Numerical study of natural convection in a vertical porous annulus with discrete heating

The enhancement of the thermal performance of heat exchanging equipment transport energy at low financial cost by various techniques is presented in this review. Various annular passage configurations have been used in the reviewed studies, namely circular, ellipse, rectangular, square, triangular, and rhombic annular channels with different fluid and boundary conditions. The effect of eccentricity in both horizontal and vertical directions on heat transfer rate in most numerical and experimental investigations for horizontal and vertical annular passages is studied. The effects of heater length, as well as the Darcy, Prandtl, Reynolds, Grashof and Rayleigh numbers on heat transfer in concentric and eccentric annular passages are also investigated. In case of rotating the inner, outer or both cylinders of the annular cylinder arrangement, the generated secondary flow influences the heat transfer to fluid flow in an annular passage. The effect of nanofluid on the increased enhancement of heat transfer in an annular channel is presented. Related studies on curved, covered annular channels showed augmented heat transfer rate in comparison with straight annular channels. In this review, a good agreement is evident between experimental and numerical data, which could help researchers design thermal systems supported by annular passages with the goal of retarding energy consumption by equipment and machineries in applications that could ultimately contribute to appeasing the global energy crisis.

A review of studies on forced, natural and mixed heat transfer to fluid and nanofluid flow in an annular passage.

Thermosolutal convection from a discrete heat and solute source in a vertical porous annulus

Impact of exponential form of internal heat generation on water-based ternary hybrid nanofluid flow by capitalizing non-Fourier heat flux model

Heat transfer: a review of 2002 literature

A numerical investigation of transient free convection in a vertical cylindrical annulus filled with a fluid saturated porous medium with the inner wall heated to a uniform temperature, the outer wall cooled to a uniform temperature and maintaining top and bottom boundaries at adiabatic condition, has been carried out. A finite difference implicit method which incorporates upwind differencing for nonlinear convective terms and the successive line over relaxation (SLOR) method for convergence are used to solve the coupled nonlinear governing equations. Heat transfer rate and flow fields are obtained for wide range of Rayleigh numbers Ra ranging from 103 to 106, Darcy numbers Da ranging from 10-1 to 10-3, radii ratio λ. in the range 1 ≤ λ ≤10, and aspect ratio A in the range 1 ≤ A ≤ 2. The numerical results indicate that the temperature and velocity fields are significantly modified and the heat transfer rate is decreased as the Darcy number decreases. The temperature and velocity fields are significantly modified by the radii ratio. The rate of heat transfer increases with an increase in radii ratio. At a high Rayleigh number the curvature effect on heat transfer is insignificant. The numerical results farther indicate that an increase in viscosity ratio (Λ) reduces the Nusselt number by enhancing the contribution of the viscous diffusion term. Copyright © 2002 by Begell House, Inc.

Numerical Study of Natural Convection in a Vertical Cylindrical Annulus Using a Non-Darcy Equation

A Glauert type laminar wall jet issuing into a stationary liquid medium lying above a wall has technical uses in wall cooling and flow control. It plays a vital role in industrial applications like cooling/heating by impingement of jet, turbine blades, film cooling, mass and heat transfer phenomena. In this regard, a steady incompressible two-dimensional laminar Glauert kind wall jet is scrutinized in this study by considering nanoparticles suspension in the base liquid sodium alginate (NaAlg) with suction and wall slip boundary conditions. Further, a comparative study is done by considering aluminum alloy(AA7075) and single-walled carbon nanotube (SWCNT) as nanoparticles. The reduced ordinary differential equations (ODEs) are numerically solved by applying Runge–Kutta–Fehlberg fourth fifth-order (RKF-45) technique along with the shooting method. Results reveal that NaAlg−SWCNT Casson nanofluid shows enhanced heat transfer than NaAlg−AA7075 Casson nanoliquid for increased values of radiation parameter. The rising values of the Casson parameter deteriorate the heat transfer rate of both nanoliquids but an inverse trend is seen for improved values of radiation parameter. 

B. M. R. Prasanna

Papers

Numerical Study of Natural Convection in a Vertical Cylindrical Annulus Using a Non-Darcy Equation

Effect of thermal radiation on heat transfer in plane wall jet flow of Casson nanofluid with suction subject to a slip boundary condition

Heat transfer augmentation in a solar air heater with conical roughness elements on the absorber

Heat transmission and air flow friction in a solar air heater with a ribbed absorber plate: A computational study

Impacts of thermal source and sink on magnetoconvection in an annular geometry: A numerical analysis.