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# Can NX include mass transport into flow simulation?

As stated in the Subject field, can the simulation results include pressure, velocities, temperature, AND mass fraction?

3 REPLIES
Solution
Solution
Accepted by topic author CT
‎08-26-2015 04:32 AM

## Re: Can NX include mass transport into flow simulation?

Hello!,

In NX Advanced Flow in addition to the mass, momentum, and energy equations, NX Flow solves general scalar equations to manage mass fractions where you can:

• Model a gas-gas mixture that contains miscible species, such as carbon monoxide in air using the Homogeneous Gas Mixture modeling object.
• Also you can use the Tracer Fluid modeling object in a flow that contains miscible species where the main fluid properties are not affected by the species, such as a smoke in air.
• And finally the NX FLOW solver can model humidity with a general scalar equation. It traces the movement of water vapor through the fluid domain, updating the density (r), specific heat at constant pressure (Cp), thermal conductivity (k), and dynamic viscosity (μ) at each iteration.

The workflow using the Homogeneous Gas Mixture is the following:

1. Create a Homogeneous Gas Mixture modeling object.

• The name you use for the material is used to name the corresponding concentration result set in post processing.
• You need to specify the molecular diffusion coefficients and turbulent Schmidt numbers for gases 2 to 5.

2. Define a gas mixture in a 3D mesh collector or a Fluid Domain simulation object.
3. (Optional) Specify initial or ambient conditions for a fluid volume with a Homogeneous Gas Mixture material.

• The mass fractions are defined for all gasses, including the primary gas.

4. (Optional) Define mixture contents in an inlet boundary condition.

• You must use an External Conditions modeling object whenever you use a Homogeneous Gas Mixture modeling object in a flow boundary condition.

5. (Optional) Modify global ambient or initial conditions to model mixtures.

• You set the mass fractions for all ambient gases on the Ambient Conditions tab of the Solution dialog box.
• You set the initial mass fractions for all gases on the Initial Conditions tab of the Solution dialog box.

6. Add mixture result sets, solve, and view mixture results.

• Select the Humidity and Mixtures check box on the Results Option tab of the Solution dialog box.
• In the Post Processing Navigator, there are result nodes for each species of the mixture except the primary gas.
• The result nodes are named GasName_M#G# — Element-Nodal where GasName is the name of the fluid material you set in the Fluid Material dialog box, M# represents the number of Homogeneous Gas Mixture modeling object and G# represents the specific gas in the mixture.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

## Re: Can NX include mass transport into flow simulation?

Truly appreciate it, Blas. In the sea of NX help manu, really need a hint or key words (NX uses) for a specific topic... Thanks again.
Solution
Solution
Accepted by topic author CT
‎08-26-2015 04:32 AM

Hello!,