Re: Water cooled brakes
Posted: Tue Jan 16, 2018 11:06 pm
On automotive disc brakes, I thought they were a derivative from the aircraft industry, not sure.
Back to water cooling, and feeling the misting total loss systems are not the point of this thread, I've already made my case in that direction.
Regarding the mentioned engineer, who the OP seems to highly regard, I can only address his mentioned idea, and wonder if it was just a quick thought being shared. Because the fact remains, the amount of heat generated by a nearly multi ton race car at triple digit speeds trying to stop as quickly as possible, repeatedly, for up to 24 hours, using water as a coolant, would be almost impossible. I've mentioned the temp limitations of water, and it would require rather high pressures to maintain a liquid state for maximum heat transfer. You normally want maximum temp differential in a heat exchanger between the ambient cooling air and the coolant, to transfer large amounts of heat. Existing systems of typical air cooled brakes have that already, in that rotors/drums glow in ambient air, with a temp difference approaching maybe a thousand degrees F, with water, 200F would be a task. An engine cooling system in a race application does not get over designed with other then with marginal over capacity, so any additional heat transfer with water cooled brakes would have to be designed in, ie, heavier/larger/more airflow/less slick aero/more complex/less reliable, etc, discounting how you would account for the different operating pressures required for the engine water coolant and a high pressurized brake coolant system, to prevent the brakes from boiling the water. Brake heat generation is very spikey and intense on a race track, whereas an engine is certainly relatively a lot more stable temp generator. Sorry, i don't see how this engineer spent much thought on his original idea, and history has proven, brakes have evolved enough to even handle much higher brake induced heat loads caused by areo drag reduction, greater traction available from DF, and most importantly, tire improvements.,
Back to water cooling, and feeling the misting total loss systems are not the point of this thread, I've already made my case in that direction.
Regarding the mentioned engineer, who the OP seems to highly regard, I can only address his mentioned idea, and wonder if it was just a quick thought being shared. Because the fact remains, the amount of heat generated by a nearly multi ton race car at triple digit speeds trying to stop as quickly as possible, repeatedly, for up to 24 hours, using water as a coolant, would be almost impossible. I've mentioned the temp limitations of water, and it would require rather high pressures to maintain a liquid state for maximum heat transfer. You normally want maximum temp differential in a heat exchanger between the ambient cooling air and the coolant, to transfer large amounts of heat. Existing systems of typical air cooled brakes have that already, in that rotors/drums glow in ambient air, with a temp difference approaching maybe a thousand degrees F, with water, 200F would be a task. An engine cooling system in a race application does not get over designed with other then with marginal over capacity, so any additional heat transfer with water cooled brakes would have to be designed in, ie, heavier/larger/more airflow/less slick aero/more complex/less reliable, etc, discounting how you would account for the different operating pressures required for the engine water coolant and a high pressurized brake coolant system, to prevent the brakes from boiling the water. Brake heat generation is very spikey and intense on a race track, whereas an engine is certainly relatively a lot more stable temp generator. Sorry, i don't see how this engineer spent much thought on his original idea, and history has proven, brakes have evolved enough to even handle much higher brake induced heat loads caused by areo drag reduction, greater traction available from DF, and most importantly, tire improvements.,
