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Re: More thoughts on earlier "turbo theory" Posted by JimBlake [Email] (#141) [Profile/Gallery] (more from JimBlake) on Tue, 2 Dec 2003 06:59:19 In Reply to: More thoughts on earlier "turbo theory", bkoeth, Mon, 1 Dec 2003 23:23:50 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I gotta get in this one... I was enjoying turkey-day for the other thread.
How does heat create low pressure on the back side of the blades? Sounds like you're confusing heat with temperature, and/or applying a state equation (Pv=RT) where it's not applicable.
It't NOT the 'heat' of the exhaust that drives a turbo. It's the ENERGY of the exhaust, which includes temperature, velocity, & pressure all taken together. The velocity will create high pressure & low pressure on opposite sides of the turbo blades, spinning them. The same exact thing happens when the wind blows on a windmill. Lift, drag, & momentum transfer...
The turbo extracts energy from the exhaust stream. As it does that, it creates back-pressure for the exhaust. Now here's where the heat comes back in... If you were to create the same back pressure with some kind of restriction (orifice or valve) the resulting exhaust would be hotter. So the turbo 'cools' the exhaust, ONLY by comparison with that case where you have the same back-pressure.
posted by 68.73.7...
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