First Pump Results

guest blogger john hare

A friend mentioned that he had adequate shop air at 150 psi to test my pump. We had just a few minutes between jobs this afternoon to see what would happen. We got positive results.

Sort of. The air volume was not enough to choke the exhaust ports and build up full pressure. The most we could get in the chamber was 40 psig, and the inlet water pressure was 30 psig.  I think it is safe to say that 10 psig boost is not going to impress anybody.

I am going to have to rent one of the high volume compressors for a day and tweek the port sizes and inlet water pressures until I get useful results, positive or negative. If I can’t get enough turbine power with the vortex, I will put turbine nozzles in to see what happens then.

The unit I will probably rent is 185 cubic feet per minute at 90 psi. That volume should get a sonic choke on the 6 ports of 1/4″ diameter. If it doesn’t, I will block some ports and try again.

On the bright side, the pump hydraulic  bearing is very steady at dry rpms that make you think of earplugs.


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I do construction for a living and aerospace as an occasional hobby. I am an inventor and a bit of an entrepreneur. I've been self employed since the 1980s and working in concrete since the 1970s. When I grow up, I want to work with rockets and spacecraft. I did a stupid rocket trick a few decades back and decided not to try another hot fire without adult supervision. Haven't located much of that as we are all big kids when working with our passions.

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11 Responses to First Pump Results

  1. MG says:

    Do you have any photos of this posted anywhere?

  2. john hare says:

    No, this was a test of opportunity, not planned. The exhaust ports were blowing a lot of mist and seemed like a lot of water. Other than the guages there was no measurement. The lexan observation port fogged up and was useless. After (if) I get full pressure pumping, then I need to get some sort of water flow meter.

  3. MG says:

    I just meant, do you have any pictures of the apparatus, not of the measurements.

  4. john hare says:

    I’ll see if I can figure out how to do that monday or so.

  5. Paul Breed says:

    A Diesel Aircomprssor like used for Jack Hammers would probably be
    the lowest cost way to do this. Any big equipment renatal place will have one.

  6. gravityloss says:

    Could you use metric units?

    Cubic meters per second (1000 L/s), megapascals (10 bar = 10 atm)). Multiply and you get rough power magnitude requirements. 1 m^3 / s * 1 N/m^2 = 1 N*m/s = 1 W
    Everything gets so much easier and more sensible, as there are no conversions or coefficients.

  7. john hare says:

    Unfortunately, my education in this field is self inflicted and erratic. When I’m dealing with sizes of hardware locally, it is all English units and I would have to convert everything to metric, with some likely errors on my part. When I’m dealing with accelerations and velocities, I’m comfortable with metric but not English units.

    It is probably more irritating to me than anyone else that I just can’t get a feel for a subject with mixed units.

  8. Paul Breed says:

    I’m confused, why a spark plug on a pump?

  9. john hare says:

    This thing is concept demonstration for staged combustion with the plug in the preburner area. I thought there was some chance that I might want to burn in the chamber above the turbine to increase the available enthalphy for turbine drive. So I had the machine shop tap in a spark plug just in case.

  10. Habitat Hermit says:

    Cool! About those 10 psig I kept back from posting something similar to this on the other post because I can’t really say anything about the markets without doing a lot of research but the way I see it your concept could potentially scale down to really small pumps, and just perhaps a 33.3% increase could be plenty enough for tiny cheap pumps?

  11. john hare says:

    After having this one built and playing with it a while, I believe I can get a small unit well under a pound for single fluid pumping. Performance is not my target so much as cheap, simple, reliable, and cheap.

    The 10 psi guage is a bit misleading. That is in the upper chamber before the turbine. After the turbine pressure drop it is back to ambient with no provision to measure gains or losses. Until I get results from the high volume diesel compressor, I won’t know for sure if there is enough pumping action for show and tell.

    I have identified several problems with the unit as designed that I intend to correct in the next test unit when I can afford it. If I can get this one up to 75 or so psi from a water source under 30 psi, I might tbe able to get help on the next one. The next one will be in the one pound range with small enough flow to test with shop air.

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