Experiments Plan

[cheertsang]

A flow accumulator was added after the water pump to regulate pressure fluctuations due to the pump.

Run the experiment without the contact chamber, measuring headloss across the flocculator:

• April 9-10: Trial 1 - started at 7:30 PM
• April 10-11: Trial 2

Run the experiment with the contact chamber, measuring headloss across the flocculator:

• April 11-12: Trial 1
• April 12-13: Trial 2

Run the experiment with the contact chamber from Spring 2017, measuring headloss across the flocculator:

• April 13-14: Trial 1
• April 14-15: Trial 2

Flocculator was cleaned out with high velocity water in between experiments.

[cheertsang]

April 10, 2018 - Trial 1 Control: no contact chamber, water pump 76 RPM, coagulant 20 RPM Checked on experiment. Clay pump seemed to be clogged, turbidity was at 0.3 NTU. PID appears to be working now, turbidity at 100 NTU. Run experiment for another 24 hours.

[cheertsang]

April 15, 2018

Added needle valve - tested it to find correct setting:

• Without needle valve: 2-3 V amplitude (0.1 s update interval), 0.4 V amplitude (1 s update interval)
• With needle valve (4): 10-12 V amplitude (0.1 s update interval), 0.6 V amplitude (1 s update interval)
• (Setting 4 yielded the smallest amplitude with the needle valve - tested 7, 6, 5, 4, 3, 2)

@monroews @TanviNaidu We have tested the headloss with the needle valve, and in both cases (0.1 s update interval and 1 s update interval), the amplitude was smaller without the needle valve - why? Also, which update interval would be better to determine the best setting to use on the needle valve? I'm hypothesizing that putting the needle valve after the turbidimeter might make the pressure measurement more steady. What do you suggest?

[monroews]

Set the update interval to be even faster so you can see the pressure spikes from each peristaltic roller that goes by.

I'm suspicious that the needle valve is on the inlet side of the flow accumulator rather than on the outlet side where it should be located.

Also, where is the pressure sensor located? Maybe that is the problem. The pressure fluctuations across the flocculator should be decreasing as you close the needle valve.

[cheertsang]

@monroews The needle valve is on the outlet side.

This is the setup of our pressure sensor. The pressure fluctuations were decreasing as we closed the needle valve, but the amplitude was still higher than without the needle valve.

[cheertsang]

April 15, 2018 With clay, water, and coagulant pumps (0.01 s update interval):

• Without needle valve: Start 1:16 PM - 20-30 V amplitude difference

• With needle valve [0]: Start 1:30 PM - 20-30 V amplitude difference

• With needle valve [1]: Start 1:45 PM - 20-25 V amplitude difference

• With needle valve [2]: Start 1:56 PM - 20-25 V amplitude difference

• With needle valve [3]: Start 2:06 PM - 20-25 V amplitude difference

• With needle valve [4]: Start 2:15 PM - 20 V amplitude difference

• With needle valve [5]: Start 2:18 PM - 20 V amplitude difference

• With needle valve [6]: Start 2:26 PM - 15-20 V amplitude difference

• With needle valve [7]: Start 2:31 PM - 20 V amplitude difference

• With needle valve [8]: Start 2:34 PM - 20-25 V amplitude difference

• With needle valve [9]: Start 2:38 PM - 20-25 V amplitude difference

We determined that the needle valve at setting 6 reduces the amplitude the most

[monroews]

I'm guessing that the interesting place to explore is between needle valve setting of 0 and 1. We need to generate significant head loss through the needle valve. You can detect head loss by the fact that the air in the accumulator will compress as the head loss through the needle valve increases. You will also notice that the flow through the flocculator temporarily decreases when you decrease the opening in the needle valve.