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Group B209002063 : Vivek Yadav (Report)

09002003 : Vinay Kumar (Report)09D02005 : Nilesh Gaikwad (Presentation Slides)09D02006 : Shekhar Mishra (Presentation)

Date of experiment:14th January 2011Date of presentation:17th January 2011

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To visually observe laminar andturbulent flow patterns

To determine the upper and lowercritical Reynolds number

Experimentally determine the friction

factor and compare with modelprediction

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Fluid flow is an integral part of anychemical industry.

understanding the phenomena of flow isneededTo avoid unnecessary wastage of energy

To develop efficient flow systemsTo study the various flow regimes of

fluids

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Reynolds NumberThe Reynolds number (Re) of a flowing fluid is obtainedby dividing the kinematicviscosity (viscous force per unit length) into the inertia

force of the fluid (velocity xdiameter)Kinematic viscosity = dynamic viscosity

fluid density

Reynolds number = Fluid velocity x Internal pipediameter

Kinematic viscosity

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The Reynolds numberis proportional to inertial force

divided by viscous force.The flow islaminar when Re < 2300transient when 2300 < Re < 4000turbulent when 4000 < Re

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Turbulent flow happens in general at high flow rates and withlarger pipes.

For pipe flow, a Reynolds number above about 4000 will mostlikely correspond to turbulent flow

Movement of a fluid in which subcurrents in the fluid displayturbulence, moving in irregular patterns, while the overallflow is in one direction. Turbulent flow is common in

nonviscous fluids moving at high velocitiesIn turbulent flow vortices, eddies and wakes make the flow

unpredictable

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a dimensionless number used in fluid flow calculations

The friction head can be related to the pressure loss due to frictionby dividing the pressure loss by the product of the accelerationdue to gravity and the density of the fluid

is the shear stress at the wallfis the Fanning friction factor of the pipev is the fluid velocity in the pipe

is the density of the fluid

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P

is pressure differenceF is the Fanning friction factor of the pipe.V is the fluid velocity in the pipe.

L is the length of pipe.gis the local acceleration of gravity.

D is the pipe diameter.

Friction factor for both laminar and turbulentcan be defined as

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the upper critical Reynolds number is2877.9 39.5 the lower critical Reynolds number is

2296.3 44.7This happens because the system showsinertia in its current state of flow

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With decreasing flow rate ,fluid velocitydecreases resulting decrease in Reynoldsnumber and vice versa.

Decrease in flow rate decrease in

pressure difference and decrease in velocity

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Reynolds number Percentage error

in Reynolds

numberFriction Factor Percentage error

in Friction Factor

15235.7 168.5 1.11 0.01620.0005 3.0914878.1144.5 0.97 0.01700.0005 2.8214777.1148.5 1.00 0.01720.0005 2.8914165.6201.7 1.42 0.01650.0006 3.856578.7 62.5 0.95 0.02620.0013 4.844565.0 47.7 1.04 0.03510.0023 6.643184.7 32.8 1.03 0.04580.0042 9.212296.3 44.7 1.95 0.06730.0082 12.231385.1 18.5 1.33 0.17450.0221 12.67216.2 6.4 2.95 6.60001.2149 18.41

Table - 3 Error Analysis in Decreasing Flow Rate Data:

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Table 4 Error Analysis in Increasing Flow Rate Data:

Reynolds number Percentage error

in Reynolds

numberFriction Factor Percentage error

in Friction Factor315.211.3 3.59 2.65750.5232 19.69315.19.9 3.14 2.64490.4969 18.79312.610.8 3.47 2.70130.5251 19.441433.111.9 0.83 0.16070.0187 11.661804.815.3 0.85 0.14180.0125 8.842877.939.5 1.37 0.07170.0059 8.303632.632.7 0.90 0.05500.0035 6.357105.160.3 0.85 0.02880.0011 3.9712568.3103.8 0.83 0.01960.0005 2.7215121.7118.1 0.78 0.01640.0004 2.44

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The upper and lower critical Reynolds numberare usually not same as the system retains itsoriginal state of flow due to inertia.

Error in the laminar region were in the range of 18 19 %

Error in turbulent region were in the range of 2 3

%.

Observed that the friction factor is a decreasingfunction with respect to the Reynolds number.

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Take reading only after stabilization of fluid intank.Height of tank 1( left tank) should be checked

regularly and should be maintain at same levelthrough out the experiment by monitoring drainvalve.Reading through scale and cylinder should be

done properly ( avoid bending and overflow incylinder) stop watch should be taken in proper care (avoid

lagging)

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Due to leakage and blockage.Level might not be stabilized properly.

Ground might not be horizontal.Human error like parallax , lag in time

stopping.

Measuring scale may not be vertical ormay bend.

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