Week 1 Unit Conversions Conservation of Mass Ideal Gas Newtonian Fluids, Reynolds No.

1. Week 1 Unit Conversions Conservation of Mass Ideal Gas Newtonian Fluids, Reynolds No. Pressure Loss in Pipe Flow Week 2 Pressure Loss Examples Flow Measurement and Valves Pump Calcsand Sizing

2. 1000 gallons of wortis transferred to a kettle through a 15 m long, 4 cm diameter pipe with a roughness of 0.01 mm. The wort flows at a velocity of 1.2 m/s and assume that its physical properties are the same as those of water. • Determine the time required to transfer all of the wort to the boil kettle, in min. • Determine the Reynolds Number. • Determine the pressure drop in the pipe, assuming that the wort remains at 72C. • Would P change if the wort were at 20C?

3. Head vs. P Head/Pressure loss in Fittings and Valves Reference Sheet

4. Consider the previous example. How would the pressure drop change if the pipework includes twelve 90 elbows and one fully open globe valve?

5. Valves – Brewery Applications Product Routing – Tight shutoff, material compatibility, CIP critical Butterfly and mixproof Service Routing – Tight shutoff and high temperature and pressure Butterfly, Ball, Gate, Globe Flow Control – Precise control of passage area Globe (and needle), Butterfly Pressure Relief – Control a downstream pressure

6. Valves – Globe Valve Single Seat - Good general purpose - Good seal at shutoff Double Seat - Higher flow rates - Poor shutoff (2 ports) Three-way - Mixing or diverting - As disc adjusted, flow to one channel increased, flow to other decreased

7. Valves – Butterfly Valve Low Cost “Food Grade” Poor flow control Can be automated

8. Valves – Mix-proof Double Seat Two separate sealing elements keeping the two fluids separated. Keeps fluids from mixing Immediate indication of failure Automated, Sanitary apps Easier and Cheaper than using manyseparate valves

10. Valves – Gate Valve Little flow control, simple, reliable

11. Valves – Ball Valve Very little pressure loss, little flow control

12. Bernoulli Equation • Notice how this works for static fluids.

13. Flow Measurement – Oriface Meter • Cd accounts for frictional loss,  0.65 • Simple design, fabrication • High turbulence, significant uncertainty P1 P2

14. Flow Meas. – Venturi Meter • Less frictional losses, Cd 0.95 • Low pressure drop, but expensive • Higher accuracy than orifice plate P1 P2

15. Flow Meas. – Variable Area/Rotameter Inexpensive, good flow rate indicator Good for liquids or gases No remote sensing, limited accuracy

16. Flow Measurement - Pitot Tube • Direct velocity measurement (not flow rate) • Measure P with gauge, transducer, or manometer P1 P2 1 2 v

17. Flow Measurement – Weir Open channel flow, height determines flow Inexpensive, good flow rate indicator Good for estimating flow to sewer Can measure height using ultrasonic meter

18. Flow Measurement – Thermal Mass Measure gas or liquid temperature upstream and downstream of heater Must know specific heat of fluid Know power going to heater Calculate flow rate

19. Pumps z = static head hf = head loss due to friction Suction Pump Delivery

20. Pumps

21. Pumps Calculate the theoretical pump power required to raise 1000 m3 per day of water from 1 bar to 16 bar pressure. If the pump efficiency is 55%, calculate the shaft power required. If the electrical efficiency is 95%, calculate the electrical power required. Denisity of Water = 1000 kg/m3 1 bar = 100 kPa

22. Pumps A pump, located at the outlet of tank A, must transfer 10 m3 of fluid into tank B in 20 minutes or less. The water level in tank A is 3 m above the pump, the pipe roughness is 0.05 mm, and the pump efficiency is 55%. The fluid density is 975 kg/m3 and the viscosity is 0.00045 Pa.s. Determine the total head and pump input and output power. 4 m Tank B 15 m Pipe Diameter, 50 mm Fittings = 5 m Tank A 8 m

23. Pumps Need Available NPSH > Pump Required NPSH Avoid Cavitation z = static head hf = head loss due to friction

24. Pumps A pump, located at the outlet of tank A, must transfer 10 m3 of fluid into tank B in 20 minutes or less. The water level in tank A is 3 m above the pump, the pipe roughness is 0.05 mm, and the pump efficiency is 55%. The fluid density is 975 kg/m3 and the viscosity is 0.00045 Pa.s. The vapor pressure is 50 kPa and the tank is at atmospheric pressure. Determine the available NPSH. 4 m Tank B 15 m Pipe Diameter, 50 mm Fittings = 5 m Tank A 8 m

25. Pump Sizing • Volume Flow Rate (m3/hr or gpm) • Total Head, h (m or ft) • 2a. P (bar, kPa, psi) • Power Output (kW or hp) • NPSH Required

26. Pumps Centrifugal Impeller spinning inside fluid Kinetic energy to pressure Flow controlled by Pdelivery Positive Displacement Flow independent of Pdelivery Many configurations

27. Centrifugal Pumps Delivery Impeller Volute Casting Suction

28. Centrifugal Pumps Flow accelerated (forced by impeller) Then, flow decelerated (pressure increases) Low pressure at center “draws” in fluid Pump should be full of liquid at all times Flow controlled by delivery side valve May operate against closed valve Seal between rotating shaft and casing

29. Centrifugal Pumps Advantages Simple construction, many materials No valves, can be cleaned in place Relatively inexpensive, low maintenance Steady delivery, versatile Operates at high speed (electric motor) Wide operating range (flow and head) Disadvantages Multiple stages needed for high pressures Poor efficiency for high viscosity fluids Must prime pump

30. Centrifugal Pumps H-Q Chart Increasing Impeller Diameter Head (or P) A B C Volume Flow Rate

31. Centrifugal Pumps H-Q Chart Increasing Efficiency Head (or P) Required NPSH A B C Volume Flow Rate

32. Centrifugal Pumps H-Q Chart Head (or P) A B C Volume Flow Rate

33. Centrifugal Pumps H-Q Chart Required Flow Capacity Head (or P) Actual Flow Capacity Required Power Volume Flow Rate

34. Pump Sizing Example Requirements 8 gpm 100 feet of head Choose the proper impeller Determine the power consumed by the pump Determine the NPSH required