Effects of perpendicular flow entry on convective heat/mass transfer from pin-fin arrays

Convective heat transfer with pin-fin arrays have been studied extensively in laboratory experiments where flow is introduced to the army uniformly ov er the channel span. However, the flow path in actual cooling designs is of ten serpentine-shaped with multiple turns, and the pin-fin array section is often located immediately downstream of a turn. The present study, using a n analogous mass transfer technique based on naphthalene sublimation, inves tigates the effects of three different, nonaxial flow entries on array heat transfer for both an inline and a staggered arrangement of pins. The measu rement acquires the mass transfer rate of each individual pin in five row b y seven column array for the Reynolds number varying from 8000 to 25,000. T he mass transfer and associated flow visualization results indicate that th e highly nonuniform flow distribution established at the array entrance and persisting through the entire array can have significant effects on the ar ray heat transfer characteristics. Compared to the conventional case with a xial-through flow entrance, the overall array heat transfer performance can be either enhanced or degraded depending on the actual inlet arrangements and array configurations.