scholarly journals Flow Analysis of Laminar Wall Jet over Curved Cavity with a Channel Mounted Fin

2019 ◽  
Vol 8 (3) ◽  
pp. 1876-1882 ◽  
Keyword(s):  
Flow Analysis ◽  
Flow Characteristics ◽  
Circuit Board ◽  
Momentum Balance ◽  
Jet Flows ◽  
Wall Jet ◽  
Fluid Flow Characteristics ◽  
Wall Jet Flow ◽  
Jet Characteristics ◽  
Fin Length

Wall jet flow is used for industrial cooling process, cooling of electronic component mounted on circuit board etc. Numerical simulations have been carried out for laminar two dimensional wall jet flows along curved cavity having a channel mounted thin fin. The commercial finite volume code FLUENT is chosen to resolve the mass balance and momentum balance equations. Fluid flow characteristics are investigated for different Reynolds number (Re=100 to 600) and for different fin geometry. The results are plotted in the form of velocity profiles and streamline contours. The effect of fin length on the laminar wall jet characteristics is also investigated.

Numerical Investigations on Effect of Obstacle in an Incompressible Laminar Wall Jet Flow

2016 ◽  
Vol 852 ◽  
pp. 747-753
Author(s):  
M Arul Prakash ◽  
K. Mayilsamy ◽  
P. Rajesh Kanna
Keyword(s):  
Vertical Wall ◽  
Flow Characteristics ◽  
Jet Flow ◽  
Bottom Wall ◽  
Wall Jet ◽  
Computational Domain ◽  
Related Area ◽  
Jet Cooling ◽  
Wall Jet Flow ◽  
Stream Function Formulation

The effect of obstacle in an incompressible laminar wall jet flow is investigated numerically. Heat transfer enhancements in cooling of heated objects are found wide application in almost all fields of engineering. Wall jet cooling is one such important application. From literature survey in the related area it is found that the influence of the presence of obstacles in the flow path of laminar wall jet needs to be investigated. The objective of the present work is to study the effect of obstacle on flow characteristics of the incompressible laminar wall jet. The wall jet is blown along a horizontal bottom wall. The obstacle block is placed on the bottom wall. A two dimensional computational domain is considered. At the left side of the computational domain a vertical wall is present. The right and top of the domains are open to ambient fluid. An in-house code developed based on vorticity-stream function formulation for the full computational domain is used to solve the problem. The flow pattern, formation and growth of recirculation, attachment and re-attachment behaviors and the velocity profiles were studied with and without obstacle. From the results of the investigations, the influences of obstacle on flow characteristics of wall jet was found more at higher Reynolds numbers and at the regions nearer to the obstacle.

Numerical modeling of Glauert type exponentially decaying wall jet flows of nanofluids using Tiwari and Das’ nanofluid model

2019 ◽  
Vol 29 (3) ◽  
pp. 1010-1038 ◽  
Author(s):  
Amin Jafarimoghaddam ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Differential Equations ◽  
Design Methodology ◽  
Analytic Solution ◽  
Jet Flows ◽  
Wall Jet ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Wall Jet Flow

Purpose The purpose of this study is to present a simple analytic solution to wall jet flow of nanofluids. The concept of exponentially decaying wall jet flows proposed by Glauert (1956) is considered. Design/methodology/approach A proper similarity variables are used to transform the system of partial differential equations into a system of ordinary (similarity) differential equations. This system is then solved analytically. Findings Dual solutions are found and a stability analysis has been done. These solutions show that the first solution is physically realizable, whereas the second solution is not practicable. Originality/value The present results are original and new for the study of fluid flow and heat transfer over a static permeable wall, as they successfully extend the problem considered by Glauert (1956) to the case of nanofluids.

scholarly journals Effects of an adiabatic fin on the mixed convection heat transfer in a square cavity with two ventilation ports

2014 ◽  
Vol 18 (2) ◽  
pp. 377-389 ◽  
Author(s):  
Fatih Selimefendigil ◽  
Hakan Öztop
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Thermal Performance ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Square Cavity ◽  
Fluid Flow Characteristics ◽  
The One ◽  
Convection Dominated ◽  
Fin Length

In this study, a square cavity with two ventilation ports in the presence of an adi-abatic fin of different lengths placed on the walls of the cavity is numerically analyzed for the mixed convection case for a range of Richardson numbers (Ri=0.1,1, 10, 100) and at Reynolds number of 300. The effect of the fin height, placement of the fin on each of the four walls of the cavity and Richardson number on the heat transfer and fluid flow characteristics is numerically analyzed. The results are presented in terms of streamlines, isotherm plots and averaged Nusselt number plots. It is observed that for the convection dominated case, fin length and its position on the one of the four walls of the cavity do not alter the thermal performance whereas when the buoyancy effects become important thermal performance increases for high fin length.

scholarly journals Heat transfer prediction in a shallow cavity effect of incoming flow characteristics

2016 ◽  
Vol 20 (5) ◽  
pp. 1519-1532
Author(s):  
Arous Madi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Characteristics ◽  
Wall Jet ◽  
Incoming Flow ◽  
Cavity Depth ◽  
Nozzle Height ◽  
Shallow Cavity ◽  
Wall Jet Flow ◽  
Flow Case

This study deals numerically with a heat transfer in a turbulent flow over a shallow cavity. Two different configurations of the incoming flow are considered: a boundary layer flow and a plane wall jet flow, in order to examine the wall jet outer layer effect on the heat transfer. This layer is an important additional turbulence source in the wall jet flow. Reynolds number and turbulence intensity effects were investigated in the boundary layer incoming flow case. The cavity depth to nozzle height ratio effect was examined in the wall jet incoming flow case. The numerical approach is based on k-? standard turbulence model. This study reveals that the heat transfer is very sensitive to the incoming flow characteristics. The turbulence intensity increase accelerates the reattachment of the shear layer at the cavity floor and enhances the heat transfer. The reattachment phenomenon seems to be less affected by the Reynolds number. However, an increase in this parameter ameliorates the heat transfer. It was also observed a heat transfer enhancement in the wall jet incoming flow case as compared to that of a boundary layer. Likewise, it was found that the augmentation of the cavity depth to the jet nozzle height ratio improves even more the heat transfer. The maximum heat transfer occurs upstream of the reattachment.

scholarly journals Effect of Furnace Gas Composition on Characteristics of Supersonic Oxygen Jets in the Converter Steelmaking Process

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3353
Author(s):  
Liujie Yao ◽  
Rong Zhu ◽  
Yixing Tang ◽  
Guangsheng Wei ◽  
Kai Dong
Keyword(s):  
High Temperature ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Converter Steelmaking ◽  
Cfd Model ◽  
Steelmaking Process ◽  
Combustion Experiment ◽  
Computational Fluid Dynamics Cfd ◽  
Fluid Flow Characteristics ◽  
Jet Characteristics

During the converter steelmaking process, the presence of supersonic oxygen jets can provide oxygen to high-temperature metal baths that promotes chemical reactions in the bath, accelerates the smelting rhythm, and facilitates a uniform distribution of the ingredients in the bath. In this paper, a computational fluid dynamics (CFD) model with combustion reactions is established and compared to the results of combustion experiment. This paper studies the behavior and fluid flow characteristics of supersonic oxygen jets under different environmental compositions under a steelmaking temperature of 1873 K. This validated CFD model can be used to investigate the effect of furnace gas on supersonic oxygen jet characteristics during the converter steelmaking process. The results indicate that the composition of furnace gas has an impact on the characteristics of the oxygen jet. Specifically, as the carbon monoxide (CO) volume fraction increases, the high velocity region of supersonic oxygen jet increases, and the high temperature and the high turbulent kinetic energy regions expand.

Numerical Simulation of Two-Dimensional Laminar Incompressible Wall Jet Flow Under Backward-Facing Step

2006 ◽  
Vol 128 (5) ◽  
pp. 1023-1035 ◽  
Author(s):  
P. Rajesh Kanna ◽  
Manab Kumar Das
Keyword(s):  
Linear Trend ◽  
Step Length ◽  
Jet Flow ◽  
Step Height ◽  
Jet Flows ◽  
Wall Jet ◽  
Two Dimensional ◽  
Backward Facing Step ◽  
Navier Stokes Equation ◽  
Wall Jet Flow

Two-dimensional laminar incompressible wall jet flow over a backward-facing step is solved numerically to gain insight into the expansion and recirculation of flow processes. Transient streamfunction vorticity formulation of the Navier-Stokes equation is solved with clustered grids on the physical domain. The behavior of the jet has been studied for different step geometry (step length, l, step height, s) and Reynolds number (Re). It is found that the presence of a step in the wall jet flow creates recirculation and the reattachment length follows an almost linear trend within the range considered for both parameters Re and step geometry. Simulations are made to show the effect of entrainment on recirculation eddy. Detailed study of u velocity decay is reported. The velocity profile in the wall jet region shows good agreement with experimental as well as similarity results. The distance where the similarity profile forms is reduced by increasing the step geometry whereas an increment in Re increases this distance. The effects of Re, step length, and step height on wall vorticity are presented. The parametric study is helpful to predict the reattachment location for wall jet flows over step.

Numerical Simulation of Two Dimensional Laminar Wall Jet Flow over Solid Obstacle

2014 ◽  
Vol 592-594 ◽  
pp. 1935-1939 ◽  
Author(s):  
M Arul Prakash ◽  
K. Mayilsamy ◽  
P. Rajesh Kanna
Keyword(s):  
Stream Function ◽  
Flow Characteristics ◽  
Relaxation Method ◽  
Jet Flow ◽  
Stream Line ◽  
Wall Jet ◽  
Two Dimensional ◽  
Algebraic Equations ◽  
Contour Plots ◽  
Wall Jet Flow

A Computational Fluid Dynamics code was developed to study the flow characteristics of two dimensional laminar incompressible flow. Stream function-vorticity formulation was used for solving two dimensional continuity and momentum equations. The unsteady vorticity transport equation is solved by alternate direction implicit scheme. The stream function equation is solved by the successive over relaxation method. A computational code in c-language was developed to solve the tridiagonal system of algebraic equations. Two dimensional flow through a channel with rectangular block at the bottom wall was considered for the validation. The streamline patterns obtained for different Reynolds number shows good agreement with published results. The code was modified to simulate an incompressible laminar wall jet flow around a solid obstacle. Simulations were carried out for different Reynolds numbers. Contour plots of Stream line, u-velocity and v-velocity were obtained. The variations of flow patterns and the development of vortices were studied and reported.

Radial Wall Jet Flow Over Sigmoidal Surfaces

2020 ◽  
Author(s):  
Leonard F. Pease ◽  
Michael J. Minette ◽  
Judith Ann Bamberger
Keyword(s):  
Velocity Profile ◽  
Jet Flows ◽  
Wall Jet ◽  
Radial Wall ◽  
Modest Contribution ◽  
Velocity Decay ◽  
Conservation Of Momentum ◽  
Fixed Beds ◽  
Wall Jet Flow ◽  
Particle Bed

Abstract Radial wall jet flows across flat smooth surfaces have been studied for decades. These studies show that the radial velocity of these jets decays inversely with distance from the nozzle with modest contribution from friction (Poreh, et al., 1967; Rajaratnam, 1976). However, the extent to which flat surface results apply to curved surfaces remains unclear. In this paper we explore the influence of settled particle bed slope on radial wall jet velocity profiles. Jet flows over particle beds often introduce curvature in the particle bed profile, but the influence of the developed curvature on the velocity profile has not been explored. We model the step change in thickness as a sigmoidal curve of variable steepness and use conservation of momentum to evaluate the velocity profile for steady fixed beds. We find that surface curvature has a significant influence on the velocity decay coefficients, provided there is a slip velocity in the vicinity of the particle bed interface, which is strictly true for particle surfaces. We show that the velocity profile attenuates because of curvature. Indeed, conservation of momentum predicts conditions where the forward momentum of the flow is directed completely upward. The solution identifies two new dimensionless groups that determine whether a curved surface is sufficient to block radial flow and force flow vertically.

Influence of Gas Condensability on Labyrinth Seal's Sealability

2014 ◽  
Vol 575 ◽  
pp. 355-362 ◽  
Author(s):  
Jie Jiang ◽  
Yi Yong Yang ◽  
Yong Jian Li ◽  
Wei Feng Huang
Keyword(s):  
Low Cost ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Labyrinth Seal ◽  
Rotating Fluid ◽  
Fluid Machinery ◽  
Leakage Loss ◽  
Labyrinth Seals ◽  
Fluid Flow Characteristics ◽  
Compressible Gas

Labyrinth seals are widely used in rotating fluid machinery, due to its simplicity, low-cost and reliability. In this paper, the effect of cavities on leakage loss in straight-through labyrinth seals are studied by changing gas condensability. The fluid flow characteristics through straight-through labyrinth seals are obtained by using viscous flow analysis along with a RNG k-ε turbulence model. The numerical calculation and various gas pressure is that leakage of compressible gas is greater than that of incompressible gas. The result is investigated by the heating effect of labyrinth seal and density characteristics of compressible gas.

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