Page 295 - Fundamentals of The Finite Element Method for Heat and Fluid Flow

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SOME EXAMPLES OF FLUID FLOW AND HEAT TRANSFER PROBLEMS
Recently, a fully explicit version of the CBS algorithm has been widely employed for both
isothermal and non-isothermal flow problems (Nithiarasu 2003; Nithiarasu et al. 2004). In
this form, the algorithm was proven to be both accurate and efficient when using unstructured
meshes. In fact, for three-dimensional problems, such as those encountered in the present
study, the unstructured mesh-based explicit CBS solver is an excellent choice. Although struc-
tured and semi-unstructured meshes are widely employed in the solution of incompressible
flows, the use of unstructured meshes is inevitable if the geometry is really complex.
The problem considered in this section concerns the simulation of heat and fluid flow
over an array of hot spherical solids resembling solder balls projecting out from a PCB
(Nithiarasu and Massarotti 2004). Two different arrangements, 25 in-line (5 × 5 equally
spaced) and 41 staggered partial spheres are analysed. The solder balls are considered to
be partial spheres, whose centres lie on the same plane (x − z) as shown in Figure 9.29.

16D

1D

19D

y x
Inflow 6D
z
(a) Geometry
D

D
D

D
0.35D

D D
(b) Staggered arrangement
Figure 9.29 Forced convection heat transfer from spherical heat sources mounted on
the wall