Heat Transfer in Parallel Plate Duct with Circular Cylinders Inserted in Staggered Arrangement

Abstract

The authors showed experimentally in what manner the local heat transfer coefficient is affected by the pitch ratio P and the offset ratio H when circular cylinders (blockage ratio R/L =0.4) are set in a staggered arrangement in a parallel plate duct in order to augment heat transfer from the plates. The distribution of local heat transfer coefficients depends on the flow pattern downstream of the cylinder which is influenced by the presence or absence of vortex shedding. The degree of augmentation is also analysed, taking account of pressure loss. In the low-Reynolds number turbulent regime, η, which is the ratio of the average heat transfer for the present system to that for a smooth duct under the condition of equivalent pumping power, is larger than unity at P=4.