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After eliminating both bucket theories, we decided that testing the last two designs in a lab would not be difficult and would give more realistic, tangible results than our calculations.
Testing
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We used the pilot plant to test our retrofit design in an environment that replicated the actual plants as closely as possible. We set the flow rate of the pilot plant at about 150L/min, which, coupled with the 7.5cm-diameter LFOM, would be roughly comparable to the 400L/min, 15cm diameter LFOM in the plant at Cuatro Comunidades.
The first design we tested was the vertical/inclined plane. We used a 5cm-wide, 60cm-long steel plate to test the effectiveness of this plan to reduce water aeration. We were looking at the amount of bubbles formed under the LFOM to determine results, and documented them photographically.
Next, we used various-sized pipes inserted within the LFOM to test the "pipe within the LFOM" theory. First, we tested a 3cm-diameter pipe by inserting it vertically into the 7.5cm-inner diameter LFOM. Second, we tested a 5cm pipe, and noticed that it produced a reduction of bubbles. After leaving the 5cm pipe in the LFOM for 5 minutes to ensure no overflow, we moved to test the 6cm pipe. This pipe also showed signs of reducing the amount of bubbles, so we left it in for 5 minutes as well to determine if it would overflow, which it eventually did.
Results and Discussion
Vertical/Incline Planes
Unfortunately, we determined visually that there was very little, if any, change in the amount of bubbles formed before and after inserting the steel plate into the LFOM. Even at various angles of inclination, the amount of bubbles formed was the same. (can you show any visual confirmation of this with pictures for both or either case?)We believe it was ineffective for two reasons. First, the spread of orifices wraps around the pipe far enough that the jets of water at the edge do not touch the steel plate. Second, the water jets are flowing fast enough that the water simply ricochets off the steel plate, instead of running down the plate as intended. See the gallery of photos below for photos illustrating our results.
"Pipe within the LFOM"
With our initial test of the 3cm pipe, there Next, we used various-sized pipes inserted within the LFOM to test the "pipe within the LFOM" theory. First, we tested a 3cm-diameter pipe by inserting it vertically into the 7.5cm-inner diameter LFOM. There was no noticeable change in the amount of bubbles formed under the LFOM. Second, we tested a 5cm pipe. This produced For the 5cm-diameter pipe we found a drastic reduction in the amount of bubbles formed under the LFOM. After leaving Keeping the 5cm pipe in the LFOM for 5 minutes showed no signs of overflowing the LFOM or even raising the water level, we decided there would be no overflow problemso we can assume that 5cm is a possible solution. Finally, we tested a 6cm pipe for 5 minutes in the LFOM. We noticed that the water level outside the LFOM rose slowly throughout the 5 minutes until the water flowed over the top of the LFOM. This clearly meant that the 6cm pipe was too big, and was causing a backup of water within the LFOM. (attach mathcad sheet here)
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At the end of all of our testing, we determined that inserting a 5cm-diameter pipe would effectively reduce the amount of bubbles produced by the LFOM, while not constricting the overall plant flow rate.