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Made available in DSpace on 2014-10-09T12:43:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:23Z (GMT). No. of bitstreams: 1 06171.pdf: 4113918 bytes, checksum: f80c43f20a8b10129dced614d40007ba (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:53:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:27Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:49:42Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:16Z (GMT). No. of bitstreams: 1 09834.pdf: 11774838 bytes, checksum: 940cf578592bd4491d6495c63535f0a7 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:43:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:23Z (GMT). No. of bitstreams: 1 06171.pdf: 4113918 bytes, checksum: f80c43f20a8b10129dced614d40007ba (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:53:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:27Z (GMT). No. of bitstreams: 0 / A pesquisa e o desenvolvimento de sistemas passivos de resfriamento de emergência são necessários para os sistemas termo-nucleares de nova geração. Algumas informações fundamentais sobre a operação desses sistemas requerem a pesquisa de alguns processos relativos à circulação natural, principalmente em condições de escoamento bifásico envolvendo processos de condensação na presença não-condensáveis, pois muitas situações encontradas são novas. A bancada experimental de circulação natural (BCN) foi utilizada para a realização de testes com diversas concentrações de não-condensáveis e níveis de potência. O não-condensável presente no circuito diminui a taxa de transferência de calor para o secundário do trocador de calor, causando baixo desempenho do trocador de calor. A presença de altas concentrações de não-condensáveis no trocador de calor propicia elevadas variações de pressão, decorrentes do processo de condensação abrupto, determinando a inversão da vazão e de fortes vibrações e esforços nas tubulações do circuito. A concentração inicial de não-condensável e a geometria do circuito, na entrada do trocador de calor, determinam o estabelecimento de transitórios com escoamento bifásico. A BCN foi modelada com o código computacional de Análise de Acidentes e Termo-Hidráulica RELAP5/MOD3.3 e, os valores calculados foram comparados com os dados experimentais, apresentando boa concordância para menores concentrações de ar. Os valores calculados para maiores concentrações de não-condensável foram satisfatórios após o circuito ter atingido a temperatura de saturação no aquecedor elétrico. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:54:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:26Z (GMT). No. of bitstreams: 1 12431.pdf: 23287148 bytes, checksum: ca5f3b291fb81099ce731e9a131ce645 (MD5) / Tese (Doutoramento) / IPEN/T / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Made available in DSpace on 2014-10-09T12:54:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:26Z (GMT). No. of bitstreams: 1 12431.pdf: 23287148 bytes, checksum: ca5f3b291fb81099ce731e9a131ce645 (MD5) / Tese (Doutoramento) / IPEN/T / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

A state-of-art research facility has been built at the University of Ottawa, which is suitable for thermalhydraulic experiments in support of the development of the Canadian Supercritical-Water-Cooled Reactor (SCWR). The facility is a recirculating flow loop, using carbon dioxide as a medium and having three different test sections, two tubes with inner diameters of 8 and 22 mm, respectively, and a three-rod bundle. The loop can operate within ranges of pressure, temperature, heat flux and mass flux, which are of interest to the current SCWR design. The present thesis includes a comprehensive description of the facility. It also documents the procedure and results of its commissioning, as well as some preliminary measurements that have been collected so far. It is intended to provide an insight to the design of the facility and its functionality and to serve as a reference for future research activities. A number of tests performed by previous researchers in other facilities were replicated and nearly identical results were obtained. It was demonstrated that the design of the facility is sound and its performance is adequate within the intended ranges of operation conditions. It is expected that the results obtained in this facility will make a significant contribution to the understanding of supercritical heat transfer and pressure losses in the SCWR context.

Made available in DSpace on 2014-10-09T12:55:30Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:16Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP