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PERANCANGAN SISTEM HEAT EXCHANGER TIPE FINNED TUBE DENGAN FLUIDA R-134a MENGGUNAKAN SOFTWARE ENGINEERING EQUATION SOLVER Ramadhani, Fajar; TK, Berkah Fajar; Rozi, Khoiri
JURNAL TEKNIK MESIN Vol 11, No 4 (2023): VOLUME 11, NOMOR 4, OKTOBER 2023
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

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Abstract

Heat exchanger adalah alat penukar kalor yang berfungsi untuk mengubah temperatur dan fasa suatu jenis fluida. Proses tersebut terjadi dengan memanfaatkan proses perpindahan kalor dari fluida bersuhu tinggi menuju fluida bersuhu rendah. Perancangan heat exchanger diperlukan untuk mendapatkan sebuah dimensi heat exchanger sesuai dengan yang diinginkan. Tujuan penelitian ini adalah untuk merancang heat exchanger dengan jenis finned tube yang dapat diaplikasikan pada sistem pendingin dan sesuai dengan parameter yang akan dirancang. Fluida kerja yang digunakan adalah R-134a. Metode yang digunakan adalah dengan simulasi numerik dengan bantuan perangkat lunak Engineering Equation Solver. Persamaan yang digunakan akan diinput kedalam perangkat lunak EES. Dari hasil pembahasan dengan input udara lingkungan dan temperatur fluida yang ditentukan didapatkan dimensi dari kondensor dan evaporator. Pada kondensor didapatkan dimensi berupa total panjang tabung yaitu 30,034 m, total jumlah tabung yaitu 39 tabung, dan luas total perpindahan panas pada kondensor sebesar 10,0191 m2. Pada evaporator didapatkan dimensi berupa total panjang tabung yaitu 30,474 m, total jumlah tabung yaitu 40 tabung, dan luas total perpindahan panas pada evaporator sebesar 10,2531m2.
STUDI NUMERIK PENGARUH ALIRAN FLUIDA PANAS PADA SALURAN INCLINED BACKWARD FACING STEP Rivo, Bara Julio; Rozi, Khoiri; Yunianto, Bambang
JURNAL TEKNIK MESIN Vol 12, No 1 (2024): VOLUME 12, NOMOR 1, JANUARI 2024
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

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Abstract

Penelitian ini mengkaji performa aliran saat melewati saluran tertutup berbentuk backward-facing step (BFS). Untuk memahami lebih lanjut mengenai karakteristik aliran pada saluran backward facing step Perlu dilakukan penelitian secara berkelanjutan, baik dalam kerangka teoritis maupun eksperimental. Dalam penelitian ini, fenomena aliran melalui backward facing step diinvestigasi secara numerik menggunakan perangkat lunak ANSYS Fluent. Efek-efek perubahan kemiringan, perubahan slope pada step, suhu aliran, dan Reynold number terhadap karakteristik aliran pada backward facing step disimulasikan. Metode penelitian yang digunakan adalah Computational Fluid Dynamics (CFD) berbasis ANSYS FLUENT 2022 dengan model turbulensi k-ε realizable. Fluida yang digunakan pada penelitian ini adalah butana. Pengaruh kemiringan dan perubahan tinggi step terhadap karakteristik distribusi aliran disimulasikan dengan kecepatan fluida inlet 10 m/s. Hasil simulasi dari penelitian ini mengungkapkan bahwa perubahan kemiringan dan ketinggian step menyebabkan perubahan pada zona resirkulasi. Zona resirkulasi memiliki pengaruh terhadap perpindahan panas pada aliran backward facing step. Semakin bertambahnya sudut kemiringan step maka kecepatan maksimum pada zona resilkulasi juga meningkat. Hal ini juga mengakibatkan pertambahan panjang daerah fluktuasi koefisien friksi. Nilai fluktuasi koefisien friksi juga semakin menurun seiring bertambahnya rasio ketinggian step. Nilai koefisien tekanan cenderung meningkat seiring mengalami penuruan seiring bertambahnya rasio ketinggian step.
PERBANDINGAN HASIL PENGUJIAN PERFORMA POMPA DAN PERHITUNGAN TEORITIS PADA KARAKTERISTIK POMPA TERHADAP KECEPATAN PUTAR IMPELLER Septiani, Zahra Dwi; Rozi, Khoiri; TK, Berkah Fajar
JURNAL TEKNIK MESIN Vol 11, No 4 (2023): VOLUME 11, NOMOR 4, OKTOBER 2023
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

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Abstract

Penelitian ini dilakukan untuk mengetahui dan memahami performa pompa sentrifugal. Beberapa aspek parameter penting seperti debit, head, dan BHP diuji dengan metode eksperimen. Model pompa sentrifugal yang digunakan dalam pengujian ini adalah pompa sentrifugal Merk EBARA tipe JESX/I 6 IE3. Pengujian pompa ini dilakukan di Lab. Thermofluida Universitas Diponegoro. Hasil-hasil pengujian untuk pompa ini menunjukan bahwa perbandingan hasil pengujian dan perhitungan teoritis terhadap kurva performa pompa sentrifugal terhadap fungsi kecepatan putar impeller memperlihatkan karakteristik head yang sama. Pada karakteristik debit dan BHP menunjukkan hasil perbandingan yang sama sampai kecepatan putar 33,33 rps. Sementara pada kecepatan di atas 33,33 rps memperlihatkan perbedaan kurva yang cukup signifikan.
STUDI PENGARUH KETINGGIAN DAN KEMIRINGAN SUDUT STEP TERHADAP KARAKTERISTIK ALIRAN THERMAL PADA BACKWARD-FACING STEP Ikraam, Muhammad Jalaal; Rozi, Khoiri; Muchammad, Muchammad
JURNAL TEKNIK MESIN Vol 12, No 2 (2024): VOLUME 12, NOMOR 2, APRIL 2024
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

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Abstract

Model aliran separasi backward facing step (BFS) memiliki peran yang sangat penting dalam pengembangan teoritis dan rekayasa. Studi aliran BFS menunjukkan kompleksitas aliran dengan fenomena seperti separasi, recirculation, vortex, dan reattachment. Fenomena separasi aliran dan reattachment berdampak besar pada drag, penurunan tekanan, dan perpindahan panas. . Temuan dari penelitian ini menunjukkan bahwa zona resirkulasi berperan penting dalam mempengaruhi perpindahan panas pada BFS. Tinggi relatif terhadap lebar step (h/H) memengaruhi ukuran zona resirkulasi, yang kemudian berdampak pada penurunan suhu fluida di sepanjang aliran downstream. Distribusi tekanan menurun seiring peningkatan rasio h/H, dengan energi kinetik turbulen dominan di daerah dekat permukaan wall. Penambahan kemiringan step menyebabkan penurunan energi kinetik turbulen, sementara peningkatan rasio h/H cenderung meningkatkannya. Kecepatan maksimum di zona resirkulasi bertambah dengan pertambahan rasio h/H dan sudut kemiringan. Meskipun sudut kemiringan step memengaruhi panjang daerah fluktuasi koefisien friksi, nilai fluktuasi tersebut cenderung menurun seiring pertambahan rasio h/H. Nilai koefisien tekanan umumnya meningkat seiring penurunan rasio h/H.
Computational Fluid Dynamics Simulation of Temperature Distribution and Flow Characterization in a New Loop Heat Pipe Model Restiawan, Muhammad Mika Ramadhani; Kusuma, Mukhsinun Hadi; Rozi, Khoiri; Kiono, Berkah Fajar Tamtomo; Yunus, Muhammad; Wirza, Alif Rahman; Pambudi, Yoyok Dwi Setyo; ButarButar, Sofia Loren; Giarno, Giarno; Hatmoko, Sumantri
JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA Vol 26, No 2 (2024): June 2024
Publisher : Pusat Teknologi Dan Keselamatan Reaktor Nuklir (PTKRN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/tdm.2024.7054

Abstract

The loop heat pipe (LHP) is considered for passive cooling systems in nuclear installations. A combined approach of simulation and experimentation is essential for achieving comprehensive knowledge of the LHP. Research on the LHP using Computational Fluid Dynamics (CFD) is necessary to understand phenomena that are challenging to ascertain experimentally. This study investigates the temperature distribution and flow characterization in a new LHP model. The method used in this research is simulation using CFD Ansys fluent software. In the simulation, the LHP has an inner diameter of 0.1016 m. This LHP features a wick made from a collection of capillary pipes without a compensation chamber. Demineralized water is used as the working fluid with a filling ratio of 100% of evaporator volume. The hot water temperature in the evaporator section is set at 70°C, 80°C, and 90°C. The temperature on the outer surface of the condenser pipe is determined using experimental temperature inputs. An inclination angle of 5° and an initial pressure of 12,100 Pa was applied to LHP. The CFD simulation results show that the temperature distribution profile under steady-state conditions in the  loop heat pipe appears almost uniform. The temperature difference between the evaporator and condenser remains consistent. The flow of working fluid in the LHP is driven by buoyancy forces and fluid flow, allowing the working fluid in the LHP to flow in two phases from the evaporator to the condenser and then condensate from the condenser back to the evaporator. In conclusion, the temperature distribution and flow patterns in the LHP are consistent with common phenomena observed in heat pipes. This modeling can be used to determine the profiles of temperature distribution and flow in LHP of the same dimensions under various thermal conditions.
Experimental Study of The Influences of Inclination Angle and Heat Load on Loop Heat Pipe Thermal Performance Pramesywari, Afifa; Kusuma, Mukhsinun Hadi; Kiono, Berkah Fajar Tamtomo; Rozi, Khoiri; Giarno, Giarno; Pambudi, Yoyok Dwi Setyo; Hatmoko, Sumantri; Emara, Haura
JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA Vol 26, No 2 (2024): June 2024
Publisher : Pusat Teknologi Dan Keselamatan Reaktor Nuklir (PTKRN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/tdm.2024.7013

Abstract

The utilization of nuclear power brings out a lot of benefits in fulfilling human power needs, however, the thermal incident caused by the failure of an active cooling system because of an earthquake followed by the tsunami such as on the Nuclear Power Plant at Fukushima Dai-Ichi Japan could be taken for lesson learn to keep improve nuclear installation operation safety aspects. Loop heat pipe (LHP) as an alternative cooling system technology could be utilized to handle thermal problems on nuclear installations. This research aims to know the influence of the inclination angle and heat load on the LHP thermal performance. The experimental investigation was performed with varying the inclination angle of 0°, 2.5°, and 5°, and heat load given at 60°C, 70°C, 80°C, and 90°C. LHP was used demineralized water working fluid with a 100% filling ratio. LHP was vacuumed on 2.666,4 Pa. The cooling air velocity in the condenser given by 2,5 m/s. The result of this experiment showed that LHP has the best thermal performance with the lowest thermal resistance of 0.0043°C/W. This result was obtained when the LHP operated with a 5° inclination angle and hot water as the heat load of 90°C. The conclusion from this research is showing better LHP thermal performance as the inclination angle increase on LHP because the steam speed that formed bigger, and condensate flows back to the evaporator faster
Experimental Investigation of Natural Circulation Stability Phenomena in a New Loop Heat Pipe Model Wirza, Alif Rahman; Kusuma, Mukhsinun Hadi; Rozi, Khoiri; Kiono, Berkah Fajar Tamtomo; Restiawan, Muhammad Mika Ramadhani; Giarno, Giarno; Pambudi, Yoyok Dwi Setyo; Yunus, Muhammad; ButarButar, Sofia Loren; Hatmoko, Sumantri; Apriandi, Nanang; Pramesywari, Afifa
JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA Vol 26, No 2 (2024): June 2024
Publisher : Pusat Teknologi Dan Keselamatan Reaktor Nuklir (PTKRN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/tdm.2024.7053

Abstract

The severe accident at the Fukushima Dai-ichi Nuclear Power Plant in Japan in 2011 highlighted the critical need for a passive cooling system to dissipate residual decay heat following the failure of active cooling systems in the nuclear facility. The loop heat pipe (LHP) is a promising technology for such applications. The objective of this research is to understand the natural circulation stability phenomena of new LHP model under varying conditions of filling ratio and heat load. The experimental methodology employed a laboratory-scale LHP model made of copper with an inner diameter of 0.104 m. The experiments were designed with filling ratios of 20%, 40%, 60%, 80%, and 100%, and hot water temperature as the evaporator heat source with variations of 60°C, 70°C, 80°C, and 90°C. The initial operating pressure was 10665.6 Pa, with a 5˚ inclination angle, demineralized water as the working fluid, and cooled by air at a velocity of 2.5 m/s. The results show that the natural circulation within the LHP occurs in two phases and maintained stability, with optimal performance observed at an 80% filling ratio and 90°C. The conclusion of this research indicates that natural circulation stability in the LHP operates well and occurs in two phases, proving that natural circulation in the LHP is effective in heat dissipation.
Solar Drying Technology: Current Research Trends and Future Perspectives Apriandi, Nanang; Raharjanti, Rani; An-nizami, Avicenna; Herlambang, Yusuf Dewantoro; Pambudi, Yoyok Dwi Setyo; Rozi, Khoiri; Negara, Komang Metty Trisna; Setyowati, Nur
Andalasian International Journal of Applied Science, Engineering and Technology Vol. 4 No. 3 (2024): November 2024
Publisher : LPPM Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijaset.v4i3.193

Abstract

Solar drying technology has become a vital innovation for sustainable food preservation and renewable energy utilization, offering an energy-efficient alternative to conventional drying methods. This study provides a comprehensive bibliometric analysis of research trends, influential authors, key institutions, and geographical contributions in the field of solar drying technology from 2004 to 2024. We analyzed 108 relevant publications using the Scopus database and VOSviewer software, revealing a significant increase in research output since 2010, with a marked surge after 2016. India and China emerge as leading contributors, driven by their large agricultural sectors and favorable solar conditions. Key research efforts have focused on improving energy efficiency, optimizing drying processes, and preserving product quality. Despite these advancements, critical gaps remain, particularly in scaling solar drying systems and integrating hybrid technologies that combine solar energy with other renewable sources. This study highlights the importance of interdisciplinary collaboration to advance technological innovation and address challenges in food security and energy sustainability. Future research should focus on developing hybrid systems, finding better ways to store energy, and studying how solar drying affects the taste and nutritional value of food in order to make it more useful in a wider range of climates and farming situations. Keywords: Solar Drying Technology, Bibliometric Analysis, Renewable Energy, Hybrid Systems, and Food Preservation.
Solar Drying Technology: Current Research Trends and Future Perspectives Apriandi, Nanang; Raharjanti, Rani; An-nizami, Avicenna; Herlambang, Yusuf Dewantoro; Pambudi, Yoyok Dwi Setyo; Rozi, Khoiri; Negara, Komang Metty Trisna; Setyowati, Nur
Andalasian International Journal of Applied Science, Engineering and Technology Vol. 4 No. 3 (2024): November 2024
Publisher : LPPM Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijaset.v4i3.193

Abstract

Solar drying technology has become a vital innovation for sustainable food preservation and renewable energy utilization, offering an energy-efficient alternative to conventional drying methods. This study provides a comprehensive bibliometric analysis of research trends, influential authors, key institutions, and geographical contributions in the field of solar drying technology from 2004 to 2024. We analyzed 108 relevant publications using the Scopus database and VOSviewer software, revealing a significant increase in research output since 2010, with a marked surge after 2016. India and China emerge as leading contributors, driven by their large agricultural sectors and favorable solar conditions. Key research efforts have focused on improving energy efficiency, optimizing drying processes, and preserving product quality. Despite these advancements, critical gaps remain, particularly in scaling solar drying systems and integrating hybrid technologies that combine solar energy with other renewable sources. This study highlights the importance of interdisciplinary collaboration to advance technological innovation and address challenges in food security and energy sustainability. Future research should focus on developing hybrid systems, finding better ways to store energy, and studying how solar drying affects the taste and nutritional value of food in order to make it more useful in a wider range of climates and farming situations. Keywords: Solar Drying Technology, Bibliometric Analysis, Renewable Energy, Hybrid Systems, and Food Preservation.