Heat (Mass) Transfer in a Rotating Two‐Pass Square Channel — Part II:Local Transfer Coefficient, Smooth Channel

Abstract

Naphthalene sublimation technique and the heat/mass transfer analogy are used to determine the detailed local heat/mass transfer distributions on the leading and trailing walls of a twopass square channel with smooth walls that rotates about a perpendicular axis. Since the variation of density is small in the flow through the channel, buoyancy effect is negligible. Results show that, in both the stationary and rotating channel cases, very large spanwise variations of the mass transfer exist in he turn and in the region immediately downstream of the turn in the second straight pass. In the first straight pass, the rotation-induced Coriolis forces reduce the mass transfer on the leading wall and increase the mass transfer on the trailing wall. In the turn, rotation significantly increases the mass transfer on the leading wall, especially in the upstream half of the turn. Rotation also increases the mass transfer on the trailing wall, more in the downstream half of the turn than in the upstream half of the turn. Immediately downstream of the turn, rotation causes the mass transfer to be much higher on the trailing wall near the downstream corner of the tip of the inner wall than on the opposite leading wall. The mass transfer in the second pass is higher on the leading wall than on the trailing wall. A slower flow causes higher mass transfer enhancement in the turn on both the leading and trailing walls.

Heat transfer measurements in a rotating two-pass square channel

“…More detailed information on the local heat transfer distribution is provided by the studies of Kukreja et al (Kukreja et al, 1998) and . In the former study the authors, by using the naphthalene sublimation technique, obtained detailed local heat/mass transfer distributions on the smooth walls of two pass square channel with 180° sharp turn while, in the latter one, by using water as working fluid, they analyzed both the convective heat transfer distribution by means of the transient liquid crystal technique and the flow field by Quantitative InfraRed Thermography Journal 2007.4:41-62.…”

Research status and development trend of rotating internal cooling of a gas turbine blade

“…Hence, axial velocity and heat transfer near the leading surface is higher than that around trailing surface in the radial inward flow passage. Kukreja et al (1998) adopted Naphthalene sublimation technique to analyse the mass transfer distribution on the leading and trailing walls of a U-shaped square smooth passage. The results showed that Coriolis forces improved mass transfer near the trailing side of the radial outward channel, but declined the mass transfer near the leading wall of radial inward pass.…”

Two-dimensional heat transfer distribution in a rotating smooth rectangular channel with four surface heating boundary condition

“…Then, many researchers started to investigate the heat transfer in a rotating channel. Kukreja et al 5 used the Naphthalene sublimation technology to investigate a rotating two-pass square channel. They also found that the rotation-induced Coriolis increases the mass transfer on the trailing wall and reduces the mass transfer on the leading wall.…”