Mean values of the convective mass/heat transfer coefficients for two porous structures-differing in both profile and the value of D-h -of the rotor of a heat regenerator were measured for horizontal and vertical positions of the axis. The flow in short curved ducts of the immovable model was forced by the pump. The results of electrolytic measurements were independent of the positioning of the axis. Final correlations of the j(M)-factor or Sh vs Re are almost identical for both duct geometries for the common range of Re. An example of the use of the results for simple heat transfer calculations illustrates a problem. The results are valid for a constant-potential/temperature boundary condition.