High resolution time-dependent calculations are performed for developing flow and heat transferin a multilouvered fin geometry to study the effect of fin pitch. In both cases, transition to unsteadinessoccurs in the wake of the exit louver at a Reynolds number of 400. The upstream spatial propagation ofinstabilities proceeds much faster for the larger fin pitch. It is also found that the nature of instabilitiesdiffers between the two fin pitches. For the larger fin pitch, louver wake instabilities play a moredominant role than louver leading edge shear layer instabilities, which dominate the smaller fin pitch.Overall heat transfer increases per fin as the fin pitch increases because of the larger mass flow ratebetween fins. However, the difference in heat transfer coefficient between the two geometries is smallexcept in the transitional and low Reynolds number range.
展开▼
