PHOTOTHERMAL TECHNIQUE FOR MEASURING THERMAL CONDUCTIVITY AND DIFFUSIVITY OF NANOFLUIDS: A NEW APPROACH
Journal Title: Periódico Tchê Química - Year 2018, Vol 15, Issue 29
Abstract
Nanofluids have become nowadays of special importance because of their different uses in industry, therefore, to propose methods to calculate their thermal properties would be useful. In this work, a new variant for the calculation of thermal conductivity and diffusivity of nanofluids is proposed; the possibilities and limitations of this non-stationary method, which uses light radiation as the heat source, are studied. Here, the light is homogenously incident on one of the end surfaces of a cylinder that has a thermally insulated side surface, setting the temperature at the other end to a constant value, then the temperature distribution is obtained as a function of the coordinate and time; adjusting the theoretical model, parabolic heat diffusion equation, to the experimental data obtained. The conditions of validity of the method to measure thermal diffusivity and thermal conductivity of fluids are analyzed; as well as, the way in which it could be used to verify the validity of the Hamilton and Crosser (HC) model in the case of nanofluids. Currently, nanofluids are used to exchange heat, as they have been found to exceed the potential of conventional refrigerants; however, the calculation of thermal properties still does not offer definitive values.
EVALUATION OF THE QUALITY OF MANANTIAL WATER SUPPLYING THE CITY OF SALVADOR (BA)
Since 2011, the Centro de Pesquisas e Desenvolvimento - CEPED performs sampling and analysis activities of the waters of the springs that supply the city of Salvador to assess the Water Quality Index (WQI). The WQI is an...
SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE 1:1 PROTON TRANSFER SALT OF MALONIC ACID WITH P-CHLOROANILINE
The design of multicomponent crystals offers a means to modify the physicochemical properties of crystals without altering the chemical properties of a particular molecule. In this study, a multicomponent crystal, the sa...
SURFACE ROUGHNESS ASSESSMENT BASED ON DISCRETE MODEL REPRESENTATION FOR ADDITIVE MANUFACTURED PARTS
With any method of manufacturing parts of their surface cannot be completely smooth, perfect. There are always more or less pronounced irregularities of various shapes and heights — traces of the casting mold, sizing rol...
THE MOST EFFICIENT CORROSION INHIBITORS FOR ALUMINUM ANODE OF ELECTROCHEMICAL CELL USED AS A CONTROLLED HYDROGEN GENERATOR
In this article the authors have presented the results of the research into the development of the most efficient anode-electrolyte combination for a hydronic electrochemical cell fitted with an aluminum anode, designed...
MINIMIZING MISCONCEPTION OF IONIZATION ENERGY THROUGH THREE-TIER DIAGNOSTIC TEST
Research about conception and misconception of specific topics in science education is still sightseen among researchers. Ionization energy is one concept that possible generate mis(understanding) for students. Therefore...