Analisis Numerik Kegagalan Exhaust Bellows Pada Pembangkit Listrik Gas Engine Akibat Beban Operasi Aktual Termo-Struktural Dan Dinamik

Lestari, Yuda Lestari (2026) Analisis Numerik Kegagalan Exhaust Bellows Pada Pembangkit Listrik Gas Engine Akibat Beban Operasi Aktual Termo-Struktural Dan Dinamik. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini bertujuan untuk menganalisis mekanisme kerusakan bellows pada exhaust system engine Wartsila W20V34SG dengan kapasitas 9.7 MW menggunakan pendekatan numerik melalui Computational Fluid Dynamics, steady-state thermal, static structural, modal, harmonic response, dan random vibration analysis. Bellows merupakan komponen fleksibel pada exhaust system yang berfungsi mengakomodasi ekspansi termal, vibrasi, dan pergerakan struktur selama kondisi operasi engine. Simulasi dilakukan untuk mengevaluasi distribusi temperatur, karakteristik aliran, distribusi tegangan, deformasi struktur, serta respons dinamis. Hasil simulasi kemudian dikorelasikan dengan data kerusakan aktual di lapangan untuk mengidentifikasi area kritis dan mekanisme kegagalan yang terjadi. Hasil penelitian menunjukkan bahwa area convolution sisi dalam merupakan lokasi paling kritis pada bellows exhaust system akibat akumulasi temperatur dan thermal loading yang tinggi karena rendahnya sirkulasi aliran gas buang, sehingga menyebabkan thermal expansion serta peningkatan tegangan, regangan, dan deformasi pada area tersebut. Selain itu, sambungan welding inner sleeve menerima pengaruh pressure fluctuation dan vibrasi exhaust system yang meningkatkan cyclic stress dan potensi fatigue failure. Hasil simulasi menunjukkan kesesuaian dengan kerusakan aktual di lapangan yang didominasi oleh crack pada area convolution dan kegagalan welding inner sleeve. Mekanisme kerusakan bellows dipengaruhi oleh kombinasi pembebanan termal dan vibrasi yang bekerja secara simultan selama operasi engine, dimana thermal expansion, resonansi, dan cyclic loading menyebabkan area convolution dan sambungan inner sleeve menjadi lokasi paling rentan terhadap inisiasi crack dan fatigue failure. Berdasarkan hasil penelitian, perbaikan bellows dapat dilakukan melalui optimasi geometri convolution, peningkatan kualitas welding inner sleeve, pengurangan vibrasi exhaust system, serta peningkatan fleksibilitas support untuk menurunkan konsentrasi tegangan pada area kritis bellows exhaust system
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This study aims to analyze the bellows failure mechanism in the exhaust system of a 9.7 MW Wärtsilä W20V34SG engine using a numerical approach through Computational Fluid Dynamics (CFD), steady-state thermal, static structural, modal, harmonic response, and random vibration analysis. Bellows are flexible components in the exhaust system that accommodate thermal expansion, vibration, and structural movement during engine operating conditions. Simulations were conducted to evaluate temperature distribution, flow characteristics, stress distribution, structural deformation, and dynamic response. The simulation results were then correlated with actual field damage data to identify critical areas and failure mechanisms. The results indicate that the inner convolution area is the most critical location in the exhaust system bellows due to the accumulation of high temperatures and thermal loading due to low exhaust gas flow circulation, which causes thermal expansion and increased stress, strain, and deformation in the convolution area. Furthermore, the inner sleeve welding joint is affected by pressure fluctuations and exhaust system vibration, which increases cyclic stress and the potential for fatigue failure. The simulation results show agreement with actual damage in the field, which is dominated by cracks in the convolution area and inner sleeve welding failure. The bellows damage mechanism is influenced by a combination of thermal and vibration loading that work simultaneously during engine operation, where thermal expansion, resonance, and cyclic loading cause the convolution area and inner sleeve connection to be the most vulnerable locations for crack initiation and fatigue failure. Based on the research results, bellows repair can be done through optimizing the convolution geometry, improving the quality of inner sleeve welding, reducing exhaust system vibration, and increasing support flexibility to reduce stress concentrations in critical areas of the exhaust system bellows

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Bellow Exhaust System, Analisis Numerik, Beban Operasi Aktual, Mekanisme Kegagalan, Pembangkit Listrik Mesin Gas, Exhaust Bellows, Numerical Analysis, Actual Operating Loads, Failure Correlation, Gas Engine Power Plant.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
Divisions:	Faculty of Industrial Technology > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Yuda Lestari
Date Deposited:	29 Jul 2026 06:54
Last Modified:	29 Jul 2026 06:54
URI:	http://repository.its.ac.id/id/eprint/139068

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