The Nozzle/Diffuser Wind Turbine




This is a step by step guide on how to  build a wind turbine by maximizing the wind speed using a nozzle/diffuser approach.
This approach was considered through various testing and prototyping to try and increase the efficiency of the wind turbine.
NOTE****Test video at step six****

Step 1: Materials

two buckets (bought from Tesco)
MDF(Medium Density Fibreboard)
safety blade/scalpel
PVA Glue 'polyvinyl acetate'(any preferable adhesive)
electric handdrill
PVC pipe(poly-vinyl chloride)
coupling(preferably oldham coupling  or any good chosen connection)
U-pol(or some kind of filler)
multimeter and variable resistor

Step 2: Making the Nozzle/diffuser

the nozzle or diffuser can be made from a funnel or a conical bucket.
in this case a bucket was used by cutting the base out.
from testing it was found that having a lip converging to the nozzle increases the wind intake, and having one diverging from the diffuser draws the wind out  by increasing the pressure.
the lip was made by vacuum forming around a wooden base( if vacuuum forming is out of the question try  using a bucket that you can bend to create the shape).
the lip is then glued onto the bucket ,using upol fill and sand off to smooth the lip over the bucket

Step 3: Making the Frame

the frame can be made with a varied type of materials(but most importantly the chosen material should be sturdy and strong enough to withstand the wind pressure.
in this case Mdf was used.
using PVA  'polyvinyl acetate ',glue stacks of mdf to the required depth necessary to support both the nozzle and diffuser.
saw off the ends and inside to shape creating a support in the middle of the frame(for the gear and blade aasembly)

Step 4: Making the Blades and Hub

The blades and hub was made with a PVC Pipe and MDF respectively( again material choice is dependent on availabilty and properties).
PVC pipe was used because the curve inside the pipe makes it possible to pitch the blades at a desirable angle and also it strong and haevy enough to withstand wind pressure and at the same time produce more torque.
The blade shape is dependent on the direction you want it to rotate(clockwise or anticlockwise), this shape ensures the wind blows the blades in a clockwise direction.
the hub
the hub was created in such away that the blades are slanted at 30 degree angle(again through testing it was found that having more blades produced more voltage but with this setup the maximum blade the hub could hold was six)

Step 5: Making the Gear Connection(using Planetry Gears)

we wanted to have blade,hub and gears in one axis so our obvious choice was to go for a planetry gear system.
Using the gear assembly of an electric hand drill we were able to have the correct size and shape for our turbine,and the chuck too was suitable for supporting the blade shaft.
using planetry gears can be a challenge because the gear ratio can be too high or low, in our case the ratio was too high so we removed the secondary layer of gears.
the generator shaft was used as the sun gear by coupling it onto the gear assembly.the wooden frame insert is to support the generator and keep it aligned to the gears

Step 6: Testing

the turbine was tested in a purposefully built wind tunnel so as to have a constant source of wind.
during the test the highest voltage were got was 16V with a resistance of 47 ohms but with a bit more tweeking we expect to get up to about 20V



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    15 Discussions


    1 year ago

    how to get know in the pressure inside?


    4 years ago on Introduction

    what benefit to use. how much amount . please give me calculation data


    To say efficiency was improved you would need to take measurements both with and without the shroud at the same windspeed. Did you do this?


    7 years ago on Step 6

    You should try letting the tips of the blades to slightly touch the walls of the yellow thing between the two buckets, this will make the turbine way more efficient ;)


    7 years ago on Introduction

    Good instructable, and great idea.
    Adding some notations to the photos to help illustrate the text, or indicate what is being pictured would make it a great instructable.


    7 years ago on Introduction

    Im curious about wind speed vs power ? Also blades size? Thanks a lot.

    I would bet that your hairy arms in the turbine housing are causing a considerable amount of drag... I don't think the hair is the problem :PYour hands take up what looks like a third of the volume of the housing. Perhaps supporting the generator with three spider wires, holding it centered and minimizing drag. I realize this is a first run. Looks great, good work! Lots to be learned from the model builders flying ducted fan jets, NASA stuff.


    7 years ago on Introduction

    I've been toying around with the idea of building a small wind turbine to keep up the power on a pair of 12 volt batteries. I don't need much power generated as the only draw on the batteries is for a camper trailer parked up on my land. So it's just lights, furnace fan, and the stove exhaust fan.
    -I'm tired of pumping up my Coleman lantern (plus the smell, uneven light, and heat) so my main power draw is going to be from my reading at night (around 4 to 6 hours).

    However I don't want to build a very large tower to get to the steady and stronger winds, as that leads me to other complications.

    You've given me a new option. Thanks!!

    - I wonder how it would work with a Savonius?


    7 years ago on Introduction

    As with most 'power' generating systems, measuring voltage alone is woefully inadequate. Put a fat resistor across there and measure the voltage across that. THAT will be a usable energy measurement. Optimizing for voltage alone is not going to get you where you want to go.

    2 replies

    the voltage was measured using a resistance of 47 ohms and we got a 17volts but wedid also use a variable resistor

    First of all, commendation son actually using a resistor. Many people seem to think they can measure the efficacy of their homebuilt generators by using open voltage and no current flow at all!

    Whats important is the amount of power produced.

    Using a varistor is interesting, but you're going to need to instrument the setup further with an ammeter so you can tell how much current is flowing. Multiply the potential difference across your load in volts by the current in amps and you'll get the power in watts.

    At 17 volts 47 ohms you're putting through 0.36 amps for a total of just over 6 watts.

    I'd think your goal would be to make that power number higher - whether its higher amps at lower voltage or higher voltage at lower amps isn't particularly important (though there will be interesting side effects that will alter the portion of the energy you can use as the load at higher amp rates)

    When you say that by tweaking you got the voltage to go higher you're being very vague. Perhaps you could discuss what tweaking you did, how the blades and/or load were modified, and how the *power* output was changed by your tweaking.


    7 years ago on Introduction

    Great Tutorial . A small turbine like this is only good for charging a cellphone. All that work for little output.

    1 reply

    Reply 7 years ago on Introduction

    yeah you are right wind turbines dont usually produce much power as expected but finding ways to improve its efficiency was a fun challenge. and when built to a larger scale using proper materials this can really be of good use.