Radiator Design Procedure

Homework, it looks like it

If your in a class and your looking for help to solve because of an assignment, then there is not much help here for you. We are not going to your home work. If your and engineer on the job and need to know where to locate the information to help solve the issue at hand! Then I am not sure I can help you either. The 1st rule of thumb is to know where to go and get the information to fulfill the requirement you wish to complete. Remembering where to get information is more important then knowing the formulas.

i am not doing any assignment/homework... i want to know how do you decide all the parameters mentioned... only procedure would also suffice...

If you are a working engineer you should not have to do this ab initio, because your employer is certainly planning to buy the heat exchanger, not build it which would be hideously expensive. Radiator manufacturers will provide tables and/or approximate formulas to use in selecting which of their products will do the job for you.

you are correct but i require those for my own knowledge...

Radiator is a heat exchanger. Thermal design of a heat exchanger is primarily concerned with the determination of the heat transfer area required to transfer a specified amount of heat between two fluids with specified flow rates and inlet temperatures. Two methods to design a heat exchanger. They are Log Mean Temperature Difference ( LMTD) Method and Effectiveness and NTU method. Please refer any heat transfer books you will get the procedures and formulas.

that is fine...can you also let me know how the number of tubes, their shape are decided

Please refer Refrigeration and Air conditioning by CP Arora ( Tata McGraw Hill ) edition page no 315 example 7.2 . Design of forced convection air cooled condenser is explained in detail.

Try the engineers tool box me thinks it may help you a little.

Regards

Hugh Reid (Former Chemist, and Manufacturing Engineer)

http://www.engineeringtoolbox.com/arithmetic-logarithmic-mean-temperature-d_436.html

thank you...i calculated the area required for cooling...how to decide the number of tubes and their shape. Are the tubes circular in cross section ?

Hi Koel,

The tubes are usually circular because circular tubing is the easiest and cheapest thing to come by. However the point of any heat exchanger is to maximise the surface area to volume ratio of the fluids and hence maximise heat transfer. So the shape of the tubes is decided by the manufacturing skills available. A modern honeycomb heat exchanger which runs very thin chambers past each other separated by very thin walls is extraordinarily efficient.

A unit about half the size of a small computer box replaces the shell and tube heat exchanger of 50 years ago the size of a large refrigerator. The modern heat exchanger is very complex to model mathematically as it runs several passes and hundreds of surfaces.

But if you are building a heat exchanger you're unlikely to do better than a counter-flow shell and tube - however the configuration depends on your requirements (for instance if you just want best bang for your buck you might use the counterflow, but if fine tuning of the output temperature is important you might use a parallel flow exchanger.)

Number of tubes and their shape comes down to your budget. Generally, the more surface area you can get, the better. For instance if you could seal the egdes well and keep the flow constant you could forgo tubes and use a few sheets of corrugated iron very closely spaced alternating the hot and cold flows.

Good luck with the plutonium enrichment reactor, if that's what you're building.

Thank you for your inputs..also wanted to ask about the use of make up/fill line connection in radiator...what if these are not provided ?

Please describe the operating environment (i.e. ambient temperature, dusty vs. clean air etc.) and nature of the load. This usually is the most important design consideration.

The maximum ambient temperature is 45 C..The radiator is to be used for power generation purpose, clean environment.