sidepot design for cooling

[neeraj]

we are competing for the first time in the formula SAE. I am having some problems in calculating the size of the opening of the side pots. On what criteria does it depend? and what should be its length?After going through some books i have come to knoe that the angle of inclination or the angle of the diffuser(side pot) should be between 5 and 10 degrees bur i could not find at what length the radiator should be placed and inclined at what angle.
We are using theCBR 600F4i bike radiator which is curved and around 50% of the core is covered by fan. can someone please suggest hoe to calculate the dimensions of the sidepots?

[neeraj]

we are competing for the first time in the formula SAE. I am having some problems in calculating the size of the opening of the side pots. On what criteria does it depend? and what should be its length?After going through some books i have come to knoe that the angle of inclination or the angle of the diffuser(side pot) should be between 5 and 10 degrees bur i could not find at what length the radiator should be placed and inclined at what angle.
We are using theCBR 600F4i bike radiator which is curved and around 50% of the core is covered by fan. can someone please suggest hoe to calculate the dimensions of the sidepots?

[Chris Allbee]

METHOD 1:

heat transfer calculations to determine desired mass flow rates through your heat exchanger. Next choose a desired operating vehicle speed and use bernoulli equations to determine length of diffuser needed to slow incoming air down to your desired speed through the heat exchanger.

METHOD 2:

make a sidepod that looks nice and hope it works.

[Kenny T Cornett]

Method #2 gets the best design points

[The AFX Master]

method #2 gets the worst endurance points http://fsae.com/groupee_common/emoticons/icon_frown.gif

[drivetrainUW-Platt]

Considering your front wheel will be blocking your "pot" called a pod by everyone else, doing flow calcualtions probably wont be necessary, radiator size is important thou, but I doubt you will gain much buy having some fancy calculated angles in and out in your body work.

[Maverik]

Did you do the heats analysis and determine the stock radiator would be suitable for our application? As said above, you need to backtrack to figure out what you want to do for a front duct. Will it make a difference in airflow, yes, the question is how much? Personally, the duct design is important but the opening in the sidepod just needs to package around the duct unless you think the aerodynamic loss associated with the entrance in the pod will be significant enough... hint, we are not F1.

[John Stimpson]

I don't think you need to worry much. We've run the CBR600 for years and only had cooling issues the year they decided to mount the radiator perpendicular to the car's longitudinal axis (D'oh!).

Try this on for size:

An 12" tall by 10" wide 1" thick radiator kept us at 215*F in California last June (it was 103* outside, 10% humidity at most, and the track surface was 125*). There was about 3" of duct prior to the core, and then the duct became circular in less than 2", with a 10" fan.

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by neeraj:
On what criteria does it depend? and what should be its length?After going through some books i have come to knoe that the angle of inclination or the angle of the diffuser(side pot) should be between 5 and 10 degrees bur i could not find at what length the radiator should be placed and inclined at what angle.
We are using theCBR 600F4i bike radiator which is curved and around 50% of the core is covered by fan. can someone please suggest hoe to calculate the dimensions of the sidepots? </div></BLOCKQUOTE>

What inclination? Build three different inclinations, do three test runs and compare the average water temperature.

What length? Build three lengths and compare the average water temperature.

3 lengths and 3 inclinations gives nine combinations. You could build the four "corners" of that design space and use statistical methods to find the optimum.

Either way, you must test or simulate and come to an objective conclusion. If you just build whatever someone on a forum tells you, you might as well tell the design judge you guessed.

Ben

[Chris Allbee]

I know that there are two schools of thought on these forums: one that says aerodynamics isn't important and one that thinks it is.

I can only say that IF you have the time to make something aerodynamically efficient it most definitely won't adversely affect performance. The same can't be said of ignoring aerodynamic concepts when designing these cars. Its about efficiency. If improving aero efficiency will allow you to run a smaller heat exchanger core, thereby saving weight, why not do it?

Again, it does require some extra time and resources, but just because you don't consider it doesn't mean its not affecting things or that its unimportant.

And if your wheel is blocking flow, give some real thought to the placement of your duct entrance. Don't assume it has to be at axle height directly behind the front suspension.

[benny41]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">

And if your wheel is blocking flow, give some real thought to the placement of your duct entrance. Don't assume it has to be at axle height directly behind the front suspension. </div></BLOCKQUOTE>

hey guys im a newbie and been given the task to design the sidepod for this years car.
Just wondering has anyone noticed a cooling gain by mounting their intake higher up than ground level. i know this would increse the centre of mass. Also what kind of designs do people think look good?
thankyou