irokin Posted October 17, 2007 Report Posted October 17, 2007 That was how the very old radiators work, quite alot of them are just big drums of water with an outlet in the bottom and the water free flowing into the top like a fish tank. Anyone want a sexy 44 gallon drum of water strapped to their Rolla or Skyline.Speedway cars often have every second fin on the water pump cut away, otherwise they either create too much pressure and things burst. Or the water goes through the radiator too fast for radiation of the heat to occur. Last time I checked (and I'm pretty sure its still there) theres a whopping great waterpump strapped to the front of my motor. If the radiators thermosyphoning while the motors running you've got a big problem. I'm not talking about 208 litres either (and its ridiculous to suggest that I am), I'm talking about the difference between a radiator of 1.5 litres and 3 litres. Quote
KE30_KE35_KE55 Posted October 17, 2007 Report Posted October 17, 2007 Can you tell me why newer cars and large V8 are more often than not using cross flow radiators? Manufactures have shaped the car to make it more aerodynamic, there is now reduced height at the front to fit the radiator tanks top and bottom , its also a case of more radiator less tank. It really does not matter what coolant flow direction as long as air can also flow through the fins. Quote
Guest Sbox Posted October 18, 2007 Report Posted October 18, 2007 (edited) Deleted Edited May 24, 2008 by Sbox Quote
Jason Posted October 18, 2007 Report Posted October 18, 2007 lulz Whats up with all the bs catfighting? Quote
KE30_KE35_KE55 Posted October 18, 2007 Report Posted October 18, 2007 (edited) Last time I checked (and I'm pretty sure its still there) theres a whopping great waterpump strapped to the front of my motor. If the radiators thermosyphoning while the motors running you've got a big problem. If the radiators thermosyphoning while the motors running No big problem just a broken fan belt. or the thermostat is closed.:lolcry: Edited October 18, 2007 by KE30_KE35_KE55 Quote
Des Posted October 18, 2007 Report Posted October 18, 2007 (edited) lulz Whats up with all the bs catfighting? That time of the month, 3 threads with bitching. Edited October 18, 2007 by AE70 Quote
irokin Posted October 18, 2007 Report Posted October 18, 2007 So you have 3 litres of hot water, your "whopping great water pump" forces it across, down, up,( through the radiator in some direction). It is now on the other side, top, bottom of the radiator and still hot, what have you achieved? Read the bit where I explained about heat transfer and radiation (also about cutting away fins on the water pump). Thermosyphon is what happens when you heat and cool liquid, you are arguing with physics. f@$k...we're not reinventing the wheel, its a radiator for crying out loud. The thermosyphon effect will be so small its negated by many other forces happening inside the cooling circuit. Quote
Guest Sbox Posted October 18, 2007 Report Posted October 18, 2007 (edited) Deleted Edited May 24, 2008 by Sbox Quote
irokin Posted October 18, 2007 Report Posted October 18, 2007 You're welcome to try and measure it, but I can guarantee you will fail. Have a bit of perspective, what you're suggesting is ridiculous. Quote
Guest Sbox Posted October 18, 2007 Report Posted October 18, 2007 (edited) Deleted Edited May 24, 2008 by Sbox Quote
KE30_KE35_KE55 Posted October 18, 2007 Report Posted October 18, 2007 You're welcome to try and measure it, but I can guarantee you will fail. Have a bit of perspective, what you're suggesting is ridiculous. It is really quiet basic stuff when the thermostat is closed the water pump circulates around the engine. no flow thru the radiator. the radiator still continues to cool through Thermosyphon. Its that simple. Quote
irokin Posted October 18, 2007 Report Posted October 18, 2007 It is really quiet basic stuff when the thermostat is closed the water pump circulates around the engine. no flow thru the radiator. the radiator still continues to cool through Thermosyphon. Its that simple. Yes I understand the concept, what I'm saying however is that if you're at what doing 200kmph, thermostats wide open, water temperature going into the radiator is 85 degrees, pressure inside the cooling system is 1.2 bar, the effect of a thermosyphon is so small that its negated entirely by other forces inside the radiator (waterpump, pressure, steam pockets blah blah blah). I'm not saying it not there, just so small that it shouldn't be a consideration in choosing between a cross flow radiator and a down flow radiator. Quote
irokin Posted October 19, 2007 Report Posted October 19, 2007 OK heres some REALLY rough maths (its friday and I can't be f@$ked doing it properly). If anyone has better data please let me know, these are just for example. Yes I know theres glycol in some coolants but for simplictys sake I'm just using water density. Say the water entering the radiator is 85 degrees C. Water exiting the radiator is 70 degrees. Water displaced by the water pump is 1ltr every 5 seconds. The density of water at 85 degrees is 0.96839 g/cc and 0.97763 at 70. Density change from top of radiator to bottom of radiator is 0.00924 g/cc. So in 5 seconds the water pump displaces 977.63cc of water and the thermosyphon effect displaces 9.45cc (0.9666%). So in one minute the water pump moves 11731.56cc and the thermosyphon moves 113.4cc. Ive probably f@$ked up something in there. Feel free to pick apart (...correct) my maths. I suspect the water pump moves alot more than 1 litre every 5 seconds. Quote
KE30_KE35_KE55 Posted October 19, 2007 Report Posted October 19, 2007 OK heres some REALLY rough maths (its friday and I can't be f@$ked doing it properly). If anyone has better data please let me know, these are just for example. Yes I know theres glycol in some coolants but for simplictys sake I'm just using water density. Say the water entering the radiator is 85 degrees C. Water exiting the radiator is 70 degrees. Water displaced by the water pump is 1ltr every 5 seconds. The density of water at 85 degrees is 0.96839 g/cc and 0.97763 at 70. Density change from top of radiator to bottom of radiator is 0.00924 g/cc. So in 5 seconds the water pump displaces 977.63cc of water and the thermosyphon effect displaces 9.45cc (0.9666%). So in one minute the water pump moves 11731.56cc and the thermosyphon moves 113.4cc. Ive probably f@$ked up something in there. Feel free to pick apart (...correct) my maths. I suspect the water pump moves alot more than 1 litre every 5 seconds. The calculations are great but it is assuming the thermostat is open for a whole minute witch i very much doubt it would be. If you have ever seen a thermostat work it may open every 30sec for 4 sec. The important point is whilst the thermostat is closed the thermosyphon effect cools more than just the radiator. Quote
Jason Posted October 19, 2007 Report Posted October 19, 2007 (edited) "The important point is whilst the thermostat is closed the thermosyphon effect cools more than just the radiator." care to elaborate? And to make sure I'm on the same page thermosyphon effect is the current loop from the expansion and condensation of different temps? Little off topic, but just thinking of the way the termostat works in this care, since its controls flowrate and not say a switch, does that mean the temp is controlled continuously and not... carnt think of the word... 'stepped' like a eletric thermo. Because if this was the case then a small flow would always be moving through the radiator (when under load)..... I just find it hard to belive its either going to be on or off and not constantly fluctuating between. Unless its got some seriously latent heat storage. Edited October 19, 2007 by Jason Quote
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