Lewis number

(Difference between revisions)

Revision as of 16:50, 17 November 2005

The Lewis number for a given species $k$ is

$Le_k \equiv \frac{\lambda}{\rho C_p D_k}$

Denoting $D_{th}= \lambda / \rho C_p$ the heat diffusivity coefficient the Lewis number can be expressed as

$Le_k = \frac{D_{th}}{ D_k}$

which is the ratio of the heat diffusion speed to the diffusion speed of species $k$ .

In many combustion models, all species are assumed to diffuse at the same speed and therefore $Le \equiv 1$

@@ Line 1: / Line 1: @@
 The Lewis number for a given species <math> k </math> is
 :<math>
-Le_k = \frac{\lambda}{\rho C_p D_k}
+Le_k \equiv \frac{\lambda}{\rho C_p D_k}
 </math>
 Denoting <math> D_{th}= \lambda / \rho C_p </math> the heat diffusivity coefficient the Lewis number
@@ Line 11: / Line 11: @@
 In many combustion models, all species are assumed to diffuse at the same speed and therefore
-<math> Le=1 </math>
+<math> Le \equiv 1 </math>
 [[Category:Dimensionless parameters]]