Thesis (Ph.D.) University of Adelaide, Dept of Mining, Metallurgical and Chemical Engineering, 1959. / Typewritten.

Thesis (M.S.)--Ohio University, August, 1990. / Title from PDF t.p.

Thesis (M.S.)--Rochester Institute of Technology, 1981. / Typescript. Includes bibliographical references (leaves 53-54).

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Made available in DSpace on 2014-10-09T12:24:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:16Z (GMT). No. of bitstreams: 1 00287.pdf: 1122753 bytes, checksum: a978ff8816ae53f9979ce18a70a88cb2 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Orientador: Marcelo Moreira Ganzarolli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-20T13:22:43Z (GMT). No. of bitstreams: 1 Simoes_RobertoMac-Intyer_M.pdf: 2139090 bytes, checksum: 0d40eb0587d86506df37c76ba2e02031 (MD5) Previous issue date: 2011 / Resumo: Realizou-se uma análise experimental para estudar a transferência de calor conjugada convecção natural-condução em um canal vertical de placas paralelas contendo aquecedores bidimensionais protuberantes discretos distribuídos uniformemente sobre a superfície de uma das placas (substrato condutivo). O objetivo é prever a distribuição de sobretemperatura local nos elementos protuberantes em um aquecimento não uniforme, baseada nas medições dos elementos da matriz da função de Green discreta inversa, chamados de coeficientes de influência conjugados. O método de superposição linear foi utilizado sob a condição de que o efeito do empuxo local é insignificante comparado com o escoamento global induzido ao longo do canal. O canal é composto de uma placa de epóxi de 0,0016 m de espessura, com sete fontes de calor protuberantes de alumínio polido montadas em sua superfície, e uma placa adiabática lisa na parede oposta. O canal tem 0,365 m de altura e 0,340 m de largura. Na análise experimental, os espaçamentos entre as paredes do canal utilizados foram b=20mm e b=30mm. A máxima potência global imposta no canal foi 70W. Os coeficientes de influência conjugados foram determinados a partir dos perfis de sobretemperaturas obtidos a partir de experimentos de aquecimento uniforme e experimentos com um elemento desligado. Esses coeficientes, em diferentes níveis de potência, foram utilizados para comparar os perfis de sobretemperatura experimentais e os perfis preditos pelo método da função de Green discreta inversa. A aplicação desta metodologia para o problema de transferência de calor conjugado por convecção naturalcondução fornece uma predição razoável da distribuição de sobretemperatura para uma dissipação de potência arbitrária nos elementos protuberantes / Abstract: An experimental analysis was performed to study conjugate natural convection-conduction heat transfer in a vertical parallel plate channel containing discrete and protruding twodimensional heaters distributed uniformly on the surface of one of the plates (conductive substrate). The objective is to predict the local overtemperature distribution in the protruding elements by nonuniform heating, based on measurements of the inverse discrete Green's function matrix elements, called conjugate influence coefficients. The linear superposition method was used, assuming the condition of negligible local buoyancy effect compared to the global flow induced throughout the channel. The channel is composed of an epoxy plate 0.0016 m thick, with seven protruding heat sources of polished aluminum mounted on its surface, and an adiabatic smooth plate on the opposite wall. The channel is 0.365 m long and 0.34 m wide, with channel wall to wall spacing of 0.02 m. In the experimental analysis, the spacing between the channel walls utilized was b=0.020m and b=30mm. The maximum global power imposed on the channel was 70W. The conjugate influence coefficients were determined from the overtemperatures profiles obtained from the uniform heating experiments and the no-power experiments. These coefficients, at different power levels, were utilized to compare the experimental overtemperature profiles and the overtemperature profiles predited by the inverse discrete Green's function method. The application of this methodology for the conjugate natural convection-conduction heat transfer problem provided a reasonable prediction of overtemperature distribution for arbitrary power dissipation in the protruding elements / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

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Includes bibliographical references. / This thesis is concerned with the numerical modelling of the transient nonlinear heat conduction problem in solid continua. The hyperbolic governing equation is specialised to a parabolic equation which is sufficient for most engineering applications. The theoretical development includes the effects of conduction, specific heat, internal heat generation and the boundary conditions of convection, radiation, specified temperatures and flux, as well as point sources in the domain. The finite element spatial semidiscretisation of the equations is formally derived from the weak form of the governing equations. Temporal discretisation is obtained through an implicit/explicit difference scheme. The material properties are allowed to be temperature dependent, and consequently a modified Newton-Raphson iterative scheme is employed to solve the equations. The fully discretised equations are solved by implementing the algorithm in an existing finite element stress analysis code. Modelling is possible using four or eight-noded isoparametric elements, and solution control is possible through choice of time step size and choice of time integration method. Five examples are employed to demonstrate the ability of the program. The results compare well with published analytical solutions.

No description available.

Detailed heat transfer coefficient distributions have been obtained for narrow converging and diverging channels with and without enhancement features. The enhancement feature considered for this study is dimples (inline and staggered) on the main heat transfer surfaces. All the measurements are presented at Reynolds numbers of 3500, 8900, 18000, and 7000, 14000, 28000 for converging and diverging channels respectively. Pressure drop measurements for the overall channel are also presented to evaluate the heat transfer enhancement geometry with respect to pumping power requirements. The test models were studied for wall heat transfer coefficient measurements using the transient liquid crystal technique. The modeled wall inner surfaces were sprayed with thermochromic liquid crystals, and a transient test was used to obtain the local heat transfer coefficients from the measured color change. Analysis of results shows that dimples, in general, have very good enhancement capabilities and staggered dimpled surfaces provide considerably higher heat transfer coefficients and a reasonable pressure drop compared to inline dimpled configuration. Additionally, this study was extended to understand the effect of strategic placement of dimples (staggered) at various locations along the channel to understand regions that contribute significantly to the overall enhancement. / Master of Science