역설계 및 CFD를 통한 저효율 프란시스 수차의 성능향상

Recently, the Korean Government is encouraged to propagate the small hydropower part in renewable energy development policy as the 「Low CO2 Green Growth」 policy. However, turbine in the Kwater operated at an average of 5.5% to 10% less than foreign turbines due to the lack of design or the manufacturing technique for the small hydropower part. Thus, maintenance fee was increased because the cavitations were excessively occurred on the main equipment (runner, guide vane, stator etc) finally, the life cycle of turbine will be shortly reduced and the frequency break down will increased. In order to update the efficiency, raise the capacity and improve the cavitations' performance, a CFD-based design system is applied to a Francis turbine replacement project with Kwater and KFMA. Therefore, the inversed design or the extensive turbulent flow 3D-simulations are performed for both the existing and new turbines at design and off design conditions. As a result, the runners are optimized to the greatest extent with a possible minimum cost under the geometrical constraints of the existing machine.