Girvin 2

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Apr 3, 2024

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1 Saskpolytechnic Palliser Campus TECHNOLOGY Course # Hydro 221 Project 2 Water Pumping System Design __________________________________________________________________ Date Project Submitted: July 13th, 2015 Civil Engineering Technology Table Of Contents Pg 1 – Title Page

2 Pg 2 – Table of Contents Pg 3 – Introduction, Water Distribution System Design Pg 4 – Water Distribution System Design Continued Pg 5 – Water Distribution System Design Continued Pg 6 – Flow Requirements Pg 7 – System Curve Pg 8 – Pump Selection Pg 9 – Pump Selection Continued Pg 10 – Pump Suction Negative Pressure Cavitation Pg 11 – Pump Suction Negative Pressure Cavitation Calculations Pg 12 – Discussion Questions Pg 13 – Ampco Pumps Company Pump Data Sheet Introduction

3 The objective of this lab is to design a water distribution system including pumps for the town of Girvin, Sk. The system is designed to supply the entire town as well as a cattle feed lot 2km west of town along highway 749. The system will be able to provide pressures in the 200kPa to 450kPa range and is not required to provide fire flow. The design uses two pumps each capable of providing full flow requirements individually for redundancy. Water Distribution System Design Water Distribution System Design Continued

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4 The water system was designed using PVC (Blue Brute) pipe for underground applications, the reservoir for this system is located 500m from the town of Girvin Saskatchewan north along the highway. A feed lot is also supplied 2km west along highway 749. A 250mm steel suction line feeds the pump for increased resistance to cavitation pressure. Two centrifugal pumps run in parallel, one being used as a primary capable of supplying the peak day demand of 1430m 3 /day, the other fully operational for redundancy and maintenance operations. The lines off the pumps are 200mm PVC with check valves to stop back flow. The lines tee into a single 200mm PVC main water line that feeds the system. Once the 200mm main water line reaches the town of Girvin at the North West corner, a tee splits the supplies to the feed lot and the town. The line to the feed lot is 200mm PVC and runs along the West edge of town to highway 749 then follows the highway 2km to the feed lot. The main pipe entering Girvin is a 150mm PVC that connects to three 50mm PVC lines that will equally distribute water across the entire Village of Girvin via 50mm PVC lines. No lines have an abrupt end allowing for flow from both directions to demands. Elevations from the reservoir (605.5m) and pumps (607.5m) drop into the town of Girvin the lowest point being the South East Corner (601m), this is the point of greatest pressure (450 kPa) and max hydraulic head was monitored at this point. The Feed lot (616m) was the point of least pressure (200kPa) and lowest hydraulic head was monitored at this point. Water Distribution System Design Continued

5 All the lines were sized for 2 distinct purposes, 1) to limit head losses and ultimately allow enough pressure to the feed lot utilizing a single pump. 2) Reduce max velocity below 2m/s respectively the highest water use scenario and preventing any damage to the system from transient flows (hammer and column separation).

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7 Flow Requirements Due to the unavailability of water usage records for Girvin, an average water use of 500Lpcd was used to calculate flow requirements. An estimated water use of 100L per head of cattle was used for the feed lot. Calculations Girvin Population: 20 Girvin Average Day Flow: 20 x 500Lpcd = 10000L/day = 10m 3 /day Girvin Peak Day Flow: 10m 3 /day x 2 = 20m 3 /day Girvin Peak Hour Flow: 10m 3 /day x 3 = 30m 3 /day Cattle Lot Max Capacity: 14000 Cattle Lot Peak Day Flow: 14000 x 100L/day = 1400000L/day = 1400m 3 /day Total Peak Flow Requirement: 30m 3 /day + 1400m 3 /day = 1430m 3 /day

8 System Curve To aid in pump selection a system characteristics curve was made for the distribution network. Design specifications required that the system pressure be between 200kPa and 450kPa. Using the WaterGEMs program the network was tested at 100%, 75%, 50% and 25% of the peak flow requirements to determine the maximum and minimum head added requirements for the pump. These requirements were then graphed to obtain the system curve. 200 400 600 800 1000 1200 1400 1600 0 5 10 15 20 25 30 35 40 45 Town of Girvin System Curve 200kPa 450kPa m3/day HA(m)

9 Pump Selection A two pump system was chosen for the distribution network to provide redundancy in case of pump downtime. Both pumps chosen are capable of providing full peak flow to the system on their own. Using the system characteristics curve a mid-point head added of 37m was chosen for our pump requirements. Using the pump-flo site 2 Ampco Pumps 3x2.5” D-Series centrifugal pumps were chosen. At peak flow these pumps are 72.1% efficient just below their peak efficiency of 73.6% and a single pump will require 8.56kW of power.

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10 Pump Selection Continued

11 Pump Suction Negative Pressure Cavitation Overall, the selected pump for this water distribution system will very effectively meet the design criteria. One issue left to address is the negative pressure from reservoir to the pump. If negative pressure is to high this can cause the water to vaporize. From our pump selected we have a NPSH required of 3.04m and we carry that increased by 10% (3.35m). In our calculations below you can interpret the static head created of 10.33m, this has deductions of head losses and elevation loss. Since the resulting NPSH available is 8.229m and we only require NPSH 3.35m for the pump to operate the possibility of cavitation is very low unless the level of the reservoir drops.

12 Pump Suction Negative Pressure Cavitation Calculations Water @ 4°C Velocity: 0.34m/s Pump elevation: 2m above resevoir 5m of 10” Sched 40 Steel Pipe Eccentric reducer: K = 0.5 Belled inlet: K = 0.5 Standard elbow: K = 0.021 x 30 = 0.63 ΣK = 1.63 Allowable NPSH R : 3.04m x 110% = 3.35m hvp = pvp/γ = 0.08894m hsp = psp/γ = 10.33m NR = vD/v = (0.34m/s x 0.25m) / 1.52x10 -6 m 2 /s = 55920 D/ε = 0.25m / 4.6x10 -5 m = 5435 f = 0.021 Major H L = 0.021[(5m/0.25m) x ((0.34m/s) 2 / 2(9.81m/s 2 ))] = 0.002m Minor H L = k(v 2 /2g) = 1.63((0.34m/s) 2 /(2 x 9.81m/s 2 )) = 0.01m NPSH A = 10.33m – 2m – 0.089m – 0.012m = 8.229m

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13 Discussion Questions 1) What is the anticipated power requirement for an electric motor (assuming a 90% electric motor efficiency), During an average day demand? Power required by pump = 8.54KW 8.54KW / 0.9 = 9.49KW for an electric motor 2) What is the pumps NPSH under maximum operating Conditions? As illustrated in the Ampco Pump data sheet the NPSH required under maximum operating conditions is 3.04m. 3) How high above the Model’s source (reservoir) water can you install the pump? Using a line suction length of 10m, we computed an allowable Hs of 6.8m. 4) What happens to your pump and the water distribution system if the reservoir levels starts to fall over time? Using a suction line length of 10m we computed the water level could drop with no horizontal displacement an additional 4.81m of elevation before NPSH A is less than 110% of the spec’d NPSH R . Beyond this point an additional pump may be required to alleviate negative pressure in the line or moving the pump in elevation closer to the water source.

14 ……….

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Girvin 2

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