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Heat transfer and flow characteristics of nanofluid in a narrow annulus: Numerical study, modelling and optimisation
Author(s) -
Bahiraei Mehdi,
Hosseinalipour Seyed Mostafa,
Hangi Morteza
Publication year - 2014
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.21853
Subject(s) - heat transfer coefficient , annulus (botany) , heat flux , nanofluid , heat transfer , materials science , thermodynamics , convective heat transfer , volume fraction , mechanics , convection , churchill–bernstein equation , reynolds number , nusselt number , physics , composite material , turbulence
Abstract This study attempts to evaluate the flow and heat transfer characteristics of water–Al 2 O 3 nanofluid in a narrow annulus. The effects of volume fraction, the size of particles and the ratio of inner wall heat flux to outer wall heat flux were investigated on the convective heat transfer coefficients and friction coefficients at inner and outer walls of the annulus. Using smaller particles caused a greater heat transfer coefficient. Meanwhile, at higher volume fractions, changing the size of particles led to more considerable changes in the convective heat transfer coefficient and friction coefficient. As per the observation made, the value of heat transfer coefficient at the inner wall was larger than that of the outer wall. In contrast with the results of applying constant properties, changing the volume fraction will change the friction coefficient in the case of using variable properties. Moreover, genetic algorithm was used in combination with compromise programming in order to find the optimum values of the input parameters using neural network correlation.