A Numerical Study of Flow and Heat Transfer Between Two Concentric Rotating Spheres with Time-Dependent Angular Velocities


Faculty of Engineering,Ferdowsi University of Mashhad


Abstract. The transient motion and heat transfer of a viscous incompressible
uid contained between
two concentric spheres, maintained at di erent temperatures and rotating about a common axis with
di erent angular velocities, is considered numerically, when the angular velocities are arbitrary functions
of time. The resulting
ow pattern, temperature distribution and heat transfer characteristics are presented
for the various cases, including exponential and sinusoidal angular velocities. An interesting e ect, of
long delays in the heat transfer of a large portion of the
uid in the annulus, is observed, because of the
angular velocities of the corresponding spheres.