Linear Flow Orifice Meter

Linear Flow Orifice Meter A Thesis Presented to the Faculty of the Graduate School of Cornell University In Fulfillment of the Requirements for the Degree of Masters of Engineering by Leah Elizabeth Buerman December 2008 i © 2008 Leah Buerman i BIOGRAPHICAL SKETCH Leah Buermans’s education includes a bachelors of science from Cornell University in Biological and Environmental Engineering Water Purification technologies have been a focus of her education for two years, during her undergraduate and graduate education Leah’s coursework includes Water Quality Analysis, Small Scale Sustainable Water Supply, Watershed Management, Environmental Systems Analysis, and Fluid Mechanics She has attained Engineer in Training Certification and is an active member of the society of Women engineers Through experiences abroad she have become aware of the high demand for low cost reliable water purification technologies in the developing world Leah’s graduate work with the Agua Clara project directly affects the design of water treatment plants in Honduras Dedicated to my Mom and Dad ACKNOWLEDGMENTS I would like to thank Professor Monroe Weber-Shirk for the immeasurable amount of help that he gave me throughout the project I would also like to thank Professor Tom Cook for this help during fabrication I would also like to thank Professor Norm Scott for this invaluable guidance during my undergraduate and graduate education Finally I would like to thank David Railsback for his innovative idea from which this project is based TABLE OF CONTENTS Pages Introduction 6-7 Chapter - Research 8-11 Introduction 8-11 Chapter – LFOM Accuracy Experiment 12-18 Introduction 12-13 Methods 14-15 Results 16-17 Discussion 18 Chapter – LFOM Point of Failure Experiment 19-25 Introduction 19-20 Methods 20-22 Results 22-24 Discussion 24-25 Chapter – MathCAD Design Code 26-30 Introduction 26 Methods 26-29 Results 30 Chapter – Preset designs 31-32 Introduction 31 Results 31-32 Appendix 33-46 References 47 INTRODUCTION Access to clean water is a human right that is unattainable by many people The Agua Clara project is working to design and build water treatment plants in Honduras, which is among the poorest countries in the world Major emphasis is placed on the integration of the plants into the communities effectively Careful consideration is made regarding the specific requirements for each community In the neighborhoods with the greatest need for water purification technologies there is often an intermittent flow of electricity Current water treatment designs control chemical dosing and flow rates with electrically powered pumps and sensors The intermittent electricity supply combined with the current system design would result in intermittent supply of ‘treated water,’ water sent intermittently through pipelines is no longer considered pure because during shut-down the pipelines will form a vacuum pressure pulling surrounding material into the pipe space contaminating future water flows The Agua Clara design requires no input of electricity for operation of the plant Water flows through the plant from high elevation to low elevation; elevation change is the energy source for the water treatment The water is treated through processes The first step in water treatment is a grit chamber which removes the large objects such as branches from the water flow using a large spacing metal grid Water is then treated with a coagulant, aluminum hydroxide, and sent through a flocculation tank The coagulant binds to the foreign particles (contaminants) in the water and creates flocs, similar to a snowflake The flocs increase in size as they move through the flocculation tank Sedimentation follows the flocculation stage, the large flocs are settled out and the clean water is drawn of the top of the sedimentation tank As a final measure the purified water is treated with chlorine to kill any bacteria remaining the water and provide a residual chlorine concentration for disinfection during transport My research is focused on the dosing of aluminum hydroxide to the water Currently the operator of the plant manually adjusts the flow rate of aluminum hydroxide as the flow rate through the treatment plant changes Automation of the process is required to more rapidly and reliably meter alum to the inflow The automation process is designed using an entrance tank, riser pipe, and float system The contaminated water flows into the entrance tank the through a riser pipe and then empties into the flocculation tank A system of floats and lever arms change the flow rate of alum based on the height of the water in the entrance tank The height of water in the entrance tank is based on the outflow of water through orifices in a riser pipe located in the entrance tank The height in the water in the entrance tank with a single outflow orifice is correlated to the square root of the flow rate according to the orifice equation Q = K orifice Aorifice g∆h Equation – The orifice equation This relationship makes metering aluminum hydroxide through a float system nearly impossible Linearization of the head of the water in the entrance tank as a function of flow rate is the goal of my project If the pattern of orifices on the riser pipe can be situated to create a linear relationship between water height in the entrance tank and the flow rate through the plant then the float system can easily adjust the alum flow rate CHAPTER Linear Flow Orifice Meter Research Introduction: The Linear Flow Orifice Meter, LFOM, was initially designed by David Railsback In order to achieve the linear relationship between flow rate and head in the entrance tank a weir was used in the riser pipe A weir is a small overflow dam that can be used for flow measurement The linear proportional weir developed by stout in 1897 achieved the linear relationship but was theoretically based, the width at the bottom of the weir approached infinity Figure 1: Linear Proportional Weir Sutro modified the design by Stout in 1908 to create a practical design The Sutro weir has a rectangular base and the flow through the weir is proportional to the height of the water through the curved portion of the weir plus 2/3 of the height of the rectangular base APPENDIX Pre-Set Flow Rate Designs: Linear Flow Orifice Meter Design for 100 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.794 cm Figure 1: A visual representation of the Riser pipe Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 3 4 5 6 7 8 9 10 34 10 11 12 13 14 15 16 17 18 19 11 12 13 14 15 16 17 18 19 20 1 1 1 1 Linear Flow Orifice Meter Design for 100 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter =0.953 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design 10 Row Height, cm Number of orifices 35 10 12 14 16 18 20 2 2 1 Linear Flow Orifice Meter Design for 200 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.794 cm Figure 1: A visual representation of the Riser pipe Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 15 4 5 6 7 8 9 10 10 11 11 12 12 13 13 14 36 14 15 16 17 18 19 15 16 17 18 19 20 2 2 Linear Flow Orifice Meter Design for 200 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter =1.429 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design Row 10 37 Height, cm 10 12 14 16 18 20 Number of orifices 3 1 2 Linear Flow Orifice Meter Design for 300 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.953 cm Figure 1: A visual representation of the Riser pipe Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 15 11 4 4 5 6 7 8 9 10 10 11 11 12 12 13 13 14 14 15 15 16 38 16 17 18 19 17 18 19 20 2 Linear Flow Orifice Meter Design for 300 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter =1.746 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design 10 Row Height, Number of 39 cm 10 12 14 16 18 20 orifices 3 1 1 Linear Flow Orifice Meter Design for 400 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.794 cm Figure 1: A visual representation of the Riser pipe Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 30 18 6 7 8 9 10 10 11 11 12 12 13 13 14 40 14 15 16 17 18 19 15 16 17 18 19 20 4 Linear Flow Orifice Meter Design for 400 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter =1.905 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design Row 10 41 Height, cm 10 12 14 16 18 20 Number of orifices 4 2 Linear Flow Orifice Meter Design for 500 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.953 cm Figure 1: A visual representation of the Riser pipe Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 26 16 7 6 7 8 9 10 42 10 11 12 13 14 15 16 17 18 19 11 12 13 14 15 16 17 18 19 20 4 3 3 Linear Flow Orifice Meter Design for 500 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial Hflowloc = 1.5cm, PiLfomorifice= 10, and orifice diameter =1.905 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design Row 10 Height, cm 10 12 14 16 18 20 Number of orifices 5 3 3 2 Linear Flow Orifice Meter Design for 700 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.953 cm Figure 1: A visual representation of the Riser pipe 43 Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 36 23 10 10 8 7 8 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 44 19 20 Linear Flow Orifice Meter Design for 700 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial Hflowloc = 1.5cm, PiLfomorifice= 10, and orifice diameter =1.905 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design Row 10 Height, cm 10 12 14 16 18 20 Number of orifices 6 3 2 Linear Flow Orifice Meter Design for 1000 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice diameter equal to 0.953 cm Figure 1: A visual representation of the Riser pipe Note: The bottom row of orifices calls for 51 orifices the drawing would not permit it so I put a large number of orifices in the bottom row 45 Table 1: A tabular view of the riser pipe design Row Height, cm Number of orifices 0 51 34 14 13 13 11 10 9 10 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 46 19 20 Linear Flow Orifice Meter Design for 1000 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter =1.905 cm Figure 1: A visual representation of the riser pipe Figure 2: A tabular view of the riser pipe design 10 Row Height, Number of 47 cm 10 12 14 16 18 20 orifices 13 5 4 3 REFERENCES 1) Thandaveswara, B.S “Hydraulics.” Indian Institute of Technology Dec 2008 47 ... tank and the flow rate through the plant then the float system can easily adjust the alum flow rate CHAPTER Linear Flow Orifice Meter Research Introduction: The Linear Flow Orifice Meter, LFOM,... Pre-Set Flow Rate Designs: Linear Flow Orifice Meter Design for 100 L/min Flow Rate The LFOM design with the smallest percent error has an initial Hflowloc = 1.5cm, a PiLfomorifice = 20, and an orifice. .. 1 1 Linear Flow Orifice Meter Design for 100 L/min Flow Rate and 10 rows The LFOM design with the easiest construction has an initial H.flowloc = 1.5cm, Pi.Lfomorifice = 10, and orifice diameter