Rotating Heat Exchangers and the Optimization of a Heat Pump

Flow and heat transfer conditions are investigated on rotating flat plates and on blades of tangential blowers. The solution of the three dimensional boundary layer equations for rotating flat plates show that 3-D effects are of influence only in the neighborhood of the axis of rotation. The conditions outside this region can be treated as flow in a 2-D system. The measurements indicate that turbulent flow exists already at Re-values much smaller than Reclit for stationary flat plates. As a result of this, high heat transfer rates can be achieved at lower average velocities. All data taken on rotating flat plates and on the blades of a tangential blower can be correlated by a single dimensionless relationship. The results obtained by theory and measurements are used to derive design curves for the construction of a heat pump. A device built in accordance to these curves performed as predicted. Discussed are also rotating furnaces, radiators and condensers for vapor driven engines.