radiator design

[BigBoss]

The only thing(s) that could change in section B are Cmin & Cmax, since you are going through different U & A values, the cold side C is a function of A (i.e. mass flow rate equals rho*A*Velocity), the hot-side C can be recalculated through an energy balance.

EDIT: Of course, the e, NTU and Qmax would also change from Cmin, Cmax.

[matsho]

i want to help me to make a design of radiator for our formula project plzz
how i designed it and the parameter of it

[jlangholzj]

Originally posted by BeaverGuy:
Later on I started using only an evaluation script. I abandoned calculating the core size. I picked tube and fin configurations and core size then just calculated Qact and ensured it was sufficient for the heat load. I did this for two reasons, the code was much shorter thus easier to check, I discovered a number of errors when the code was about a year and a half old, and solved much faster though that was a only a difference of a few seconds versus 1- 2 minutes.

This is what my current script does in EES for our radiator sizing. I've not had a chance to actually make an iteration loop and may try that in matlab. (I'm assuming that matlab uses resources considerably better than EES does) The current file works rather well and compliments the use of fan pressure curves as well as a few other lookup tables.

doesn't change a whole lot in 8-9 years does it

as an edit:

I went back and looked at some of your earlier posts....strangely enough the "compact heat exchangers" book is also what I've used as a reference with making our project and the NTU equation.

Further expanding on this I've had a chance to verify the design with some track data and its within 5% of the expected design...fits pretty darn well!

[jlangholzj]

Originally posted by matsho:
i want to help me to make a design of radiator for our formula project plzz
how i designed it and the parameter of it

and you're REALLY going to do this???? There's 16-17 PAGES of great information in here...and you're going to post in the thread with AALLLLllll that information....and beg for it...

[jjnoble]

Does anyone have any information on sizing radiator lines? Knowing my coolant temp and flow rate is there a way to properly size the hose?

[jd74914]

You are going to want to size your lines for pressure drop. In general, more water flow through a radiator is directionally better, so you want to size the lines for minimal pressure drop to avoid moving downward in the pump curve.

[jlangholzj]

You are going to want to size your lines for pressure drop. In general, more water flow through a radiator is directionally better, so you want to size the lines for minimal pressure drop to avoid moving downward in the pump curve.

generally an excellent practice. I did however take a look at ours (we ran a twin radiator setup) because I was concerned that since the one set of tubes were longer than the other, that we'd see excessive pressure drop in the longer side, leading to reduced flow in that particular radiator. I found that at the 1" tube that the bike runs its ~negligible. I also place a paddle flow meter in line with the system at both the pump and each of the two radiators...again...pretty minimal.

What I'm venturing to guess is happening (just an educated guess here) is that if you look at the pressure drop of the lines vs the pressure drop of the radiator core, the drop in the core is going to be significantly higher than say the lines. what I'd really like to see though is do the analysis Jim is talking about and see how much smaller we can go without overly restricting flow

[xander18]

I need to design a cooling system can anyone tell me how?!?!

....

Just kidding. I've read this whole thread and some literature as well. I'm going to make a Matlab program similar to what BeaverGuy used (outlined here: http://www.fsae.com/forums/showthrea...ll=1#post27076). One issue: what function to use to get NTU (step 4 in the quoted post I linked to)? I'm looking at the charts in this PDF (http://educypedia.karadimov.info/library/98254.pdf) or available in any thermal textbook. Unless there's an existing function for this I'll just extrapolate a number of points from this and create a 3D fit plot in Matlab.

Edit:
So I found this like 10 minutes after I made this comment. Whoops.
http://www.mathworks.com/matlabcentr...ffectiveness.m

Since this thread has been so helpful for me, I'll try to give back a little bit. A thesis called "Cost Effective Method for the Evaluation of a Formula SAE Engine Cooling System" is available on the U of Illinois website (https://www.ideals.illinois.edu/bits...pdf?sequence=3). It has a lot of good empirical data for Thi, Tho, Tci, Tco, coolant flow rates for an F4i, and air velocity with various levels of ducting and fans. I used the data in this paper as a test data set for some of the Matlab calculations I'm doing. Also, other teams running an F4i will probably be able to directly use some of this data. Other cooling system designers may find it useful.

[mshorter]

I'm tasked with designing the radiator for the Brown University 2015 car and have read through the thread but still have a few lingering questions. Firstly, how do teams design radiator/cooling systems for both the noise event/static testing, where the engine is run at or near redline for extended periods of time with no airflow to the radiator and events like enduro where we can rely to some extent on air being forced through by the motion of the car. Currently, the fan has power supplied from the ECU only when the coolant reaches a certain temperature, so we are not constantly drawing obscene amounts of power from the alternator, but of course designing for a static car leads to a heavier radiator. However, one advantage of running a very large fan is immediate cooling response if needed...

Is there any consensus towards pulling air through the radiator or pushing it? Our team has been running a pusher but some people in this thread are saying that pullers are better for airflow while the car is moving. For reference, we are using this fan https://webstore.spalusa.com/content..._3206_SPEC.pdf

Also, are there any resources on CFD/other methods for optimizing ducting/the airflow through the radiator? I've seen references to possibly using CFD but nothing useful so far.

[Swiftus]

...but of course designing for a static car leads to a heavier radiator. However, one advantage of running a very large fan is immediate cooling response if needed...

mshorter - Welcome! It is always good to see new people getting involved on the forums!

Which team are you from?

Before just giving you an answer, I would ask you to reconsider the source of the heat you are trying to reject. Is the heat necessary for rejection directly proportional to the RPMs of the engine? If not, then in what case(s) would it diverge?