Local Optimum Channel Height for Pressure Drop and Heat Transfer in the Herringbone Wavy Channel
The purpose of the present study is to investigate the optimal channel height (gap of wavy channel) for the pressure drop and heat transfer of the air flow in a herringbone wavy channel. A numerical analysis was carried out for the plane (0°), herringbone wavy angles of 14.9°, 17.6°, 20° and 30°, channel height to wave length ratios from 0.06 to 1.2, and Reynolds numbers from 170 to 45,000. The local optimum f and j factors were found for channel height to wave length ratios less than 0.3. The optimum value migrated to larger
pitch ratios as the wave angle and inlet velocity increased. The size of the vortex between herringbone waves affected the f and j factors at low Reynolds numbers; however, the strength of the vortex affects the factors at high Reynolds numbers. The results give valuable information in the design of heat exchangers with wavy channels.