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All Journal International Journal of Electrical and Computer Engineering International Journal of Power Electronics and Drive Systems (IJPEDS) Jurnal Teori dan Aplikasi Fisika
Arief Sudarmaji
Departemen Fisika Fakultas Matematika Dan Ilmu Pengetahuan Alam Universitas Indonesia
Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Materials Science & Nanotechnology Physics

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Design and performance of very low head water turbines using a surface vorticity model algorithm Ridwan Arief Subekti; Budi Prawara; Anjar Susatyo; Ahmad Fudholi; Sastra Kusuma Wijaya; Arief Sudarmaji
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 13, No 2: June 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v13.i2.pp1140-1149

Abstract

This study explores the numerical optimization of water turbine runner profile performance using a surface vorticity model algorithm. The turbine is designed on a laboratory scale and operates at a net head of 0.09 m, 400 rpm, and a water flow rate of 0.003 m3/s. The initial design of the turbine runner was optimized to minimize losses in the hydrofoil. The optimization algorithm is coded in MATLAB software to obtain the optimal stagger angle that will be used in the water turbine design. Furthermore, design validation was performed using computational fluid dynamics analysis ANSYS CFX to determine the water turbine performance. The settings used in ANSYS CFX include the reference pressure of 1 atm, turbulence model shear stress transport, and inlet boundary conditions using total pressure and static pressure outlet boundary conditions. The computational fluid dynamics analysis reveals that by optimizing the design, the efficiency of the water turbine increases by approximately 2.6%. The surface vorticity model algorithm can be applied to optimize the design of the water turbine runner.
Runner profile optimisation of gravitational vortex water turbine Ridwan Arief Subekti; Sastra Kusuma Wijaya; Arief Sudarmaji; Tinton Dwi Atmaja; Budi Prawara; Anjar Susatyo; Ahmad Fudholi
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 5: October 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i5.pp4777-4788

Abstract

This study discusses the numerical optimisation and performance testing of the turbine runner profile for the designed gravitational water vortex turbine. The initial design of the turbine runner is optimised using a surface vorticity algorithm coded in MATLAB to obtain the optimal stagger angle. Design validation is carried out using computational fluid dynamics (CFD) Ansys CFX to determine the performance of the turbine runner with the turbulent shear stress transport model. The CFD analysis shows that by optimising the design, the water turbine efficiency increases by about 2.6%. The prototype of the vortex turbine runner is made using a 3D printing machine with resin material. It is later tested in a laboratory-scale experiment that measures the shaft power, shaft torque and turbine efficiency in correspondence with rotational speeds varying from 150 to 650 rpm. Experiment results validate that the optimised runner has an efficiency of 45.3% or about 14% greater than the initial design runner, which has an efficiency of 39.7%.
Dynamic Viscosity Measurement Method Based on the Stokes Drag of Prolate Ellipsoidal Mass Arifrahman Yustika Putra; Efta Yudiarsah; Arief Sudarmaji
Jurnal Teori dan Aplikasi Fisika Vol 12, No 1 (2024): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v12i1.14205

Abstract

Viscometer plays an important role in the field of tribology. One way to measure viscosity is to use the Stokes drag principle in the underdamped harmonic oscillation phenomenon. This paper proposes a dynamic viscosity measurement method based on the related physical laws. Our experimental model involves a prolate ellipsoidal mass that experiences underdamped harmonic oscillation within viscous liquid samples. We observed the oscillations of the prolate ellipsoid to obtain the viscous damping coefficient of each sample and substituted it to the theoretical formula of dynamic viscosity. Experimental data suggest that the mathematical model has failed to predict the viscosity values of the samples. In addition, the regression curve of the reference viscosity and the measured viscous damping coefficient shows that the two quantities have an exponential relation instead of linear relation as explained in the theoretical model. We considered the regression formula as the empirical measurement transfer function and used it to measure the viscosity of an ISO VG 150 industrial oil sample. This measurement resulted in a 2.40 % of relative error percentage. Lastly, this measurement method is only valid for measuring samples with viscosities ranging from 0.0400 Pa s to 0.256 Pa s.
Co-Authors Ahmad Fudholi Anjar Susatyo Anjar Susatyo Arifrahman Yustika Putra Bambang Soegijono Budi Prawara Budi Prawara Efta Yudiarsah, Efta Ganis Sanhaji, Ganis La Ode Husein ZT Muhammad Hikam Ridwan Arief Subekti Ridwan Arief Subekti Sastra Kusuma Wijaya Septian Rahmat Adnan Tinton Dwi Atmaja