Conjugate Heat Transfer Analysis on a graphics card.

AIM

The aim of this challenge is to simulate the Conjugate Heat transfer on graphics card

OBJECTIVES

The main objectives of this simulation is as follows

• Appropriate flagging of solid and fluid zones in the graphics card
• velocity should be varied for different cases.
• The maximum temperature and the heat transfer coefficient attained by the graphics card
• Identification of hotspots within the domain.

CHT ON GRAPHICS CARD(BASE LINE MESH)

There are mainly the following stages in the setiing up of the graphics card

• Geometry
• Mesh
• Setup
• Solution
• Results

Geometry

The first step in the geometry stage we import the graphics card into spaceclaim and then we name the various parts in the graphics card and then create an enclosure around it.

Once the enclosure is created, we have to enable the share topology for the creation of conformal mesh in the geometry.

Mesh

The base line mesh was created with the element size of 0.01m and the number of elements for this particular case was 84578 elements. First we create a base line mesh to get an idea of how the mesh will look like and will work on refining the mesh. The conformal mesh is created as the share topology was enabled in spaceclaim.

Setup

The setup for this simulation is as follows

1. Solver - pressure solver
2. Slover state - steady state
3. Turbulence model - K-epsilon with standard function
4. Material - Air
5. Cell zone - Source term = 781250000 W/m^3
6. Inlet velocity = 1 m/s
7. Inlet temperature = 300 K

For the source term the assumed value of heat generated by the graphics card is 50 W and the volume of the processor is 64mm^3. therefore converting the volume to cubic metre we have the heat generation term to be calculated as 781250000 W/m^3

Residual plot

Now we can see that the simulation has run for 1000 iterations but the solution has converged after 250 iterations.

Results

Temperature Contour

Heat Transfer Coefficient Contour

In both the contour plots the blue surface shows the inlet from which the air enters to cool the processor.

CHT ON GRAPHICS CARD(FINE MESH FOR 1m/s velocity)

There are mainly the following stages in the setiing up of the graphics card

• Geometry
• Mesh
• Setup
• Solution
• Results

Geometry

The first step in the geometry stage we import the graphics card into spaceclaim and then we name the various parts in the graphics card and then create an enclosure around it.

Once the enclosure is created, we have to enable the share topology for the creation of conformal mesh in the geometry.

Mesh

The base line mesh was created with the element size of 0.002m and the number of elements for this particular case was 320272 elements. First we create a base line mesh to get an idea of how the mesh will look like and will work on refining the mesh. The conformal mesh is created as the share topology was enabled in spaceclaim.

Setup

The setup for this simulation is as follows

1. Solver - pressure solver
2. Slover state - steady state
3. Turbulence model - K-epsilon with standard function
4. Material - Air
5. Cell zone - Source term = 781250000 W/m^3
6. Inlet velocity = 1 m/s
7. Inlet temperature = 300 K

For the source term the assumed value of heat generated by the graphics card is 50 W and the volume of the processor is 64mm^3. therefore converting the volume to cubic metre we have the heat generation term to be calculated as 781250000 W/m^3

Residual plot

Now we can see that the simulation has run for 500 iterations but the solution has converged after 350 iterations.

Results

Temperature Contour

Heat Transfer Coefficient Contour

CHT ON GRAPHICS CARD(FINE MESH FOR 3 m/s VELOCITY)

There are mainly the following stages in the setiing up of the graphics card

• Geometry
• Mesh
• Setup
• Solution
• Results

Geometry

The first step in the geometry stage we import the graphics card into spaceclaim and then we name the various parts in the graphics card and then create an enclosure around it.

Once the enclosure is created, we have to enable the share topology for the creation of conformal mesh in the geometry.

Mesh

The base line mesh was created with the element size of 0.002m and the number of elements for this particular case was 320272 elements. First we create a base line mesh to get an idea of how the mesh will look like and will work on refining the mesh. The conformal mesh is created as the share topology was enabled in spaceclaim.

Setup

The setup for this simulation is as follows

1. Solver - pressure solver
2. Slover state - steady state
3. Turbulence model - K-epsilon with standard function
4. Material - Air
5. Cell zone - Source term = 781250000 W/m^3
6. Inlet velocity = 3 m/s
7. Inlet temperature = 300 K

For the source term the assumed value of heat generated by the graphics card is 50 W and the volume of the processor is 64mm^3. therefore converting the volume to cubic metre we have the heat generation term to be calculated as 781250000 W/m^3

Residual plot

Now we can see that the simulation has run for 500 iterations but the solution has converged after 350 iterations.

Results

Temperature Contour

Heat Transfer Coefficient Contour

CHT ON GRAPHICS CARD(FINE MESH FOR 5 m/s VELOCITY)

There are mainly the following stages in the setiing up of the graphics card

• Geometry
• Mesh
• Setup
• Solution
• Results

Geometry

The first step in the geometry stage we import the graphics card into spaceclaim and then we name the various parts in the graphics card and then create an enclosure around it.

Once the enclosure is created, we have to enable the share topology for the creation of conformal mesh in the geometry.

Mesh

The base line mesh was created with the element size of 0.002m and the number of elements for this particular case was 320272 elements. First we create a base line mesh to get an idea of how the mesh will look like and will work on refining the mesh. The conformal mesh is created as the share topology was enabled in spaceclaim.

Setup

The setup for this simulation is as follows

1. Solver - pressure solver
2. Slover state - steady state
3. Turbulence model - K-epsilon with standard function
4. Material - Air
5. Cell zone - Source term = 781250000 W/m^3
6. Inlet velocity = 5 m/s
7. Inlet temperature = 300 K

For the source term the assumed value of heat generated by the graphics card is 50 W and the volume of the processor is 64mm^3. therefore converting the volume to cubic metre we have the heat generation term to be calculated as 781250000 W/m^3

Residual plot

Now we can see that the simulation has run for 1000 iterations but the solution has converged after 250 iterations.

Results

Temperature Contour

Heat Transfer Coefficient Contour

MAXIMUM TEMPERATURE AND HEAT TRANSFER COEFFICIENT

CASE	Maximum Temperature(K)	Maximum Heat transfer coefficient(W/m^2K)
Base mesh	939.7	1065
Fine mesh for 1 m/s velocity	1017	1081
Fine mesh for 3 m/s velocity	1132	1081
Fine mesh for 5 m/s velocity	1019	1081

CONCLUSION

1. As we refine the mesh the contour plots are more accurate
2. When the velocity is increased there the accuracy of temperature contour is more accurate
3. The hotspoys are the zones where temperature and heat transfer coefficient is high on graphics card
4. CHT analysis on graphics card helps to control cooling of the processor