Experiment 5 Pipe Flow-Major and Minor losses ( review) The goal is to study pressure losses due to viscous ( frictional) effects in fluid flows through pipes H Reservoir Differential Pressure Gauge- measure ΔP Flow meter Pipe D L Valve Schematic of experimental Apparatus Pipes with different Diameter, Length, and surface characteristics will be used for the experiments

Major and Minor losses Total Head Loss( hLT) = Major Loss (hL)+ Minor Loss (hLM) Due to sudden expansion, contraction, fittings etc Due to wall friction In this experiment you will find friction factor for various pipes K is loss coefficient must be determined for each situation For Short pipes with multiple fittings, the minor losses are no longer “minor”!!

Differential Pressure Gauge- measure ΔP Major loss Differential Pressure Gauge- measure ΔP L V ρ μ ε Pipe D Physical problem is to relate pressure drop to fluid parameters and pipe geometry Using dimensional analysis we can show that

Friction factor

Friction Factor For Laminar flow ( Re<2300) inside a horizontal pipe, friction factor is independent of the surface roughness. For Laminar flow For Turbulent flow ( Re>4000) it is not possible to derive analytical expressions. Empirical expressions relating friction factor, Reynolds number and relative roughness are available in literature

Friction factor correlations f is not related explicitly Re and relative roughness in this equation. The following equation can be used instead

Moody’s chart for friction factor Increases Laminar f=64/Re Smooth Transition ReD

Minor Losses Valves Bends T joints Expansions Contractions Flow separation and associated viscous effects will tend to decrease the flow energy and hence the losses The phenomenon is fairly complicated. Loss coefficient ‘K’ will take care of this complicities

Experiment 5 - New Experimental Set up H Reservoir Digital Manometer To measure ΔP

Experiment 5 - Experimental Steps & Details H Reservoir Overall Measurements Measure the Reservoir Height, H Measure the Distances L1, L2, etc. Measure the distances Δx1, Δx2, etc. Measure the pipe diameters L1 Δx1 For EACH PIPE Follow Steps below Set the reservoir height, H, to the maximum level, approx. close to the ‘spill-over’ partition height. Record the level. Adjust the flow rate to a relatively high value, wait for steady flow to be established. Measure the flow rate. Measure the pressure drop, ΔP, for this flow rate. Reduce the flow rate, by using the valves, repeat steps 1 & 2. Reduce the reservoir height and repeat steps 1-3. Repeat all steps until 3 reservoir heights have been measured Hence for each pipe, you will measure ΔP, for six flow rates (3 H x 2 valve openings) L2 Δx2 L3 Δx3 L4 Δx2