Mécanique des fluides : accès libre

The authors investigate thermal performance of pure water, nanofluid, ammonia and methanol on the warmth pipe with 18 cm long and 0.01m in diameter during this paper, approximately. The typical difference between temperature profile of ethanol and methanol is about 36.4% during this case. The three polynomials with second order are defined during this study. The fluid passes through the warmth pipe, experimentally. The curve fitting and regression of the experimental correlations show the accuracy of three curves are proper then the predictions of temperature profile within the external zones are feasible.

The design of water system systems is taken into account a combinatorial optimization task during which the diameter of every one among the pipes are often considered as a choice variable. The matter is to work out a group of diameters in order that the value function is minimized (depending on the length, diameter and material of the pipes) subject to hydraulic and commercial constraints. However, the chosen set of diameters will have a big influence on the energy losses thanks to the hydraulic balance of the system. Therefore, it's necessary to use techniques that allow finding solutions that are viable under multiple criteria. Within the present work the incorporation of the human think about the decision-making process during the multi-objective optimization of the planning of the water system system is shown. The event of algorithms, products of the sensible experience and implementation in CAD systems, influences the decrease of the search universe within the optimization as measured using the notation Big-O. Benefits provided by the CAD System to assist the designer are presented. The paper ends with conclusion and recommendation of future works.

In this study, experiments are designed to research the consequences of ultrasonic flowers of zinc nanoparticles on the properties of petroleum flow. The rheological and thermal properties of the petroleum containing nanoparticles were investigated in vitro. The nanoparticles were prepared by ultrasonic method in petroleum . Experiments were administered during a hot tube for plain oil and nanoparticles containing flowers of zinc. The effect of temperature changes, addition of nanoparticles and tube length on the values of friction coefficient, velocity, conductivity coefficient, overall heat transfer coefficient, thermal diffusion coefficient and kinematic viscosity were investigated. For nano oil (containing 1wt.% Zinc oxide) Reynolds number decreased to 0.99 initial value, Prandtl number decreased to 0.951 initial value, Peclet number increased to 0.94 initial value.

Mixed convection flow during a tubular enclosure crammed with nanofluid within the presence of a magnetic flux is numerically investigated within the present study. Rock bottom and top curved wall of the enclosure are respectively kept isothermally hot and funky while the remaining walls are insulated. The governing equations are formulated supported Boussinesq assumptions and solved with finite element method. The computation is administered for mixed convection regime and also natural convection regime with fixed values of remaining parameters. An in depth parametric discussion is presented for the physical properties of flow and temperature distributions in terms of streamlines, isotherms, average heat transfer rate within the flow domain. The results show that the flow and temperature fields suffering from varying of pertinent parameters. Moreover, heat transfer rate is increased by 139.50% with the rise in Richardson number from 0.1 to 100. The increasing rate of warmth transfer thanks to Ri is respectively decreased by 58.11% with varying of Ha from 0 to 60 and increased by 23.97% with the addition of nanoparticles up to three. Comparison is performed against the previously published results on the idea of special cases and located to be in excellent agreement.

Nano fluids are dispersions of high thermal conductivity nano particles during a base fluid, and offer potential to enhance thermal conductivity of it. Literature data on the effect of particle size on the thermal conductivity enhancement of nano fluids are inconsistent and limited. Hence within the present study, the effect of particle size on thermal conductivity enhancement of distilled water- Al₂O₃ nano fluid has been investigated experimentally using transient hot wire apparatus. The particle volume concentration of Al₂O₃ nano particles for mean diameter of 15 nm and 60 nm are varied between 0.1 and 3%. The enhancement within the thermal conductivity is approximately 22% and 17% for 15 nm and 60 nm particle size respectively, at 3% particle volume concentration at 30οC. These experimental results are according to the predictions from the Brownian movement based model, show that the enhancement within the thermal conductivity of the distilled water- Al₂O₃ nano fluid decreases with a rise within the particle size.