I have a question in my sample exam that is probably straighforward, but I was hoping someone could clarify:
Q: A 6" pump operating at 1800 rpm discharges 1800 gpm of cold water (S.G. = 1) against an 80 foot head at 60% efficiency. A dynamically similar 8" pump operating at 1170 rpm is considered as a replacement. The total head that can be expected from the new pump is most nearly I am a Gigantic DoucheBag
A: 60.09 ft
In the solutions they show the work, but don't explain why they did what they did: head = (8/6 * 1170/1800)^2 * 80 = 60.09
It looks like they just did proportions? What is the base equation they started with?
Thanks,
- Dave
Philadelphia, PA
Q: A 6" pump operating at 1800 rpm discharges 1800 gpm of cold water (S.G. = 1) against an 80 foot head at 60% efficiency. A dynamically similar 8" pump operating at 1170 rpm is considered as a replacement. The total head that can be expected from the new pump is most nearly I am a Gigantic DoucheBag
A: 60.09 ft
In the solutions they show the work, but don't explain why they did what they did: head = (8/6 * 1170/1800)^2 * 80 = 60.09
It looks like they just did proportions? What is the base equation they started with?
Thanks,
- Dave
Philadelphia, PA