Pulsating or Intermittent Flow Waterblock - Page 2

bigben2k · 07-12-2004, 07:20 PM

16gpm at that pressure would surely raise the water temp, but no such pressures here.

I went up and down the paper yesterday, and noted a few things:

First, the experiment is *not* for a submerged jet. A submerged jet would have additional turbulence, and more "spreading" (a quote). This is important because...

2nd, the piston pump would work best here, but the duty cycle is going to be 50% or less, simply because of the open loop.

3rd, the paper identifies a "square" wave output with high pulses as being optimal.

So... a piston pump would typically provide a perfect sine wave output, but by adding a pressure valve (i.e. an in-line pressure relief valve), it should be possible to reproduce something close to a square wave.

But...

The author of the paper makes no pressure measurements (not applicable), and I suspect that the sudden variations in pressure are actually breaking up the boundary layer, which gives this effort a whole new angle.

Aleck · 07-13-2004, 01:18 AM

how bout using those pulsating shower heads....??

should be easy to get hold of em...

Kobuchi · 07-13-2004, 02:15 AM

You've got it, Aleck.

Something flutters inside the showerhead. Cheap and simple, and plastic no doubt.

Also dental hygene: Waterpik

EDIT: Checked one of those massaging showerheads - it outputs 2,800 pulses per minute.

07-12-2004, 07:20 PM	#26
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	16gpm at that pressure would surely raise the water temp, but no such pressures here. I went up and down the paper yesterday, and noted a few things: First, the experiment is not for a submerged jet. A submerged jet would have additional turbulence, and more "spreading" (a quote). This is important because... 2nd, the piston pump would work best here, but the duty cycle is going to be 50% or less, simply because of the open loop. 3rd, the paper identifies a "square" wave output with high pulses as being optimal. So... a piston pump would typically provide a perfect sine wave output, but by adding a pressure valve (i.e. an in-line pressure relief valve), it should be possible to reproduce something close to a square wave. But... The author of the paper makes no pressure measurements (not applicable), and I suspect that the sudden variations in pressure are actually breaking up the boundary layer, which gives this effort a whole new angle. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

07-13-2004, 01:18 AM	#27
Aleck Cooling Neophyte Join Date: Nov 2003 Location: Malaysia Posts: 29	how bout using those pulsating shower heads....?? should be easy to get hold of em...

07-13-2004, 02:15 AM	#28
Kobuchi Cooling Savant Join Date: Jan 2003 Location: BC, Canada Posts: 313	You've got it, Aleck. Something flutters inside the showerhead. Cheap and simple, and plastic no doubt. Also dental hygene: Waterpik EDIT: Checked one of those massaging showerheads - it outputs 2,800 pulses per minute.

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