MATHEMATICAL MODELS FOR COMPUTING EFFECTIVE VISCOSITY AND ITS APPLICATION IN THE DESIGN AND EVALUATION OF NETWORKS PIPES

Abstract

At the present time, the effective viscosity (µe) is an important parameter in the technological calculations related with the transport of no-Newtonians fluids. To obtain mathematical Models it was necessary to organize the information reported in different papers that try on the topic. This information was transformed with the objective of studying the dependence of the effective viscosity with the temperature, the concentration and the gradient of speed in pipes, for different foods and
molasses of sugar Industry. The mathematical models were obtained by STATGRAPHICS. For guava pulps the models was
obtained for a range of concentrations among 6 and 17,6 % of solids, and temperatures between 10 and 25 oC. In Molasses were studied concentrations between 73 and 78 % of solids, for a temperature of 40 oC, for tomato pulps the concentrations were between 4,3 and 19,7 % of solids with a temperature of 25 oC. The lowest value of multiple correlation coefficients was 98,77 and the estimate standard error presents the first significant figure in the hundredth. The validation of these models was made through hypothesis tests, using information obtained in the laboratory. These models were introduced in software to carry out calculations related with the evaluation and
the design of systems of pipes–pumps. This software was applied in the industry with satisfactory results.