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No presente trabalho, efetuou-se uma revisão bibliográfica do existente acerca dos diferentes tipos de nanopartículas, aplicações e modelos matemáticos existentes para descrever as propriedades de nanofluidos. Realizou-se ainda a análise e enquadramento matemático da massa volúmica de nanofluidos de Al2O3 em H2O para diferentes concentrações volúmicas e para diferentes temperaturas. Contrário à maioria das propriedades dos nanofluidos, os modelos teóricos acerca da massa volúmica resumem-se na maioria da literatura ao modelo apresentado por Pak e Cho. A investigação existente apresenta o estudo da massa volúmica para muito baixas concentrações de nanopartículas, apresentando o modelo como eficiente na determinação da massa volúmica para os nanofluidos. Tal levou à revisão de tal modelo no presente trabalho, assim como a aplicação de possíveis ajustes a considerar, como o efeito da temperatura, fator maioritariamente desprezado no modelo prévio. Face à colaboração com o Núcleo de Biomateriais e Nanotecnologias do Centro de Inovação em Engenharia e Tecnologia Industrial (NBIN-CIETI) do Instituto Superior de Engenharia do Porto, que preparou experimentalmente os nanofluidos e forneceu os seus dados, para temperaturas entre 15 e 70 °C, e concentrações entre 0,01 e 2 % em fração volúmica, criou-se ainda uma aplicação para simulação do modelo de Pak e Cho, para análise em paralelo com dados experimentais. O objetivo desta é que se possa visualizar em tempo real o comportamento da massa volúmica em função da temperatura e a sua variação com diferentes concentrações de nanopartículas. Esta aplicação permite uma visualização gráfica do comportamento da massa volúmica do nanofluido enquanto se realiza o estudo do mesmo.
The present work showcases a bibliographic review of the existent content regarding the different types of nanoparticles, their applications and the existing mathematical models to express the properties of nanofluids. This paper also includes the analysis and mathematical adjustment of density on Al2O3 in H2O, based on different concentrations and temperatures. Contrary to most other nanofluids’ properties, density, so far, has mostly been described through Pak and Cho’s model. Existing research presents the study of the density for very low concentrations of nanoparticles, revealing the model as efficient in determining the density of nanofluids. Thus, a review of such model is present in this work, as well as the application of possible adjustments to consider, such as the effect of temperature, a factor mostly ignored in the previous model. From the collaboration with the Biomaterials and Nanotechnology Centre, part of the Centre of Innovation in Engineering and Industrial Technology (NBIN-CIETI) of the Superior Institute of Engineering of Porto, which experimentally prepared the nanofluids and provided their data, for temperatures between 15 and 70 °C, and concentrations between 0.01 and 2 % in volume fraction, an application was also created to simulate the Pak and Cho model, for analysis alongside experimental data. Its objective is to visualize in real time the behaviour of the density as a function of temperature and its variation with different concentrations of nanoparticles. This application allows a graphical visualization of the behaviour of the nanofluid's density while studying it.
The present work showcases a bibliographic review of the existent content regarding the different types of nanoparticles, their applications and the existing mathematical models to express the properties of nanofluids. This paper also includes the analysis and mathematical adjustment of density on Al2O3 in H2O, based on different concentrations and temperatures. Contrary to most other nanofluids’ properties, density, so far, has mostly been described through Pak and Cho’s model. Existing research presents the study of the density for very low concentrations of nanoparticles, revealing the model as efficient in determining the density of nanofluids. Thus, a review of such model is present in this work, as well as the application of possible adjustments to consider, such as the effect of temperature, a factor mostly ignored in the previous model. From the collaboration with the Biomaterials and Nanotechnology Centre, part of the Centre of Innovation in Engineering and Industrial Technology (NBIN-CIETI) of the Superior Institute of Engineering of Porto, which experimentally prepared the nanofluids and provided their data, for temperatures between 15 and 70 °C, and concentrations between 0.01 and 2 % in volume fraction, an application was also created to simulate the Pak and Cho model, for analysis alongside experimental data. Its objective is to visualize in real time the behaviour of the density as a function of temperature and its variation with different concentrations of nanoparticles. This application allows a graphical visualization of the behaviour of the nanofluid's density while studying it.
Description
Keywords
Nanofluidos Nanopartículas Massa volúmica Temperatura Fração volúmica COMSOL Nanofluids Nanoparticles Density Temperature Concentration