DIY Tesla Impulse Turbine

[Steamchick]

Thanks Toymaker. Sounds good! I am very interested in your turbine, as the one I have have been trying (made by the late Chairman of my local model engineering club) is a bit unknown, and I have hesitated dismantling it as I understand he carefully assembled it for good balance. Very similar in size to yours.
From what you are doing, I feel more confident about giving mine a lot more steam and heat!
Thanks!
K2

 

[Nerd1000]

Do you have an equation to calculate flow rate through a centrifugal water pump which includes impeller blade height or thickness?

Being that a centrifugal pump is not a positive displacement machine, the flow rate will be set by many variables, most notably the amount of restriction on the flow at the inlet and outlet. You can get an idea of the amount of pressure the impeller can generate at a given flow rate by using velocity triangles and the Euler pump and turbine equation.

 

[Toymaker]

Thank you Gemini (Google's AI), for finding the flow rate equation I've been looking for.

The flow rate of a centrifugal pump impeller can be determined using the following equation:

Q = π * D * B * ω / 60

where:

• Q is the flow rate (in cubic meters per hour)
• π is a mathematical constant approximately equal to 3.14159
• D is the impeller diameter (in meters)
• B is the impeller width (in meters)
• ω is the angular velocity of the impeller (in revolutions per minute)
• 60 is a constant to convert from revolutions per minute to revolutions per hour

Once Q is known, the following equation can be used to find power needed to drive the pump.

Power (kW) = Q* P * SG / 3600
where:

• Q is the flow rate (in cubic meters per hour)
• P is pressure in Bar
• SG is Fluid's Specific Gravity (water = 1)

 

[Steamchick]

This seems to be straightforward and simple:
I think it should also apply to a Tesla pump? - using the plate gaps to be the equivalent of "B"?
Outside my experience, so maybe this is a stupid question? But on various types of rotary oil pumps (on cars, motorcycle engines, etc.) the clearances between rotors and housings are critical to prevent "flow-back" and loss of pressure &/or flow. E.g.

But I guess that is because they work towards their limit of pressure, and not so much flow. Are these "displacement pumps" rather than "inertial pumps"?
What is the corollary for leak-back on a centrifugal pump? Side rotor clearance I guess, and is there a problem with clearance around the outer diameter of the rotor? I can imagine that fluid leaking at the sides could travel from the outer "higher speed (and pressure?) zone" to the inner "lower speed zone" causing loss of performance from re-cycling of fluid, which is minimised by close fitting of parts. But does it matter if the housing around the outer diameter is close fitting or not? - Maybe not as on the outside there is only fluid at pressure and flow for the outlet, and no inlet to leak back to?
Sorry, I can't get my head around what is going on, to work it out.
Maybe it is something like:- the pump can deliver a maximum flow based on the equation above, but pressure is based on how the flow is restricted downstream - or not - at anything below a maximum pressure determined by the rotor outer diameter speed?
I have a feeling that max pressure is at zero flow, and max flow is at zero pressure. but we work somewhere between those points in real life.
Can anyone teach me what is really happening? - or point me to a website so I can learn a bit? (I have been otherwise engaged so not had time yet to study this properly). And I'm feeling a bit "thick" today... so ignore me if I am too far off track.
Thanks,
K2

 

[Nerd1000]

This seems to be straightforward and simple:
I think it should also apply to a Tesla pump? - using the plate gaps to be the equivalent of "B"?
Outside my experience, so maybe this is a stupid question? But on various types of rotary oil pumps (on cars, motorcycle engines, etc.) the clearances between rotors and housings are critical to prevent "flow-back" and loss of pressure &/or flow. E.g.
View attachment 159822View attachment 159823View attachment 159824 But I guess that is because they work towards their limit of pressure, and not so much flow. Are these "displacement pumps" rather than "inertial pumps"?
What is the corollary for leak-back on a centrifugal pump? Side rotor clearance I guess, and is there a problem with clearance around the outer diameter of the rotor? I can imagine that fluid leaking at the sides could travel from the outer "higher speed (and pressure?) zone" to the inner "lower speed zone" causing loss of performance from re-cycling of fluid, which is minimised by close fitting of parts. But does it matter if the housing around the outer diameter is close fitting or not? - Maybe not as on the outside there is only fluid at pressure and flow for the outlet, and no inlet to leak back to?
Sorry, I can't get my head around what is going on, to work it out.
Maybe it is something like:- the pump can deliver a maximum flow based on the equation above, but pressure is based on how the flow is restricted downstream - or not - at anything below a maximum pressure determined by the rotor outer diameter speed?
I have a feeling that max pressure is at zero flow, and max flow is at zero pressure. but we work somewhere between those points in real life.
Can anyone teach me what is really happening? - or point me to a website so I can learn a bit? (I have been otherwise engaged so not had time yet to study this properly). And I'm feeling a bit "thick" today... so ignore me if I am too far off track.
Thanks,
K2

This covers it pretty well.

https://www.nuclear-power.com/nucle...trifugal-pumps/eulers-turbomachine-equations/