Fluid Flow and Heat Transfer in an Annulus With Ribs on the Rotating Inner Cylinder Surface

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
S. Gokul ◽  
M. Deepu
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Thermal Performance ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Reynolds Numbers ◽  
Cylinder Surface ◽  
Turbulent Fluid Flow ◽  
Cylindrical Annulus ◽  
Volume Method

Abstract Numerical studies on heat transfer in Taylor-Couette-Poiseuille flow in a cylindrical annulus with ribs mounted on the rotating inner cylinder are presented. The present study focuses on two different types of ribs, namely, longitudinal ribs and helical ribs. Three-dimensional, steady, incompressible, turbulent fluid flow is solved using a semi-implicit method for pressure linked equations (SIMPLE) algorithm based finite volume method. The numerical solution method is validated using two sets of benchmark experimental data. Extensive numerical computations are carried out at various Reynolds numbers (2100 < Re < 2400) and modified Taylor numbers (30,000 < Tam < 90,000) for annulus with and without ribs. Ribs enhance the transport of heat and momentum by inducing more vorticity and turbulence in the flow. The overall performance is presented in terms of thermal performance factor (TPF), which takes in to account the heat transfer as well as pressure drop in the ribbed annulus. Helical ribs are found to offer superior thermal performance than its longitudinal counterpart.

Heat Transfer Improvement in a Square Duct with Diagonal Inclined Ribs

2014 ◽  
Vol 931-932 ◽  
pp. 1144-1148
Author(s):  
Supattarachai Suwannapan ◽  
Ratsak Poomsalood ◽  
Pongjet Promvonge ◽  
Withada Jedsadaratanachai ◽  
Thitipat Limkul
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Reynolds Numbers ◽  
Square Duct ◽  
Flow And Heat Transfer ◽  
Pitch Ratio ◽  
Volume Method ◽  
Heat Transfer Improvement

This research presents a numerical study of turbulent periodic flow and heat transfer in threedimensional isothermalfluxed square duct with diagonal inclined rib inserted. The fluid flow and heat transfer characteristics are presented for Reynolds numbers in the range of 4000 to 20,000. The computations based on the finite volume method, and the SIMPLE algorithm has been implemented. Effects of rib pitch ratios (0.5 to 2) at a single blockage ratio of 0.2 and attack angle of 60o on heat transfer and friction factor in the duct are examined and their results of the inclined rib are also compared with those of the smooth duct. It is found that the inclined rib provides higher heat transfer rate and friction factor than the smooth duct for all cases. In addition, the decreasing of the pitch ratio leads to the rise in the Nusselt number and friction factor.

scholarly journals Numerical study on characteristics of flow and thermal fields around rotating cylinder

10.30544/450 ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 71-86
Author(s):  
Kamel Korib ◽  
Mohamed ROUDANE ◽  
Yacine Khelili
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Rotation Rates ◽  
Rotating Circular Cylinder ◽  
Flow And Heat Transfer ◽  
Lift And Drag ◽  
Energy Equations ◽  
Volume Method

In this paper, a numerical simulation has been performed to study the fluid flow and heat transfer around a rotating circular cylinder over low Reynolds numbers. Here, the Reynolds number is 200, and the values of rotation rates (α) are varied within the range of 0 < α < 6. Two-dimensional and unsteady mass continuity, momentum, and energy equations have been discretized using the finite volume method. SIMPLE algorithm has been applied for solving the pressure linked equations. The effect of rotation rates (α) on fluid flow and heat transfer were investigated numerically. Also, time-averaged (lift and drag coefficients and Nusselt number) results were obtained and compared with the literature data. A good agreement was obtained for both the local and averaged values.

Natural Convection Cooling of an Array of Flush Mounted Discrete Heaters Inside a 3D Cavity

2017 ◽  
Vol 9 (3) ◽  
pp. 698-721 ◽  
Author(s):  
V. P. M. Senthil Nayaki ◽  
S. Saravanan ◽  
X. D. Niu ◽  
P. Kandaswamy
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Heat Removal ◽  
Simple Algorithm ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Cold Walls ◽  
Volume Method

AbstractAn investigation of natural convective flow and heat transfer inside a three dimensional rectangular cavity containing an array of discrete heat sources is carried out. The array consists of a row and columnwise regular arrangement of identical square shaped isoflux discrete heaters and is flush mounted on a vertical wall of the cavity. A symmetrical isothermal sink condition is maintained by cooling the cavity uniformly from either the opposite wall or the side walls or the top and bottom walls. The other walls of the cavity are maintained adiabatic. A finite volume method based on the SIMPLE algorithm and the power law scheme is used to solve the conservation equations. The parametric study covers the influence of pertinent parameters such as the Rayleigh number, the Prandtl number, side aspect ratio of the cavity and cavity heater ratio. A detailed fluid flow and heat transfer characteristics for the three cases are reported in terms of isothermal and velocity vector plots and Nusselt numbers. In general it is found that the overall heat transfer rate within the cavity for Ra=107 is maximum when the side aspect ratio of the cavity lies between 1.5 and 2. A more complex and peculiar flow pattern is observed in the presence of top and bottom cold walls which in turn introduces hot spots on the adiabatic walls. Their location and size are highly sensitive to the side aspect ratio of the cavity and hence offers more effective ways for passive heat removal.

scholarly journals Hybrid lattice Boltzmann and finite volume method for fluid flow and heat transfer simulations

2015 ◽  
Author(s):  
◽  
Zheng Li
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Methods ◽  
Hybrid Method ◽  
Three Dimensional ◽  
Multiscale Methods ◽  
Tracking Method ◽  
Flow And Heat Transfer ◽  
Interface Location ◽  
Volume Method

The fluid flow and heat transfer problems encountered in industry applications span into different scales and there are different numerical methods for different scales problems. Multiscale methods are needed to solve problems involving multiple scales. In this dissertation, multiscale methods are developed by combining various single scale numerical methods, including lattice Boltzmann method (LBM), finite volume method (FVM) and Monte Carlo method. Two strategies exist in combing these numerical methods. For the first one, the whole domain is divided into multiple subdomains and different domains use various numerical methods. Message passing among subdomains decides the accuracy of this type of multiscale numerical method. For the second one, various parameters are solved with different numerical methods. These two types of multiscale methods are both discussed in this dissertation. In Chapters 3 and 4, the whole domain is divided into two subdomains and they are solved with LBM and FVM respectively. This LBM-FVM hybrid method is verified with lid driven flows and natural convections. In Chapter 5, a LBM-FVM hybrid method is proposed to take both advantages of LBM and FVM: velocity field and temperature file are solved with LBM and FVM respectively. MCM has advantages in solving radiative heat transfer, and LBM-MCM hybrid method is proposed in Chapter 6. Numerical investigation for melting problems are carried on in this dissertation. The key point in solving the melting problem is how to obtain the interface location. To overcome the disadvantages in the now existing numerical methods, an interfacial tracking method is advanced to calculate the interface location. In Chapter 7, low Prandtl fluid natural convections are solved with LBM to discuss the oscillation results. Based on these results, low Prandtl number melting problems are solved using LBM with interfacial tracking method in Chapter 8. High Prandtl number melting problems in a discrete heated enclosure are solved using FVM with interfacial tracking method in Chapter 9. To take both advantages of LBM and FVM, melting problems are solved with LBM-FVM hybrid method in chapter 10, while interfacial tracking method is advanced by porous media assumptions in fluid flow field simulation process. Problems in Chapters 3-10 are all in two-dimensional and three-dimensional problems are more general than them in the realistic applications. Double LBM-MRT model for three-dimensional fluid flow and heat transfer is proposed and three types of natural convections in a cubic cavity are discussed in Chapter 11. For the first two types of cubic natural convections, the present results agreed very well with the benchmark solutions or experimental results in the literature. The results from the third type exhibited more general three-dimensional characters. Three-dimensional melting problems are solved with the proposed double LBM-MRT model with interfacial tracking method in Chapter 12. Numerical results in three conduction melting problems agree with the analytical results well. Taking Chapter 11 results in consideration, the double LBM-MRT model with interfacial tracking method is valid to solve three-dimensional conduction or convection controlled melting problems. Two convection melting problems in a cubic cavity are also solved. With a lower Rayleigh number, the convection effects are weaker; side wall effects are smaller; melting process carries on slower.

Swirl-Affected Turbulent Fluid Flow and Heat Transfer in a Circular Tube

1984 ◽  
Vol 106 (4) ◽  
pp. 766-773 ◽  
Author(s):  
E. M. Sparrow ◽  
A. Chaboki
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Reynolds Numbers ◽  
Initial Portion ◽  
Turbulent Fluid Flow ◽  
Flow And Heat Transfer ◽  
Swirl Angle ◽  
Turbulent Airflow ◽  
Visualization Experiments ◽  
Thermal Entrance

Experiments were performed to study the fluid flow and heat transfer characteristics for turbulent airflow in a tube in which there is a decaying axisymmetric swirl. Measurements were made of the local swirl angle at the tube wall and of the local Nusselt number and friction factor, all as a function of position along the length of the tube. Supplementary flow visualization experiments were performed to establish the axisymmetry of the swirl and to explore the pattern of fluid flow at the inlet of the tube. The swirl angle was found to decay exponentially along the tube, with the decay being more rapid at lower Reynolds numbers. The swirl gave rise to substantial heat transfer enhancement in the initial portion of the tube. The enhancement prevailed over a greater length of the tube at higher Reynolds numbers than at lower Reynolds numbers. Compared with the enhancements encountered in the conventional thermal entrance region in a nonswirling pipe flow, those associated with swirl are substantially greater and longer lived.

Thermal Enhancement in Tubes with Dual Twisted Tapes

2015 ◽  
Vol 751 ◽  
pp. 239-244
Author(s):  
Pratchya Somravysin ◽  
Smith Eiamsa-ard ◽  
Wayo Changcharoen ◽  
Vichan Kongkaitpaiboon ◽  
Monsak Pimsarn
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Thermal Performance ◽  
Transfer Rate ◽  
Simple Algorithm ◽  
Twisted Tapes ◽  
Twist Ratio ◽  
Constant Wall Heat Flux ◽  
Thermal Phenomena ◽  
Volume Method

Influence of the dual twisted tapes (DTs) on the heat transfer enhancement in a circular tube is reported. The effects of twist ratio (y/w = 2.0, 3.0 and 4.0) on the heat transfer rate, friction factor, and thermal performance factor in a tube under constant wall heat flux were investigated in turbulent regions. Computations, based on a finite volume method, and the SIMPLE algorithm, were carried out by QUICK schemes. From the numerical results, heat transfer rate and pressure loss increased as twist ratio of tape (y/w) decreased. Based on the same pumping power consumption, the optimum thermal performance was achieved by the use of the tapes with twist ratio of 3.0. In addition, the predictions of flow-thermal phenomena (streamline, velocity vector, TKE and local Nusselt number) are also described.

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