Derived Values – Mass Flow

Derived Values – Mass Flow

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How to calculate mass flow in COMSOL Multiphysics

Mass flow calculation is one of the most practical result reporting in Computational Fluid Dynamics (CFD). For this aim in COMSOL Multiphysics, Derived Values has been employed and Simulation of Supersonic Air-to-Air Ejector CMS is used to illustrate this.

Derived Values

Compute the primary mass flow.

Line Integration 1

  1. In the Results toolbar, click More Derived Values and choose Integration>Line Integration.
  2. In the Settings window for Line Integration, type Primary Mass Flow in the Label text field.
  3. Locate the Data section. From the Dataset list, choose Study 1/ Adaptive Mesh Refinement Solutions 1 (sol3).
  4. From the Parameter selection (Refinement level) list, choose Last.
  5. Locate the Selection section. From the Selection list, choose Primary inlet.
  6. Locate the Expressions section. In the table, enter the following settings:
ExpressionUnitDescription
hmnf.rho*wkg/(m*s) 
  • Click Evaluate.

Derived Values

Compute the secondary mass flow.

Line Integration 2

  1. In the Results toolbar, click More Derived Values and choose Integration>Line Integration.
  2. In the Settings window for Line Integration, type Secondary mass flow in the Label text field.
  3. Locate the Data section. From the Dataset list, choose Study 1/Adaptive Mesh Refinement Solutions 1 (sol3).
  4. From the Parameter selection (Refinement level) list, choose Last.
  5. Locate the Selection section. From the Selection list, choose Secondary inlet.
  6. Locate the Expressions section. In the table, enter the following settings:
ExpressionUnitDescription
hmnf.rho*wkg/(m*s) 
  • Click Evaluate.

Derived Values

Compute the mixed mass flow.

Line Integration 3

  1. In the Results toolbar, click More Derived Values and choose Integration>Line Integration.
  2. In the Settings window for Line Integration, type Mixed mass flow in the Label text field.
  3. Locate the Data section. From the Dataset list, choose Study 1/ Adaptive Mesh Refinement Solutions 1 (sol3).
  4. From the Parameter selection (Refinement level) list, choose Last.
  5. Locate the Selection section. From the Selection list, choose Outlet.
  6. Locate the Expressions section. In the table, enter the following settings:
ExpressionUnitDescription
hmnf.rho*wkg/(m*s) 
  • Click Evaluate.


CMS
CMS Website
Computational Modeling and Simulation is the simulation center of Acamech that models Mechanical Engineering Problems, especially Multiphysics Simulation; including Fluid Flow (CFD), Structural Mechanics, Acoustics, Heat Transfer as a unique Multiphysics problem. We use COMSOL Multiphysics, MATLAB, and Autodesk Inventor.

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