... ISHMT-ASME and 15th National Conference on Heat and Mass transfer conference, Jan12-14, Pune, 2000. [23] Zhang, Y. M., Gu, W. Z. and Han, J. C., “Heat transfer and friction in rectangular channels ... position of 0.25 and relative roughness pitch of 8.0, with an angle of attack of 60º and with relative roughness height of 0.037 performers better then the other relative gap position. Therefore ... roughness arrangement with an angle of attack of 60° shows better heat transfer performance compared to that of the 45° rib arrangement. Lau et al. [6, 7] investigated the heat transfer and friction...