By neglecting the influence of tubes, this paper adopts a simplified two-dimensional approach to deal with laminar convection of air through wavy finned-tube exchangers. Pressure drop and heat transfer characteristics are investigated in the fully developed region of the flow channels between adjacent fins. The solutions are presented for several space ratios (height over length of a module) and two corrugation angles. They concern laminar flows both below and above the onset of the self-sustained oscillations that precede the transition to turbulence. Fully developed velocity and thermal fields are computed by imposing anti-periodic conditions at inlet/outlet sections of a single calcuiation cell. In the range of Reynolds numbers investigated, Nusselt numbers and friction factors first increase with space ratios (up to a value depending on the corrugation angle), then start decreasing with increasing space ratios.
Effect of space ratio and corrugation angle on convection enhancement in wavy channels
COMINI, Gianni;NONINO, Carlo;SAVINO, Stefano
2003-01-01
Abstract
By neglecting the influence of tubes, this paper adopts a simplified two-dimensional approach to deal with laminar convection of air through wavy finned-tube exchangers. Pressure drop and heat transfer characteristics are investigated in the fully developed region of the flow channels between adjacent fins. The solutions are presented for several space ratios (height over length of a module) and two corrugation angles. They concern laminar flows both below and above the onset of the self-sustained oscillations that precede the transition to turbulence. Fully developed velocity and thermal fields are computed by imposing anti-periodic conditions at inlet/outlet sections of a single calcuiation cell. In the range of Reynolds numbers investigated, Nusselt numbers and friction factors first increase with space ratios (up to a value depending on the corrugation angle), then start decreasing with increasing space ratios.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.