@mrwayne. A quick question, and sorry if it has already been answered. In building a table top model of a Zed. is there an ideal ratio of Diameter to height? In other words,, is tall and narrow best, or short and fat?
Many thanks.

Quote from: neptune on August 24, 2012, 09:27:07 AM
@mrwayne. A quick question, and sorry if it has already been answered. In building a table top model of a Zed. is there an ideal ratio of Diameter to height? In other words,, is tall and narrow best, or short and fat?
Many thanks.

Good question;
Capture method:
Since the stroke length is determined by your flat topping the output - and the overlap of the ringwalls and Riser walls are reduced in this model during stroke - length is better.
If you are trying to capture the ideal and the lesser value during stroke - width is better.
Give and take:
A short wide model has a shorter stroke and greater lifting capacity -
A tall model has a longer stroke and or has more wiggle room.
A short model needs less precharge volume (assuming the Pod is the same size)
Additional consideration:
If I was doing short and fat - I would do larger gaps - reduce the pod size.
I recommend three times taller than the width of the average of the diameters - sounds funny - but it works pretty good as a starting point.
Mechanical function:
- if you are using / stroking, or squeezing a pump - you can use a lever to increase stroke length (short and fat is fine) - as long as you designed the force to accommodate.
If you are pumping directly from the ZED, then you know the stroke length, and power needed
Close the loop: (assuming you have the power down)
You must have enough stroke length for precharge and stroke volume - my machine is limited by the pump selection - it could do much more if I had matched the system to its capability.
Thanks
Wayne

@Mrwayne. Just what the doctor ordered as we say in the UK. That is great information that will benefit all who wish to replicate.

Attached is information on how to calculate water height using sensor Psi for the non-transparent model builders. Information was gleaned from one of Wayne's calculator. The sensors do not have to be directly connected as shown. Other methods, such as combinations of different types of tubing to the sensors could be used.

Edit: Tubing from the bottom with an air column extended upward would allow for the use of cheaper air sensors, instead of water sensors.

Regards, Larry

Quote from: webby1 on August 24, 2012, 02:38:08 PM
A test I did a while ago.

Using my 345g piston and a 680g lift mass.

Setup system so that the piston resting on the water holds the lift mass up just a little.

Place cup on top of piston and add 70g of water, piston sinks about 1\2 inch and the risers rise just shy of 1\8 inch, add another 70g of water to cup and piston sinks about another 1\2 inch and risers rise about another 1\8 inch, add another 70g of water and piston sinks to bottom and risers lift until blowout.

Reset the system but this time I hold the risers still and add about 120g of water to the cup on top of the piston, piston sinks about 3\4 inch, slowly allow risers to rise and the piston falls about another 1 inch and the risers lift over 1\2 inch but under 3\4 inch.

I tried adding more lift mass but the results were similar up to a point where I was not able to lift and any addition to the input just blew water out.

My conclusion is that the more potential stored under the risers the better the lift.

Well Done!
That effect become more dramatic with larger gaps ...
The idea of keeping energy in the system was counter intuitive to my Engineers - until they saw that test.
Keep it up!
Wayne