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All Journal Jurnal Vokasi Mekanika IRA Jurnal Teknik Mesin dan Aplikasinya (IRAJTMA)
Revaldo Nur Hidayat
Universitas Negeri Padang
Automotive Engineering Education Energy Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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Analysis Of The Effect Of Penstock Diameter Variation And Nozzle Flow Velocity On Pelton Turbine Performance Using Computational Fluid Dynamics (CFD) Revaldo Nur Hidayat; Randi Purnama Putra; Yolli Fernanda; Fitrah Qalbina
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/18k9e415

Abstract

The performance of a Pelton turbine in micro-hydropower plants is influenced by penstock design and fluid flow conditions. Variations in penstock diameter can lead to changes in head loss, flow velocity, and energy transfer efficiency. This study aims to analyze the effect of penstock diameter variation and nozzle flow velocity on Pelton turbine performance under different head conditions using the Computational Fluid Dynamics (CFD) method.Simulations were conducted using penstock diameters of 4 inches, 5 inches, and 6 inches with ANSYS software. The results show that the respective head losses are 0.010 m, 0.006 m, and 0.0028 m, indicating that larger diameters reduce friction losses in the flow. The corresponding nozzle velocities are 8.90 m/s, 9.08 m/s, and 8.64 m/s, with the highest value observed at the 5-inch diameter due to the balance between flow rate and energy losses. The resulting torque values are 2.13 Nm, 2.55 Nm, and 2.60 Nm, while the rotor rotational speeds are 150.87 W, 189.07 W, and 194.90 W. The effective power generated is 65.59 W, 80.21 W, and 77.79 W, with efficiencies of 43.77%, 42.44%, and 39.95%, respectively. The results indicate that a 5-inch penstock diameter provides the most optimal performance, as it achieves the best balance between head loss, flow distribution, and fluid energy transfer.
Analisis Kondisi Spherical Roller Bearing terhadap Efisiensi Kinerja Mill Fan Revaldo Nur Hidayat
IRA Jurnal Teknik Mesin dan Aplikasinya (IRAJTMA) Vol 4 No 3 (2025): Desember
Publisher : CV. IRA PUBLISHING

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56862/irajtma.v4i3.330

Abstract

This study analyzes the condition of the spherical roller bearings of the Mill Fan at a cement plant in the Finishing Mill Unit. Spherical roller bearings are important components that affect the smoothness and efficiency of Mill Fan operation. The objective of this study is to analyze the relationship between the condition of spherical roller bearings and Mill Fan efficiency, calculate their theoretical life, and compare it with their actual field service life. The method employed involves collecting operational data from the central control room, such as pressure, shaft rotation, flow capacity, and motor power, and then calculating the efficiency and estimating the service life of the spherical roller bearings. The results show that the theoretical service life of the spherical roller bearings is 16.3 years, while the actual service life is only 8.5 years, or 51.5% of the design life. The Mill Fan efficiency before spherical roller bearing replacement was 68.92%; it decreased after replacement and then increased to 76.95% in the subsequent period. The conclusion of this study is that the difference between the theoretical and actual service life of spherical roller bearings is affected by lubrication quality, operating load, operating temperature, and cement dust contamination. Periodic condition monitoring and preventive maintenance are necessary to improve reliability and extend the service life of spherical roller bearings. This research provides a basis for evaluating more effective maintenance strategies and operational efficiency of Mill Fans in the cement industry.
Co-Authors Fitrah Qalbina Putra, Randi Purnama Yolli Fernanda