Numerical investigation of heat transfer over a backward facing step (BFS), using nanofluids is presented. Different volume fractions of nanoparticles are presented in the base fluid besides different type of nanoparticles have been used. The finite volume technique is used to solve the momentum and energy equations. The distribution of Nusselt number at the top and the bottom walls of the BFS ...

The attention of the present paper is focused on the intensive heat removal with arrays of impinging jets. Three jet configurations are tested which involve variation of geometric parameters such as nozzle shape, diameter and nozzle-tonozzle spacing and impingement distance and of flow rate. The convective heat transfer coefficient is measured with infrared thermography applied to the heatedthi...

We report experimental results for the heat transport, as expressed by the Nusselt number Nu, by turbulent Rayleigh-Bénard convection in a cylindrical sample of aspect ratio Γ ≡ D/L = 0.50 (D = 1.12 m is the diameter and L = 2.24 m the height). The measurements are for the Rayleigh-number range 10 <∼ Ra <∼ 10 15 and for a Prandtl number Pr ' 0.86. At these large Ra the results were exceptionall...

We report Nusselt number measurements from high Prandtl number turbulent thermal convection experiments. The experiments are conducted in four fluids with the Prandtl number Pr varying from 4 to 1350 and the Rayleigh number Ra from 2x10(7) to 3x10(10), all in a single convection cell of unity aspect ratio. We find that the measured Nusselt number decreased about 20% over the range of Pr spanned...

Graetz and Nusselt studied heat transfer between a developed laminar fluid flow and a tube at constant wall temperature. Here, we extend the Graetz–Nusselt problem to dense fluid flows with partial wall slip. Its limits correspond to the classical problems for no-slip and no-shear flow. The amount of heat transfer is expressed by the local Nusselt number Nux, which is defined as the ratio of co...

The effect of inclination angle on the steady laminar free convection in a rectangular enclosure (aspect ratio = 5), which is discretely heated by an isoflux flush mounted small heater (L / H = 0.125) is studied numerically. The local and average Nusselt numbers are compared at inclination angles from 0 (bottom heating) to 180o (top heating), for modified Rayleigh numbers 102 ≤ Ra* ≤ 106. The t...

in this paper, natural convection heat transfer over a vertical plate in a darcy porous medium saturated with a nanofluid subject to heat generation/absorption was theoretically studied. the governing partial differential equations were transformed to a set of ordinary differential equations using similarity transformations and solved using finite difference method. the influence of parametric ...

entry region of a rectangular microchannel is investigated. The wall heat flux is peripherally constant and varies exponentially with respect to the axis of the microchannel. The flow is assumed to be hydrodynamically fully developed. The three-dimensional energy conservation equation is solved numerically for different aspect ratios. Surface interaction parameters consist of momentum accommoda...

in the present study the effect of curvature ratio and coil pitch for tio2/water nanofluid laminar flow on heat transfer behavior and pressure drop through helical coils with different geometries was investigated experimentally. the tio2/water nanofluids at 0.25% to 2% particle volume concentrations have been prepared by using a two-step method. the experiments were performed for coils with cur...