Oronzio Manca^*, Sergio Nardini, Daniele Ricci

Frontiers in Heat and Mass Transfer, Vol.2, No.1, pp. 1-8, 2011, DOI:10.5098/hmt.v2.1.3007

Abstract Convective heat transfer may be enhanced passively by adopting rough surfaces. Ribs break the laminar sub-layer and create local turbulence in the channel, reducing thermal resistance and enhancing the heat transfer. However, higher losses are expected. In this paper a numerical investigation is carried out on air forced convection in a rectangular ribbed channel. A three-dimensional model is developed to study the effect of the angle between the fluid flow direction and the ribbed surface, provided with rectangular turbulators, in the turbulent flow. Simulations s that Nusselt numbers as well as the pressure drops increase as the inclination angles increase. More >

Anand Shukla^a, Alok Chaube^b, Shailesh Guptac^†, Arvind Sirsath^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.14

Abstract One of the traditional methods used to improve the efficiency of a gas turbine is to increases the inlet temperature; thereby increasing the power output and in turn, the efficiency. The internal cooling passages of blades are roughened by artificial roughness to improve the cooling performance. The present study investigates the convective heat transfer and friction factor (pressure drop) characteristics of a rib-roughened square duct. The test section of the duct is roughened on its top and bottom wall with V and ᴧ- shaped square ribs. In the study, the Reynolds number (Re) varied from 10,000 to 40,000, the relative… More >

Amnart Boonloi¹, Withada Jedsadaratanachai^2,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 81-106, 2023, DOI:10.32604/fhmt.2023.041547

Abstract Simulation of fluid-flow topology and thermal behavior in a round tube heat exchanger (RTHX) installed by three V-rib sets is reported. The expected phenomena for the rib installation are the generated vortex flow, impinging flow, greater fluid blending and thermal boundary layer disturbance (TBLD). These phenomena are key causes of the augmentation of heat transfer potentiality and thermal efficiency of the RTHX. Effects of rib height (b₁ = 0.05D – 0.25D and b₂ = 0.05D – 0.25D), rib pitch or rib spacing (P = D, 1.5D and 2D) and fluid directions (positive x (+x flow direction) and negative x (–x… More > Graphic Abstract

Mohamed Salmi^1,2, Younes Menni³, Ali J. Chamkha^4,5,*, Houari Ameur⁶, Rachid Maouedj⁷, Ahmed Youcef⁷

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 147-173, 2021, DOI:10.32604/cmes.2021.012839

Abstract The hydrothermal behavior of air inside a solar channel heat exchanger equipped with various shaped ribs is analyzed numerically. The bottom wall of the exchanger is kept adiabatic, while a constant value of the temperature is set at the upper wall. The duct is equipped with a flat rectangular fin on the upper wall and an upstream V-shaped baffle on the lower wall. Furthermore, five hot wall-attached rib shapes are considered: trapezoidal, square, triangular pointing upstream (type I), triangular pointing downstream (type II), and equilateral-triangular (type III) cross sections. Effects of the flow rates are also inspected for various Reynolds… More >

Sanjay K. Sharma¹, V. R. Kalamkar^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 295-319, 2018, DOI:10.3970/cmes.2018.114.295

Abstract The three-dimensional numerical investigation of an incompressible flow through rib roughened solar air heater is carried out. A combination of thin transverse and truncated ribs is attached on the absorber plate to study its effect on the heat transfer and friction factor. The parameters in the form of Reynolds number (Re) of 4000-16000, relative roughness pitch (P/e) of 8-18 and relative roughness height (e/Dh) of 0.0366-0.055 is considered for the analysis. The CFD code ANSYS FLUENT is used to solve the governing equations of turbulent flow. The RNG k–ε turbulence model is used to solve the transport equations with enhanced… More >

K.B. Mustapha ^1,2

CMC-Computers, Materials & Continua, Vol.42, No.2, pp. 141-174, 2014, DOI:10.3970/cmc.2014.042.141

Abstract This study investigates the sensitivity of the flexural response of a ribconnected system of coupled micro-panels with traction-free surfaces. Idealized as a two-dimensional elastic continuum with a finite transverse stiffness, each micropanels’ behavior is examined within the framework of the biharmonic mathematical model derived from the higher-order, size-dependent strain energy formulation. The model incorporates the material length scale, which bears an associative relationship with the underlying polymer’s averaged Frank elastic constant. Upper estimates of the eigenvalue of the system, under fully clamped edges and simplysupported edges, are determined by the Rayleigh method. The adopted theory for the micro-panel’s behavior takes… More >