Heat transfer in rotating spiral channel with two opposite planar walls roughened by skew ribs

► Heat transfer properties of rotating spiral ribbed channel at speed 0-900 rev/min are examined. ► Local and averaged Nu on inner, outer, ribbed walls with co- and counter rotations are analyzed. ► Vortices induced by centrifugal forces interact with Coriolis forces and rib-tripped flows to modify heat convection. ► Synergetic rotation, curvature and rib effects elevate HTE at co-rotating conditions. ► Nu correlations for rotating inner, outer and ribbed walls are generated.