.IBPSA.Fluid.HeatExchangers.BaseClasses.HANaturalCylinder

Information

This model calculates the convection coefficient h for natural convection from a cylinder submerged in fluid. h is calcualted using Eq 9.34 from Incropera and DeWitt (1996). Output of the block is the hA value.

The Nusselt number is computed as

Nu_D = (0.6 + (0.387 Ra_D^(1/6))/(1+(0.559 Pr) ^(9/16))^(8/27))²);

where Nu_D is the Nusselt number, Ra_D is the Rayleigh number and Pr is the Prandtl number.
This correclation is accurate for Ra_D less than 10¹².

h is then calculated from the Nusselt number. The equation is

h = Nu_D k/D

where k is the thermal conductivity of the fluid and D is the diameter of the submerged cylinder.

References

Fundamentals of Heat and Mass Transfer (Fourth Edition), Frank Incropera and David DeWitt, John Wiley and Sons, 1996

Contents

Revisions

• August 29, 2014 by Michael Wetter:
  Refactored function calls for medium properties.
• May 10, 2013 by Michael Wetter:
  Revised implementation to use hA_nominal as a parameter, and compute the associated surface area A. This revision was required to have a consistent computation of the hA values inside and outside of the coil in the heat exchanger model of the water tank.
• February 26, 2013 by Peter Grant:
  First implementation.