Chord length of NACA 0012 AIRFOIL FOR VERTICAL RURBINE 1

[toohurt]

HEllo all,

i am working on a project "hybrid solar wind power generation system" i am using vertical axis wind turbine. i have calculated the swift area and length of my turbine and select NACA 0012 air foils for the turbine blades. the problem i have is how to calculate the chord length of those blades, once i have the chord length i can calculate the thickness of blades, but how to get the chord length, is there any relation b/w swift area and chord length or such kind of relation so i can calculate the chord length.
i search all over the internet but could not find a solution to my problem, hopes some one might here help me.

peace...

 

[rb1957]

the chord is the distance from the leading edge to the trailing edge. i guess you should have googled "aerodynamic chord".

another day in paradise, or is paradise one day closer ?

 

[toohurt]

yes i have googled that too, but couldnt find any satisfied answer

 

[rb1957]

"In aeronautics, chord refers to the imaginary straight line joining the leading and trailing edges of an airfoil. The chord length is the distance between the trailing edge and the point on the leading edge where the chord intersects the leading edge." from the wiki hit for "aerodynamic chord"

another day in paradise, or is paradise one day closer ?

 

[toohurt]

but thats not exactly the same thing, mine is related to turbine blade. that might be different from that on e u r talking about

 

[rb1957]

take a (horizontal) section through your vertical axis turbine.

draw a line from the leading edge (normal to the tangent) to the training edge.

why would it not be so ?

another day in paradise, or is paradise one day closer ?

 

[toohurt]

i think u didnt get my point, what i want is to calculate the chord length of foil theoretically...i need some formulas or what ever there may be so i can design my final blade to my calculated dimensions

 

[rb1957]

?

are you sizing the aero-foil to meet a load (power generated in a specific wind?) ?

maybe its ... swept area/(length*number of blades)

have you looked up vertical axis wind turbines ?



another day in paradise, or is paradise one day closer ?

 

[toohurt]

yes thats exactly what i want to do...i want to meet it a required power....
are u sure that formula is correct

 

[berkshire]

Too hurt
Maybe this can help you.
B.E.

You are judged not by what you know, but by what you can do.

 

[toohurt]

let suppose i have swept area of 4 feet and length of turbine 3.7 feet...the power generated is 150 watt...
now i want to calculate the chord length of blades that can generate this power...what calculations i need to do to get the chord length

 

[toohurt]

berkshire i also get that link on internet..thank you
but what i want to do is to calculate the chord length for my swept area

 

[rb1957]

this is sounding more like a school assignment ?

power generated also depends on wind speed, and propeller rpm.

do you have a vertical turbine design book ?

another day in paradise, or is paradise one day closer ?

 

[Nereth1]

I know nothing of vertical turbines but I would imagine standard methods involving lift and drag coefficients of the chosen aerofoil can be used to generate the result for torque generated by ntegrating along the length of the turbine? Every segment of the turbine is just a bit of wing getting hit with a particular angle of attack and wind speed given by its position on the turbine, the turbine RPM, and the free stream velocity, no?

I suppose spanwise flow and so on might be unusually significant in the case of a vertical turbine but I'm hoping the accuracy you need doesn't require taking it into account.

 

[toohurt]

no this is not a school assignment, i am working on this project..
the wind speed is 4.91 m/s
i m having deifficulty in calculating the chord length,

 

[berkshire]

toohurt (Mechanical) (OP)
Why don't you pick an arbitrary length, run through your calculations , then re-iterate to get an answer you can use.
B.E.


You are judged not by what you know, but by what you can do.

 

[berkshire]

toohurt,
Are you trying to make something like this?
B.E.

You are judged not by what you know, but by what you can do.

 

[verymadmac]

Its been a long time since I had anything to do with wind turbines.

I recall that on a VAWT the chord length / Diameter sets the top end wind speeds for power output due to blanketing effects.

Calculating the performance of the turbine will require 360 degree AOA lift drag curves for NACA0012 which do exist (I have a copy somewhere taken from a American wind-turbine journal published in the 70's).

 

[GregLocock]

"no this is not a school assignment, i am working on this project..
the wind speed is 4.91 m/s"

O RLY

While I can see someone designing for a particular windspeed as a learning exercise, I'd a thunk any commercial product would be more interested in some sort of robust optimisation vs a range of windspeeds.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[tbuelna]

As noted, with either a HAWT or VAWT what matters is the torque produced at the rotor axis from the lift forces created by the blades. With a HAWT, the blade lift varies greatly over a single shaft rotation. While the prevailing wind speed and direction is constant, the relative wind speed the blade sees varies as the blade retreats and advances during a rotation. There is also the turbulence effects as the blades rotate thru the downwind sector of the opposing blades and rotor mast.