[lef47671]

Hi guys,


i am wondering how fluent calculates the surface area of a inlet surface in a 2d axisymmetric simulation.
I try to simulate the flow of two gases (air and methane) through a combustor in a combustion chamber. A drawing of the geometry is attached.
In my opinion the real surface area of "Inlet 1" is S1 = pi*R1^2 = 28.27 mm2 since the line of "Inlet 1" with the length of R1 leads to a circular surface. BUT Fluent says the surface area of "Inlet 1" is 405.27mm2 (im reporting the surface area of "inlet 1" in the calculation.
The real surface area of "Inlet 2" should be S2 = pi*R3^2 - pi*R2^2 = 480.66mm2 since this is a annular surface. But Fluent says the surface area is 1611,6 mm2...

Does anybody know how fluent calculates these surface areas?

[CFDKareem]

If the domain is setup correctly, the area should be correct (see picture).

For axisymmetric models the axis of revolution is the X-axis, not the edge you defined as "axis". Make sure your domain is located directly on the X-axis.

From the numbers you are getting it looks like the axis defined is off the X-axis.

[lef47671]

Hi,

thank you for your answer. My Problem was that my "axis" was NOT located at the x-axis.