Hydro Differential pressure exchange over unity system.

[mondrasek]

This is a point of discussion, can the venting be used and still have the risers sink.

I can't see why not.  The water definitely needs to be vented out and it is under pressure.  The water pressure is a function of the volume of water in the ZED.  By reducing the volume of water (venting) the pressure is reduced.  And reduction in one or the other or possibly both causes the Pod/Risers to sink.

What I have observed is that when I want to vent back into the reservoir with the smallest needed drop that the rate of descent is slow for both the risers and the reservoir, where as the lift I can do much faster.

I am venting by releasing water directly from the bottom of the Pod chamber through a valve.  If I open the valve wide, the water in the input tube drops very rapidly and outpaces the drop of the Pod/Risers.  And if I close the vent valve while the water levels are in this unbalanced state then the water level in the input tube will rise again as the ZED drops and the system reestablishes equilibrium.  The faster drop in the input tube is likely because there is much more flow restriction in the ZED and it's water entrance/exit path.  If I open the valve a slighter amount I can watch the ZED Pod/Riser and the fill tube water levels drop smoothly and at a balanced rate.

Rise and sink rates appear to me (so far) to just be a function of the efficiency of the input/output plumbing and the internal ZED flow rates.

M.

[neptune]

@Webby. Cryptic words from Wayne about two months ago.[cant find it now]


     "Keep stroke short. Will explain later. Trust me."


Make sense?

[TinselKoala]

@mond: why can't you just take your outlet "drain" from the top two inches, and plumb it directly into the bottom inlet, and have it flow around perpetually, extracting work from a little turbine wheel on the way? That is, I believe, essentially what you are proposing, with the complication of doing the work extraction a little more remotely.

When we consider venting at the same level the water is introduced as input there is no difference in the pressures and no energy is lost.

And there is also no work that can be performed by the water in this way.  You are proposing letting water run out.... which MUST occur from a region of higher pressure to a region of lower pressure, otherwise no flow. And then you are proposing letting water run back in at the same pressure and volume..... not physically possible, I don't think.
Besides, I thought the input water had to be introduced at the center bottom. You are actually removing it under pressure from the bottom, lifting it up -- and pouring it back _into the bottom_ by pouring it into the top of the input tube which is plumbed to the bottom of the chamber, right?


Nobody is working through the numerical problem that wildew presented? It's an interesting exercise, took me an hour to do it, several pages of sketches and figuring, and I learned a few things on the way to an answer. Did I do it right? "yes, I think, correct so far" is pretty much all the feedback I've gotten on this interesting problem.

[mondrasek]

@TK,

I've made no attempt to manufacture a complete miniature self running (dual) ZED system.  I have only constructed a single three layer ZED for testing of the input energy vs. output energy ratio as so many times has been requested and stated as necessary.  And I posted one admittedly hurried and sloppy data point prematurely just for those that wanted to try and make that calculation.  Why have you or anyone else not done so?

I have posted measured input values.  Are they not enough to calculate input energy?
I have posted measured output values.  Are they not enough to calculate output energy?

The input causes the extra ~2.5 lbs of "load" mass to lift.  This "load" mass is to simulate the hydraulic rams that produce the pressurized hydraulic oil that is accumulated in Wayne's system.  This "load" is then removed and not used while the system is reset to initial start conditions.  I think it is a pretty good first test of the model I have built.  Don't try to pretend that the model or the test is anything more or less than it is, please.

Could you please just run the numbers or do you just want to pick at it/me?  I'm on vacation, remember?

M.

[see3d]

Sorry for the delay in getting these to you,, I will play more and see if I can get at least an average value,,,

The numbers as best as I can get them.

I can not measure the retainers, my calipers do not fit down past the extender.

Riser diameter is between 38.7mm and 38.85mm
Riser height is between  124.57mm and 125mm
Weight is 22g (I have superglue a washer on top)

Pod diameter is between 27.09mm and 27.2mm
pod height is between   91.95mm and 92.17mm
weight is 18g

Pod chamber volume is 84ml
first gap between retainers is 32ml (this one is not used)
second gap is 43.8ml

Pod chamber WITH pod inside and held down is 28ml.

material thickness is .19mm to .22mm

Only a few runs so far but the numbers are strange and I am having to hit the base a lot and hard to shake things down.

Added mass on riser 55g lift 20mm
reservoir fluid 30g lifted 165mm

added mass on riser 75g lift 20mm
reservoir fluid 27g  lifted 153mm

forgot to add that the setup likes to change itself but I am trying to use a centered water to air start position.

Webby,

Thanks for measuring this.  It will take me some hours to translate this to inch/pounds units and set up an initial standardized sim model for it.  I will let you know if I am missing anything or have questions as I proceed.

Even though all my geometry inputs are in inches, I can probably add a button that converts the output tables of the sim to mm/g without too much trouble.  Or should it be cm/kg to get a better match to inches and pounds?

Thanks again,
Dennis