
234 Heat Transfer: Thermal Management of Electronics
The same results could have been obtained by using the average convection heat
transfer coefficient over the entire length of the heat spreader,
, and using the
Newton’s law of cooling for the entire heat spreader area,
10.4.2 Tu r B u l e n T Fl o w o v e r a Fl a T pl a T e w i T h un i F o r m Te m p e r a T u r e
If the local Reynolds number is larger than 5 × 10
5
, ow will be turbulent. There are
no closed form solutions for the boundary layer equations of turbulent ows over a
at plate. However, turbulent ows have been extensively studied, experiment