CHT Analysis on a Graphics card

 CHT Analysis on a Graphics card

AIM:

1. To perform a steady-state conjugate heat transfer analysis on a model of a graphics card. 

2.Run the simulation by varying the velocity from 1m/sec to 5m/sec for at least 3 velocities and discuss the results.

3.Find out the maximum temperature and heat transfer coefficient attained by the processor.

EXPLANATION:

Conjugate heat transfer is defined as the heat transfer between two domains by exchange of thermal energy. For a system the thermal energy available is defined by its temperature and the movement of thermal energy is defined by its heat flux through the outer walls. Heat transfer in solid happens through conduction and walls by convection and in liquid phase through convection.

CHT provides the temperature prediction and the hotspot regions at the solid-fluid interface and we can also predict the heat transfer accurately for example- Conduction through solids, convection through fluid, and thermal radiation. It also provides the velocity and pressure distribution of fluid moving inside the solid. We can also use CHT in design optimization for improvement for heat transfer and cooling capacity.

  A video card (also called a graphics card, display card, graphics adapter, or display adapter) is an expansion card that generates a feed of output images to a display device (such as a computer monitor). Most video cards are not limited to a 6-inch simple output. Their integrated graphics processor can perform additional processing, removing this task from the central processor of the computer.

We are following below process to get results:

1.Geometry:

 We are loading the premade geometry and then in the workbench option click on share option to share the topology.

 

Base:

Fins:

Processor:

Then close geometry and open mesh.

2.Mesh:

Here we are generating mesh and using default element size.

Then we are naming the parts of the geometry like inlet, outlet, wall, fins, processor, base.

We choose surface select option during selection of inlet, outlet and Wall.

Then we use body select to select fins,processor and base.so we have to hide the enclouser by select the enclouser by body select and then right click and hide body.

 Fins:

Processor:

 

Base:

Then update mesh and close it.

3. setup:

 

In domain

solver: pressure-based, steady ,Absolute

In Physics

Energy equation is enabled

viscous- k-omega,SST

Zones- boundary condition- Inlet-velocity 2m/s(rest boundary condition keep as default)

Materials- material type-fluid -air

                                    Solid-Aluminium, base-metal(made up), processor-metal(made up)

To choose made-up material go to fluent database then material type-solid, choose Aluminium then copy then name it as any made up material in the poop up window generated, then in the material section change its property.

Processor-metal:

base-metal:

 

Aluminium:

Then come to the cell zone and select the portions of the geometry and select its type fluid/ solid in below and then edit.

Then choose base,fins,processor as solid and edit.

base:

fins:

Now in the processor heat will be generated so we have to give the processor as source term and amount of heat generated.

The power consumption of today's graphics cards has increased a lot. The top models demand between 110 and 270 watts from the power supply; in fact, a powerful graphics card under full load requires as much power as the rest of the components of a PC system combined"

Taking this fact we will assume the power consumed to be 55 (being half of the upgraded graphic card)

Heat generated=55/(64*10^-9) =859375000 W/m^3

Processor:

Now all is set in physics.

In solution

choose standard solution, initialize, take number of iteration-210

4. Results:

processor temperature:

Fins temperature:

velocity contour:

 

 Processor heat transfer coefficient:

 

 case-2:

Here velocity at the inlet is 4m/s and in mesh we are going to refine the size of mesh.

overall mesh 

 element size: 3mm

Body sizing:fins

element size:0.5 mm

Body sizing: processor

element size: 0.5 mm

Body sizing: base

element size: 0.5 mm

  

Rest set-up are same as previous.

Results:

Processor temperature:

 

Fins temperature:

 

Velocity contour:

 

Processor  heat transfer coefficient:

 

 

 

 case-3:

Here we take the velocity as 5 m/s and rest are same as previous.

Result:

Processor temperature:

 

Fins temperature:

 

Velocity contour:

 

Processor heat transfer coefficient:

 

Data Table:

	pocessor temperature (kelvin)	Fins temperature (kevin)	velocity of air (m/s)	processor heat transfer coefficient (w/m^2 k)	number of elements
case-1	506	506	2	625
case-2	376	376	4	846
case-3	369	369	5	914

 

video files:

Processor temperature:

https://www.youtube.com/watch?v=Y_RyX8jZl4g

Fins temperature:

https://www.youtube.com/watch?v=Mb39O9xiPhw

Velocity contour:

https://www.youtube.com/watch?v=Ciw2vT5SOlA

Processor Heat Transfer Coefficient:

https://www.youtube.com/watch?v=Y11WF0U9D-U

 

conclusion:

 

1. As the number of elements increases the accurate results of temperature distribution is obtained
2. From the above table, it is fairly notable that, the net temperature of components of graphics cards decreases with an increase in inlet velocity.
3. Hence it can be inferred that a higher inlet velocity results in better cooling and lower the average temperature thus keeping the components safe from damage.
4. Furthermore, it can be observed that the temperature of components increases as the inlet velocity decreases from 5 m/s to 1m/s, also proving that higher velocity results in better cooling.