Tan, Wan Ching (2018) Analysis And Performance Study Of Point-Absorber Wave Energy Converters Using Flow-3D_. Masters thesis, Universiti Sains Malaysia.
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Abstract
Tenaga ombak telah menjadi salah satu sumber tenaga yang paling berpotensi dan dengan itu ia telah menarik perhatian pihak kerajaan dan syarikat-syarikat tenaga. Dalam usaha untuk memenuhi permintaan tenaga global yang semakin meningkat, penciptaan alat mengekstrak tenaga bagi generasi akan datang perlu lebih cekap dari segi kos operasi yang lebih rendah dan kelasakan juga perlu diambil kira bagi alat penukar tenaga di luar laut. Oleh itu, reka bentuk awal alat penukar tenaga adalah sangat penting bagi ramalan sifat hidrodinamik. Dalam kajian ini, interaksi struktur ombak dengan alat mengekstrak tenaga dikaji dengan menggunakan Flow-3D. Analisis pengiraan dinamik bendalir (CFD) berdasarkan persamaan Reynolds Purata Navier Stokes (RANS) digunakan untuk mengkaji interaksi antara ombak dan struktur, dan kesan lokasi antara alat. Kaedah berangka dengan kos pengiraan yang munasabah boleh menjadi satu alternatif kepada ujian eksperimen fizikal dalam bidang kejuruteraan luar laut. Latar belakang kajian ini diperkenalkan, termasuk kaedah yang digunakan dalam kajian ini, diikuti oleh kajian kes untuk menunjukkan kesesuaian model berangka. Ini termasuk pegesahan penjanaan ombak dan ramalan prestasi “point-absorber”. Ia telah menunjukkan bahawa model berangka mampu perambatan gelombang pemodelan dan interaksi dengan struktur termasuk kesan tidak linear dengan tahap ketepatan yang munasabah. Penukar tenaga “point-absorber” telah dipilih sebagai objek dalam kajian ini. Pendekatan RANS dalam domain masa meningkatkan ketepatan apabila berbanding dengan potensi berasakan kaedah teori. Pengaruh penukar “point-absorber” terhadap prestasi mereka kemudiannya disiasat di bawah keadaan ombak yang tidak sekata dalam usaha untuk meningkatkan prestasi keseluruhan. Kajian ini menghasilkan pemahaman yang lebih baik terhadap masalah struktur ombak dan telah melanjutkan pelbagai model RANS digunakan dalam penyelidikan tenaga ombak. Keputusan menunjukkan bahawa keadaan fasa optimum boya boleh diperolehi dengan melaraskan ketumpatan dan diameter “point-absorber”. Kajian mendapati bahawa boya “point-absorber” dengan ketumpatan 100kg/m3 dan 0.2m diameter adalah saiz optima bagi keadaan yang ditentukan dalam kajian ini dengan menghasilkan kuasa sebanyak 126.49N. _______________________________________________________________________________________________________ Wave energy has become one of the most promising energy resources and hence has attracted more attention from the governments and energy companies. In order to meet the growing demands on global energy, the next generation of energy extracting devices need to be more efficient with less operation cost, and as an offshore structure, the survivability also needs to be taken into consideration. Therefore, it is vital that the hydrodynamic behaviour of the energy device can be predicted accurately at the initial design stage. In this research, the wave structure interaction with application to wave energy device is studied numerically using Flow-3D. The computational fluid dynamic (CFD) analysis based on the Reynolds Average Navier Stokes (RANS) equations is used to investigate the interaction between wave and structure, and array effects among devices. The numerical method with a reasonable computational cost can be an alternative to physical experimental test in offshore engineering. The background to this research is firstly introduced, including methodologies adopted in this study, followed by a series of case study to demonstrate the applicability of the numerical model. These include wave generation validation and the predication of the performance of wave point absorber. It has been shown that the numerical model is capable of modelling wave propagation and interaction with structure including nonlinear effect with a reasonable degree of accuracy. The wave point absorber energy device has been chosen as the object to study. The RANS approach in time domain improves the accuracy when compared with the potential theory based method. The influence of wave point absorber devices array on their performance is then investigated under the irregular wave conditions in order to improve the overall performance. The study yields an improved understanding of wave-structure problem and has extended the range of RANS model used in wave energy research. Results show that optimum phase condition of buoys can be obtained by adjusting the mass density and diameter. Studies found that cylinder buoy of mass density of 100kg/m3 with 0.2m diameter is the optimal size for the condition set in this research with the produced maximum force of 136.49N.
| Item Type: | Thesis (Masters) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4705 |
| Subjects: | T Technology T Technology > TJ Mechanical engineering and machinery > TJ181-210 Mechanical movements |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Mekanikal (School of Mechanical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 13 Jun 2019 09:47 |
| Last Modified: | 13 Jun 2019 09:47 |
| URI: | http://eprints.usm.my/id/eprint/44602 |
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