Hydraulic Cooler Sizing (cross post)
Hydraulic Cooler Sizing (cross post)
(OP)
I posted this in the wrong forum before. Perhaps a mod can delete the previous one?
I'm trying to size a cooler based on actual heat created in a system. In a closed loop circuit, do I consider leakage from the charge pump (10-15% of charge flow * charge setting), leakage through the pump case (10-15% of max flow * Delta P), and leakage through the motor case (10-15% of max flow * Delta P)? Just want to make sure I'm not doubling up on the pump and motor case.
For Delta P in the pump and motor case I am using (pressure setting - charge setting). I am running two cases to determine worst case -- high speed, low pressure and low speed, high pressure. HP of the prime mover limits high speed, high pressure instance.
Comments?
I'm trying to size a cooler based on actual heat created in a system. In a closed loop circuit, do I consider leakage from the charge pump (10-15% of charge flow * charge setting), leakage through the pump case (10-15% of max flow * Delta P), and leakage through the motor case (10-15% of max flow * Delta P)? Just want to make sure I'm not doubling up on the pump and motor case.
For Delta P in the pump and motor case I am using (pressure setting - charge setting). I am running two cases to determine worst case -- high speed, low pressure and low speed, high pressure. HP of the prime mover limits high speed, high pressure instance.
Comments?





RE: Hydraulic Cooler Sizing (cross post)
Are you also considering system losses(heat) in addition to pump and motor losses?
I have yet to see a system that had too much cooling capacity.
Ted
RE: Hydraulic Cooler Sizing (cross post)
This is mobile equipment, so space is a premium. I can't just use the largest cooler I can find like I'd like to. I really need to size it right.
Thanks,
J
RE: Hydraulic Cooler Sizing (cross post)
There might be some port to port leakage at the valve plate of the rotating group, but realisitically most of it goes to case.
Also add a bit for the case churning heat from the pump rotating.
A big variable is the cooler efficiency: just alight coating of dust, or slower air flow, make sa big difference. Mfr tests are usually optimistic, at least in my environment.
I am cautious and conservative. I don't think I have ever been beaten on because a cooler was too big. They just run it harder and longer until complaining of heat.
I know space is a premium, but it costs a whole lot more to find that space after the machine is built....
RE: Hydraulic Cooler Sizing (cross post)
And I agree with kcj - slightly oversize the cooler to account for dirt/debris buildup. The extent you over-design it will depend on the application and clientele.
And lastly, it pays to try out different fans, fan spacers and shrouds. In general the fan should be not be tight against the engine nor the radiator/cooler. I had a bunch of different length spacers and would do an optimization test. I have picked up 5-15% airflow just by changing the fan spacer or fan. In general the longer you can make the shroud the better, and if you can avoid sharp edges and corners even better. Look at the shroud on FWD cars to get an idea of the best shapes and contours.
ISZ