EXPERIMENT : FM 202 NATURE OF FLOW MOTIVATION AND OBJECTIVES - PowerPoint PPT Presentation

CL-232 EXPERIMENT : FM 202 NATURE OF FLOW

MOTIVATION AND OBJECTIVES MOTIVATION  Majority of chemical-processing operations are conducted in the fluid phase.  Important for efficient designing of such operations OBJECTIVES  Visually observe flow pattern during turbulent and laminar flow.  To deduce the critical Reynolds number for the transition from the two types of flow patterns.  To determine friction factor and verify the relation between f and Re .

SCHEMATIC DIAGRAM

THEORY  Low velocity- laminar flow (no lateral mixing) , high velocity- turbulent (eddy formation).  Measure of turbulence (N Re )D/ 𝜈 .  Friction factor:  f = Δ Pg c D/ 2 L ρ V 2 .(Definition)  For turbulent f = 0 .046N Re −0.2 . ( 50000 < N Re < 10 6 )  f = 0.0014 + 0.125N Re -0.32 . ( 3000 < N Re < 3 × 10 6 )  For laminar flow : f = 16/N Re .

EXPERIMENTAL PROCEDURE Adjust flow rate Wait for water level in tank B to stabilise Record H2 Record Volumetric Flow Find velocity of flow in the pipe Repeat from step 1

CALCULATION PROCEDURE VELOCITY=VOLUME RECORDED N Re = ρ v D/ μ VOLUME, TIME TIME*AREA Δ P= Δ H*g* ρ f OBS f THEO Δ H=H1-H2

RESULTS AND DISCUSSIONS  Relation between the observed and theoretical friction factors  The upper critical Reynolds number  The lower critical Reynolds number  Uncertainty in measurements

Conclusion  In the laminar region, friction factor and Reynolds number are inversely proportional to each other.  Some extra energy will have to be supplied to a fluid to change its flow regime from laminar to turbulent and vice-versa

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