Effects of Joule Heating on Magnetic Field Inside a Channel Along with a Cavity

AbstractA computational solution has been made to obtain flow and temperature field inside a channel with a cavity under magnetic field and joule effect. The left side of the cavity is shorter than right side. Mixed convection heat transfer is studied. Finite element method is used to solve governing equations of laminar flow. The study investigates the effects of three parameters such as Hartmann number, joule parameter and Prandtl numbers for pure mixed convection (Ri = 1). For the specified conditions streamline contours and isotherm contours are obtained and later on the variation of overall Nusselt number and exit temperature are obtained for the aforementioned parameters. It is found that the aforesaid parameters are extremely effective parameter on flow field and temperature distribution. It is also found that both Hartmann number and joule parameter play important role to control the mode of heat transfer

NATURAL CONVECTION IN A CAVITY WITH A BLOCK MOUNTED ON IT

Düşey duvarına blok monte edilmiş oyuk içerisinde, bloğun yeri ve boyutunun doğal taşınım üzerindeki etkisi sayısal olarak incelenmiştir. Bloklar tamamen yalıtımlı ve blok yerleştirilmiş düşey duvarın diğer duvara göre daha sıcak olduğu kabul edilmiştir. Problem için zamana bağlı olmayan çözümler elde edilmiştir. Hesaplamalar Rayleigh sayısının 104<Ra<106 değerleri için yapılmıştır. Düşey duvara yerleştirilen bloğun doğal taşınım akış hareketi ve ısı transferini büyük ölçüde etkilediği tespit edilmiştir. In this study natural convection in a cavity with a block mounted on a vertical wall was investigated numerically. The effects of the placement and, the dimensions of block on natural convection were studied. The block mounted vertical wall was warmer than the outer vertical wall and block itself was insulated perfectly. A SIMPLEM algorithm was used based on finite control volume approach for calculations. Calculations were performed in the range of 103<Ra<105. It was found that the block mounted on the wall have significant effect on natural convection heat transfer and flow field

Mixed Convection of Hybrid Nanofluids in an Annulus

&nbsp;In this study, mixed convection in an annulus formed by two horizontal isothermal cylinder surfaces and filled with hybrid nanofluids was examined with Galerkin weighted residual finite element method. The outer cylinder is rotating and inner cylinder is stationary. Influence of Rayleigh number, angular rotational speed of the outer cylinder, eccentricity of the inner cylinder, solid volume fractions of different nanoparticles (alumina, copper, hybrid particles between 0 and 0.02) on the fluid flow and heat transfer characteristics were analyzed. It was observed that average heat transfer enhances with Rayleigh number, solid volume fractions of nanoparticles and eccentricity ratio and reduces as the angular rotational speed of the outer cylinder increases. Adding nanoparticles was found to be advantageous for lower values of Rayleigh number and higher values of angular rotational speed. At the highest volume fraction of Cu nanoparticles, average Nusselt number increases by 31.75 % when the inner cylinder center moves in +y direction. Nanofluid with hybrid nanoparticles gives heat transfer rates which are higher than that of with alumina and lower than that of with copper nanoparticles for the same volume fraction

MHD thermogravitational convection and thermal radiation of a micropolar nanoliquid in a porous chamber

This work studies the thermogravitational transmission and thermal radiation of micropolar nanoliquid within

Analysis of thermal mixing in circle shaped body inserted inclined channel

In this study, thermal mixing (TM) phenomena in a rectangle channel with adiabatic circle shaped body are investigated experimentally. Two parallel jets in different temperatures are located in the channel which has a circular exit hole to supply continuity of mass. Experiments are carried out for different inclination angle of the channel. Also, effects of ratio of flow rate, jets diameters, and temperature difference between hot and cold jets were analyzed. A circle shaped passive element with low thermal conductivity is located into channel to control thermal mixing. Thermal mixing index is calculated from measured temperatures. Experimental results showed that thermal mixing of fluid is effected from geometric parameters, drastically. It is found that TM is function of the temperature difference of inlet jets

An analysis on Free Convection Cooling of a 3×3 Heater Array in Rectangular Enclosure using Cu-EG-Water Nanofluid

This paper deals with the study of natural convection cooling of a discrete heater array in Cu-EG-water nanofluid filled rectangular enclosure. A 3 × 3 array of non-protruding heat sources is embedded on one of the vertical walls of the enclosure while the top horizontal and opposite vertical walls are assumed to be isothermally cold. The remaining portions in which the heaters are mounted and all other walls are insulated. The above setup is modeled into a system of partial differential equations which are solved numerically using finite volume method based on the Semi-Implicit Method for Pressure Linked Equation (SIMPLE) algorithm and power law scheme. The wide range of parameters for computation are the aspect ratio of the enclosure, the mixture proportion of Ethylene glycol-water, the solid volume fraction of the nanoparticle along with two different thermal conductivity models. It is observed that the proper choice of the computation parameters and thermal conductivity models could be able to maximize the heat transfer rate from the heater array. Also, the results obtained in this study will provide new guidelines in the field of electronic equipment cooling

Excitations of optically driven atomic condensate in a cavity: theory of photodetection measurements

Recent experiments have demonstrated an open system realization of the Dicke quantum phase transition in the motional degrees of freedom of an optically driven Bose-Einstein condensate in a cavity. Relevant collective excitations of this light-matter system are polaritonic in nature, allowing access to the quantum critical behavior of the Dicke model through light leaking out of the cavity. This opens the path to using photodetection based quantum optical techniques to study the dynamics and excitations of this elementary quantum critical system. We first discuss the photon flux observed at the cavity face and find that it displays a different scaling law near criticality than that obtained from the mean field theory for the equivalent closed system. Next, we study the second order correlation measurements of photons leaking out of the cavity. Finally, we discuss a modulation technique that directly captures the softening of polaritonic excitations. Our analysis takes into account the effect of the finite size of the system which may result in an effective symmetry breaking term.Comment: 18 pages, 5 figure

Численная модель системы вывода электронного пучка медицинского ускорителя

A novel incremental ring rolling process is proposed, in which a narrow mandrel is moved both radially and axially. The process has potential to allow flexible near-net-shape forming of both hot and cold rings, and has been assessed by experiments on commercial cold ring rolling machines, a physical simulation using wax rings, and two finite element models. The results suggest that the process is technically feasible although the cycle time increases with the degree of flexibility and the stability of deformation depends on careful design of the tool path

Analytical approach for entropy generation and heat transfer in CNT-nanofluid dynamics through a ciliated porous medium

The transportation of biological and industrial nanofluids by natural propulsion like cilia movement and self-generated contraction-relaxation of flexible walls has significant applications in numerous emerging technologies. Inspired by multi-disciplinary progress and innovation in this direction, a thermo-fluid mechanical model is proposed to study the entropy generation and convective heat transfer of nanofluids fabricated by the dispersion of single-wall carbon nanotubes (SWCNT) nanoparticles in water as the base fluid. The regime studied comprises heat transfer and steady, viscous, incompressible flow, induced by metachronal wave propulsion due to beating cilia, through a cylindrical tube containing a sparse (i.e. high permeability) homogenous porous medium. The flow is of the creeping type and is restricted under the low Reynolds number and long wavelength approximations. Slip effects at the wall are incorporated and the generalized Darcy drag-force model is utilized to mimic porous media effects. Cilia boundary conditions for velocity components are employed to determine analytical solutions to the resulting non-dimensionalized boundary value problem. The influence of pertinent physical parameters on temperature, axial velocity, pressure rise and pressure gradient, entropy generation function, Bejan number and stream-line distributions are computed numerically. A comparative study between SWCNT nanofluids and pure water is also computed. The computations demonstrate that axial flow is accelerated with increasing slip parameter and Darcy number and is greater for SWCNT- nanofluids than for pure water. Furthermore the size of the bolus for SWCNT-nanofluids is larger than that of the pure water. The study is applicable in designing and fabricating nanoscale and microfluidics devices, artificial cilia and biomimetic micro-pump

Defining the causes of sporadic Parkinson's disease in the global Parkinson's genetics program (GP2)

The Global Parkinson’s Genetics Program (GP2) will genotype over 150,000 participants from around the world, and integrate genetic and clinical data for use in large-scale analyses to dramatically expand our understanding of the genetic architecture of PD. This report details the workflow for cohort integration into the complex arm of GP2, and together with our outline of the monogenic hub in a companion paper, provides a generalizable blueprint for establishing large scale collaborative research consortia