The Reynolds number is a dimensionless group defined for a fluid flowing in a pipe as Re Durho/μ whereD is pipe diameter, u is fluid velocity, rho is fluid density, and μ is fluid viscosity. When the value of the Reynolds number is less than about 2100, the flow is laminar-that is, the fluid flows in smooth streamlines. For Reynolds numbers above 2100, the flow is turbulent, characterized by a great deal of agitation. Liquid methyl ethyl ketone (MEK) flows through a pipe with an inner diameter of 2.067 inches at an average velocity of 0.48 ft/s. At the fluid temperature of 20°C the density of liquid MEK is 0.805 g/cm3 and the viscosity is 0.43 centipoise [1 cP 1:00 103 kg / m s]. Without using a calculator, determine whether the flow is laminar or turbulent. Show your calculations.

Question

Engineering

Darwin Sheppard

21 January, 01:17

The Reynolds number is a dimensionless group defined for a fluid flowing in a pipe as Re Durho/μ whereD is pipe diameter, u is fluid velocity, rho is fluid density, and μ is fluid viscosity. When the value of the Reynolds number is less than about 2100, the flow is laminar-that is, the fluid flows in smooth streamlines. For Reynolds numbers above 2100, the flow is turbulent, characterized by a great deal of agitation. Liquid methyl ethyl ketone (MEK) flows through a pipe with an inner diameter of 2.067 inches at an average velocity of 0.48 ft/s. At the fluid temperature of 20°C the density of liquid MEK is 0.805 g/cm3 and the viscosity is 0.43 centipoise [1 cP 1:00 103 kg / m s]. Without using a calculator, determine whether the flow is laminar or turbulent. Show your calculations.

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Answers (1)

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Frederick Murray · Answer 1

the flow is turbulent

Explanation:

The Reynolds number is given by

Re=ρVD/μ

where

V=fluid speed=0.48ft/s=0.146m/s

D=diameter=2.067in=0.0525m

ρ=density=0.805g/cm^3=805Kg/m^3

μ=0.43Cp=4.3x10^-4Pas

Re = (805) (0.146) (0.0525) / 4.3x10^-4=14349.59

Re>2100 the flow is turbulent

Note: if you do not want to use a calculator you can use the graphs to calculate the Reynolds number according to their properties