Optimal Design of Impeller according to Blade Shape Variation Using CFD Simulation

CFD를 이용한 블레이드 형상 변화에 따른 블로워 임펠러 최적설계

Abstract

The objective of this study was to investigate the influence of the blade shape on the impeller performance, for design optimizing of the high airflow impeller. First, the quantity, angle, and length of blades, which are considered to have a large influence on the impeller performance, were selected as design variables. Then, 27 cases of impeller shapes were selected according to the design of experiment (DOE). To predict the conduct of the blower based on the selected impeller shape, flow analysis was performed using the immersed solid method of ANSYS CFX. In the CFD results, the highest airflow was expected in the impeller having a combination of 50 EA, $6^{\circ}$ and 5 mm. Finally, a blower with the original impeller shape and the optimized impeller shape was fabricated using a 3D printer, and the analysis tendency and experimental tendency were verified through experiments.

본 논문에서는 높은 풍량을 갖는 임펠러 형상 최적 설계를 위하여, 블레이드 형상이 임펠러의 성능에 미치는 영향을 파악하였다. 먼저 임펠러 성능에 큰 영향을 미칠 것이라 판단되는 블레이드 개수, 각도, 길이를 설계변수로 선정하고, 실험계획법에 의거하여 정한 설계 수준에 따라 각기 다른 27가지 임펠러 형상을 설계하였다. 그리고 블레이드 형상 변화에 따른 임펠러 성능변화를 예측하기 위해 ANSYS CFX로 유동해석을 진행하였다. CFD 결과, 블레이드 개수 50개, 각도 $6^{\circ}$, 길이 5 mm 조합의 임펠러 형상에서 가장 높은 풍량이 발생되었다. 마지막으로 해석 결과를 바탕으로 3D프린터를 이용하여 기존 임펠러 형상과 시험군 임펠러 형상을 제작하였고, 블로워의 토출구에서의 유량을 측정하여 CFD 결과와 비교하는 검증 실험을 진행하였다.

Fig. 1 Flow Chart of Impeller Design

Fig. 2 Original Impeller Model

Fig. 3 Average Velocity according to Design Variation

Fig. 4 Fluid Domains and Impeller of Simulation:(a) Domain of Fluid Zone; (b) Domain of The Blower fan

Fig. 5 Results of Fluid Domain Size Verification Test

Fig. 6 Mesh Convergence Test Results

Fig. 7 Volume Flux According to Blade Quantity Variation

Fig. 8 Volume Flux According to Blade Angle Variation

Fig. 9 Volume Flux According to Blade Length Variation

Fig. 10 Outlet Area of Blower

Fig. 11 Velocity Vector Contours at Different Span Wise Locations of 20, 50, and 80%

Fig. 13 The Set-up of Verification Experiments

Fig. 14 Comparison Between 3D Printed Fan and Existing Fan

Table 1 Design Criteria for Blade

Table 2 Mesh Information of Mesh Convergent Test

Table 3 Mesh Information of Each Domain

Table 4 Domain Condition

Table 5 Boundary Condition

Table 6 Velocity, Velocity w Contour at Outlet

Table 7 Pressure Contours at Different Span Wise Locations of 20, 50, and 80%

Table 8 Velocity Contours at Different Span Wise Locations of 20, 50, and 80%

Fig. 12 Housing and Impeller for Verification Experiment: (a) 3D Printed Blower Fan; (b) Manufactured Blower Fan

Table 9 The Results of Verification Experiments