Friction Factors Pumping and You Understanding how friction

Friction Factors, Pumping and You Understanding how friction affects your bottom line

Introduction • Sizing a pump properly saves money! • Must overcome friction • Watch out for cavitation!

Presentation Overview • • • Understanding Friction Factors Fluid Flow Mechanics Trends in Friction Factors Experimental Procedure Results Conclusions

Understanding Friction Factors • What are friction factors? – Energy Balance • What goes in must come out (sort of…) – Bernoulli’s Equation Work In or Out Elevation Change ↓ ↓ ↑ Pressure Change ↑ Velocity Change ↑ Friction Losses

Understanding Friction Factors • Okay, but what is F? ↑ Friction Factor Egads, we’ve found one!

Trends in Friction Factors • What effects a friction factor? – Properties of the pipe, i. e. roughness – Fluid properties and mechanics • Laminar vs. Turbulent Flow

Trends in Friction Factors • Reynolds Numbers – Accounts for velocity, geometry, density and viscosity, and how! • Re<2000, Laminar Flow • 2000<Re<4000, Transition • 4000<Re, Turbulent Flow

Trends in Friction Factors • Moody Diagrams – Based on experimental work – Gives Darcy friction factors by Reynolds number and pipe roughness – Resulting Equations for Fanning friction factors: • Laminar Conditions: • Turbulent Conditions:

Trends in Friction Factors

Trends in Friction Factors • 2 Methods to determine ‘f’: – Trust the Moody Diagram – Physical Experimentation • Measure pressure drop over horizontal pipe

Experimental Procedure • Two pipes selected with differing roughness • A 2%wt solution of Na. Cl was run through pipes at various flowrates • Pressure drop was measured across 10 ft. sections of pipe.

Results

Conclusions and Recommendations • Overall trend of Moody diagram is very accurate • Moody diagram gives a good estimate for friction factors • Additional tests should be performed using longer pipes • Minimal friction is money saved

Review • • • Understanding Friction Factors Fluid Flow Mechanics Trends in Friction Factors Experimental Procedure Results Conclusions

Gratitude • Thanks to lab partners: – Mike Mellas – Allyson Lundberg • Fluid mechanics theory and equations: – Dr. Eric Eddings – de Nevers, Noel. Fluid Mehanics for Chemical Engineers (Third Edition). New York: Mc. Graw-Hill, 2005.

Q&A Time! Questions?