Rotational heat pipes (RHPs) with a trigonal cross section was recently proposed by Lee et al. Inside the tube of these RHPs the condensate liquid film flows down the wall in the direction vertical to the tube axis due to centrifugal force and then the liquid returns to the evaporator along the edges. The Nusselt analysis model of laminar film condensation was applied and the solutions were compared with the experimental data. Concerning about the Nu vs Re the same relation was obtained as that for vertical plate except the length scale. The thickness of condensate film was found to be uniform along the surface due to increasing centrifugal force with surface length for a given heat flux and rotational speed.