Abstract: The phenomenon of mixed convection heat transfer through Al2O3-water nanofluid inside a horizontal ventilated enclosure is studied numerically. The obtained results demonstrate clearly the positive role of the nanoparticles addition on the improvement of the heat transfer rate and the mean temperature within the cavity. The flow structure and the temperature distribution within the cavity are seen to be very affected by the Reynolds number and the heating type. Also, it is shown that, in general, the decreasing heating mode is more favorable to the heat transfer while the cooling efficiency is found to be more pronounced by applying the increasing heating type.

Key words: Mixed convection, ventilated cavity, injection, nanofluid, varying heating.

 Abstract: In this work,we treat thethermal development problem, for apseudoplasticfluid in asinglepipe. A fully developed flow is supposed at the pipe inlet, with an imposedtemperature at the surface inthe case of aheating andcooling. In addition, the effect ofviscous dissipationis considered. Finite difference method with an implicit scheme is used to solve the energy equation. The main objectiveof the workisto provide results, enabling to well understandthe effect of viscous dissipationassociated with that ofrheological behavior. For this, different values oftheBrinkman(Br) number characterizing theheat generation byviscousfriction, and therheological index(n)have been taken in heating situation as well as cooling. It has been found that the fluid shear-thinning (n↓) significantly reduces the dissipative effect, by reducing the friction between the fluid layers.

Keywords:Forced convection; thermaldevelopment; pseudoplasticfluid; viscous dissipation.

 Abstract: Mixed convection within a rectangular cavity confining a Newtonian fluid is studied analytically and numerically in thecase where the horizontal walls, whose upper one is moving, are adiabatic, whereas those vertical are submitted to uniform density offlux. Numerical calculations are carried out for values of governing parameters within the ranges, 0.1 ? Ri ? 103 , 0.1 ? Re ? 10 ,0.1 ? Pr ? 50 and A = 20, where Ri is the Richardson number, Re is the Reynolds number, Pr is the Prandtl number and A is theaspect ratio. In such a situation, the obtained results testify of a strong influence of Pr on flow and heat transfer characteristics.Key words: Heat transfer; mixed convection; lid-driven rectangular cavity.

Keywords: Heat transfer; mixed convection; lid-driven rectangular cavity.

 Abstract: Over the years, all parts of a commercial refrigerator, such as the compressor, heat exchangers, refrigerant, and packaging,have been improved considerably due to the extensive research and development efforts carried out by academia and industry.However, the achieved and anticipated improvement in conventional refrigeration technology are incremental since this technology isalready nearing its fundamentals limit of energy efficiency is described is ‘magnetic refrigeration’ which is an evolving coolingtechnology. The word ‘green’ designates more than a colour. It is a way of life, one that is becoming more and more commonthroughout the world. An interesting topic on ‘sustainable technologies for a greener world’ details about what each technology isand how it achieves green goals. Recently, conventional chillers using absorption technology consume energy for hot water generatorbut absorption chillers carry no energy saving. With the aim of providing a single point solution for this dual purpose application, aproduct is launched but can provide simultaneous chilling and heating using its vapour absorption technology with 40% saving inheating energy. Using energy efficiency and managing customer energy use has become an integral and valuable exercise. Thereason for this is green technology helps to sustain life on earth. This not only applies to humans but to plants, animals and the rest ofthe ecosystem. Energy prices and consumption will always be on an upward trajectory. In fact, energy costs have steadily risen overlast decade and are expected to carry on doing so as consumption grows. Refrigerants such as hydrochloroflurocarbons (HCFCs) arepresent in the ground source heat pump (GSHP) systems and can pose a threat to the environment through being toxic, flammable orhaving a high global warming potential.

Key words: Absorption cycles, environment, heat pumps, refrigeration cycles, thermodynamic

 Abstract: This paper investigates the validation of an empirical method that estimates the hydrodynamic coefficients of streamlinedunderwater vehicles. These coefficients are non-dimensional parameter appearing in the equation of motion of the vehicle. Datcom(U.S, Air Force compilation code) is used to determine these coefficients in aquatic medium. The body configuration in this studyincludes axisymmetric body without wing tail or body tail. Results obtained with the Datcom are presented here and compared toexperimental results taken from a Planar Platform Mechanism mounted over a towing tank. A 6dof balance was used to extract themeasurements forces and moments acting on the derived vehicle. These measurements were carried out at typical speeds ofautonomous underwater vehicles (0.2-0.6 m / s) by varying the angles of inclination (0-15 degrees). This study was limited to theaxial forces which mean the coefficient of drag. Static hydrodynamic characteristics computed by Datcom method are shown to agreeclosely with experimental results for torpedo slender body of circular cross sectional.

Keywords: Underwater Vehicle, Hydrodynamic coefficients, Towing Tank, Datcom.