How can I design a radiator for 100 kW of heat rejection?

[mech-eng]

hi, all. I have to design a radiator rejecting 100 kw of heat.how can I find example projects.

 

[mech-eng]

I am trying to design a radiator.there are concepts as number of tubes per pass and
number of passes.then are passes bigger tubes consisting of smaller tubes?

 

[256bits]

If you are talking about shell and tube heat exchanger, then the shell has a certain volume. Inside would be tubes. One fluid would flow through the tubes and exchange heat with another fluid flowing throught the shell.
Through the use of baffles, the flowing through the shell, or the fluid flowing through the tubes, can be made to have what is called passes, and as many as you want, but usually limited to a smaller number.

A one pass shell, one pass tube design has all shell fluid exchanging heat with all tubes, parallel flow or counter flow.

A two pass shell, one pass tube design, has all shell fluid exchanging heat with half the tubes parallel flow, and then the other half of tubes counter flow.
A one pass shell, two pass tube design has all shell flow exchanging heat with all the tube flow half the tubes in parallel flow, and then with hlaf the tubes in counter flow.

And so on...( if I have the explanations correct )

There can also be crossflow design of the fluid(s)

See
http://en.wikipedia.org/wiki/Heat_exchanger
for some pics

and
http://en.wikipedia.org/wiki/Shell_and_tube_heat_exchanger
for some more pics.

 

[sanka]

This is a very general question for something that, in reality,is quite complicated. There are entire books dedicated to designing heat exchangers. You need to provide a bit more info. regarding your radiator. For example is it air-cooled or water-cooled? Are you restricted in terms of space available? What is the working fluid?

As a general starting point, you can calculate your area using the equation;
$\dot{Q}$ = UAΔT which can be arranged to find the area;
A=$\dot{Q}$/UΔT where ΔT is your desired temperature difference between the 2 fluids and U is the overall heat transfer coefficient. This can be determined from some correlation depending on flow conditions, geometry, etc. Q is then the heat flow of 100kW you referred to.

As I said, it can be quite difficult to design an efficient heat exchanger. However, if you are not restricted in terms of space (or money), then I recommend you simply estimate a value for U based on those given in appropriate literature and apply a factor of safety to it. What I mean by that is to simply oversize your heat exchanger to ensure it will reject all the heat.