Convection Heat Transfer Coefficients Equations and Calculator

Related Resources: heat transfer

Convection Heat Transfer Coefficients Equations and Calculator

Heat Transfer Engineering
Thermodynamics
Engineering Physics

Simplified relations for natural convection heat transfer coefficients for various geometries in air at atmospheric pressure for laminar flow conditions.

Convection Heat Transfer Equation and Calculator

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Geometry	W/m²· °C (ΔT in °C, L or D in mm)	Btu/h · ft² (ΔT in °F, L or D in ft)
Vertical Plate or Cylinder	h_conv = 1.42 (ΔT / L)^0.25 ^Open Vertical Plate or Cylinder Calculator	h_conv = 0.29 (ΔT / L)^0.25 ^Open Vertical Plate or Cylinder Calculator
Horizontal Cylinder	h_conv = 1.32 (ΔT / L)^0.25 ^Open Horizontal Cylinder Calculator	h_conv = 0.27 (ΔT / L)^0.25 ^Open Horizontal Cylinder Calculator
Hot Surface Facing Up	Horizontal plate (L = 4A/p, where A is surface area and p is perimeter h_conv = 1.32 (ΔT / L)^0.25 ^Open Horizontal Plate Calculator	Horizontal plate (L = 4A/p, where A is surface area and p is perimeter h_conv = 0.27 (ΔT / L)^0.25 ^Open Horizontal Plate Calculator
Hot Surface Facing Down	Horizontal plate (L = 4A/p, where A is surface area and p is perimeter h_conv = 0.59 (ΔT / L)^0.25 Open Horizontal Plate Calculator	Horizontal plate (L = 4A/p, where A is surface area and p is perimeter h_conv = 0.12 (ΔT / L)^0.25 Open Horizontal Plate Calculator
Components on Circuit Board	h_conv = 2.44 (ΔT / L)^0.25 Open Components on Circuit Board Calculator	h_conv = 0.50 (ΔT / L)^0.25 Open Components on Circuit Board Calculator
Small Components, Wires in Free Air	h_conv =3.53 (ΔT / L)^0.25 Open Small Components, Wires in Free Air Calculator	h_conv = 0.72 (ΔT / L)^0.25 Open Small Components, Wires in Free Air Calculator
Sphere	h_conv = 1.92 (ΔT / L)^0.25 Open Sphere Calculator	h_conv = 0.39 (ΔT / L)^0.25 Open Sphere Calculator