Three-Dimensional Numerical and Experimental Analysis of Fluid by a0z144mx

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									 Three-Dimensional Numerical and
 Experimental Analysis of Fluid Flow
in Micro Channels and Micro-Pin-Fin
              Arrays


          Elizabeth Gregg and Huilin Xie
             Electronic Cooling
• Number of transistors
  has been increasing at
  an exponential rate
• Directly related to an
  increase in heat flux
• Conventional air
  cooling methods are
  not enough
Liquid-Cooled Miniature Heat Sinks
• Capable of dissipating
  large amount of heat
  from small area
• Made from copper of            Miniature
                                 Heat Sink
  silicon
• Contains micro-scale
  heat transfer
  enhancement structures      High-Heat-Flux
                                  Device
• Utilizes water,
  refrigerant or Fluorinert
  as coolant
 Micro-Scale Enhanced Structures
• Geometries
  – Parallel-Plate Fins
  – Square, Circular,
    Diamond, Elliptical
  – Aligned
  – Staggered
                Applications
• Electronic Modules in
  Aircraft
• Power Component in
  Spacecraft
• Switching Components
  in Power Electronics
• Diode arrays in Laser
  Systems
                 Objectives

• To numerically simulate the fluid flow of water
  across an array of staggered micro-pin-fins
  using ANSYS Fluent
• To determine the pressure drop for a range of
  Reynolds numbers and flow conditions
• To validate numerical results against
  experimental data
    Fluid Flow in Micro-Channels
• Geometry
  – Rectangular Duct
  – 50 microns by 150
    microns
• Boundary Conditions
  – No slip condition at walls
  – Reynolds's number of
    100
  – Outlet pressure set to
    Zero
              Rectangular Duct
                             Mesh
• Assumptions
   – Steady State
   – Laminar Flow
   – Incompressible Fluid
• Meshing
   – Hexahedral Cells
   – Bias at Walls
Results
High-Performance Computing
          on Pople
             • Created Journal and
               Submit files to run in
               parallel
             • Ran with four
               processers
             • Parallel results
               matched results from
               local computer
Experimental Pressure Drop Across
   Circular Micro-Pin-Fin Arrays
Conclusion and Still to Come
Questions?
                                           Geometry


•Rectangle pins
•Reynolds Number
  110<Re<330
•Assumptions
      •Laminar flow
      •Adiabatic Walls
      •Incompressible fluid


Measurement
 Pressure drop between inlet and
outlet(pin too small, no sensors can fit
into it)
                      Top View
• Dimension
  200µm × 200µm × 670µm

• One dimensional Flow

• Computation domain
        Numerical Model

                          Outlet




Inlet
Meshes
         Cell Number



             66k




             95k




           1 million
                    Prediction Method
Pressure Drop=
Inlet Pressure + Outlet Pressure
             +
average pressure of planes × 83
Streamline at Inlet
Streamline at last Pin
Velocity Profile at Pin3, 9 and 17
Velocity Profile after Pin 9
                              Pressure Drop Across Pins
                                    for 95k Mesh
           4.50E-01

           4.00E-01

           3.50E-01

           3.00E-01

           2.50E-01
Pressure
                                                                    0.181566 m/s
  (bar)
           2.00E-01                                                 0.83397 m/s
                                                                    1.65292 m/s
           1.50E-01

           1.00E-01

           5.00E-02

           0.00E+00
                      0   5        10                15   20   25
                                        Pin Number
                             Percent Error VS. Meshes
                45.00%


                40.00%


                35.00%


                30.00%
Percent Error




                25.00%
                                                                                                     66k
                                                                                                     95k
                20.00%
                                                                                                     1m

                15.00%


                10.00%


                 5.00%


                 0.00%
                         0   200   400   600   800           1,000   1,200   1,400   1,600   1,800
                                                     G max
                          Pressure Drop Vs. Meshes
                2.5




                 2




                                                                                          Experimental
                1.5
Pressure Drop




                                                                                          Numerical_1
    (bar)




                                                                                          66k
                                                                                          95k
                 1
                                                                                          209k
                                                                                          474k
                                                                                          1 million
                0.5




                 0
                      0   200   400   600   800        1000   1200   1400   1600   1800
                                            G_max (kg/m^2s)

								
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