Numerical Simulation of Liquid-Liquid Taylor Flow With Heat Transfer

2019 ◽  
Author(s):  
Marcel Kwakkel ◽  
Maria Fernandino ◽  
Carlos A. Dorao
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Spectral Element ◽  
Smooth Transition ◽  
Navier Stokes ◽  
Field Methods ◽  
Taylor Flow ◽  
Dynamic Interface ◽  
Cahn Hilliard Equation ◽  
Transfer Properties

Abstract Numerical simulation of Taylor flows presents several challenges. At the dynamic interface physical properties are discontinuous, which is especially challenging for the thin film between the droplet and the wall. Phase-field methods, which are derived from thermodynamic principles, define the interface as a smooth transition between phases. By coupling the Cahn-Hilliard equation with the Navier-Stokes and energy equation, both interface dynamics and heat transfer can be captured. In the work presented, the resulting system of equations are solved by a parallel h-adaptive least-squares spectral element method. To approximate the solution with sufficient numerical accuracy, C1 Hermite basis functions and a space-time formulation have been applied. It is widely accepted in the literature that the droplet characteristics such as length, velocity and dynamic interaction among them affect the heat transfer properties of Taylor flow. To gain understanding, their effect on heat transfer and pressure drop for liquid-liquid Taylor flow in microchannels must be studied in more detail.

Two Dimensional Simulations of Enhanced Heat Transfer in an Intermittently Grooved Channel

2000 ◽  
Author(s):  
M. Greiner ◽  
P. F. Fischer ◽  
H. M. Tufo
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Spectral Element ◽  
Local Heat ◽  
Navier Stokes ◽  
Computational Domain ◽  
Two Dimensional ◽  
Number Range ◽  
Element Technique ◽  
Outflow Boundary

Abstract Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600 ≤ Re ≤ 1800. The computational domain has seven contiguous transverse grooves cut symmetrically into opposite walls, followed by a flat section with the same length. Periodic inflow/outflow boundary conditions are employed. The development and decay of unsteady flow is observed in the grooved and flat sections, respectively. The axial variation of the unsteady component of velocity is compared to the local heat transfer, shear stress and pressure gradient. The results suggest that intermittently grooved passages may offer even higher heat transfer for a given pumping power than the levels observed in fully grooved passages.

DYNAMICAL BEHAVIORS AND NUMERICAL SIMULATION OF A LORENZ-TYPE SYSTEM FOR THE INCOMPRESSIBLE FLOW BETWEEN TWO CONCENTRIC ROTATING CYLINDERS

2012 ◽  
Vol 22 (05) ◽  
pp. 1250124 ◽  
Author(s):  
HEYUAN WANG
Keyword(s):  
Numerical Simulation ◽  
Incompressible Flow ◽  
Stokes Equations ◽  
Type System ◽  
Period Doubling ◽  
Navier Stokes ◽  
Rotating Cylinders ◽  
Taylor Flow ◽  
Dynamical Behaviors ◽  
Low Dimensional

In this paper, we investigate the problem of dynamical behaviors and numerical simulation of Lorenz systems for the incompressible flow between two concentric rotating cylinders. A spectral Galerkin method is used to derive a model system of axisymmetric Couette–Taylor flow, a three-mode system, which is structurally similar to the Lorenz system, is obtained by a suitable three-mode truncation of the Navier–Stokes equations for the incompressible flow between two concentric rotating cylinders. The stability of the three-mode system is discussed, the existence of its attractor is given. Moreover, numerical simulation results indicate that this low-dimensional model exhibits a route to chaos via a period doubling cascade. Using these numerical results we explain successive transitions of Couette–Taylor flow from Laminar flow to turbulence in the experiment.

Two-Dimensional Simulations of Enhanced Heat Transfer in an Intermittently Grooved Channel

2002 ◽  
Vol 124 (3) ◽  
pp. 538-545 ◽  
Author(s):  
M. Greiner ◽  
P. F. Fischer ◽  
H. M. Tufo
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Spectral Element ◽  
Local Heat ◽  
Navier Stokes ◽  
Computational Domain ◽  
Two Dimensional ◽  
Number Range ◽  
Element Technique ◽  
Outflow Boundary

Two-dimensional Navier-Stokes simulations of heat and momentum transport in an intermittently grooved passage are performed using the spectral element technique for the Reynolds number range 600⩽Re⩽1800. The computational domain has seven contiguous transverse grooves cut symmetrically into opposite walls, followed by a flat section with the same length. Periodic inflow/outflow boundary conditions are employed. The development and decay of unsteady flow is observed in the grooved and flat sections, respectively. The axial variation of the unsteady component of velocity is compared to the local heat transfer, shear stress and pressure gradient. The results suggest that intermittently grooved passages may offer even higher heat transfer for a given pumping power than the levels observed in fully grooved passages.

Optimization of Wall Cooling in Gas Turbine Combustor Through Three-Dimensional Numerical Simulation

2005 ◽  
Vol 127 (4) ◽  
pp. 704-723 ◽  
Author(s):  
R. Gordon ◽  
Y. Levy
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Gas Turbine Combustors ◽  
Structural Problems ◽  
Prediction Reliability ◽  
Solid Walls

This paper is concerned with improving the prediction reliability of CFD modeling of gas turbine combustors. CFD modeling of gas turbine combustors has recently become an important tool in the combustor design process, which till now routinely used the old “cut and try” design practice. Improving the prediction capabilities and reliability of CFD methods will reduce the cycle time between idea and a working product. The paper presents a 3D numerical simulation of the BSE Ltd. YT-175 engine combustor, a small, annular, reversal flow type combustor. The entire flow field is modeled, from the compressor diffuser to turbine inlet. The model includes the fuel nozzle, the vaporizer solid walls, and liner solid walls with the dilution holes and cooling louvers. A periodic 36 deg sector of the combustor is modeled using a hybrid structured/unstructured multiblock grid. The time averaged Navier-Stokes (N-S) equations are solved, using the k-ε turbulence model and the combined time scale (COMTIME)/PPDF models for modeling the turbulent kinetic energy reaction rate. The vaporizer and liner walls’ temperature is predicted by the “conjugate heat transfer” methodology, based on simultaneous solution of the heat transfer equations for the vaporizer and liner walls, coupled with the N-S equations for the fluids. The calculated results for the mass flux passing through the vaporizer and various holes and slots of the liner walls, as well as the jet angle emerging from the liner dilution holes, are in very good agreement with experimental measurements. The predicted location of the liner wall hot spots agrees well with the position of deformations and cracks that occurred in the liner walls during test runs of the combustor. The CFD was used to modify the YT-175 combustion chamber to eliminate structural problems, caused by the liner walls overheating, that were observed during its development.

A Numerical Simulation of Combined Radiation and Natural Convection in a Differential Heated Cubic Cavity

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
P. Kumar ◽  
V. Eswaran
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Natural Convection ◽  
Optical Thickness ◽  
Three Dimensional ◽  
Variable Density ◽  
Navier Stokes ◽  
Complex Flow ◽  
Fluid Properties ◽  
Flow Phenomena

This article presents a numerical simulation of combined radiation and natural convection in a three-dimensional differentially heated rectangular cavity with two opposite side walls kept at a temperature ratio Th/Tc=2.0 and Tc=500 K, with others walls insulated. A non-Boussinesq variable density approach is used to incorporate density changes due to temperature variation. The Navier–Stokes (NSE), temperature, as well as the radiative transfer (RTE) equations are solved numerically by a finite volume method, with constant thermophysical fluid properties (except density) for Rayleigh number Ra=105 and Prandtl number Pr=0.71. The convective, radiative, and total heat transfer on the isothermal and adiabatic walls is studied along with the flow phenomena. The results reveal an extraordinarily complex flow field, wherein, along with the main flow, many secondary flow regions and singular points exist at the different planes and are affected by the optical properties of the fluid. The heat transfer decreases with increase in optical thickness and the pure convection Nusselt number is approached as the optical thickness τ>100, but with substantially different velocity field. The wall emissivity has a strong influence on the heat transfer but the scattering albedo does not.

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