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Particle Image Velocimetry was performed on the 1-D scale-up Solar Oven at three discrete water temperatures (30o C, 50o C, and 70o C) in order to characterize how the role of convection currents changes over the heating of the oven. One way to predict and describe velocity distribution in convection cells is the dimensionless Grashof number: 
Where:
B = distance between hot and cold bodies
ρ = density of fluid at mean temperature
∆T = temperature difference
β = inverse of mean temperature
g = gravitational acceleration
µ = viscosity of fluid at mean temperature
This ratio of buoyant to viscous forces describes a fluid's natural ability to form convection currents. Using PIV, we are able to directly measure convection cell mean strength and location over varying heating conditions.
Due to time constraints, we were unable to alter pot quantity or placement and instead measured change of convection over varying temperature. During the experiment, we had a thermal sink of a black pot with 5 lbs. of water in the center of the oven. The field of view covered the right side of the oven from the bottom black plate to the pot on the left side. In order for the camera to be able to view inside the oven from the front, the plywood door had to be removed and a piece of glass was duct taped into place. Additionally, the back of the oven is covered with reflective sheet metal. This had to be covered with a piece of cardboard duct taped into place. We assume these changes had a negligible effect on oven performance. 
Figure 1 - PIV schematic
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Figure 2 - Picture of PIV setup in DeFrees lab.
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An Aragon Ion laser was used at a wavelength of 488 nm. This wavelength was chosen because it provided the highest emission from the particular laser and also was imaged brighter on our particular camera than the other principal emission wavelengths. In order to spread the beam into a laser sheet, a cylindrical lens was placed above the oven and the sheet was dispersed through the top glass sheets.
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The oven was heated with 15 halogen lamps located 24" from the top of the oven in an array of:
Figure 3 - Lighting arrangement of halogen lamps above PIV setup.
The oven started at room temperature and the 5 lb. pot of water started at roughly 20o C before heating with the lamps began.
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An image size of 600 x 800 pixels was used as that was the default output of the camera. An image capture rate of 30 Hz was used because it non-redundantly captured particle movements on the order of 1-3 pixels between image pairs.
Figure 4 - Front view of PIV experiment being run.
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Figure 5 - Top view of PIV experiment being run.
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