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Thread: radiator design

  1. #21
    What sort of oil cooler setup are you running? We're looking into removing the stock F3 cooler, replacing it with a remote filter mount, oil thermostat, and ATV-sized external oil cooler. It's looking like we need to machine 4 parts to do that, plus buying steel braided hose and fittings, did you guys do something similar?


    -Luke Thompson
    Vandals Racing 2003-04
    University of Idaho

  2. #22
    Junior Member
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    Apr 2003
    Location
    Austin, TX USA
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    That's basically what we did, but only machined a threaded extension for the oil filter. We ran an oil cooler from Pegasus (~4" x 10") along with a sandwich plate from Pegasus (removed the stock oil cooler, threaded the sandwich plate on, and threaded the oil filter onto the plate). Then we just needed braided hose to go from the sandwich plate to the cooler.

    We ran an F4i, and I've never worked with an F3. If it has the larger rectangular oil cooler (like the F2) there may be some fabrication tasks to convert it.

    David

  3. #23

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    Nov 2002
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    Calgary, Alberta, Canada
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    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LukeT:
    ....... Right now we're testing a 12x9x1.4 18 fpi radiator off the Honda Rubicon ATV, using a mathmodel that a (now)grad student developed it _should_ be of adequate size...


    -Luke Thompson
    Vandals Racing 2003-04
    University of Idaho<HR></BLOCKQUOTE>

    same size as we used last year and we found it to bee a bit too big. This year i think we will go with Approx 7*15*1.5...... at least thats what the calcs and tests are saying.

  4. #24
    I am a new member of the formula racing team at Mayaguez. I have to design a radiator and I need the basics, since this is the first time I'm doing this. I hope someone can help me.

    sincerily, Nexal Flores

  5. #25
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    It is my first time with the team and my first time designing a radiator. But I have everything down pretty good right now. The best thing to do is read Compact Heat Exchangers by W.M. Kays and A.L. London. It will give you the theoretical background neccesary to design the radiator once you have the real world data like heat load and fluid flow rates.

  6. #26
    We're a first year team experiencing all sorts of problems so by advide may not be the best. However, we've found "Compact Heat Exchangers" by Kays and London to be extrememly helpful. The only problem we're running into is that there isn't really much in the book in terms of core cofigurations for small cars and motorcycles. Another book we're trying to find is "Fundamentals of Heat Exchanger Design" by Shah. Appearently Shah worked for GM and his books have more of an automotice slant on the information contained.

    On that note, how much design are the more experienced teams doing? Are you able to find core configurations/ tube pass configurations for common bike radiators? If so where from?

    Thanks.

    Jonathan Strunk
    Cooling System Team Leader
    Mercer FSAE
    Mercer University
    Macon, GA

  7. #27
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    you don't need much info on core configurations as that is what you are designing. You do however need tube and fin size information , for which a current radiator would be a suitable source. As for the number of passes to make that is also your decision as is the number of tubes deep to make the core.

    we got our radiator from Griffon radiator last year and the dimensions for the tubes are .085" high by 1.25" wide and a common wall thickness for alluminum tubes is .010" and fin thickness of .006"

    These are the numbers I'm going to use for tube height, wall thickness and fin thickness while adjusting tube width, during my design.

    I'm not doing much with the cooling design this year other than sizing the radiator, however I woudl like to get an electric water pump and a have the ECEs build a water pump and fan controller next year that way it might be possible to go to an even smaller radiator.

  8. #28

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    Nov 2002
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    Calgary, Alberta, Canada
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    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Frank:
    .........................
    Both functions also had a quite large scalar constant. ie.. the zero flow rate condition caused cooling (as you would expect)

    example:
    cooling= 0.2*wfr + 1.5kw (for given afr)
    cooling= 0.6*afr + 1.2kw (for given wfr)

    Now, for our system, the waterflow rate had quite a low linear constant, the airflow constant was nearer one.

    .......

    <HR></BLOCKQUOTE>
    Did you find any correlations between the overall heat transfer coefficient water flow, airflow, water temp differences?

    Just wondering because i received heat transfer data from our radiator MFG and i've been trying to determine an experimental heat transfer coefficient and match it to values I calculated.

  9. #29
    Senior Member
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    PJL,
    depending on the flow configurations you can get analytical relationships between heat transfer coeeficient, and flow rates and temperatures. However, for an unmixed crossflow arangement there isn't a closed analytical solution relating the number of transfer units to the efficiciency and heat capacity rates.
    Using the following relations you can find a heat transfer coeeficient from your test data for flow rates and temperatures. The terminology is that from Compact Heat Exchangers by Kays and London.
    Ntu=A*U/Cmin
    Eff=[Cc*(Tc,out-Tc,in)]/[Cmin*(Th,in-Tc,in)]
    where R=Cmin/Cmax
    Eff=f(R,Ntu), if you can find a relation for unmixed crossflow and solve for Ntu, you should then be able to solve for the heat transfer cooeficients


    I just found an SAE paper relating temperature and flowrate changes to Specific Disipation. There may be some helpful equations in there for you.here is the link

  10. #30
    We have just tested our 2004 radiator 275*300*40mm and a 10 inch davies craig fan.

    Calculations have been made following the test day and we estimated the following. At air flow of 250L/s we achieved 10.4 kW of cooling. The pressure drop accross the core is 55 Pa. This was confired by water side calculations. From the data recorded we would estimate that the out car requires 30 - 50 % more capacity. It is interesting that people are saying not to use greater than a 25mm core though.

    We measured an air off temperature of 65 degrees and 30 degree ambient at incoiming water temperature of 105 degrees.

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