Fish Flume

Introduction: Fish Flume

About: Student projects from Brown University's School of Engineering. Courses include Advanced Fluid Mechanics and Mechanical Vibrations. Course instructor: Prof. Daniel Harris.

The purpose of this instructable is to show how to construct a tank and pump system for a lab studying how Zebrafish larvae align themselves in water flow. The set up constructed is meant to satisfy three criteria. First, it needs to produce a laminar flow, second, the flow rate and direction needs to be easily controlled by users, and lastly, the tank needs a mechanism to contain the larvae in the laminar flow region.

Step 1: Materials

Step 2: Build Tank

Materials:

  • ¼” Acrylic Sheet
  • ⅛” Acrylic Sheet
  • Gorilla Glue
  • Mesh

Tools:

  • Laser cutter

Step 1: Download the illustrator files

Step 2: On the ¼” sheet laser cut the tank walls

Step 3: On the ⅛” sheet laser cut the window frames

Step 4: Make mesh windows

Use gorilla glue glue to sandwich mesh between 2 acrylic window frames

Trim mesh so only the “window” are covered with mesh and the middle section is left clear

Step 5: Assemble Tank

Use Gorilla Glue to attach the tank walls to the base

Step 6: Fit window pane pieces into notches on the tank walls

Step 3: Build Pump Control System

Materials/Components:

  • 3 220 resistors
  • L298N motor driver
  • Arduino Uno
  • 3 push buttons
  • 2 potentiometers
  • LCD module
  • breadboard
  • USB cord for Arduino
  • Wires
  • External Power Source (12 volt supply source)
  • 12 volt pump

Step 1: Assemble the circuit as shown in the diagram

Diagram Key:
A. Potentiometer controlling LCD screen brightness

B. Potentiometer controlling voltage setting (duty cycle percentage)

C. Push buttons that start pump (one for each pump direction)

D. Motor driver

E. Arduino

Step 2: Solder wires on the positive and negative terminals of the pump, making sure wires are long enough to extend from pump to the motor driver

Step 3: Attach pump to motor driver by screwing the wires from the pump into the “Out 1” and “Out 2” ports of the the motor driver as indicated in the motor driver diagram

(Motor driver image from: https://components101.com/modules/l293n-motor-dri... )

Step 4: Use the USB cord cable to connect the Arduino to laptop

Step 5: Download Arduino code and upload to Arduino (after code downloaded keep Arduino connected to laptop to power the Arduino)

Step 6: Connect to external power supply
To connect to the external power supply, screw wires into the 12V and GND ports of the motor driver. Use Alligator clips to connect these wires to the positive and ground of the power supply. To prevent damage to the motor, turn on the power supply and set to 11 volts before connecting the power supply to the motor driver.

Step 4: Tank Operation

Step 1: To connect to tank, insert pump tubing into the holes cut out into tank front

Step 2: Start pump by pressing either button labeled as “C” in the first diagram or the green and black square buttons in the second diagram

Step 3: Adjust speed and screen brightness with the potentiometers

Step 4: Turn off with small black push button

Step 5: Calibrate Pump Voltage Settings and Flow Rate

Materials:

  • 2 containers
  • Mass scale
  • Pump system
  • Stopwatch/timer
  • Water

Procedure:

Step 1: Use scale to measure and fill one container with 200 grams of water. Keep the second container empty

Step 2: Tape down both containers and place one pump tube in each container

Step 3: Connect voltage source to motor driver and set voltage to 11 volts

Step 4: Verify the inlet and outlet tubes for each pump direction and make sure inlet tube of direction 1 is in the full cup

Step 5: Use potentiometer to set pump voltage to 100% (may be only able to hit 99%)

Step 6: Start pump in direction 1 and start timer once pump starts

Step 7: Stop timer once the full cup is empty but keep pump running until all the water has worked through the pump

Step 8: Record the time and direction and voltage percentage

Step 9: Keep voltage setting the same and start pump in direction 2. Begin timer once pump starts and stop once the full cup has completely emptied

Step 10: Record pump direction, voltage percentage, and time

Step 11: Repeat steps 5-10 with the voltage percentage set as 95%, 90%, 85%, and 80% or until the voltage percentage is too low for the pump to start

Analysis:

For more information on analysis of flow rate see the calculations and validations section of report.

Step 1: Using 1g = 1ml, calculate the volumetric flow rate for each run by dividing 200 ml by the time in seconds for the pump to empty one of the cups

Step 2: Plot voltage percent vs volumetric flow rate, as seen in the figure

  1. Plot should show a linear relationship between voltage percentage and flow rate
  2. Use plot when choosing voltage settings for future runs in order to get desired flow rate (for example based on the results above to achieve flow rate around 1.3 ml/s set voltage to 93 %)
  3. The average flow rate can be determined by dividing the volumetric flow rate by the flow cross sectional area (tank width multiplied by water height)
  4. The table included shows flow velocities calculated based on the volumetric flow rates calculated

Step 6: Visual Validation of Laminar Flow in the Tank

Materials:

Tank components:

  • Flume
  • Mesh components
  • Peristaltic pump
  • Tubing for the peristaltic pump
  • Voltmeter
  • Flow reversing arduino
  • 200 ml of water

Objective specific components:

  • Food dye

Procedure:

Step 1: Configure the tank and and pump set up

Step 2: Set the voltmeter to 11V

Step 3: Set the arduino percent volt output to the 99%

Step 4: Start the pump and let it run for 30 seconds

Step 5: Add a 3 drop of dye as close to the outlet tube as possible

Step 6: Let the dye get pulled through the pump tubing and observe the flow profile at the inlet

Step 7: Visually confirm the flow profile looks like figure A from the top down view and F from a side view as it enters the first observation chamber

Step 8: Visually confirm the flow profile looks like figure B from the top down view and F from a side view as it continues through the first observation chamber

Step 9: Visually confirm the flow profile looks like figure C from the top down view and F from a side view as it exits the first observation chamber and starts to travel around the bend

Step 10: Visually confirm the flow profile looks like figure D from the top down view and F from a side view as it continue to travel around the bend

Step 11: Visually confirm the flow profile looks like figure E from the top down view and F from a side view as it enters the second observation chamber

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