Conjugate Heat Transfer Analysis on a graphics card.
AIM: To perform the steady state conjugate heat transfer analysis on a model of a graphics card
Theoritical Background:
The term conjugate heat transfer (CHT) describes the processes which involve variations of temperature within solids and fluids, due to thermal interaction between the solids and fluids. The exchange of thermal energy between the two physical bodies is called study of Heat Transfer, the rate of transferred heat is directly proportional to the temperature difference between the bodies.
Conjugate heat transfer corresponds with the combination of heat transfer in solids and heat transfer in fluids. In solids, conduction often dominates whereas in fluids, convection usually dominates. Efficiently combining heat transfer in fluids and solids is the key to designing effective coolers, heaters, or heat exchangers. Forced convection is the most common way to achieve high heat transfer rate. In some applications, the performances are further improved by combining convection with phase change.
Heat transfer in solids and heat transfer in fluids are combined in the majority of applications. This is because fluids flow around solids or between solid walls, and because solids are usually immersed in a fluid.
Graphic Card:
A graphics card (also called a display card, video card, display adapter, or graphics adapter) is an expansion card which generates a feed of output images to a display device like monitor. The Graphics Card is responsible for rendering an image to your monitor, it does this by converting data into a signal your monitor can understand.
Geometry of Graphics Card
Processor Fins Base Enclosure
Baseline setup
Meshing:
Element size = 10.289 mm Number of nodes = 15922, Number of elements = 84873
Fluent setup:
Simulation type: Steady state simulation
Solver: Pressure based , Turbulance model : K-epsilon turbulance model with standard wall functions
Materials: Fins : Copper(solid), Base : Alluminium(solid), Processor: Gold(solid), Enclosure: Air(fluid)
Residual plots
Post Processing:
Temperature contour on Cut Plane
Velocity contour on Cut plane
Wall heat transfer coefficient on the Cut plane
Global range
Local range
Wall heat transfer coefficient on baseline setup
Temperature contour on fin, base and processor
Temperature Contour on Processor (local range)
Refined setup
We have refined the mesh using body sizing option for different components of graphic card
Default element size = 2mm
Fin body sizing = 0.5mm, Processor body sizing = 0.5mm, Base body sizing = 1mm
Number of Nodes = 61,983 Number of elements = 3,25,484
We are studying the refined case for 3 different values of inlet velocity
Case 1 : When inlet velocity is 1m/s
Residual plots
Post processing
Temperature contour on Cut plane
Velocity contour on Cut plane
Wall heat transfer coefficient on Cut plane
Global range
local range
Wall heat transfer Coefficient on refined setup
Temperature Contours on fin, base and processor
Temperature Contour on Processor (local range)
Case 2: When inlet velocity = 3m/s
Residual plot
Post processing:
Temperature Contour on Cut plane
Velocity Contour on Cut plane
Wall heat transfer Coefficient on Cut plane
Global range
local range
Wall heat transfer Coefficient on Fin, base and processor
Temperature Contour on fin, base
Temperature Contour on Processor (local range)
Case 3: When inlet velocity = 5 m/s
Residual plot
Post processing:
Temperature Contour on Cut plane
Velocity Contour on Cut plane
Wall heat transfer coefficient on Cut plane
Global range
Local range
Temperature Contour on fin, base
Wall heat transfer coefficient on Fin, base and processor
Temperature Contour on Processor (local range)
TABULATION:
The results of the above cases are tabulated below
Observations:
The heat transfer rate is directly affected by velocity. As we increase the velocity the Total temperature on the graphic card reduces. Meshing the geomety plays a important role to capture the heat transfer in the complex geometry.
Processor, which is the heat source is the potential hot spot of graphic card, because its the only component which consumes power. Fins play a major role in the transfer of heat.