Funneling wind
Funneling wind
(OP)
I live in a area where the wind comes from the North-West most of the year. In winter (when the air is denser) the wind velocities are very high. So with this in mind I was thinking of building a funnel (5m X 5m entrance reduced to a 0.5m dia cylinder. Inside the cylinder ther would be a one or multiple stage turbine (static vanes and power vanes). I would like your comments on this and some usefull equations. I used Area1 * Speed1 = Area2 * Speed2, this gives me incredibly high velocities for the ratio previously detailled (higher than the speed of sound). Q1. Is the air density reduced as you funnel it? What do you think the efficiency (in %) of a turbine can be?





RE: Funneling wind
RE: Funneling wind
e.g wind 10m/s (36Km/hr)
A1V1=A2V2 -> 25sqrm*10m/s = (pi(0.25)^2-pi(0.2)^2)V2
V2 = 250/.07 = 3571m/s.
I am also an EE, I would like to use the electricity generated to electrolyse water and generate Hydrogen (this would be a later phase) Ph1 would be a grid tie-in to pay the bills for further expanssion, but 0.03$ per Kwh it takes a while.
Other concerns(scale 1 to 10): Snow and brime-5, turbulance-2, turbine parts-8, gearbox-8, generator-3, inverter-3, money-8.
RE: Funneling wind
To simplify, the static pressure (SP) plus the velocity pressure (VP)at one point must equal the SP plus VP at the second point in the system. The practical implication is that should the velocity go up, the static pressure must go down.
The VP of the wind is expressed by .5 * (mass)(velocity)^2.
The static pressure in the throat can't be negative, so there is a limit on the velocity of the air in the throat. This is based on the upstream total pressure. For wind, this isn't much, compared to say, a wind tunnel, where there is a huge motor-driven fan or compressor.
This is fundamentally why you don't see much in the way of funnel's or concentrators in the wind turbine technology. You can't get something for nothing. Sorry.
In your comtemplated design, the throat would choke off flow. Since power is porportional to momentum flow (mass times velocity), you would get less power output with your funnel (due to losses) that you would putting your vanes out in the open.
RE: Funneling wind
in the middle ?
<nbucska@pcperipherals.com>
RE: Funneling wind
I have started to learn about Bernoulli and his Physics in search of a ratio of mouth to throat area with acceptable air flow. Perhaps it is disappointingly only 1.1:1 or an interesting 10:1.
The second part of the Turbine (stator(s) and rotor(s)) is that for me it seems easier to build an aerodynamically “perfect” short blade (less than 12” for example) than a 15foot radius 3 bladed propeller, also easier to design. Of course the turbine would turn quite rapidly and one should plan accordingly. Any ideas on a name for the apparatus: FunWind: FunnelPower…
The Idea of a Wind Funnel is more to protect the turbine apparatus so it could be built on the ground. This has some advantages: lower cost for one. The disadvantage is obvious it's tuff to turn the entire thing into the wind. I got the idea by observing the snow drift in the winter. The wind comes uninterrupted from the bay for over 20 Miles and then it’s a 70foot or so cliff. Anyway it is from a mostly steady direction and is of high velocity. The funnel would also serve to allow less than centered wind to still power the turbine (at 60deg from center the useful wind drops to less than 5%).
I have started to learn about Bernoulli and his Physics in search of a ratio of mouth to throat area with acceptable air flow. Perhaps it is disappointingly only 1.1:1 or an interesting 10:1.
The second part of the Turbine (stator(s) and rotor(s)) is that for me it seems easier to build an aerodynamically “perfect” short blade (less than 12” for example) than a 15foot radius 3 bladed propeller, also easier to design. Of course the turbine would turn quite rapidly and one should plan accordingly. Any ideas on a name for the apparatus: FunWind: FunnelPower…
RE: Funneling wind
However, why is it easier to build a short bladed system where presumably the rotational speed will lead to serious balancing problems that to build a long bladed rotor? Folks have been building windmills for thousands of years with long blades, with shutters like a louvered door or with furling sails....and they can develop some very useful energy.
RE: Funneling wind
The remarks on this have been very intelligent!
John
RE: Funneling wind
RE: Funneling wind
Let me know how your experiment goes. It will be a good learning experience no matter what.
john@johnhoward.net
Have a great day!
John
RE: Funneling wind
Please keep on being "crazy", but always doing something you believe on, even in the end, you just goy one more try,... until you get some solution. That´s for that we live in this planet, to do things for fun, as well.
Cheers!
zzzo
RE: Funneling wind
What you said makes sense! The windfunnel technology needs flows with significant momentum in order to get good relation between flow momentum and the losses inside of the funnel. Besides that, you should to choose the rigth location and orientation for such ugly funnel...in some property of yours, of your father-in-law, maybe..
Cheers!
zzzo
RE: Funneling wind
Larry
RE: Funneling wind