Development of Turbine for Supercritical CO₂ Power Generation

One dimensional design was conducted to develop the drive turbine for supercritical CO₂ power system. Designed drive turbine was 2 MW class and 1-stage radial turbine. Specific speed analysis and specific diameter analysis were conducted to estimate the basic specification of turbine, i.e. efficiency, rpm, power, rotor diameter. To manage the thrust force of drive turbine, turbine rotor and pump impeller were back to back layed out. Rotational speed was selected considering the specific speed condition of turbine and pump. One dimensional design was conducted to determine flow angle and dimension of drive turbine. Also, to analyze the characteristic of loss in turbine rotor, it was classified by the source of loss, i.e. incidence loss, passage loss, trailing edge loss, exit energy loss, tip clearance loss and windage loss. One dimensional analysis results were used to calculate amount of losses and these values were compared in design and off design point. In this analysis, passage loss and tip clearance loss were dominant for all operation region. At the lower expansion ratio condition, the loss was increased, and it was stabled more than expansion ratio 3. Even the loss analysis was conducted with simple theoretical equations, the characteristic of loss was identified well and these information can be used as a reference in minimizing loss in turbine rotor.