HEAT TRANSFER IN TOROIDAL TUBES AT LARGE PRANDTL NUMBERS.

The temperature distribution in the cross section of a toroidal tube as Pr yields infinity is considered. In the limit, the temperature is constant along the current lines of the secondary flow. The temperature distribution along the streamlines satisfies an equation obtained from the initial equation (Pr does not equal infinity ) by integration over the closed streamlines. The boundary condition for this equation follows from the closure of the boundary layer around the tube wall and the symmetry plane.