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이중 브리지 유로단면을 갖는 막 없는 미세유체 연료전지의 최적설계
오지현(Ji-Hyun Oh),브엉티엔 융(Tien-Dung Vuong),김광용(Kwang-Yong Kim) 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.5
본 연구에서는 이중 브리지 유로단면을 갖는 막 없는 미세유체 연료전지의 성능을 향상시키기 위한 유로단면 형상의 최적설계가 수행되었다. 연료전지의 전력밀도는 Navier-Stokes 방정식, 질량수송 방정식 및 Butler-Volmer 방정식 등을 사용한 전기화학적 해석을 통해 평가하였다. 신경망을 응용한 대리모델과 유전 알고리즘을 기반으로 하는 최적화 기법을 사용하여 목적함수인 최대 전력밀도를 극대화하도록 최적설계를 수행하였다. 설계 변수로 이중 브리지 유로단면의 브리지 높이, 내부유로 너비 및 외부유로 너비를 사용하였다. 결과적으로 브리지 높이와 내부유로 너비의 증가 및 외부유로 너비의 감소는 전력밀도를 효과적으로 증가시켰다. 최적 형상은 기준 형상에 비교하여 최대 전력밀도가 252% 더 향상된 것으로 나타났다. In this study, design optimization was performed to improve the performance of a membraneless microfluidic fuel cell having a flow-channel with a double-bridge cross-section. By numerically calculating the governing equations, including the Navier-Stokes’, mass-transport, and Butler-Volmer equations, electrochemical phenomena in the fuel cell were analyzed, and the performance of the fuel cell was evaluated. Additionally, an optimization was performed to maximize the peak power density (that is, the objective function) using a genetic algorithm combined with a surrogate model based on a radial-based neural network. Bridge height, inner channel width, and outer channel width were selected as design variables for optimization. Resultantly, an increase in the bridge height and the inner channel width, and a decrease in the outer channel width, effectively increased the peak power density. Furthermore, the optimal shape demonstrated peak power density, which was 252% higher than that of the reference shape.
Ky-Quang Pham,Quang-Hai Nguyen,Tien-Dung Vuong,Cong-Truong Dinh 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2
This paper investigates a novel casing treatment method, called recirculation-bleeding channels, which combine a recirculation channel with additional bleeding channels. The system consists of 36 channels distributed around the blades and located on rotor shroud surface of a single-stage transonic axial compressor. This study focuses on its effects on aerodynamic performance of a single-stage transonic axial compressor, NASA Stage 37. Validation of numerical model of NASA Stage 37 was performed using experimental data for the single-stage transonic axial compressor. A common drawback of flow recirculation and air bleeding is the reduction in efficiency; however, numerical results showed that with the presence of recirculation-bleeding channels, both stall margin and adiabatic efficiency of the single-stage transonic axial compressor were increased as compared to the smooth casing with small penalty in pressure ratio. A parametric study of the recirculation-bleeding channels was performed for six geometric parameters. With recirculation-bleeding channels, the compressor could reach the stall margin of 13.85% at maximum while still retaining an increase in peak adiabatic efficiency. It is also showed that proper adjustments of the channels design can eliminate the deficiency in pressure ratio at peak efficiency condition.