DIY Tesla Impulse Turbine

[Toymaker]

I suspect (but am guessing!) that the smaller holes are putting proportionally more air in the turbine slots and at a higher velocity, and less air impinging on the outer metal surface of the rotor where it simply goes around the outside and out the exhaust?
Gas velocity is everything in the turbine. - And putting it where you want it, versus NOT putting it where you do NOT want it is the key to efficiency.
What was the pressure gauge steady at with the larger holes, and what is it steady at now?
K2

As the videos show, there isn't a steady pressure time period; when I open the valve to the compressor's air tank, all the air inside the tank rushes out through the nozzles. Tank pressure starts out at 100 psi and steadily decreases in just a few seconds.

 

[Toymaker]

I suspect (but am guessing!) that the smaller holes are putting proportionally more air in the turbine slots and at a higher velocity, and less air impinging on the outer metal surface of the rotor where it simply goes around the outside and out the exhaust?
K2

My current theory (and it is just a theory) on why smaller nozzle holes have resulted in increased power from the turbine:

As I mentioned previously, larger nozzle holes required a larger air flow than my compressor tank was able to supply, so I blocked off half the holes in each of the six nozzle arrays. Although this configuration allowed the turbine to spin and do work, an unplanned result was that half the discs in the turbine, which had no air nozzle holes shooting high velocity air at them, were now free to function as a Tesla compressor. I suspect exhaust air from open, working nozzles, once it reached the open, center area of the disc stack, was being sucked into the discs with closed off nozzles and being flung against the inside walls of the container shell, where it interfered with the air jets from working nozzles.

The nozzle arrays with the smaller holes have no holes blocked off, resulting in no section of the turbine discs to inadvertently become compressor sections, sucking power from the turbine.

 

[Steamchick]

The height of jet - even momentarily still represents the water pressure achieved. So it there is a wall you can hit you can see how high you get for max pressure (probably when the air is at/near max pressure!). Knowing the number of vanes, you can possibly hear a musical note of the pressure pulsations as vanes pass the outlet (pressure pulsations in the water at the jet will generate some sound in the air) - from which you can deduce the frequency of noise, and dividing by the no. of vanes can deduce the rpm... Lots to measure already. Get your thinking cap on.
K2

 

[Toymaker]

The height of jet - even momentarily still represents the water pressure achieved. So it there is a wall you can hit you can see how high you get for max pressure (probably when the air is at/near max pressure!). Knowing the number of vanes, you can possibly hear a musical note of the pressure pulsations as vanes pass the outlet (pressure pulsations in the water at the jet will generate some sound in the air) - from which you can deduce the frequency of noise, and dividing by the no. of vanes can deduce the rpm... Lots to measure already. Get your thinking cap on.
K2

K2, I applaud both your curiosity and your creative problem solving ideas,....however, at this point in time, I believe my project time is better spent finishing my monotube boiler which will allow me to properly test this turbine at the design pressures of 500 psi.

 

[NapierDeltic]

Hi Toymaker. Maybe I am not the best to give advise, but my educated guess is as follows. Gas turbines are extremely hungry pieces of equipment. A small jet engine with the diameter of your turbine delivers maybe even tens of kW, so on reverse, unless you provide constant power/ gas quantities of the same magnitude you won't obtain stable operation on a mid-range workload that allows you to properly test and adjust the turbine. My best bet would be to find a very high flow compressed air source -like you'll find in a plant - to do adjustments. Maybe monotube boiler could give you required gas flow, but monotube boilers tend to be very unstable in operation and complexity of controlling all parameters of boiler-turbine compound could drive you crazy. I don-t mean it can't be done, but I won't advise to. And of course, unless you try, you'll never know.

 

[Toymaker]

Hi Toymaker. Maybe I am not the best to give advise, but my educated guess is as follows. Gas turbines are extremely hungry pieces of equipment. A small jet engine with the diameter of your turbine delivers maybe even tens of kW, so on reverse, unless you provide constant power/ gas quantities of the same magnitude you won't obtain stable operation on a mid-range workload that allows you to properly test and adjust the turbine. My best bet would be to find a very high flow compressed air source -like you'll find in a plant to do adjustments. Maybe monotube boiler could give you required gas flow, but monotube boilers tend to be very unstable in operation and complexity of controlling all parameters of boiler-turbine compound could drive you crazy. I don-t mean it can't be done, but I won't advise to. And of course, unless you try, you'll never know.

Thanks for the good advice NapierDeltic. Tens of kW is in the range I'm hoping for.

I'm keenly aware of the difficulties of obtaining stable operation from a monotube boiler, which is why I'm using a microcontroller to monitor and control parameters such as fuel and air flow, as well as pressure in and output; the ECU is the part of the boiler I'm currently working on. I briefly spoke about the ECU (Engine Control Unit) here: Electronic Control and there's more on the burner-boiler unit here: Monotube Flash Boiler Design.

Back in the 1970s, a small company known as SES (Steam Engine Systems) built several test cars using monotube boilers, which were electronically controlled; SES
Back in that pre-computer time, the ECU was said to take up the entire trunk space of the car. Fortunately for me, today's microcontrollers are much smaller, easy to acquire and not too expensive.

 

[NapierDeltic]

Thanks for the good advice NapierDeltic. Tens of kW is in the range I'm hoping for.

I'm keenly aware of the difficulties of obtaining stable operation from a monotube boiler, which is why I'm using a microcontroller to monitor and control parameters such as fuel and air flow, as well as pressure in and output; the ECU is the part of the boiler I'm currently working on. I briefly spoke about the ECU (Engine Control Unit) here: Electronic Control and there's more on the burner-boiler unit here: Monotube Flash Boiler Design.

Back in the 1970s, a small company known as SES (Steam Engine Systems) built several test cars using monotube boilers, which were electronically controlled; SES
Back in that pre-computer time, the ECU was said to take up the entire trunk space of the car. Fortunately for me, today's microcontrollers are much smaller, easy to acquire and not too expensive.

Thank you very much, Toymaker and I am (will be) following you with much interest. If I am allowed to skew a bit your topic, Traian Vuia -who happens to be my fellow countryman -was one of the first to design research and promote a fast generating monotube steam boiler, starting maybe since 1902, which he called "catalytic burning steam generator" :
https://www.researchgate.net/public...bution_to_the_development_of_propulsive_power

I obviously read long time ago about his work. Some of is outdated, some too optimistic, some is experimental and systematic and still valid. Anyway, hence my interest.
And also from my belief that steam hasn't shown yet its best! As a non-specialist, I am really interested in your experimentation both for monotube boiler and for Tesla turbine, another technical marvel!
I wish you Good Luck and I will rejoice of it!