CFD 및 실험에 의한 튜블러형 상반전 수차의 성능해석에 관한 연구

Abstract

The differential pressure existing within the city water pipelines can be used efficiently to generate electricity like the energy generated through gravitational potential energy in dams. However, the pressure energy is often wasted by using pressure reducing valves at the inlet of water cleaning centers. Instead of this, a micro counter-rotating hydraulic turbine can be used to convert pressure energy. For the present study a Counter-Rotating Tubular Type Micro-Turbine is considered with the front runner connected to generators rotor and the rear runner connected to the generators stator. It is possible to achieve high efficiency or miniaturization by making the generator diameter in half or making existing voltage double using this configuration. In this paper, the performance and efficiency of a Counter-Rotating Tubular Type Micro-Turbine is investigated numerically by a commerical CFD code and experimentally.

The results are summarized as follows.

(1) This study analyzed the performance of the micro counter-rotating hydraulic turbine by comparing CFD and experimental results using several design parameters.

(2) When the flow rate is increased, it is seen that the circumferential velocity just before the rear runner also increases. This effect also increases the rotation of the rear runner.

(3) Experimental results showed that the head, power and efficiency of the turbine was approximately 5% lower than the predicted CFD results. The best efficiency point for RA54 is obtained at Q=0.155m3/s where η=72.59%, P=11.47kW, and △H=10.43m.

(4) The best CFD model was RB53 which had diffuser at Q=0.25m3/s. When a diffuser is installed, the Head and Power decreased but the efficiency increased by approximately 4%. At this condition, the efficiency, turbine output power and head were η=84.72%, P=14.69kW, and H=6.9m respectively.