1. Team Aquifers: Flow Control Device James Berg Jamison Hill Stephen Russo Scott Weeks CEE 454 - December 2004

2. Outline Introduction Introduction Project Goals Project Goals Design Process Design Process Our Design Our Design Test Results Test Results Use in Developing Countries Use in Developing Countries Recommendations for Further Research Recommendations for Further Research System Modeling System Modeling Conclusions Conclusions

3. Project Goals Create a Point of Use Flow Control Device THAT… THAT… Maintains constant flow rate (20 L/day) through a slow sand filter Maintains constant flow rate (20 L/day) through a slow sand filter Is easy to build, use, and maintain Is easy to build, use, and maintain Has a low cost of construction Has a low cost of construction Uses common materials Uses common materials

4. Our Design Process Brainstorm ideas: Brainstorm ideas: Float Valves Float Valves Clock Mechanism Clock Mechanism Pulley/Balance Pulley/Balance Chicken Waterer Chicken Waterer Elimination based on design criteria Elimination based on design criteria No/minimal moving parts No/minimal moving parts No precision machining No precision machining Easy to adjust flow rate and maintain the system Easy to adjust flow rate and maintain the system

5. Preliminary Design

6. Our Design: How it Works Airtight Raw Water Tank Filter Aspirator Tube Constant Head Basin OrificeClear Well

7. Surface tension effects here Flow Control Animation

8. Range of Flow Rates: Equations for Constant Head Above an Orifice Flow rate: Flow rate: Surface Tension: Surface Tension: Force of Gravity on a drop: Force of Gravity on a drop: Pressure force from water above: Pressure force from water above:

9. Range of Flow Rates: Analysis Range: 16.5 – 28.6 L/D Flow Rate (L/day) Head (cm) No flow Sufficient head for flow

10. Testing the System

11. Test Results: Volume in Clear Well Steady flow into clear well = 14 mL/min Steady flow into clear well = 14 mL/min Graph: Volume in Clear Well vs. Time

12. Test Results: Derivative of Volume Graph: Flow (Derivative of Volume) vs. Time

13. Test Results: Flow Through Filter BUT flow through the filter varied greatly!! BUT flow through the filter varied greatly!! Graph: Flow through Slow Sand Filter vs. Time

14. Testing: Steady State Solution??? Observation: When vacuum in raw water tank is completely lost, flow increases Observation: When vacuum in raw water tank is completely lost, flow increases Hypothesis: Can minimize flow peaks by maintaining vacuum in the tank Hypothesis: Can minimize flow peaks by maintaining vacuum in the tank Solution: Small hole in the side of the aspirator tube allows steady flow of air bubbles Solution: Small hole in the side of the aspirator tube allows steady flow of air bubbles

15. Test Results: Conclusions Able to control the average flow rate out of the flow control device Able to control the average flow rate out of the flow control device The flow through the sand filter was very inconsistent The flow through the sand filter was very inconsistent Spikes of high flow Spikes of high flow Long periods of no flow Long periods of no flow Achieved high removal of turbidity Achieved high removal of turbidity Raw water initially had turbidity of 90 NTU Raw water initially had turbidity of 90 NTU Water in the effluent had turbidity of 3 NTU Water in the effluent had turbidity of 3 NTU

16. Applications in Developing World As a flow control device for chlorine or alum delivery, our device is: As a flow control device for chlorine or alum delivery, our device is: Cheap Cheap Easy to build Easy to build Has no moving parts, so as not prone to failure Has no moving parts, so as not prone to failure With more research, it might be successfully used after a sand filter. In this case, it also: With more research, it might be successfully used after a sand filter. In this case, it also: Controls the flow of clean water, so it will not clog an orifice Controls the flow of clean water, so it will not clog an orifice Can be used for water that is extremely dirty as long as the filter is working properly Can be used for water that is extremely dirty as long as the filter is working properly

17. Restrictions to Use in Developing World Prototype was made from lab materials Prototype was made from lab materials PVC could replace flexible tubing PVC could replace flexible tubing Almost any type of waterproof container could be used for the flow control basin Almost any type of waterproof container could be used for the flow control basin Biggest obstacle: creating an airtight raw water tank Biggest obstacle: creating an airtight raw water tank We considered trying to make a regular 5 gallon bucket airtight, but realized it would be hard to get it to form a vacuum quickly. We considered trying to make a regular 5 gallon bucket airtight, but realized it would be hard to get it to form a vacuum quickly. Need Further Research! Need Further Research!

18. Future Research Areas of focus: Areas of focus: Build with easily obtainable materials Build with easily obtainable materials Test it as a chlorine delivery mechanism Test it as a chlorine delivery mechanism Minimize spikes Minimize spikes Mathematical Model Mathematical Model

19. Modeling our system mathematically Using a system of first-order non- linear differential equations

20. Why Model We know our basic device works We know our basic device works Improve the design by testing (much quicker through computer simulations!!) Improve the design by testing (much quicker through computer simulations!!) Investigate fundamental relationships Investigate fundamental relationships Investigate ways to improve device (adjusting head loss, air flow) Investigate ways to improve device (adjusting head loss, air flow) TWEAK Parameters TWEAK Parameters As an example, it took me 6 seconds to simulate a 6 hour filter run As an example, it took me 6 seconds to simulate a 6 hour filter run

21. The Model A system of three simultaneous differential equations models: A system of three simultaneous differential equations models: Rate of change of volume in the upper tank Rate of change of volume in the upper tank Volume in the basin Volume in the basin Moles of air in upper tank Moles of air in upper tank Uses Energy Equation, Continuity (mass balance), Darcy-Weisbach, Ideal Gas Law, and Orifice Flow Equation Uses Energy Equation, Continuity (mass balance), Darcy-Weisbach, Ideal Gas Law, and Orifice Flow Equation Details on your handout Details on your handout

22. Model Diagram

23. Simulation Results

24. Flow Through Filter

25. A Constant Head Device?

26. Conclusions Not a constant head device Not a constant head device But works as a good flow control, oscillations small and approach zero with increasing time But works as a good flow control, oscillations small and approach zero with increasing time A self-dampening oscillator that approaches steady-state. A self-dampening oscillator that approaches steady-state. Further tweaking will allow us to reduce bias, and overshoot, calculate decay function for peaks Further tweaking will allow us to reduce bias, and overshoot, calculate decay function for peaks

27. Questions???

28. THE END