Week 10 - MRF project

Objective:

The main objective of this project is to provide analysis and standards for modelling MRF fan using ICEPAK.

Theory:

MRF is a simple, robust CFD technique used for modelling rotating turbo machinery. In MRF technique a constant speed of rotation is assigned. The mesh model does not rotate, instead the navier stokes equations are solved at different points.

Geometry:

The geometry of the cad model is in dimension of 730x12x180, with inlet and outlet vents.

fan properties:

RPM of 6000 is set to fan model

Meshing:

Meshing assemblies is separately done to obtain non conformal meshing.

Multi-level meshing is done to reduce the mesh counts.

To check for validation of mesh

Macros>> productivity>> validation>> automatic case check tool

It checks the assembly interface between the various objects and assembly.

Mesh display in x direction

Mesh display in y direction

Mesh display in z direction

Mesh model for fan object

General set up:

Boundary conditions

Flow conditions

Temp 20 degree

Pressure 0Pa

Radiation temp 20degree

Default fluid air

Default solid extruded Al

Radiation: off

Transient setup: steady

No of iterations: 1000

Flow convergence: 0.001

Energy convergence: 1e-10

Joule heating: 1e-7

Parallel setting:

No of processors- 4

Post processing plots

Convergence plot

Temperature object contour

Temperature in X axis

Temperature in Y axis

Temperature in Z axis

Temperature monitor points:

The solution remains constant after it reaches 700 iterations. The max temperature recorded is 100 degree and min temperature is 0.

Velocity monitor points:

The solution remain unchanged after it reaches 700 iteration. The max velocity recorded is 15 m/s.

Velocity y axis:

The max velocity recorded is 2.34 m/s and min of 2.66 m/s.

Velocity z axis:

Velocity streamlines:

the max velocity streamline is 17 m/s across the fan to cool the entire cabinet.

Conclusion:

MRF reduces error in prediction of temperature of components, because it throws the flow directly into components. MRF model is precise in predicting flow, turbulence and noise level. This model gives accurate prediction of flow, temperature in high density electronics.