scholarly journals Effects of Temperature Dependent Thermal Conductivity and Viscous Dissipation on Free Convective Flow along a Vertical Flat Plate with Asymptotic Solution

2017 ◽  
Vol 36 ◽  
pp. 33-46
Author(s):  
AKM Safiqul Islam ◽  
MA Alim ◽  
Md Rezaul Karim ◽  
ATM M Rahman
Keyword(s):  
Thermal Conductivity ◽  
Prandtl Number ◽  
Asymptotic Solution ◽  
Surface Temperature ◽  
Skin Friction ◽  
Viscous Dissipation ◽  
Temperature Profiles ◽  
Conductivity Variation ◽  
Variation Parameter ◽  
Thermal Conductivity Variation

This paper reports us the surface temperature distribution effects of free convective flow along a vertical flat plate with temperature dependent thermal conductivity and viscous dissipation with asymptotic solution. The governing equations with associated boundary conditions reduce to local non-similarity boundary layer equations for this phenomenon are converted to dimensionless forms using a suitable transformation. The transformed non-linear equations are then solved using the implicit finite difference method together with Keller-box technique. Numerical results of the velocity and temperature profiles, skin friction and surface temperature profiles for different values of the thermal conductivity variation parameter, the Prandtl number and the viscous dissipation parameters are presented graphically. Also we considered the asymptotic solution for the effect of the thermal conductivity variation parameter, the Prandtl number and the viscous dissipation parameters in skin friction and surface temperature profiles. Detailed discussion is given for the aforementioned parameters. A good similarity is found in small and large value solution with all value solution for the thermal conductivity variation parameter, the Prandtl number and the viscous dissipation parameter for skin friction and surface temperature. Divergence is found near one (1).GANIT J. Bangladesh Math. Soc.Vol. 36 (2016) 33-46

scholarly journals Effects of Conduction Variation on MHD Natural Convection Flow along a Vertical Flat Plate with Thermal Conductivity

2016 ◽  
Vol 8 (3) ◽  
pp. 237-248
Author(s):  
A. K. M. S. Islam ◽  
M. A. Alim ◽  
M. R. Karim ◽  
A. T. M. M. Rahman
Keyword(s):  
Thermal Conductivity ◽  
Surface Temperature ◽  
Flat Plate ◽  
Skin Friction ◽  
Convection Flow ◽  
Temperature Profiles ◽  
Conductivity Variation ◽  
Variation Parameter ◽  
Thermal Conductivity Variation ◽  
Vertical Flat Plate

This paper reports the effect of conduction variation of free convection flow along a vertical flat plate on magnetohydrodynamic (MHD) with thermal conductivity. The governing equations with associated boundary conditions reduce to local non-similarity boundary layer equations for this phenomenon are converted to dimensionless forms using a suitable transformation. The transformed non-linear equations are then solved using the implicit finite difference method together with Keller-box technique. Numerical results of the velocity and temperature profiles, skin friction and surface temperature profiles for different values of the magnetic parameter, the thermal conductivity variation parameter, the Prandtl number and the conduction variation parameters are presented graphically. Detailed discussion is given for the effect of the aforementioned parameters. Opposite scenario is found in skin friction and surface temperature for the thermal conductivity variation parameter. Significant effect is found in skin friction and surface temperature for conduction variation parameter.

scholarly journals Effects of viscous dissipation on natural convection flow along a sphere with radiation and heat generation

2013 ◽  
Vol 10 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Salina Aktar ◽  
Mahmuda Binte Mostafa Ruma ◽  
M. A. Alim
Keyword(s):  
Friction Coefficient ◽  
Surface Temperature ◽  
Skin Friction ◽  
Viscous Dissipation ◽  
Heat Generation ◽  
Linear Equations ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Temperature Profiles ◽  
Generation Parameter

The effects of viscous dissipation on free convection flow along a sphere with radiation and heat generation have been investigated in this paper. The governing equations with associated boundary conditions for this phenomenon are converted to dimensionless forms using a suitable transformation. The transformed non-linear equations are then solved using the implicit finite difference method. Numerical results of the velocity and temperature profiles, skin friction coefficient and surface temperature profiles for different values of the of viscous dissipation parameter Vd ( 0.0 to 4.0), radiation parameter Rd (0.0 to 1.0), the Prandlt number Pr (0.72 to7.0)and the heat generation parameter Q (0.2 to 0.6) are presented graphically. Detailed discussion is given for the effects of the aforementioned parameters. Significant effect is found in the velocity and temperature profiles, skin friction coefficient and surface temperature distribution for the Prandtl number, heat generation and radiation parameters. DOI: http://dx.doi.org/10.3329/jname.v10i1.12809

Numerical Simulation & Experimental Investigation of SMT Laser Microsoldering Thermal Process

1991 ◽  
Vol 226 ◽  
Author(s):  
Wang Chunqing ◽  
Qian Yiyu ◽  
Jiang Yihong
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Experimental Investigation ◽  
Thermal Process ◽  
Light Wave ◽  
Light Reflection ◽  
Lead Wire ◽  
Wire Surface ◽  
Conductivity Variation ◽  
Thermal Conductivity Variation

AbstractIn this paper,a numerical simulation of thermal process in the SMT laser microsoldering joint has been developed, in which, the influence on thermal process of the factors such as the thermal conductivity variation of solder with temperature, light reflection coefficient of the lead wire surface, and heat exchange on the surface of SMT materials all have been considered. In order to carry this numerical calculation practice and prove it's results,the reflexive characteristic of light wave to the SMT materials has been gauged,and the dynamic temperature process of laser microjoint has been measured by a new experimental method which was invented by the authors.The results of numerical simulation have been borne out by the tests, and the influences of heating parameters on thermal process has been analysed in this paper.The conclusions will be advantageous to the further study of the microjoint quality control in the SMT laser microsoldering.

scholarly journals Surface temperature and free-stream velocity oscillation effects on mixed convention slip flow from surface of a horizontal circular cylinder

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 13-23
Author(s):  
Zia Ullah ◽  
Muammad Ashraf ◽  
Saqib Zia ◽  
Ishtiaq Ali
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Mixed Convection ◽  
Surface Temperature ◽  
Skin Friction ◽  
Slip Velocity ◽  
Free Stream ◽  
Slip Flow ◽  
Stream Velocity ◽  
Velocity Oscillation

The present phenomena address the slip velocity effects on mixed convection flow of electrically conducting fluid with surface temperature and free stream velocity oscillation over a non-conducting horizontal cylinder. To remove the difficulties in illustrating the coupled PDE, the primitive variable formulation for finite dif?ference technique is proposed to transform dimensionless equations into primitive form. The numerical simulations of coupled non-dimensional equations are exam?ined in terms of fluid slip velocity, temperature, and magnetic velocity which are used to calculate the oscillating components of skin friction, heat transfer, and cur?rent density for various emerging parameters magnetic force parameter, ?, mixed convection parameter, ?, magnetic Prandtl number, ?, Prandtl number, and slip factor, SL. It is observed that the effect of slip flow on the non-conducting cylinder is reduced the fluid motion. A minimum oscillating behavior is noted in skin friction at each position but maximum amplitude of oscillation in heat transfer is observed at each position ? = ?/4 and 2?/3. It is further noticed that a fluid velocity increas?es sharply with the impact of slip factor on the fluid-flow mechanism. Moreover, due to frictional forces with lower magnitude between viscous layers, the rise in Prandtl number leads to decrease in skin fiction and heat transfer which is physi?cally in good agreement.

Multi-scale numerical prediction of flow-induced thermal conductivity variation in micro-injection molded heat sink

2016 ◽  
Vol 24 (3) ◽  
pp. 566-573
Author(s):  
杨灿 YANG Can ◽  
曹泽卫 CAO Ze-wei ◽  
尹晓红 YIN Xiao-hong ◽  
阚君武 KAN Jun-wu ◽  
程光明 CHENG Guang-ming ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Numerical Prediction ◽  
Multi Scale ◽  
Conductivity Variation ◽  
Injection Molded ◽  
Thermal Conductivity Variation

The measurement of thermal conductivity variation with temperature for Sn-20wt.% In based lead-free ternary solders

2013 ◽  
Vol 554 ◽  
pp. 63-70 ◽  
Author(s):  
Esra Öztürk ◽  
Sezen Aksöz ◽  
Kazım Keşlioğlu ◽  
Necmettin Maraşlı
Keyword(s):  
Thermal Conductivity ◽  
Lead Free ◽  
Conductivity Variation ◽  
Thermal Conductivity Variation

Impact of Thermodiffusion on Temperature Fields in Stationary Nanofluids

2007 ◽  
Author(s):  
Patricia E. Gharagozloo ◽  
Ken E. Goodson ◽  
John K. Eaton
Keyword(s):  
Thermal Conductivity ◽  
Enhancement Factor ◽  
Silicone Oil ◽  
Thermal Conductivity Enhancement ◽  
Temperature Fields ◽  
Coupled Transport ◽  
Conductivity Enhancement ◽  
Conductivity Variation ◽  
Potential Impact ◽  
Thermal Conductivity Variation

The research community has reported a large variety of at times contradictory thermal conductivity enhancements for nanofluids. Some of the differences may result from thermodiffusion, which is the coupled transport of heat and nanoparticles in a temperature gradient. Thermodiffusion can influence the apparent conductivity observed in a given experimental setup. This work explores the potential impact of thermodiffusion on the inconsistencies of the previous results and on the observed temperature dependence of the thermal conductivity enhancement. The thermal conductivity variation with temperature is captured using infrared microscopy. The thermal conductivity distribution varies significantly over the temperature range 27 – 73°C. This work also explores the potential impact of aggregation, gravitational separation, and thermodiffusion on the time-evolution of the thermal conductivity. For 1 percent by volume aluminum oxide in deionized water, this work finds a thermal conductivity enhancement of between 1 and 15 percent depending on temperature and time, which corresponds to an enhancement factor of between 1 and 15. For 0.2 percent by volume carbon nanotubes in silicone oil, this work finds a thermal conductivity enhancement of 8 percent with no dependence on temperature, which corresponds to an enhancement factor of 40.

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