Modeling and Optimization of Gaseous Slip Flow Forced Convection in Rectangular Microducts Using Particle Swarm Optimization Algorithm

2018 ◽  
Author(s):  
Waqar A. Khan ◽  
Nawaf N. Hamadneh
Keyword(s):  
Heat Transfer ◽  
Shear Stress ◽  
Particle Swarm Optimization ◽  
Aspect Ratio ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Particle Swarm Optimization Algorithm ◽  
Slip Flow ◽  
Swarm Optimization ◽  
Gaseous Slip Flow

In this study, pressure driven gaseous slip flow is investigated in microducts of rectangular cross-section. The range of Knudsen numbers Kn in the flow regime is taken as 0.001 ≤ Kn ≤ 0.1 and aspect ratio is taken as 0 ≤ ε ≤ 1. To incorporate rarefaction effects, the effects of slip velocity and temperature jump boundary conditions are taken in to account. The dimensionless momentum and energy equations are solved using MATLAB to obtain the dimensionless velocity and temperature gradients for different values of Knudsen numbers and aspect ratio. Using these gradients, the dimensionless shear stress and heat transfer rate are obtained numerically. The numerical solution can be validated for the special cases when there is no slip (continuum flow), ε = 0 (parallel plates) and ε = 1 (square microducts). An artificial neural network is used to develop separate models for dimensionless shear stress and heat transfer rate and particle swarm optimization algorithm is used to obtain optimum values for both parameters. Using these results, minimum dimensionless shear stress and maximum heat transfer rate can be determined in the microducts under consideration in the slip flow regime. The optimal values of P0 and Nu are found when ε = 1 and Kn = 0.001.

scholarly journals Modeling and Optimization of Gaseous Thermal Slip Flow in Rectangular Microducts Using a Particle Swarm Optimization Algorithm

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 488 ◽  
Author(s):  
Nawaf Hamadneh ◽  
Waqar Khan ◽  
Ilyas Khan ◽  
Ali Alsagri
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Artificial Neural Network ◽  
Shear Stress ◽  
Particle Swarm Optimization ◽  
Transfer Rate ◽  
Particle Swarm Optimization Algorithm ◽  
Swarm Optimization ◽  
Slip Regime ◽  
Physical Quantities

In this study, pressure-driven flow in the slip regime is investigated in rectangular microducts. In this regime, the Knudsen number lies between 0.001 and 0.1. The duct aspect ratio is taken as 0 ≤ ε ≤ 1 . Rarefaction effects are introduced through the boundary conditions. The dimensionless governing equations are solved numerically using MAPLE and MATLAB is used for artificial neural network modeling. Using a MAPLE numerical solution, the shear stress and heat transfer rate are obtained. The numerical solution can be validated for the special cases when there is no slip (continuum flow), ε = 0 (parallel plates) and ε = 1 (square microducts). An artificial neural network is used to develop separate models for the shear stress and heat transfer rate. Both physical quantities are optimized using a particle swarm optimization algorithm. Using these results, the optimum values of both physical quantities are obtained in the slip regime. It is shown that the optimal values ensue for the square microducts at the beginning of the slip regime.

Application of metaheuristic algorithms in optimum thermal design analysis of a rectangular porous fin subjected to both insulated and convective tip conditions

2020 ◽  
Vol 234 (8) ◽  
pp. 1175-1188
Author(s):  
Tuhin Deshamukhya ◽  
Dipankar Bhanja ◽  
Sujit Nath
Keyword(s):  
Heat Transfer ◽  
Particle Swarm Optimization ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Firefly Algorithm ◽  
Particle Swarm ◽  
Thermal Design ◽  
Swarm Optimization ◽  
Porous Fin ◽  
Adomian Decomposition

In this novel optimization analysis, a rectangular porous fin subjected to convective tip conditions along with insulated end condition is studied. The aim is to optimize the important variables responsible for transferring heat from fin with insulated as well as convective tip to the surrounding in order to get a higher rate of heat transfer from the fin surface. Temperature-dependent solid and fluid thermal conductivities as well as variable internal heat generation is considered. To obtain heat dissipation rate through porous fin, the nonlinear governing equation is first solved analytically using Adomian decomposition method. Then the heat transfer rate, i.e., objective function of this problem is optimized with three powerful metaheuristic techniques, namely firefly algorithm, particle swarm optimization and gravitational search algorithm. A comparative analysis has revealed that fins with convective end show significantly higher heat transfer rate compared to their insulated end counterparts. Particle swarm optimization showed marginally higher heat transfer values compared to firefly algorithm but firefly algorithm took less computational effort to reach the optimum value.

scholarly journals A RANS K-? SIMULATION OF 2D TURBULENT NATURAL CONVECTION IN AN ENCLOSURE WITH HEATING SOURCES

2019 ◽  
Vol 20 (1) ◽  
pp. 229-244
Author(s):  
Mehdi Ahmadi ◽  
Seyed Ali Agha Mirjalily ◽  
Seyed Amir Abbas Oloomi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Kinetic Energy ◽  
Aspect Ratio ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Turbulent Natural Convection ◽  
Cold Source ◽  
Thermal Sources

ABSTRACT: This study is conducted to investigate turbulent natural convection flow in an enclosure with thermal sources using the low-Reynolds number (LRN) k-? model. This enclosure has a cold source with temperature Tc and a hot source with temperature Th as thermal sources, other walls of the enclosure are adiabatic. The aim of this study is to predict the effect of change in Rayleigh number, repositioning of cold and hot sources, and thermal sources aspect ratio on the flow field, temperature, and rate of heat transfer. To achieve this aim, the equations of continuity, momentum, energy, turbulent kinetic energy, and kinetic energy dissipation are employed in the case of 2D turbulence with constant thermo-physical properties except the density in the buoyancy term (Boussinesq approximation). To numerically solve these equations, the finite volume method and SIMPLE algorithm are used. According to the modeling results, the most optimal temperature distribution in the enclosure is seen when the hot source is below the cold source. With decreasing distance between hot and cold sources, heat transfer rate increases. The maximal heat transfer rate is derived via study of the heating sources aspect ratio. In constant positions of cold and hot sources on a wall, the heat transfer rate increases with increasing Rayleigh number (Ra=109-1011). ABSTAK: Kajian ini dijalankan bagi mengkaji perubahan semula jadi aliran perolakan dalam tempat tertutup dengan sumber haba menggunakan model k-? nombor Reynolds-rendah (LRN). Bekas tertutup ini mempunyai dua sumber haba iaitu sumber sejuk dengan suhu Tc dan sumber panas dengan suhu Th, manakala dinding lain bekas ini adalah adiabatik. Tujuan kajian ini adalah bagi mengesan perubahan nombor Rayleigh, mengubah sumber sejuk dan panas dan nisbah sumber haba kepada kawasan aliran, suhu dan halaju perubahan haba. Bagi mencapai tujuan tersebut, persamaan sambungan, momentum, tenaga, tenaga kinetik perolakan, dan pengurangan tenaga kinetik telah dilaksanakan dalam kes perolakan 2D dengan sifat fizikal-haba berterusan (malar) kecuali isipadu terma keapungan (anggaran Boussinesq). Bagi menyelesaikan persamaan ini secara berangka, kaedah isipadu terhad dan algorithma MUDAH telah digunakan. Berdasarkan keputusan model, suhu distribusi optimal dalam bekas tertutup dilihat apabila sumber panas adalah kurang daripada sumber sejuk. Dengan pengurangan jarak antara sumber panas dan sejuk, kadar pertukaran haba meningkat. Kadar pertukaran haba maksima telah diperoleh melalui kajian nisbah  aspek sumber pemanasan. Kadar pertukaran haba bertambah dengan bertambahnya nombor Rayleigh  (Ra=109-1011), pada posisi tetap sumber sejuk dan panas pada dinding bekas.

Cooling of a Hot Torus

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Rajai S. Alassar ◽  
Mohammed A. Abushoshah
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Boundary Conditions ◽  
Heat Transfer Rate ◽  
Governing Equation ◽  
Transfer Rate ◽  
Radial Direction ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Toroidal Coordinates

The problem of a hot torus left to cool in a medium of known temperature is studied. We write the governing equation in toroidal coordinates and expand the temperature in terms of a series in the angular direction. The resulting modes in the radial direction are numerically obtained. We consider both isothermal and convective boundary conditions and study the effect of Biot number and aspect ratio on the heat transfer rate.

scholarly journals Intensification of Heat Transfer in Cavity Partially Heated and Filled with Nanofluid (Cu-Water)

2015 ◽  
Vol 55 ◽  
pp. 173-179
Author(s):  
Ridha Jmai ◽  
Brahim Ben Beya ◽  
Taieb Lili
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Heat Transfer Rate ◽  
Finite Volume ◽  
Transfer Rate ◽  
Heat Sources ◽  
Flow And Heat Transfer ◽  
Vertical Walls

Natural convection in a rectangular cavity with aspect ratio (Ax), partially heated and filled with a nanofluid (Cu-Water) has been studied numerically. Two heat sources with length (B) are placed on the opposite vertical walls; the remainder of the walls is maintained adiabatic while the horizontal walls are brought to a cold temperature. The equations governing the flow are solved using a finite volume home code using a multigrid technique. Among the parameters governing the flow, a detailed study on the effects of the aspect ratio (Ax) and the length of the source (B) on flow and heat transfer rate is given. The results are shown in terms of streamlines and isotherms. It was found that the transfer of heat significantly increases with the aspect ratio (Ax) and the length of the source (B). A correlation expressing the Nusselt number as a function of (Ax) and d is established.

scholarly journals Enhancement of natural convection heat transfer in concentric annular space using inclined elliptical cylinder

2020 ◽  
Vol 17 (2) ◽  
pp. 89-99
Author(s):  
Houssem Laidoudi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Heat Transfer Rate ◽  
Inclination Angle ◽  
Transfer Rate ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Elliptical Cross

The governing equations of continuity, momentum and energy are numerically solved to study the laminar natural convection heat transfer of Newtonian fluid confined within two concentric cylinders. The inner cylinder is elliptical cross-section with different aspect ratio E = 0.1 to 0.5 and it is considered to be hot, whereas the outer cylinder is circular and it is supposed to be cold.    The annular spacing between the cylinders is defined based on radii ratio (RR = 2.5). Also, the inner cylinder is inclined with an inclination angle (θ = 0 to 90). The main purpose of this study is to determine the effects of inclination angle (θ = 0° to 90°), aspect ratio of inner cylinder (E = 0.1 to 0.5), Prandtl number (Pr = 0.71 and 7.01) and Rayleigh number (Ra = 103 to 105) on fluid flow and heat transfer rate. The flow patterns and temperature distributions are potted in terms of streamlines and isotherms respectively. The obtained results showed that increase in inclination angle enhances the heat transfer rate of inner cylinder for all values of aspect ratio. Also, for the inclination angle          (θ = 90°), the decrease in aspect ratio (E) improves the heat transfer rate of inner cylinder.

scholarly journals Periodic mixed convection of a nanofluid in a cavity with top lid sinusoidal motion

2011 ◽  
Vol 225 (9) ◽  
pp. 2149-2160 ◽  
Author(s):  
A Karimipour ◽  
A H Nezhad ◽  
A Behzadmehr ◽  
S Alikhani ◽  
E Abedini
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Mixed Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Richardson Number ◽  
Volume Fraction ◽  
Temperature Profiles ◽  
Sinusoidal Motion ◽  
Periodic State

The periodic mixed convection of a water–copper nanofluid inside a rectangular cavity with aspect ratio of 3 is investigated numerically. The temperature of the bottom wall of the cavity is assumed greater than the temperature of the top lid which oscillates horizontally with the velocity defined as u =  u0 sin ( ωt). The effects of Richardson number, Ri, and volume fraction of nanoparticles on the flow and thermal behaviour of the nanofluid are investigated. Velocity, temperature profiles, and streamlines are presented. It is observed that when Ri < 1, heat transfer rate is much greater than when Ri > 1. The higher value of Ri corresponds to a lower value of the amplitude of the oscillation of Nu m in the steady periodic state. Moreover, increasing the volume fraction of the nanoparticles increases the heat transfer rate.

Natural Convection in a Vertical Microchannel

2005 ◽  
Vol 127 (9) ◽  
pp. 1053-1056 ◽  
Author(s):  
Cha’o-Kuang Chen ◽  
Huei Chu Weng
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Flow Rate ◽  
Transfer Rate ◽  
Temperature Jump ◽  
Volume Flow Rate ◽  
Slip Flow ◽  
Velocity Slip ◽  
Volume Flow

It is highly desirable to understand the fluid flow and the heat transfer characteristics of buoyancy-induced micropump and microheat exchanger in microfluidic and thermal systems. In this study, we analytically investigate the fully developed natural convection in an open-ended vertical parallel-plate microchannel with asymmetric wall temperature distributions. Both of the velocity slip and the temperature jump conditions are considered because they have countereffects both on the volume flow rate and the heat transfer rate. Results reveal that in most of the natural convection situations, the volume flow rate at microscale is higher than that at macroscale, while the heat transfer rate is lower. It is, therefore, concluded that the temperature jump condition induced by the effects of rarefaction and fluid-wall interaction plays an important role in slip-flow natural convection.

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