SailNet Community - View Single Post - water flow GPM per HP of an engine?
View Single Post
  #14  
Old 05-05-2012
SlowButSteady's Avatar
SlowButSteady SlowButSteady is offline
Senior Slacker
 
Join Date: Feb 2010
Location: SoCal
Posts: 4,223
Thanks: 0
Thanked 17 Times in 15 Posts
Rep Power: 5
SlowButSteady is on a distinguished road
Re: water flow GPM per HP of an engine?

Quote:
Originally Posted by JimsCAL View Post
More importantly, you forgot the rather significant heat in the exhaust. Basically the heat rejected is roughly split equally between the cooling water and the exhaust. So your cooling water estimate is about double what's needed.
Actually, I did think about it. But I assumed that the water and the exhaust gases would be at equilibrium by the time they got to the end of the system. That may not be true, strictly speaking. However, unlike a car, truck, or anything else with a dry exhaust, we're talking about a wet system. As such, the exhaust gases must be pretty close to thermal equilibrium with the water. If that weren't the case the hot gases would cause localized heating of the seawater. That would, in turn, cause precipitation of the calcium salts (i.e., "scale") all along the exhaust hose. While this definitely does happen at the mixing elbow, it's usually much less of a problem downstream (particularly after the water lift muffler). So, the heat of the exhaust gas may take some of the energy away from the engine, but not all that much.
__________________
Never forget them. Do something to prevent it from happening again.
Charlotte Bacon, Daniel Barden, Rachel Davino, Olivia Josephine Gay, Ana M. Marquez-Greene, Dylan Hockley, Dawn Hochsprung, Madeleine F. Hsu, Catherine V. Hubbard, Chase Kowalski, Jesse Lewis, James Mattioli , Grace McDonnell, Anne Marie Murphy, Emilie Parker, Jack Pinto, Noah Pozner, Caroline Previdi, Jessica Rekos, Avielle Richman, Lauren Rousseau, Mary Sherlach, Victoria Soto, Benjamin Wheeler, Allison N. Wyatt
Reply With Quote Share with Facebook