Optimization and Computational Fluid Dynamics - Department of ...

262 Marco Manzan, Enrico Nobile, Stefano Pieri and Francesco Pinto
Warm fluid Warm fluid
Cold fluid
(a)
Warm fluid
Cold fluid
(b)
Warm fluid
Fig. 8.25 (a)Originaldesign0,withθ =60 ◦ ;(b) optimized design 134, with θ =42 ◦
(a) (b)
Fig. 8.26 (a) Heat flux on the wall for the original design; (b) heat flux on the wall for
the optimized design
maintaining the same ∆T. These results have been duly verified by running
grid-independence tests at several grid resolutions, up to 5 × 10 5 cells. The
newly optimized geometry has a sharper shape of the walls and a lower value
of the corrugation angle, i.e., θ =42 ◦ , which means a major length of the
repeating module. The original and optimized profiles are given in Fig. 8.25,
while the local Nusselt number distribution on the interface wall, for the
original and optimized design, are presented in Fig. 8.26.
8.9 Concluding Remarks
In this chapter, we have described our approach for the multi-objective shape
optimization of convective periodic channels, which represent a fundamental
building block of many heat exchangers. The optimization is performed for a
fluid of Prandtl number 0.7, representative of air and other gases, assuming
fully developed velocity and temperature fields, and steady laminar conditions.
We considered first the optimization of two-dimensional channels, described
either by linear piecewise corrugated walls, or by wavy NURBSbased
profiles. It has been observed that simpler linear piecewise channels,