Bejan number

English

Named after Template:W.

Template:Lb A dimensionless number: the ratio of heat transfer irreversibility to total irreversibility due to heat transfer and fluid friction: $B e = \frac{\dot{S}'_{g e n, Δ T}}{\dot{S}'_{g e n, Δ T} + \dot{S}'_{g e n, Δ p}}$ , where $\dot{S}'_{g e n, Δ T}$ is the entropy generation contributed by heat transfer and $\dot{S}'_{g e n, Δ p}$ is the entropy generation contributed by fluid friction.
Template:Lb A dimensionless number: the pressure drop along the fluid path length in both external flows and internal flows: $B e_{L} = \frac{Δ p L^{2}}{μ ν}$ , where $μ$ is the dynamic viscosity, $ν$ is the momentum diffusivity (or Kinematic viscosity) and $L$ is fluid path length.