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All Journal ROTOR: JURNAL ILMIAH TEKNIK MESIN Jurnal Rekayasa Mesin Jurnal Elemen
Fajarningrum, Nurmala Dyah
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Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Control & Systems Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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PENGARUH VARIASI DESAIN SUDU TERHADAP KARAKTERISTIK HIDRODINAMIKA TURBIN AKSIAL VORTEX ULTRA LOW HEAD MENGGUNAKAN METODE CFD Khanif, Masnurojak Bin; Rahman Saleh, Arif; Fajarningrum, Nurmala Dyah; Sulistiyo, Raka Mahendra
ELEMEN : JURNAL TEKNIK MESIN Vol. 11 No. 1 (2024)
Publisher : POLITALA PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34128/je.v11i1.279

Abstract

Renewable energy is being developed by many advanced countries due to its positive impacts. Indonesia has a high potential for hydropower generation using axial vortex turbines, which are effective at low head heights. Researchers use experimental methods, employing CFD simulations with specific boundary conditions. In one blade variation, testing was conducted 18 times with speed variables (20, 40, 60, 80, 100, 120 RPM) and blade angles of 22.5°, 35°, 40°. Torque data was collected after achieving convergence. The results showed the highest torque at 22.5° blade angle and 80 RPM speed, amounting to 2.4 N.m, and efficiency of 57.90% at 120 RPM. Researchers concluded that the decrease in torque is caused by the increase in vortex flow, reducing interaction between the blade and fluid after 80 RPM, while the increase in torque before 80 RPM is due to minimal swirling in the basin.
ANALISIS VARIASI KEMIRINGAN SUDUT TURBIN SINGLE BLADE TERHADAP EFISIENSI DAN DAYA PADA ARCHIMEDES SCREW MENGGUNAKAN COMPUTIONAL FLUID DYNAMICS (CFD) Ahmad, shofiyuddin Ali; Fajarningrum, Nurmala Dyah; Iswahyudi, Sigit
ELEMEN : JURNAL TEKNIK MESIN Vol. 11 No. 2 (2024)
Publisher : POLITALA PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34128/je.v11i2.291

Abstract

The potential for renewable energy in Indonesia is abundant, such as water energy. This energy potential can be used for Micro Hydro Power Plants (PLTMH). This study aims to study the effect of turbine head angle and screw angle parameters on the efficiency and power of screw-type water turbines. The angles used are turbine shaft angles of 20 °, 25 °, and 30 ° at screw angles of 22 ° and 26 °. Then a design was made using Autodesk Inventor and then simulated using Ansys software. The results of the study showed that the greatest power and the greatest turbine efficiency were obtained at a screw angle of 26 ° with a turbine shaft angle of 30 ° with a power value of 80072.98 watts and an efficiency of 95.37%. While the lowest power and efficiency were at a screw angle of 22 ° and a shaft angle of 20 ° with a power value of 72643.44 watts with an efficiency of 86.52%. So from this research, it was found that the good angle value is at the variation of the thread angle of 26° and the turbine shaft angle of 30°.
ANALYSIS OF CAVITATION LEVEL IN WADASLINTANG HYDROPOWER PLANT USING THOMA CAVITATION FACTOR Prasetyo, Budi; Saputra, Trisma Jaya; Fajarningrum, Nurmala Dyah
ROTOR Vol. 17 No. 2 (2024)
Publisher : Jurusan Teknik Mesin Fakultas Teknik Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/rotor.v17i2.53593

Abstract

Turbine damage can be caused by several causes, including damage to the turbine due to cavitation on the surface of its blades. Miscalculation of the position or location of the turbine can occur and will result in this cavitation. The Thoma cavitation factor is used to determine whether the turbine operation is safe from cavitation. This research was conducted at the Wadaslintang Hydroelectric Power Plant. The research used a quantitative descriptive research method. This study aims to determine the level of cavitation that occurs in the Francis turbine at an actual reservoir elevation of 169.23 meters above sea level with maximum guide vane openings to minimum guide vane openings. At variations in guide vane openings of 100% and 80% cavitation occurs, while at guide vane openings of 76%, 60%, 40%, and 20% cavitation does not occur. The larger the guide vane opening, the cavitation level is in a more dangerous condition because the difference between the cavitation factor and the critical cavitation factor is smaller, with the difference values ​​of 1.285073, 1.023435, 0.970782, 0.763080, 0.506127, and 0.253081, respectively. The smaller the guide vane opening, the smaller the risk of cavitation, but the power generated is also smaller. Safe operating conditions from cavitation with the greatest power are found at a guide vane opening of 76%-80%. Keywords: francis turbine, guide vane, cavitation, thoma cavitation factor.
ANALISIS VARIASI KEMIRINGAN SUDUT TURBIN SINGLE BLADE TERHADAP EFISIENSI DAN DAYA PADA ARCHIMEDES SCREW MENGGUNAKAN COMPUTIONAL FLUID DYNAMICS (CFD) Ahmad, shofiyuddin Ali; Fajarningrum, Nurmala Dyah; Iswahyudi, Sigit
ELEMEN : JURNAL TEKNIK MESIN Vol. 11 No. 2 (2024)
Publisher : POLITALA PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34128/je.v11i2.291

Abstract

The potential for renewable energy in Indonesia is abundant, such as water energy. This energy potential can be used for Micro Hydro Power Plants (PLTMH). This study aims to study the effect of turbine head angle and screw angle parameters on the efficiency and power of screw-type water turbines. The angles used are turbine shaft angles of 20 °, 25 °, and 30 ° at screw angles of 22 ° and 26 °. Then a design was made using Autodesk Inventor and then simulated using Ansys software. The results of the study showed that the greatest power and the greatest turbine efficiency were obtained at a screw angle of 26 ° with a turbine shaft angle of 30 ° with a power value of 80072.98 watts and an efficiency of 95.37%. While the lowest power and efficiency were at a screw angle of 22 ° and a shaft angle of 20 ° with a power value of 72643.44 watts with an efficiency of 86.52%. So from this research, it was found that the good angle value is at the variation of the thread angle of 26° and the turbine shaft angle of 30°.
Visualization of Two-Phase Flow Regime in Vertical Pipe Airlift pump Fajarningrum, Nurmala Dyah; Hadi Sufyan, M. Fendy Kussuma; Fahadha, Rizqa Ula; Deendarlianto, Deendarlianto; Kurniawan, Dedy
Jurnal Rekayasa Mesin Vol. 19 No. 1 (2024): Volume 19, Nomor 1, April 2024
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v19i1.5136

Abstract

An airlift pump can be used to move from one location to another. The pump lifts liquid or solid particles from air bubbles through a vertical pipe. In this experiment, the airlift pump system was modified using a microbubble generator installed on the injector to produce air bubbles. Two injectors were installed with a swirl model. This study aims to visualise the flow pattern that forms in a vertical pipe when air bubbles lift water toward the endpoint. The flow pattern was observed by varying airspeed and water column h in the vertical pipe. The method in this study was carried out using a two-phase flow (air-water). An acrylic pipe with an inner diameter of 50 mm and a height of 327 cm was used in this study. The immersion ratios were set to 0.44, 0.50, 0.56, 0.62, and 0.68. Air was injected into the system through a compressor injector, and air release was controlled by an airflow meter. m ³/h, 1.5 m ³/h, 2 m ³/hour, 2.5 m ³/h, and 3 m ³/h. The flow pattern in the thriller pipe is captured using a video camera. The research results show that bubble, slug, churn, and annular flow patterns are formed owing to variations in the airflow injected into the system. The slug flow changed to an annular flow as the slug flow speed increased. The slug and churn flows lifted the water, and the annular flow reversed the buoyancy force of the slug and churn flows. This study concludes that the ratio of the water column height in the vertical pipe affects the driving force for lifting water to the separator. The greater the immersion ratio, the better is the pump performance. In addition, the influence of the injected airflow forms a flow pattern that can move water from the bottom to a certain height.
PENGARUH VARIASI DESAIN SUDU TERHADAP KARAKTERISTIK HIDRODINAMIKA TURBIN AKSIAL VORTEX ULTRA LOW HEAD MENGGUNAKAN METODE CFD Khanif, Masnurojak Bin; Rahman Saleh, Arif; Fajarningrum, Nurmala Dyah; Sulistiyo, Raka Mahendra
ELEMEN : JURNAL TEKNIK MESIN Vol. 11 No. 1 (2024)
Publisher : POLITALA PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34128/je.v11i1.279

Abstract

Renewable energy is being developed by many advanced countries due to its positive impacts. Indonesia has a high potential for hydropower generation using axial vortex turbines, which are effective at low head heights. Researchers use experimental methods, employing CFD simulations with specific boundary conditions. In one blade variation, testing was conducted 18 times with speed variables (20, 40, 60, 80, 100, 120 RPM) and blade angles of 22.5°, 35°, 40°. Torque data was collected after achieving convergence. The results showed the highest torque at 22.5° blade angle and 80 RPM speed, amounting to 2.4 N.m, and efficiency of 57.90% at 120 RPM. Researchers concluded that the decrease in torque is caused by the increase in vortex flow, reducing interaction between the blade and fluid after 80 RPM, while the increase in torque before 80 RPM is due to minimal swirling in the basin.
Co-Authors Ahmad, shofiyuddin Ali Budi Prasetyo Dedy Kurniawan Deendarlianto Fahadha, Rizqa Ula Khanif, Masnurojak Bin M. Fendy Kussuma Hadi Sufyan Rahman Saleh, Arif Raka Mahendra Sulistiyo Sigit Iswahyudi Trisma Jaya Saputra