Radiator Sizing?
Radiator Sizing?
(OP)
I am aware that this is a very broad question, but was wondering if there is an approximate method to evaluating a needed radiator size? For example, lets take a 200hp, turbocharged engine, 1.8L, 4cyl motor. I know there are lots of variables in this problem such as the coolant flow rate, air speed, radiator heat transfer coefficient, etc, and detailed analysis would be needed to properly size the radiator. I am looking basically for a worst case scenario. First of all what would be a good assumption for how much heat is dissipated to the coolant from the IC engine. As I read, that would be about 1/3 of total power, which assuming 1/4 only goes down to the groud, that would mean almost 200kW gets transfered to the coolant. Now, at steady state, are radiators sized to cope with this condition or some precentage of that? To start would two flow conditions be sufficient, for example at idle, and at max power output, in order to size the radiator? What is a typical heat transfer coefficient, U for an automotive radiator of average size 3.0L? I found it very dificlut to find any information, data, U, effectiveness, etc on automotive radiators, if anybody can provide me with a good source, website, book for this type of data that would be great. Thanks for reading.
Best Regards,
Cymeryss
Best Regards,
Cymeryss





RE: Radiator Sizing?
Chumley
RE: Radiator Sizing?
I don't have any info on heat transfer of radiators I'm afraid.
Andy
Engine Heat to Exhaust Coolant Oil Brake Other
Speed Fuel
7080 100% See Other 7% 2% 27% 64%
7019 100% See Other 7% 2% 27% 63%
6959 100% See Other 8% 4% 27% 61%
6707 100% See Other 8% 4% 27% 61%
6457 100% See Other 8% 4% 28% 60%
6205 100% See Other 8% 4% 28% 60%
5955 100% See Other 9% 4% 29% 59%
5454 100% See Other 9% 4% 29% 57%
4951 100% See Other 8% 3% 30% 58%
4649 100% See Other 9% 4% 30% 58%
4600 100% See Other 9% 4% 30% 57%
4550 100% See Other 9% 3% 30% 57%
4450 100% See Other 9% 3% 29% 59%
3949 100% See Other 9% 4% 28% 59%
3450 100% See Other 10% 4% 31% 55%
2949 100% See Other 10% 4% 30% 56%
2444 100% See Other 12% 4% 32% 51%
RE: Radiator Sizing?
Cheers
Greg Locock
RE: Radiator Sizing?
has anyone done any work figuring out how over designing the coolant system decreases fuel efficiency? For example -- If you design the radiator surface area for the absolute highest thermal load (towing a trailer up a hill at 85 mph) the radiator cross sectional area will cost fuel efficiency at lower loads where that much area is not needed.
The same thing could be said about the water pump; designed to pump the amount of coolant necessary for cooling at maximal loads, resulting in excess power being used to generate a coolant flow that's too high most of the time.
The only area that I can see this being addressed is in the design of cooling fans and clutches.
RE: Radiator Sizing?
Davies Craig make a plastic, electrically driven water pump with a microprocessor controlled electric motor that senses water temperature, and increases pump speed according to temperature.
The air duct to the radiator could also be thermostatically controlled to adjust air flow, and if correctly designed, could significantly reduce the drag caused by the duct when the minimum airflow was required.
I don't know if this is being done, just that it must be possible.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Radiator Sizing?
RE: Radiator Sizing?
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Radiator Sizing?
Andy
RE: Radiator Sizing?
Cymeryss
RE: Radiator Sizing?
EngWatP WatinT WatoutT Wat_flo
RPM Bar(g) øC øC l/min
7080 0.69 89 94.5 142.5
7019 0.73 91.5 97.4 140.9
6959 0.78 93.6 99.7 140
6707 0.81 93.6 99.8 140.8
6457 0.75 89.2 95 144.3
6205 0.78 92.8 98.8 139
5955 0.77 90.3 96.5 140.2
5454 0.73 87.2 93.5 131.9
4951 0.77 93 98.9 120.7
4649 0.78 91.1 97.2 114.8
4600 0.78 90.3 96.3 114.1
4550 0.78 89.5 95.6 112.8
4450 0.77 88.9 95 110.7
3949 0.76 88.1 94.3 99.6
3450 0.75 89.9 95.6 86.9
2949 0.76 90.6 96.7 73.2
2444 0.77 90.6 97.3 59.3
1939 0.78 90.1 97.6 46.4
1438 0.78 89.1 97.7 34.8
1039 0.79 87.5 97.7 25.7
Based on some other data for a 2.0L I4, I've got pressure drops of ~45kPa&105L/min@5000rpm and 55kPa&135L/min@6000rpm.
Andy
RE: Radiator Sizing?