Numerical Solutions of Natural Convection Flow of a Dusty Nanofluid About a Vertical Wavy Truncated Cone

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Natural Convection ◽  
Mass Transport ◽  
Numerical Solutions ◽  
Convection Flow ◽  
Governing Equations ◽  
Natural Convection Flow ◽  
Two Phase ◽  
Heat And Mass Transport ◽  
Implicit Finite Difference ◽  
Control Skin

This paper reports the numerical results for the natural convection flow of a two-phase dusty nanofluid along a vertical wavy frustum of a cone. The general governing equations are transformed into parabolic partial differential equations, which are then solved numerically with the help of implicit finite difference method. Comprehensive flow formations of carrier and dusty phases are given with the aim to predict the behavior of heat and mass transport across the heated wavy frustum of a cone. The effectiveness of utilizing the nanofluids to control skin friction and heat and mass transport is analyzed. The results clearly show that the shape of the waviness changes when nanofluid is considered. It is shown that the modified diffusivity ratio parameter, NA, extensively promotes rate of mass transfer near the vicinity of the cone, whereas heat transfer rate reduces.

Turbulent Natural Convection Flow on a Heated Vertical Wall Immersed in a Stratified Atmosphere

1989 ◽  
Vol 111 (2) ◽  
pp. 378-384 ◽  
Author(s):  
A. K. Kulkarni ◽  
S. L. Chou
Keyword(s):  
Natural Convection ◽  
Numerical Solutions ◽  
Vertical Wall ◽  
Leading Edge ◽  
Transitional Flow ◽  
Convection Flow ◽  
Ambient Atmosphere ◽  
Ambient Conditions ◽  
Natural Convection Flow ◽  
Turbulent Natural Convection

This paper presents a comprehensive mathematical model and numerical solutions for a natural convection flow over an isothermal, heated, vertical wall immersed in an ambient atmosphere that is thermally stratified. The model assumes a laminar flow near the leading edge, which then becomes a transitional flow, and finally becomes fully turbulent away from the leading edge. Effects of several typical cases of ambient stratification on heat transfer to the wall, peak velocity, and temperature are examined. It is found that the velocity field is affected more significantly by the “memory” of upstream ambient conditions than the temperature field.

scholarly journals Effect of Suction/Injection on Unsteady Hydromagnetic Convective Flow of Reactive Viscous Fluid between Vertical Porous Plates with Thermal Diffusion

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
I. J. Uwanta ◽  
M. M. Hamza
Keyword(s):  
Natural Convection ◽  
Thermal Diffusion ◽  
Convective Flow ◽  
Perturbation Series ◽  
Convection Flow ◽  
Series Method ◽  
Natural Convection Flow ◽  
Implicit Finite Difference Scheme ◽  
Exothermic Chemical Reaction ◽  
Implicit Finite Difference

An investigation is performed to study the effect of suction/injection on unsteady hydromagnetic natural convection flow of viscous reactive fluid between two vertical porous plates in the presence of thermal diffusion. The partial differential equations governing the flow have been solved numerically using semi-implicit finite-difference scheme. For steady case, analytical solutions have been derived using perturbation series method. Suction/injection is used to control the fluid flow in the channel, and an exothermic chemical reaction of Arrhenius kinetic is considered. Numerical results are presented graphically and discussed quantitatively with respect to various parameters embedded in the problem.

Magnetohydrodynamic Natural Convection Flow on a Sphere in Presence of Heat Generation

2005 ◽  
Vol 10 (4) ◽  
pp. 349-363 ◽  
Author(s):  
Md. M. Molla ◽  
M. A. Taher ◽  
Md. M. K. Chowdhury ◽  
Md. A. Hossain
Keyword(s):  
Natural Convection ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Convection Flow ◽  
Surface Shear Stress ◽  
Natural Convection Flow ◽  
Surface Shear ◽  
Local Skin ◽  
Boundary Layer Equations ◽  
Keller Box Method

The present work describes the effect of magnetohydrodynamic natural convection flow on a sphere in presence of heat generation. The governing boundary layer equations are first transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations arethen solved numerically using the Keller-box method. Here we have focused our attention on the evolution of the surface shear stress in terms of local skin friction and the rate of heat transfer in terms of local Nusselt number, velocity distribution as well as temperature distribution for a selection of parameter sets consisting of heat generation parameter Q (= 0.0, 0.5, 1.0, 2.0) and the magnetic parameter M (= 0.0, 0.2, 0.5, 0.8, 1.0). Numerical solutions have been considered for Prandtl number Pr (= 0.7, 1.0, 2.0).

scholarly journals Conjugate Effects of Thermal and Mass Diffusion on Natural Convection Flow from a Heated Sphere with Internal Heat Generation or Absorption

2019 ◽  
Vol 67 (1) ◽  
pp. 13-20
Author(s):  
Sadia Masud ◽  
Nepal Chandra Roy
Keyword(s):  
Natural Convection ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Internal Heat ◽  
Mass Diffusion ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Heat Generation Or Absorption ◽  
The Mathematical Model ◽  
Unsteady Natural Convection

We examine the conjugate effects of thermal and mass diffusion on the unsteady natural convection flow from a heated sphere. The mathematical model of the problem is made into a system of nonsimilar partial differential equations introducing appropriate transformations. We solve this system employing the implicit finite difference technique. Numerical solutions have been elucidated with the skin friction as well as heat and mass transfer for varying Prandtl number, Schmidt number, combined buoyancy parameter, and heat generation or absorption parameter. Dhaka Univ. J. Sci. 67(1): 13-20, 2019 (January)

Fluid-structure interaction analysis of transient convection heat transfer in a cavity containing inner solid cylinder and flexible right wall

2019 ◽  
Vol 29 (10) ◽  
pp. 3756-3780 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Habibis Saleh ◽  
Mohammad Ghalambaz ◽  
Ali J. Chamkha ◽  
Ishak Hashim
Keyword(s):  
Natural Convection ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Convection Flow ◽  
Solid Cylinder ◽  
Governing Equations ◽  
Natural Convection Flow ◽  
Content Type ◽  
Structure Interaction ◽  
The Right

Purpose This paper aims to investigate the fluid structure interaction analysis of conjugate natural convection in a square containing internal solid cylinder and flexible right wall. Design/methodology/approach The right wall of the cavity is flexible, which can be deformed due to the interaction with the natural convection flow in the cavity. The top and bottom walls of the cavity are insulated while the right wall is cold and the left wall is partially heated. The governing equations for heat, flow and elastic wall, as well as the grid deformation are written in Arbitrary Lagrangian–Eulerian formulation. The governing equations along with their boundary conditions are solved using the finite element method. Findings The results of the present study show that the presence of the solid cylinder strongly affects the transient solution at the initial times. The natural convection flow changes the shape of the flexible right wall of the cavity into S shape wall due to the interaction of the flow and the structure. It is found that the increase of the flexibility of the right wall increases the average Nusselt number of the hot wall up to 2 per cent. Originality/value To the best of the authors' knowledge, the unsteady natural convection in an enclosure having a flexible wall and inner solid cylinder has never been reported before.

Experimental Study of the Cooling Performance of the PAFS (Passive Auxiliary Feedwater System) During Transient Operation

2013 ◽  
Author(s):  
Byoung-Uhn Bae ◽  
Seok Kim ◽  
Yu-Sun Park ◽  
Kyoung-Ho Kang
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Two Phase ◽  
Cooling Performance ◽  
Start Up ◽  
Gas Effect ◽  
Effect Test

PAFS (Passive Auxiliary Feedwater System) is one of the advanced passive safety systems adopted in the APR+ (Advanced Power Reactor plus) being developed in Korea. The PAFS aims at completely replacing the conventional active auxiliary feedwater system by cooling down the steam generator’s secondary side with a natural driving force mechanism; i.e., it can remove the core decay heat by condensing steam in a passive condensation heat exchanger (PCHX) submerged inside the passive condensation cooling tank (PCCT). With an aim of validating the cooling and operational performance of the PAFS, the separate effect test facility named as PASCAL (PAFS Condensing Heat Removal Assessment Loop) has been constructed. In this study, postulated transient scenarios occurring in the PAFS were simulated to evaluate the performance of the condensation heat transfer and investigate the thermal hydraulic phenomena of the two-phase natural convection flow. The transient test matrix is composed of inadvertent MSSV (Main Steam Safety Valve) opening test (MO), PAFS start-up actuation test (SU), and non-condensable gas effect test (NC). In the MSSV opening test, MSSV was intentionally opened and closed several times and the characteristics of the natural convection flow were investigated. The experimental results showed that the cooling performance of the PAFS could be recovered after inadvertent opening and closing the MSSV. Start-up actuation test simulated the initial transient when the PAFS actuation signal was generated and the natural convection flow was initiated in the loop, and any significant two-phase flow instability was not observed in the test. The purpose of the non-condensable gas effect test is to study the characteristics of the condensation heat transfer in the heat exchanger when the nitrogen gas was injected. The test results proved that the existence of the non-condensable gas up to 1% of the steam did not produce a meaningful decrease of the cooling capability in the PAFS. From the experimental results described above, the cooling and operating performance of the PAFS was validated with respect to occurrence of the various transient scenarios and it was proved that the function of the PAFS can be effectively performed during the transient situation. The result will be also utilized in validation of the thermal hydraulic system code in the future.

Sign in / Sign up

Export Citation Format

Share Document