Interrelation between the Local Acceleration of Laminar Flow in a Channel and the Anomalous Heat Transfer Enhancement in Inclined Two-Row Grooves

Abstract

The anomalous enhancement of laminar separation flow and heat transfer (AELSFHT) is studied in a channel with two rows of 26 densely packed grooves inclined at angles of ±45° in the case of uniform flow at the entry and the Reynolds number Re varying from 1000 to 5500. The local flow acceleration is validated, when the greatest flow velocity becomes of the order of 1.8 in dimensionless units and the wall layer becomes thinner above the spherical entry segments. In this case, the longitudinal velocity increases to a value of 1.4 at a distance y = 0.005 from the wall for Re = 2500. The interrelation between the local acceleration at the channel center and the AELSFHT is established, the minimum value of the negative acceleration amounting to –25 at Re = 5500 and the relative heat removal from the structured region of the channel reaching up to 5.2.