To calculate power output of the turbine we had to find the wind sweep area, which is found by multiplying the diameter of the blades and the height of the tower. For our VAWT system we used a height of 3.2 feet and a diameter of 30.94 ft to give us a sweep area of 99ft
To find our Pwind, we multiplied venus’s air density, of 67, by the wind speed which we assumed to be 2mph on average, and the sweep area by 0.5.
To calculate losses we took percentage losses of mechanical loss, transmission loss, efficiency caps, by Bertz Law, and wake loss to find our efficiency.
We worked with multiple efficiency ratings to give the best reasonable predictions for our system.
To calculate our RPM we multiplied 60 by our wind speed and TSR divided by pi times diameter.
Ppower is then our efficiency times our Pwind.
TSR was obtained by our Power/RPM times 30/pi.
Our initial torque was obtained with the formula T=(Ppower/RPM)*(30/pi).
To achieve as much power as possible, we used a two gear gearbox which connects the low speed shaft to the high speed shaft, the gear ratio for this gear box was 3.7:1, slowing RPM but increasing torque.
RPM was consistent through efficiency models, but torque constantly changed.
Our torque values for each given efficiency is given in increments of 10%, up to a max of 40%, the highest metric we believed our model could achieve. At the lowest efficiency of 10%, our turbine produced 72.25t, which increased to 144.52t at 20%, 216.78t at 30% and 289.03t at 40%.
The process of power sent to the generator also has efficiency loss, and we gave each value a set loss value to best reflect how a generator could produce a wattage. We selected our generator to operate at an starting efficiency of 10%, and increasing by 10% until 40%, where we believed under the stresses of Venus, reliability and consistency of better efficiency could not be certain. With our generator at 10%, and our Turbine at 10%, we found our lowest generated power was 7 watts, while if our model was at its best, at both 40% for turbine and generator, we could produce 115 watts of power per hour. We found the average power generated could be 46 watts per hour.
For protection we chose materials that could survive the harsh temperatures while maintaining as much structural integrity as possible, alloys primarily made of Titanium, Tungsten, Steel and Lead were proposed. Electrical components would be made of copper insulated with carbon fiber mesh. The internal components would be able to withstand the heat and pressure of venus and should be able to operate without internal cooling. Lubrication could be provided by liquid metal alloys such as a carbon-gallium mixture, or the gear teeth could sustain activity to the 60 day mark.
Exterior components consisted of the outer shell metal, covered in a 0.5in thick carbon fiber mesh, which is acid and corrosive resistant while being able to withstand the heat, we suspect this mesh on its own could improve the metals lifespan by roughly 20 days before failing. Over the mesh would be an applied a 0.2in thick epoxy resin consisting of carbon fiber, while much more resistant to corrosion than the mesh, its make-up degrades with UV radiation, but for little weight addition could add roughly a week to the lifespan of the system before affecting the underlying mesh. In case of compression becoming an issue, we can still keep the structural integrity of the turbine if thinner blades are required.
The housing of the base is 18x18in Ti-6Ai-4v (titanium alloy) on the exterior, and 17.5x17.5in on the interior. Total depth of the base is 24in.
The mass of the entire assembly is 271.151lb, volume is 1516.15in^3, surface area is 8776.210in^2.
Gear ratio for the two-speed gearbox is 15:56. The initial gear is 15, with an initial rpm of 10.865 and initial torque 77.42Nm. The output gear is 56 with an rpm of 2.91 and torque of 289.03Nm.
Comments
Post a Comment