Steady state Conjugate heat transfer analysis on a graphics card
Objective
- Find out the maximum temperature attained by the processor.
- Prove that the simulation has achieved convergence with appropriate images and plots.
- Find out the heat transfer coefficient at appropriate areas of the model.
- Identify potential hotspots on the model.
Conjugate Heat Transfer:-
When ever their is a heat transfer from solid volume to fluid volume or vice-versa by exchaning their thermal properties at their interface in order to simulate this case conjugate heat transfer analysis is used.Conjugate heat transfer analysis basically describe the processes which involve variations of temperature within solids and fluids, due to thermal interaction between the solids and fluids.
Applications:-
It helps us to simulate & understand thermal systems like heat sinks,cooler,exhaust port of vehicle,HVAC,ICE etc.
Case 1:Baseline Mesh
Step 1.Geometry
- Below image is basically the image of a graphic card which consist of base,fins & processor
- Since,we are doing conjugate heat transfer analysis we need to create fluid volume so,for this we have create enclosure from enclosure option.
- Below image shows enclosure which enclose garphic card.
- In order to generate conformal mesh we need to on share topology.
Step 2.Meshing
Before creating mesh we need to give name selection such as inlet,outlet etc.
- Below image baseline mesh on enclosure which enclose garphic card.
- Below image shows baseline mesh on graphic card which consist of base,fins & processor.
- Element size=10mm
- Total element generated=85501
- Total node generated=16068
- The above stat of elements can been in below image
- Below image shows conformal mesh this is happen just because we have on shared topology in geometry stage.
Step 3.Setup
In order to setup Conjugate heat transfer analysis following steps is followed
- Type of analysis:Steady-state
- Viscous model:K-epsilon because of turbulent flow
- Material:
- Aluminium for Fins
- Steel for Base
- Copper for Processor
- Air for Fluid volume
Now,we have to define Boundary condition
- Inlet:velocity=5m/s & Temperature=300k
- Outlet:0 gauge pressure
- Internal heat generation in processor :5e7 W/m^3
After initializing the solution,in the postprocessing menu we can create contour plot to monitor how temperature variation is taking place in the solid & fluid volume,also we can create solution animation of this contour plot to observe it.
Plots:
Residue plot
- In the above image we can see that the solution get converege at 100 iteration.
Temperature plot on cut-plane
- In the above,image we can see that Temperature variation on cut-plane & the solution is bit inaccurate because in this case we did baseline mesh solution
Temperature plot on garphic card
- In the above,image we can see the temperature variation on graphic card.
Velocity plot on cut-plane
- In the above,image we can see that velocity variation on cut-plane & the solution is bit inaccurate because in this case we did baseline mesh solution
Wall Heat transfer coefficient on cut-plane
- In the above,image we can see that maximum Wall Heat transfer coefficient achieve in this case is 1152 W m^-2 k^1.
Case 2:Refined Mesh
Step 1.Geometry
- Below image is basically the image of a graphic card which consist of base,fins & processor
- Since,we are doing conjugate heat transfer analysis we need to create fluid volume so,for this we have create enclosure from enclosure option.
- Below image shows enclosure which enclose garphic card.
- In order to generate conformal mesh we need to on share topology.
Step 2.Meshing
Before creating mesh we need to give name selection such as inlet,outlet etc.
- Below image baseline mesh on enclosure which enclose garphic card.
- Below image shows baseline mesh on graphic card which consist of base,fins & processor.
- Element size=10mm
- Total element generated=85501
- Total node generated=16068
- The above stat of elements can been in below image
- Below image shows conformal mesh this is happen just because we have on shared topology in geometry stage.
Step 3.Setup
In order to setup Conjugate heat transfer analysis following steps is followed
- Type of analysis:Steady-state
- Viscous model:K-epsilon because of turbulent flow
- Material:
- Aluminium for Fins
- Steel for Base
- Copper for Processor
- Air for Fluid volume
Now,we have to define Boundary condition
- Inlet:velocity=5m/s & Temperature=300k
- Outlet:0 gauge pressure
- Internal heat generation in processor :5e7 W/m^3
After initializing the solution,in the postprocessing menu we can create contour plot to monitor how temperature variation is taking place in the solid & fluid volume,also we can create solution animation of this contour plot to observe it.
Plots:
Residue plot
- In the above image we can see that the solution get converege at 100 iteration.
Temperature plot on cut-plane
- In the above,image we can see that Temperature variation on cut-plane & the solution is bit inaccurate because in this case we did baseline mesh solution
Temperature plot on garphic card
- In the above,image we can see the temperature variation on graphic card.
Velocity plot on cut-plane
- In the above,image we can see that velocity variation on cut-plane & the solution is bit inaccurate because in this case we did baseline mesh solution
Wall Heat transfer coefficient on cut-plane
- In the above,image we can see that maximum Wall Heat transfer coefficient achieve in this case is 1152 W m^-2 k^1.
Hotspots
We can see potential hotspots at two places which is shown below
- In the below image we can potential hotspots at the center of the fins plate,this is because this plate is in contact with top surafce of the processor
- In the below image we can potential hotspots at the center of the base plate,this is because this plate is in contact with bottom surafce of the processor
Conclusion
As we refined the mesh frome case 1 to case 2 clearly we can say that case 2 has more accurate results because in this case we have use sizing method for graphic card.
Comparison of results:-