Flow and heat transfer in a curved pipe with periodically varying curvature

A numerical analysis is carried out for the study of the flow and heat transfer for a laminar low in a pipe with periodically varying finite (not very small) curvature. The effects of the flow rate (Re), the Prandtl number (Pr), the pipe-period (κ) and the pipe-amplitude (a) on the heat transfer ratio (heat transfer of curved pipe to straight pipe) are studied. The results show that an increase in the amplitude and/or a decrease in the wavelength of a periodic wavy pipe can enhance the heat transfer rate significantly. The ratio of the heat transfer ratio to the friction ratio is greater than one which means a net benefit of heat transfer enhancement.