Ambareen Khan¹, Sher Afghan Khan², Mohammed Nishat Akhtar^1,*, Abdul Aabid^3,*, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2007-2028, 2024, DOI:10.32604/fdmp.2024.049368 - 23 August 2024

Abstract When better fuel-air mixing in the combustion chamber or a reduction in base drag are required in vehicles, rockets, and aeroplanes, the base pressure control is activated. Controlling the base pressure and drag is necessary in both scenarios. In this work, semi-circular ribs with varying diameters (2, 4, and 6 mm) positioned at six distinct positions (0.5D, 1D, 1.5D, 2D, 3D, and 4D) inside a square duct with a side of 15 mm are proposed as an efficient way to apply the passive control technique. In-depth research is done on optimising rib size for various More > Graphic Abstract

Vigneshvaran Sethuraman¹, Parvathy Rajendran^1,*, Sher Afghan Khan², Abdul Aabid³, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1847-1866, 2024, DOI:10.32604/fdmp.2024.049441 - 06 August 2024

Abstract This study deals with base pressure management in a duct for various values of the Mach number (M), namely, Mach number corresponding to sonic and four supersonic conditions. In addition to the Mach number, the nozzle pressure ratio (NPR), the area ratio, the rib dimension, and the duct length are influential parameters. The following specific values are examined at M = 1, 1.36, 1.64, and 2, and NPRs between 1.5 and 10. The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct. When the… More >

Amnart Boonloi¹, Withada Jedsadaratanachai^2,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 81-106, 2023, DOI:10.32604/fhmt.2023.041547 - 30 November 2023

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)… 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 - 22 December 2020

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… 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 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… 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… More >

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 More >