Open Systems

[tinman]

The demonstraton shows that more power transfers to the fan with the valve opened rather than closed.  It does not determine that the power in the outflow exceeds the power consumed generating the inflow. 

If I connect a DC power source to a fixed resistor and that to a variable resistor I can readily show that  a value of the variable resistor exists that maximizes the power transferred to that variable resistor.  What I cannot do is show that the power exceeds the power drawn from the power source.  We would also see that the less power that the load draws from the power source the greater the percentage of power through the variable load resistor is of the diminishing power drawn.

The demonstraton shows that more power transfers to the fan with the valve opened rather than closed. It does not determine that the power in the outflow exceeds the power consumed generating the inflow

It shows exactly that. More force is exerted on the fan blades when the valve is open,thus more work is being done. The power to create the inflow is exactly equal to the power of the out flow with the valve closed->energy can be neither created nor destroyed. The rest of the power consumed to create the inflow is disipated as heat. Shall we go back to the tanks Mark?. I can set this up with the 20ltr tank,and show a run from the tank with and without the venturi open. We could put say 40psi into the tank,and wait for the gas temperature to rest at ambiant temperature,then see how long and how high the power output from our little generator go's with the venturi closed off. We could then do the exact same run with the venturi open. Which do you think will be able to do more work?.

[LibreEnergia]

It shows exactly that. More force is exerted on the fan blades when the valve is open,thus more work is being done. The power to create the inflow is exactly equal to the power of the out flow with the valve closed->energy can be neither created nor destroyed. The rest of the power consumed to create the inflow is disipated as heat. Shall we go back to the tanks Mark?. I can set this up with the 20ltr tank,and show a run from the tank with and without the venturi open. We could put say 40psi into the tank,and wait for the gas temperature to rest at ambiant temperature,then see how long and how high the power output from our little generator go's with the venturi closed off. We could then do the exact same run with the venturi open. Which do you think will be able to do more work?.

This demonstrates nothing other than a more efficient nozzle. Try the same experiment without a venturi but simply vary the nozzle shape and diameter. You'll find exactly the same effect occurring. A nozzle that can generate a higher velocity flow will produce more lift on the fan and hence more output to the generator.

Since you are not actually measuring the energy potential of the source you can't make any pronouncement at all that an energy gain has occurred.

[MarkE]

It shows exactly that. More force is exerted on the fan blades when the valve is open,thus more work is being done. The power to create the inflow is exactly equal to the power of the out flow with the valve closed->energy can be neither created nor destroyed. The rest of the power consumed to create the inflow is disipated as heat. Shall we go back to the tanks Mark?. I can set this up with the 20ltr tank,and show a run from the tank with and without the venturi open. We could put say 40psi into the tank,and wait for the gas temperature to rest at ambiant temperature,then see how long and how high the power output from our little generator go's with the venturi closed off. We could then do the exact same run with the venturi open. Which do you think will be able to do more work?.

Tinman there is no measure of the energy required to generate the flow in the tube.  So that is a dead stop to determining outflow energy over inflow energy right there.  It shows only what you see, more power transferred to the blades in one condition rather than the other.  We can make the blade spin faster by increasing the power in the tube and/or by improving the impedance match between the blade and the outflow from the tube.  Surely you agree that if we were to for example change the angle of the blades that we could change the fan speed a lot without hardly affecting the flow through the tube at all.  We can turn that right around by changing the geometry of the nozzle.

[tinman]

Tinman there is no measure of the energy required to generate the flow in the tube.  So that is a dead stop to determining outflow energy over inflow energy right there.  It shows only what you see, more power transferred to the blades in one condition rather than the other.  We can make the blade spin faster by increasing the power in the tube and/or by improving the impedance match between the blade and the outflow from the tube.  Surely you agree that if we were to for example change the angle of the blades that we could change the fan speed a lot without hardly affecting the flow through the tube at all.  We can turn that right around by changing the geometry of the nozzle.

We could indeed change the angle of the blades to make it more efficient,but once again,the venturi open would still produce more torque from the fan. We have a higher gas flow with the venturi open than we do with it closed. Maybe we show the difference where flow angle or geometry dosnt matter. Maybe we show usful work being done by way of the flow of gas lifting a mass in a given amount of time?. It takes more energy to accelerate a given mass in a shorter period of time-dose it not?. So how about we do something really simple,like put a pingpong ball(our mass),into a tube of a given length,and see how fast it travels through that tube with and without the venturi open?.

[MarkE]

We could indeed change the angle of the blades to make it more efficient,but once again,the venturi open would still produce more torque from the fan. We have a higher gas flow with the venturi open than we do with it closed. Maybe we show the difference where flow angle or geometry dosnt matter. Maybe we show usful work being done by way of the flow of gas lifting a mass in a given amount of time?. It takes more energy to accelerate a given mass in a shorter period of time-dose it not?. So how about we do something really simple,like put a pingpong ball(our mass),into a tube of a given length,and see how fast it travels through that tube with and without the venturi open?.

Changing a variable and noting that the fan speeds only tells us that more power was imparted to the fan blades.  Since that can occur for several reasons, it does not tellwhich of those reasons or combinations of those reasons.

Isn't your hypothesis that you can perfom more work than energy you input by plumbing your apparatus to the local environment?  If that is what you are trying to get to, then the experiment design effort should try and falsify that as directly and simply as possible.