Numerical simulation of Darcy-Forchheimer flow of third grade liquid with Cattaneo-Christov heat flux model

2017 ◽  
Vol 41 (12) ◽  
pp. 4352-4359 ◽  
Author(s):  
T. Hayat ◽  
M. Ijaz Khan ◽  
S. A. Shehzad ◽  
M. Imran Khan ◽  
A. Alsaedi
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Third Grade ◽  
Flux Model ◽  
Heat Flux Model ◽  
Forchheimer Flow

Direct Numerical Simulation and RANS Modeling of Turbulent Natural Convection for Low Prandtl Number Fluids

2004 ◽  
Author(s):  
I. Otic´ ◽  
G. Gro¨tzbach
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Kinetic Energy ◽  
Prandtl Number ◽  
Direct Numerical Simulation ◽  
Turbulent Heat Flux ◽  
Turbulent Heat ◽  
Temperature Variance ◽  
Flux Model ◽  
Heat Flux Model

Results of direct numerical simulation (DNS) of turbulent Rayleigh-Be´nard convection for a Prandtl number Pr = 0.025 and a Rayleigh number Ra = 105 are used to evaluate the turbulent heat flux and the temperature variance. The DNS evaluated turbulent heat flux is compared with the DNS based results of a standard gradient diffusion turbulent heat flux model and with the DNS based results of a standard algebraic turbulent heat flux model. The influence of the turbulence time scales on the predictions by the standard algebraic heat flux model at these Rayleigh- and Prandtl numbers is investigated. A four equation algebraic turbulent heat flux model based on the transport equations for the turbulent kinetic energy k, for the dissipation of the turbulent kinetic energy ε, for the temperature variance θ2, and for the temperature variance dissipation rate εθ is proposed. This model should be applicable to a wide range of low Prandtl number flows.

Direct Numerical Simulation of Turbulent Channel Flow With Heat Transfer for Low Prandtl and High Reynolds and Comparison With Algebraic Heat Flux Model

2015 ◽  
Author(s):  
Haomin Yuan ◽  
Elia Merzari
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Flux ◽  
Reynolds Number ◽  
Prandtl Number ◽  
Direct Numerical Simulation ◽  
Liquid Metals ◽  
Turbulent Channel Flow ◽  
Flux Model ◽  
Heat Flux Model

The flow characteristic of fluid at low Prandtl number is of continued interest in the nuclear industry because liquid metals are to be used in the next-generation nuclear power reactors. In this work we performed direct numerical simulation (DNS) for turbulent channel flow with fluid of low Prandtl number. The Prandtl number was set to 0.025, which is representative of the behavior of liquid metals. Constant heat flux was imposed on the walls to study heat transfer behavior, with different boundary conditions for temperature fluctuation. The bulk Reynolds number was set as high as 50,000, with a corresponding friction Reynolds number of 1,200, which is closer to the situation in a reactor or a heat exchanger than used in normally available databases. Budgets for turbulent variables were computed and compared with predictions from several RANS turbulence models. In particular, the Algebraic Heat Flux Model (AHFM) has been the focus of this comparison with DNS data. The comparisons highlight some shortcomings of AHFM along with potential improvements.

Nonlinear Dynamics of Cattaneo–Christov Heat Flux Model for Third-Grade Power-Law Fluid

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Bhuvnesh Sharma ◽  
Sunil Kumar ◽  
Carlo Cattani ◽  
Dumitru Baleanu
Keyword(s):  
Heat Flux ◽  
Differential Equations ◽  
Power Law ◽  
Shear Thinning ◽  
Third Grade ◽  
Power Law Fluid ◽  
Conservation Of Energy ◽  
Flux Model ◽  
The Impact ◽  
Heat Flux Model

Abstract A rigorous analysis of coupled nonlinear equations for third-grade viscoelastic power-law non-Newtonian fluid is presented. Initially, the governing partial differential equations for conservation of energy and momentum are transformed to nonlinear coupled ordinary differential equations using exact similarity transformations which are known as Cattaneo–Christov heat flux model for third-grade power-law fluid. The homotopy analysis method (HAM) is utilized to approximate the systematic solutions more precisely with shear-thickening, moderately shear-thinning, and most shear-thinning fluids. The solution depends on various parameters including Prandtl number, power index, and temperature variation coefficient. A systematic analysis of boundary-layer flow demonstrates the impact of these parameters on the velocity and temperature profiles.

Influence of Catteneo-Christov Heat Flux Model on Mixed Convection Flow of Third Grade Nanofluid over an Inclined Stretched Riga Plate

2018 ◽  
Vol 387 ◽  
pp. 121-134 ◽  
Author(s):  
Manoj Kumar Nayak ◽  
A.K. Abdul Hakeem ◽  
Oluwole Daniel Makinde
Keyword(s):  
Heat Flux ◽  
Mixed Convection ◽  
Fluid Velocity ◽  
Third Grade ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Linear Temperature ◽  
Riga Plate ◽  
Flux Model ◽  
Heat Flux Model

Nature of the very idea of Cattaneo-Christov heat flux model and its influence on the mixed convection flow of third grade nanofluid subject to inclined stretched Riga plate has been studied. The study furthers the case for introducing temperature dependent viscosity modeled by Reynolds. A numerical solution of the transformed boundary layer equations has been accomplished by fourth order R-K and shooting methods. The study itself has pointed out that buoyancies (thermal as well as solutal) and viscosity parameters augment the fluid velocity while increase in Deborah number yields unperturbed diminishing trend of non-linear temperature profiles.

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