Ambient temperature of exhaust shaft
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: Ambient temperature of exhaust shaft
: Ambient temperature of exhaust shaft -- maverickai	Post Reply	Top of thread	Forum

Posted by: zekeman ® 12/15/2007, 18:04:54 Author Profile eMail author Edit

You don't mean "ambient" temperature of a shaft. A shaft does not have ambient temperature. Outside air has ambient temperature. What do you mean? A better explanation or a drawing might be helpful

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: : Ambient temperature of exhaust shaft
: : Ambient temperature of exhaust shaft -- zekeman	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 12/16/2007, 09:08:57 Author Profile eMail author Edit

I suspect maverickai is asking how to calculate the operating steady state temperature of the exhaust pipe after the engine is at operating temperature. The best equation I am aware of is: Three calibrated thermocouples (or thermisters) placed in key locations and measured with calibrated equipment. Not to short you on an equation, however this is the fastest and most accurate method I know of for determining actual system operating temperature with a boat-load of data and drawings. Modified by Kelly Bramble at Sun, Dec 16, 2007, 09:09:51

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: : : Ambient temperature of exhaust shaft
: : : Ambient temperature of exhaust shaft -- Kelly Bramble	Post Reply	Top of thread	Forum

Posted by: zekeman ® 12/17/2007, 09:47:41 Author Profile eMail author Edit

If that's the case , then the differential equation is Q*c *dT/dx =h*2*pi*r(To-T) where T= temperature of gas and wall, assuming much higher heat ransfer from gas to wall than from wall to outside air To = outside air temp, deg F Q=mass flow rate lbs/hr c= specific heat of gases h= heat transfer outside to pipe wall, BTU/HRFTdegF, use 3 for hot pipe r= radius of pipe in feet First order ODE solution is T-To= (Te-To)*e^-lambda*x where Te= exhaust temp, deg F lamda=2pi*r*h/Qc

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