Grashof Number (pipes)

The Grashof Number for Pipes calculator computes the Grashof number for pipes based on the coefficient of expansion, surface temperature, bulk temperature, diameter of the pipe, kinematic viscosity and the acceleration due to gravity.

INSTRUCTIONS: Choose units and enter the following:

• (β)  Coefficient of thermal expansion in (1/K)
• (g) Acceleration due to gravity.
• (T_s)  Surface temperature
• (T_∞) Bulk temperature
• (D)  Pipe Diameter
• (ν) Kinematic Viscosity

Grashof Number for Pipes (Gr_D):  The calculator returns the Grashof Number.

Heat Transfer Calculators

• Grashof Number (pipes)
• Grashof Number (bluff bodies)
• Grashof Number (flat vertical plate)
• Richardson Number 
• Reynold's Number

The Math / Science

The Grashof Number for pipes is a dimensionless number in fluid dynamics and heat transfer which approximates the ratio of the buoyancy to viscous force acting on a fluid. It frequently arises in situations involving natural convection. The Grashof Number formula for pipes is:

`Gr_D=(g·β(T_s-T_∞)D^3)/ν^2`,

where:

• Gr_D is the Grashof Number for Pipes
• g is the gravitational acceleration
• β is coefficient of thermal expansion in (1/K)
• T_s is the surface temperature
• T_∞ is the bulk temperature
• D is the pipe diameter
• ν is the kinematic viscosity

Note: the default gravitational acceleration is 9.80665 m/s2, which is the acceleration due gravity at sea level in SI units.

References

Wikipedia (https://en.wikipedia.org/wiki/Grashof_number)