Designing a Water Hammer Flow Loop - Where do I start?
Designing a Water Hammer Flow Loop - Where do I start?
(OP)
I am working on a project where I need to design a flow loop capable of generating a water hammer event.
It needs to be fairly simple, and fairly compact (approx 2x3 feet).
I was thinking of something simple - a rectangular flow loop with a pump, and a valve on a straight section. When the valve is actuated, it stops the flow and generates a water hammer event.
My background is aerospace engineering, and most of this work is entirely new to me. Any advice or helpful reading links would be greatly appreciated.
It needs to be fairly simple, and fairly compact (approx 2x3 feet).
I was thinking of something simple - a rectangular flow loop with a pump, and a valve on a straight section. When the valve is actuated, it stops the flow and generates a water hammer event.
My background is aerospace engineering, and most of this work is entirely new to me. Any advice or helpful reading links would be greatly appreciated.





RE: Designing a Water Hammer Flow Loop - Where do I start?
RE: Designing a Water Hammer Flow Loop - Where do I start?
The goal is to trigger a water hammer event on a straight run pipe, and measure the response of the piping to the pressure surge associated with the water hammer. It would be a parametric study - changing parameters such as pipe diameter, valve closing time, fluid properties (fresh vs salt water), etc.
Ideally there would be no ruptures or failures, and the system will be over designed to withstand the elevated pressures.
My main problem is I don't have a feel for how all the components will go together. Does the pump need to be in-line with the flow?
RE: Designing a Water Hammer Flow Loop - Where do I start?
The air-cannon configurations seem to use a compressed air configuration with a quick opening butterfly valve.
Substitute a slug of water for the pumpkin.......and you got it.
However, I do agree with the above post regarding length of piping.
I believe that you will need a much longer run of piping to get results.
Specifically, what effects are you interested in evaluating ?
RE: Designing a Water Hammer Flow Loop - Where do I start?
Unfortunately the motivation for this project is similar to a flow loop with a valve, and so the small scale version must be fairly similar.
RE: Designing a Water Hammer Flow Loop - Where do I start?
Ted
RE: Designing a Water Hammer Flow Loop - Where do I start?
If not, how long of a pipe section would I need? Let's assume a 6 ft x 1 ft rectangular flow loop, with a valve in the middle of the 6ft 'test section'. 3 ft would be ~.0006 sec in between reflections, or ~1.7 kHz. An accelerometer with a 20kHz frequency response should be able to resolve the different peaks.
RE: Designing a Water Hammer Flow Loop - Where do I start?
RE: Designing a Water Hammer Flow Loop - Where do I start?
The pump I will be using is a Taco Inc Model FE 1206 3500 RPM, 5.45" impeller. It is capable of ~100 gpm flow w/ approx 75 ft head.
RE: Designing a Water Hammer Flow Loop - Where do I start?
http://en.wikipedia.org/wiki/Water_hammer
Theres an equation to calculate the min valve closing time in order to avoid a hammer.
Best regards
Morten
RE: Designing a Water Hammer Flow Loop - Where do I start?
Maybe this helps?
RE: Designing a Water Hammer Flow Loop - Where do I start?
Any pressure transducers must be fast acting and data logger nust be capable of at least 100 points per sec. Check out www.ventomat.com and see their explanation of of their research into air valves and waterhammer. Without these equipment they missed the peaks in surge events.
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http://waterhammer.hopout.com.au/
RE: Designing a Water Hammer Flow Loop - Where do I start?
To the extent piping flexibilty yields minute changes in piping volume for minor pipe deflections, then it might follow the piping system flexibility would affect results as well.
RE: Designing a Water Hammer Flow Loop - Where do I start?
4700 ft/sec is like 3200 mph or about Mach 4.5 - faster than an SR-71.
If anything was flying around my house at that speed - I would leave!! If there was anything left to leave!!!