Lailatus Sa'diyah Yuniar Arifianti, Mohammad Rizanto Juliarsyah, Y.P. Irwanda, A. Khoirul, Sudirman Rizki Ariyanto, Ferly Isnomo Abdi, Fithrotul Irda Amaliah, Yustin Setiya Widoretno, S.M. Himmawan
GWVTs make possible micro-hydropower at ultra-low heads where conventional turbines are impractical. This study targets the persistent gap of suboptimal runner design and outlet losses through the optimization of a radial closed-hub GWVT for reliable high-efficiency operation under low head. The contribution of this research is a compact, reproducible CFD-Taguchi L9 workflow ranking runner parameters by importance, linking vortex descriptors to performance; the research contribution is an engineering design map (N, L, β1, β2) that can be directly applied at low-head sites. Methods include the use of free-surface CFD (VOF, steady RANS k-ϵ, MRF) together with a mesh-independence study and a Taguchi L9 array to span the number of blades, N, blade length, L, entry angle, β1, and exit angle, β2. Simulations were run at Q ≈ 0.6 m3/s and H ≈ 0.86 m; torque/efficiency and flow fields (λ2 iso-surfaces, VOF α=0.5) were analyzed. Results indicate torque plateaus from ≥0.8 million cells; a ≈ 2.22-million-cell grid offers a sound accuracy-cost trade-off. The main-effects ranking is L > β2 > N ≈ β1. The optimum (N=13, L=45°, β1=11.51°, β2=3°) provides 628 N·m and ≈58.8% efficiency (≈+89% torque vs. baseline), along with a deeper, more axisymmetric core with cleaner discharge. This implies that the most effective levers for performance are lengthening the blades and minimizing the exit angle. This workflow now provides a practical path to robust design. Confirmation runs, URANS/LES, and prototype testing will follow in due course, and generalization to field conditions will be carried out. © The Authors, published by EDP Sciences, 2025.
Department of Automotive Engineering Technology, Universitas Negeri Surabaya, Ketintang, Surabaya, 60231, Indonesia; Department of Mechanical Engineering, Malang State Polytechnic, Jl. Soekarno Hatta No.9, Malang, 65141, Indonesia; Departement of Electrical Engineering, Universitas Negeri Surabaya, Ketintang, Surabaya, 60231, Indonesia; Departement of Mechanical and Energy, Politeknik Elektronika Negeri Surabaya, Jl. Raya ITS Sukolilo, Surabaya, 6011, Indonesia
