Studi Numerik Pengaruh Variasi Volume Phase Change Material (PCM) terhadap Proses Absorpsi dan Respons Termo-Mekanik pada Metal Hydride (MH) Prismatic Storage

Musyarofah, Musyarofah (2026) Studi Numerik Pengaruh Variasi Volume Phase Change Material (PCM) terhadap Proses Absorpsi dan Respons Termo-Mekanik pada Metal Hydride (MH) Prismatic Storage. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penyimpanan hidrogen berbasis Metal Hydride (MH) LaNi5 menjadi salah satu metode yang menjanjikan karena memiliki densitas penyimpanan volumetrik tinggi, tekanan operasi relatif rendah, dan tingkat keamanan yang lebih baik dibandingkan metode konvensional. Konfigurasi reaktor prismatik menawarkan fleksibilitas desain dan integrasi modular pada sistem penyimpanan hidrogen. Namun, proses absorpsi hidrogen LaNi5 bersifat eksotermik sehingga menghasilkan kalor reaksi yang dapat meningkatkan temperatur MH bed. Selain fenomena termal, pembentukan fasa hidrida LaNi5H6 selama proses hidrogenasi menyebabkan hydrogen-induced swelling yang mengubah karakteristik internal MH bed. Penelitian sebelumnya banyak mengembangkan integrasi Phase Change Material (PCM) untuk meningkatkan manajemen termal dan kinetika absorpsi. Namun, pengaruh variasi volume PCM terhadap evolusi sifat MH bed dan respons termo-mekanik reaktor prismatik masih belum dikaji secara terintegrasi.
Pada penelitian ini dikembangkan model numerik tiga dimensi berbasis kopling CFD-FEM untuk menganalisis pengaruh variasi volume PCM terhadap karakteristik termal, kinetika absorpsi hidrogen, evolusi sifat MH bed, dan respons termo-mekanik pada reaktor penyimpanan hidrogen prismatik. Hasil simulasi menunjukkan bahwa peningkatan ketebalan PCM menghasilkan pengendalian temperatur yang lebih efektif, dengan temperatur akhir MH bed pada variasi ketebalan terbesar mencapai 309,63 K. Peningkatan ketebalan PCM juga mempercepat absorpsi hidrogen, ditunjukkan oleh waktu pencapaian fraksi reaksi X = 0,95 yang berkurang sebesar 13,13% dibandingkan variasi ketebalan terendah. Pemodelan porositas dinamis menghasilkan temperatur rata-rata MH bed 6,17% lebih rendah dan fraksi reaksi 28,21% lebih tinggi dibandingkan model dengan porositas konstan pada akhir simulasi. Dari sisi mekanik, equivalent von Mises stress meningkat tajam pada tahap awal absorpsi dan kemudian menurun seiring perubahan kondisi termal reaktor, dengan nilai tegangan akhir masing-masing variasi berada pada 49,45-62,24 MPa. Hasil tersebut menunjukkan bahwa integrasi PCM dan pemodelan evolusi porositas akibat hydrogen-induced swelling berperan dalam menentukan karakteristik termal, kinetikan absorpsi, dan respons termo-mekanik reaktor MH prismatik.
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LaNi5 Metal Hydride (MH)-based hydrogen storage is a promising method because it offers high volumetric storage density, relatively low operating pressure, and greater safety compared to conventional methods. A prismatic reactor configuration offers design flexibility and modular integration in hydrogen storage systems. However, the hydrogen absorption process in LaNi5 is exothermic, generating reaction heat that can increase the temperature of the MH bed. In addition to thermal effects, the formation of the LaNi5H6 hydride phase during hydrogenation induces hydrogen-induced swelling, altering the internal characteristics of the MH bed. Previous research has extensively explored the integration of Phase Change Materials (PCM) to improve thermal management and absorption kinetics. However, the impact of PCM volume variations on the evolution of MH bed properties and the thermomechanical response of the prismatic reactor has not yet been comprehensively studied. In this study, a three-dimensional numerical model based on CFD-FEM coupling was developed to analyze the effects of PCM volume variations on thermal characteristics, hydrogen absorption kinetics, the evolution of MH bed properties, and the thermomechanical response in a prismatic hydrogen storage reactor. Simulation results show that an increase in PCM thickness results in more effective temperature control, with the final MH bed temperature at the greatest thickness variation reaching 309.63 K. Increasing the PCM thickness also accelerates hydrogen absorption, as indicated by the time to reach a reaction fraction of X = 0.95, which was reduced by 13.13% compared to the thinnest thickness variation. Dynamic porosity modeling resulted in an MH bed average temperature that was 6.17% lower and a reaction fraction that was 28.21% higher compared to the model with constant porosity at the end of the simulation. From a mechanical perspective, the equivalent von Mises stress increased sharply in the early stages of absorption and then decreased as the reactor’s thermal conditions changed, with the final stress values for each variation ranging from 49.45 to 62.24 MPa. These results indicate that the integration of PCM and the modeling of porosity evolution due to hydrogen-induced swelling play a role in determining the thermal characteristics, absorption kinetics, and thermomechanical response of the prismatic MH reactor.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Coupled CFD – FEM, Hydrogen-Induced Swelling, Metal Hydride LaNi5, Phase Change Material (PCM), Respons Termo – Mekanik Coupled CFD – FEM, Hydroge-Induced Swelling, Metal Hydride LaNi5, Phase Change Material (PCM), Thermo – Mechanical Response
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ165 Energy storage. T Technology > TJ Mechanical engineering and machinery > TJ265.E23 Thermodynamics.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Musyarofah Musyarofah
Date Deposited:	05 Aug 2026 03:48
Last Modified:	05 Aug 2026 03:48
URI:	http://repository.its.ac.id/id/eprint/143905

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