CFD radiator flow 101

If you want to cram a large amount of stuff into an engine bay that was not there when the car was conceived  (like a 2 liter  Vauxhall with a turbo and inter-cooler), while still keeping the original shape of the car., you might run into some packaging issues  Not a easy thing to do in an engine bay that would barely fit a piece of carry-on luggage.

Now if you want say 300 bhp (perfectly sane as the original car produces 38 bhp.. if itś worth doing, its worth overdoing) you need the keep the whole lot cool. Due to the space constraints the radiator is partly shrouded by the bonnet as it need to go up all the way to use all of the available space. The question is : will the top part actually do anything useful, and if not, how do you get it to play along Hence this small foray in making CFD do actual stuff. The ´model´ was made using Salome 6 and the CFD using Code Saturne 3.0 and visualisation was done in ParaView .


Doing it properly (modeling the whole lot with heat exchange etc etc) is quite complex and if you are good at it you could apply it to all kinds of problems using cooling (laptops , nuclear reactors, beer.. well anything that needs to lose heat in general)). Putting the radiator (inducing a mix of resistive and inductive resistance, is a bit tricky for meshing as you will need to define the radiator with a special kind of mesh  (there is supposed to be an porous option, but it is  rather sparsely documented. more like not at all)


So I have limited my question to the very simple: will a simple baffle or two redistribute the airflow across the radiator without inducing a whole lot of turbulence?


A super simple model as a starting point. The air enters at 20m/s in the left hand side and exits out of the right hand side. The dam defines the shrouded area and the two planks angled upward at 12 degrees so that the included angle to reduce the chance on flow separation. It is quite far from reality but modelling is quite time intensive and often not very intuitive.


The colour of the streamlines indicates the amount of turbulence. So adding a few plates does do a few things. First of all it seems reduce the amount of turbulence, second it does seems to shift a portion of the flow upward around the corner.




Screenshot - 06232014 - 07:27:49 PM


wings vs no wings

Screenshot - 06232014 - 07:44:48 PM

no plates

Screenshot - 06232014 - 08:11:27 PM

with the two plates

Screenshot - 06232014 - 07:44:36 PM








Tagged ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: