scholarly journals Theoretical Study of Convection Heat Transfer and Fluid Dynamics in Microchannels with Arrayed Microgrooves

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hai-Ping Hu
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Theoretical Study ◽  
Fluid Velocity ◽  
Convection Heat Transfer ◽  
Velocity Slip ◽  
Jump Condition ◽  
Point Matching ◽  
Research Areas ◽  
Analysis Scheme

The analysis of heat transfer and fluid dynamics in a microchannel is currently one of numerous important research areas. The present study investigated the heat transfer and fluid dynamics in a microchannel with arrayed microgrooves. The boundary conditions in the microchannel and microgrooves were the velocity slip condition and temperature jump condition. The numerical calculations in the present study were based on a new numerical analysis scheme that was used to name modified point-matching methods. The methods are applied to calculate the two items coefficients of the series expressions of velocity in the microchannel with microgrooves. The methods analyzed four items coefficients of the series expressions of temperature in the microchannel with microgrooves. In addition, the fluid velocity, temperature distribution, Knudsen number effect, fluid friction factor in the microchannel, and heat transfer were discussed.

scholarly journals Effect of Velocity Slip Boundary Condition on the Flow and Heat Transfer of Cu-Water and TiO2-Water Nanofluids in the Presence of a Magnetic Field

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Abdelhalim Ebaid ◽  
Fahd Al Mutairi ◽  
S. M. Khaled
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Velocity ◽  
Velocity Slip ◽  
Slip Boundary Condition ◽  
Dual Solutions ◽  
Slip Condition ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Flow And Heat Transfer

In nanofluid mechanics, it has been proven recently that the no slip condition at the boundary is no longer valid which is the reason that we consider the effect of such slip condition on the flow and heat transfer of two types of nanofluids. The present paper considers the effect of the velocity slip condition on the flow and heat transfer of the Cu-water and the TiO2-water nanofluids over stretching/shrinking sheets in the presence of a magnetic field. The exact expression for the fluid velocity is obtained in terms of the exponential function, while an effective analytical procedure is suggested and successfully applied to obtain the exact temperature in terms of the generalized incomplete gamma function. It is found in this paper that the Cu-water nanofluid is slower than the TiO2-water nanofluid for both cases of the stretching/shrinking sheets. However, the temperature of the Cu-water nanofluid is always higher than the temperature of the TiO2-water nanofluid. In the case of shrinking sheet the dual solutions have been obtained at particular values of the physical parameters. In addition, the effect of various physical parameters on such dual solutions is discussed through the graphs.

Flexible Hybrid Reinforced Pipe-Bend Stiffener Interface Design With Optimized Thermal Performance

2014 ◽  
Author(s):  
Amirhossein Salimi ◽  
Mark Kalman ◽  
Liang Yu
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Interface Design ◽  
Pipe Wall ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Flexible Pipe ◽  
Pipe Bend ◽  
Free Convection Heat ◽  
High Thermal Resistance

Flexible pipe risers are often protected from over-bending with a bend stiffener at the lower end of an I-tube in FPSO installations. Due to the high thermal resistance of the polyurethane bend stiffener, there is a potential risk for both riser and bend stiffener to exceed their temperature limits. This paper presents classical and computational fluid dynamics thermal models and analyses to confirm that free convection heat transfer from the pipe wall to the water in the gap between the pipe and bend stiffener, and buoyancy driven flow along the gap is sufficient to maintain the temperature of the pipe layers and bend stiffener within allowable values. Details of the models and solutions for an example riser with 120 °C design temperature in a Gulf of Mexico installation is presented.

Numerical Modeling of Micro Fin Arrays Using Slip Flow and Temperature Jump Boundary Conditions

2008 ◽  
Author(s):  
C. B. Sobhan ◽  
Muhsin M. Ameen ◽  
Praveen P. Abraham
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Temperature Jump ◽  
Slip Flow ◽  
Convection Heat Transfer ◽  
Transient State ◽  
Velocity Slip ◽  
Operating Pressure ◽  
Parametric Studies ◽  
Explicit Finite Difference

A numerical investigation of natural convection heat transfer from a rectangular fin array of microscale dimensions, where a “down and up” flow pattern occurs, is carried out. The stream function vorticity formulation is used in the analysis and the governing equations of the transient two dimensional field are solved using an explicit finite difference scheme. The dimensions of the domain are such that the problem falls under the slip flow regime. The non continuum effects are modeled through Maxwell’s velocity slip and Smoluchowski’s temperature jump boundary conditions. The steady state velocity and temperature distributions in the field are obtained by marching through the transient state. The average heat transfer coefficient and the Nusselt Number are calculated. The influence of the fin spacing, fin height and operating pressure on the performance of the fin array is studied through parametric studies and some conclusions are drawn regarding the significance of non continuum effects in the micro scale dimensions considered.

scholarly journals Numerical investigation fluid velocity and heat transfer on the stretching sheet by VIM method and optimization fluid temperature and velocity parameter by Prandtl number and viscoelastic parameter

2021 ◽  
Author(s):  
Pooya Pasha ◽  
Ali Hosin Alibak ◽  
Hossein Nabi ◽  
Farzad tat Shahdost
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Iteration Method ◽  
Stretching Sheet ◽  
Fluid Velocity ◽  
Convection Heat Transfer ◽  
Fluid Temperature ◽  
Viscoelastic Parameter ◽  
Velocity Changes ◽  
Variation Iteration Method

This study aimed at investigating the variation of heat transfer and velocity changes of the fluid flow along the vertical line on a surface drawn from both sides. In the beginning, the several parameters such as Prandtl number and viscoelastic effect evaluated for heat transfer and fluid velocity by variation Iteration method. The results were compared with the numerical method. The second part of the description relates to the use RSM method in the Design Expert software. In this paper by using the RSM method, optimized the fluid velocity and heat transfer passing from the stretching sheet. By increasing the Prandtl number, the convection heat transfer 43 % increased ratio the minimum Prandtl number. In accordance with balanced modes for Prandtl number and viscoelastic parameter and wall temperature, the best optimization occurred for fluid velocity and fluid temperature with f=0.67 and θ=0.606. The results of variation iteration method are accurate for the nonlinear solution. As the value of k increases, the value of fluid velocity indicates an increase and by increase Prandtl number, the value of Temperature decreases.

LATTICE BOLTZMANN SIMULATION ON NATURAL CONVECTION HEAT TRANSFER IN A TWO-DIMENSIONAL CAVITY FILLED WITH HETEROGENEOUSLY POROUS MEDIUM

2006 ◽  
Vol 17 (06) ◽  
pp. 771-783 ◽  
Author(s):  
WEI-WEI YAN ◽  
YANG LIU ◽  
ZHAO-LI GUO ◽  
YOU-SHENG XU
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Fluid Velocity ◽  
Convection Heat Transfer ◽  
Published Data ◽  
Lattice Boltzmann Simulation ◽  
Natural Convection Problem ◽  
Boltzmann Method

The natural convection problem in a square cavity filled with heterogeneously porous medium is solved by lattice Boltzmann method. The temperature distribution is fully coupled with the fluid velocity through relaxation time. The present calculated results are in good agreement with available published data. It is found that the porosity of porous media near the walls has significant influence on the heat transfer, and the porosity of middle porous medium has little influence on the natural convection. It is of particular interest for thermal management in electronic packages, since it can reduce the space of air.

scholarly journals Velocity Slip Effect on MHD Power-Law Fluid over a Moving Surface with Heat Generation, Viscous Dissipation and Thermal Radiation

2021 ◽  
pp. 103-112
Author(s):  
Falana Ayodeji ◽  
Babatope. O Pele
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Differential Equations ◽  
Power Law ◽  
Fluid Velocity ◽  
Velocity Slip ◽  
Transverse Magnetic ◽  
Power Law Fluid ◽  
Moving Surface ◽  
Linear Ordinary Differential Equations

The problem of laminar boundary layer flow of power-law fluid over a continuous moving surface in the presence of a transverse magnetic field with velocity slip was investigated. The governing partial differential equations for the flow and heat transfer were transformed into non-linear ordinary differential equations using the similarity method. These equations were solved numerically by applying the fourth-order Runge-Kutta method with a shooting technique. The solution is found to be dependent on various parameters such as power-law index, magnetic field parameter, suction, and injection parameters. The effect of various flow parameters in the form of dimensionless quantities on the flow field is discussed and graphically presented. It was observed that an increase in the magnetic property results to a decrease flow of fluid velocity and also, an increase in the Prandtl number results to an increase in the rate of heat transfer.

scholarly journals G EXPERIMENTAL AND THEORETICAL STUDY OF FORCED CONVECTION AROUND A CYLINDER EMBEDDED IN POROUS MEDIA

2020 ◽  
Vol 20 (2) ◽  
pp. 164-179
Author(s):  
Abeer Aamer ◽  
Suhad Abd-hameed
Keyword(s):  
Heat Transfer ◽  
Porous Material ◽  
Forced Convection ◽  
Test Section ◽  
Average Nusselt Number ◽  
Theoretical Study ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Theoretical Results ◽  
Good Agreement

An experimental and theoretical study of air forced convection heat transfer at Reynoldsnumber (1091.5 to 1560) around a circular cylinder placed in an iron test section (0.2x0.2x0.4m3) filled with saturated porous material glass balls of 5mm in diameter. A copper circularcylinder heater of diameter 0.015m and length 0.2m is heated electrically; it is located indifferent positions in X and Y direction within the test section. The forced convection heattransfer is simulated using the ANSYS program (Fluent). The results showed that the surfacetemperature distribution of the cylinder has the same trends for the different locations withinthe test section. The average Nusselt number increases with Reynolds number and heat flux.Also, the results show that the use of porous material improves heat transfer by 67.4%. Themaximum percentage deviation between the experimental and theoretical results is 1.622%.Moreover, experimental correlations were introduced and comparison was performedbetween the present results with the previous studies and it gives a good agreement.

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