/h1 + b/k = 1/h2 where h is the local heat transfer coefficient b is the breadth and k is the thermal conductivity of the material.
my question is how do i calculate the local heat transfer coefficient?
can anybody help?





RE: heat transfer coefficent
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: heat transfer coefficent
RE: heat transfer coefficent
en.wikipedia.org/wiki/Heat_transfer_coefficient
s3.amazonaws.com/suncam/npdocs/119.pdf · PDF file
RE: heat transfer coefficent
Latexman has nailed your problem. If you give some info about the nature of the system, you can get some really good advice. Often one side controls- if you are cooling vapor it could be as low as U=20 BTU/(h-sqft-F); if you are condensing steam against clean cooling water it could be as high as 350 BTU/(h-sqft-F). To you resistance equation it is typical to add fouling factors which can often dominate.
If you have an exchanger already in similar service, you should calculate the U that you are actually getting. This will help you make a reasonable call and check the design. You should recognize that h1, h2. k, and b will come directly from the exchanger design, but specifying the fouling factors is a 100% owner responsibility.
best wishes,
sshep
RE: heat transfer coefficent
I appreciate reading your posts!
Q:
When you find the glass that fell out of the space shuttle payload section when the doors opened, what was it full of? -technically: if not in any atmosphere, ambiently-