PSS Fall 2010
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Experimental Design
The PSS team's current experimental setup is to test the failure prediction of the velocity gradient model for various sets of tubes diameters at different up flow velocities (described in Table1).
To isolate the effects of the velocity gradients from the effects of capture velocity, we chose set a constant capture velocity of 10 m/day for all tubes and tubes were designed without a constant length to diameter (L/D) ratio to meet these requirements. The L/D ratio is found by taking the length of a plate and dividing by the spacing between plates or in the case of tube settlers, the diameter. The design approach taken by the team was deemed acceptable because the research aims to propose improved plate settler design parameters (capture velocity and velocity gradient) over conventional parameters like L/D.
Table 1 - Values of the tube sizes for the three different upflow velocities.
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Upflow Velocities
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1 mm/s
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2 mm/s
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5 mm/s
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Tube Diameter
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Tube Lengths
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1/4 in
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0.116 m
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0.242 m
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0.623 m
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3/8 in
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0.174 m
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0.364 m
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0.934 m
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1/2 in
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0.231 m
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0.485 m
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1.245 m
Detailed Task List
A Detailed Task List was created to lay out the planned research for the team for Fall 2010.
Reflection Report I Report I provides a detailed description of the planned research and what we think is the game plan in order to scale the apparatus.
Reflection Report II Report II provides a sketch of what the improved apparatus will look like (using two chemicals and pulleys to control the entrance tank float)
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5/8 in
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0.289 m
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0.606 m
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1.556 m
A schematic of the system used for measuring the performances of different tube sizes is given in Figure 1. The sequence of events for a typical experiment is as follows:
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