Brake Worksheet

[blykins]

Well, I can give you formulas for deriving pad temperature based on heat transfers in both accounts like I described earlier.

q'' = convective heat flux
h = heat transfer coefficient (you will need these for the various materials you're anticipating using....i.e. material for rotors, and the material for the pads.
t=thickness of pad
k = thermal conductivity ( you will need to find this also for the various materials)
Tp = Temp of pad
Tinf = Temperature infinity....i.e. temp of ambient air
A = area of pad. This will be a doozy to find out....each pad will be different...you might just wanna use a general catch-all number for all pads...maybe a general area for single piston calipers, one for dual piston, one for quad piston...etc....


Now with that being said, total heat flux will be the sum of the conduction between the metals, and the convection between the metals and the ambient air.

So if you focus on the pad, you can generalize that on one side of the pad during braking contact, you will have conduction heat transfer from the pad to the rotor....and there will also be air flowing around the caliper and part of the pad itself.

qtotal = (k(Tp-Tinf))/t) + hA(Tp-Tinf)

That's gonna be as close as I can get ya without some deeper analysis of piston diameters, air flow, etc....

q should come out in W....

What I haven't stated from the beginning is that you're gonna need some sample temperatures to get you started....because you have basically two unknowns.....the heat flux (q) and the pad temperatures. You can probably get some sample values of each and interpolate.

I know this is as clear as mud...I'm doing the best I can...it's been like almost 3 years since I've had this course...and like almost everything else, you don't use it after you take it in class.

I'll try to help you as much as I can...let me know if you have any questions...I'll try to explain what I did....