Help w Thermodynamics of a Radiator/Fan System?

[bonnevilleZ]

I am looking for help modeling a simple thermodynamic system representing a heat exchanger and a fan (as in a typical automotive arrangement, water to air). It doesn't need to be textbook, but I need something "close enough" to work for estimating the viability of different designs.

Some of the variables I'd like to adjust are the dimensions of the radiator (which affects Q but im unsure of the formula), the heat load input, the temperature of the water, the ambient temperature, and the CFM of air flowing through the radiator. I understand these systems follow curves and I guess I just need to solve for the balance point.

Any help is much appreciated..

thanks,
Steve

 

[IRstuff]

The basic equation is still Newton's:
area*htc*delta_t

Beyond that, it's primarily refinement of the parameters

TTFN

FAQ731-376

 

[MikeHalloran]

You can probably find some partially appropriate application engineering data from guys who make industrial fan-cooled liquid coolers. That will at least give you an idea of how the cooler capacity scales with face area... with an industrial, serious, noisy, fan.

Cars have less 'serious' fans, for acoustic and cost reasons, and because if the underhood aero is done right, the fans can be switched off above a modest speed.

Because of that aero, e.g. how the air gets past the bumper, through the radiator, and out of the engine compartment, and presence and geometry of chin spoilers and such, you may find that your worst case situation is _not_ at max power output.



Mike Halloran
Pembroke Pines, FL, USA