Brief introduction to Laminar flow and Reynolds number.

1. What Is Laminar Flow?
Original Presentation by
Tony Green, B.CHE
April 2005
http://www.tonygreen.name
© Tony Green 2011 1

2. What Is Laminar Flow?
Agenda
Applications of Laminar Flow
Factors Determining Laminar
Flow
Description of the Relationship
describing Laminar Flow
Review / Questions
http://www.tonygreen.name
© Tony Green 2011 2

3. What Is Laminar Flow?
Applications
Aeronautics Industry - Air
Fuel Usage of Planes
Semiconductor Industry – In
Thermal Based Mass Flow
Controllers
Pharmaceutical Industry -
Unidirectional Flow in Laminar
Flow Cabinets (Particles)
http://www.tonygreen.name
© Tony Green 2011 3

4. What Is Laminar Flow?
http://www.tonygreen.name
© Tony Green 2011 4

5. What factors determine whether
What Is Laminar Flow?
flow is laminar?
Length of pipe – defined as L
Diameter of pipe – defined as D
which is 2 times the radius (2R=D)
 Differential Pressure – P from
the pipe inlet to pipe outlet or P2-P1
Density of fluid – Mass per unit
Volume
Viscosity of fluid – resistance of a
fluid to flow,R
http://www.tonygreen.name
http://www.tonygreen.name
© Tony Green 2010
© Tony Green 2011 5

6. What Is Laminar Flow?
Please Note:
Viscosity Is Dependent Upon
Temperature of a Fluid and Refer
to Flow
Density Is Intrinsic to the Fluid and
Does Not Change During Flow
http://www.tonygreen.name
© Tony Green 2011 6

7. What Is Laminar Flow?
Flow region is defined by
Reynolds Equation
RE = D X X
Where D equals Diameter ,
equals Velocity, equals density
and equals viscosity
Dimensionless allows scalability
http://www.tonygreen.name
http://www.tonygreen.name
© Tony Green 2011
© Tony Green 2011 7

8. What Is Laminar Flow?
Flow Regions:
Laminar = RE < 2100
Transitional = 2100< RE < 4000
Turbulent = RE > 4000
http://www.tonygreen.name
© Tony Green 2011 8

9. What Is Laminar Flow?
http://www.tonygreen.name
© Tony Green 2011 9

10. What Is Laminar Flow?
http://www.tonygreen.name
© Tony Green 2011 10

11. What Is Laminar Flow?
What does the Reynolds Number really
mean?
Viscous forces – Internal to fluid
Inertial Forces – External to fluid
RE of the ratio between Inertial and
viscous forces of
FI
RE = ----
Fv
This will determine property of flow
http://www.tonygreen.name
http://www.tonygreen.name
© Tony Green 2011
© Tony Green 2011 11

12. What Is Laminar Flow?
Review:
What is Laminar Flow?
What is the difference between
Viscosity and Density?
What is Reynolds Equation?
Laminar flow affect in
applications?
http://www.tonygreen.name
© Tony Green 2011 12

13. What Is Laminar Flow?
Thank You very much for your time!
More about the author can be read at
the author website listed below or his
blog at
http://www.markanthonygreen.blogspot.
com
http://www.tonygreen.name
© Tony Green 2011 13