Nos amis Anglais!

Salut! :(
Je suis ravi de voir que nos amis anglais sont finalement comme nous, se posent les mêmes questions que nous et résolvent leurs problèmes comme nous!

flashtwo
Guest
Re: Matching water pump to steam engine
« Reply #2 on: April 16, 2009, 12:33:03 PM »
Hi,
Assuming the pump ram is connected directly to the engine and its strokes per minute is the same as the engine RPM, then you work out the steam VOLUME consumption per rev:-
Volume = stroke x (diameter/2)squared x PI x number of cylinders
and double the Volume if double acting. (PI = 3.142). To be more accurate you should also consider the thickness of the piston and the volume it takes up.
Looking up the "Model Engineers Handbook" by Tubal Cain, section 8 we have the skeleton steam tables (you don't want to see the complete steam tables !), then for a steam pressure of 50psi (gauge) water expands 414 times, therefore dividing the steam volume by 414 will then give the water volume per stroke. If the steam was being exhausted at atmospheric pressure, then water expands 1665 times.
Once you have the water volume, you multiply it by a pump efficiency value (I use 1.15), since the pump clack valves do not close immediately and the pump may be only 87% efficient. From the water volume you can then work out the pump ram diameter and stroke.
The above calculations will get you in the right ball park, but steam leaks, pressure drop across the regulator valve and varying boiler pressure will complicate matters.
Ian.
D'accord , c'est en anglais, mais on explique la même chose sur ce forum, en plus clair, parce qu'en Français! Juste pour dire qu'on est au niveau ! :study:
Cordialement!