radial inflow blades in a generally axial direction 21 residual enthalpy can be converted to shaft power in a separate gas phase turbine or by the addition of blading to the shaft 16 the device accomplishes the above unexpected combination of items while avoiding erosion of the liquid conversion surfaces which are protected by the liquid film the device also accomplishes the unexpected combination of items while avoiding erosion of the gas blades by separating the liquid from the gas by the high centrifugal forces of the rotating surface other means to convert two phase flow energy to useful power are shown in fig2 a two phase flow at generally high pressure 24 enters a two phase nozzle structure inlet 25 the pressure of the flow is lowered in a two phase nozzle passage 26 in non rotating body 27 the lowering of pressure causes the two phase mixture to be accelerated to a generally higher velocity the resulting two phase jet 27b see broken lines and arrow 27a impinges in a generally tangential direction onto a rotating surface 28 on rotor 28a integral with shaft 29 the large centrifugal forces produced by the rotating surface result in separation of the gas phase from the liquid phase and in the formation of liquid layer 30 on the rotating surface 28 fig2 shows a cross section of the nozzle and device the directions of the two phase flow and separated liquid correspond to those shown in the drawing of fig1 the separated liquid film is slowed to the velocity of the rotating surface 18 by friction the resulting drag forces produce a torque.