Ayat N. Mahmood¹, Amer A. Abdulrahman¹, Laith S. Sabri^1,*, Abbas J. Sultan¹, Hasan Shakir Majdi², Muthanna H. Al-Dahhan³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 239-256, 2024, DOI:10.32604/fdmp.2023.028015

Abstract Hydrodynamics characterization in terms of flow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies. This review presents recent studies on the typical flow regimes established in bubble columns. Some effort is also provided to introduce relevant definitions pertaining to this field, namely, that of “void fraction” and related (local, chordal, cross-sectional and volumetric) variants. Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail. In the second part of the review, the attention is shifted to cases with internals of various types (perforated… More >

K. Venkateswara Raju^a,*, A. Parandhama^a , M.C. Raju^b , K. Ramesh Babu^a

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-8, 2018, DOI:10.5098/hmt.10.25

Abstract This manuscript presents an analytical investigation on unsteady MHD free convective viscous incompressible flow of electrically conducting Jeffery fluid with heat source, past an infinite vertical porous flat plate in slip flow regime. A uniform magnetic field perpendicular to the plate is applied. The presence of thermal radiation, heat source, radiation absorption and chemical reaction are included. The effects of flow parameters and thermo physical properties on the velocity temperature and concentration fields across the boundary layer are investigated. The forms of the wall Shear stress, Nusselt number and Sherwood number are derived. The results are shown in figures and… More >

O. M. Oyewola^a,b,* , O. S. Ismail^b , M. O. Olasindeb , O. O. Ajide^b

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-8, 2022, DOI:10.5098/hmt.18.30

Abstract In this work, attempt is made to investigate the effect of cylindrical arrangement on the thermal and flow fields within the mixed convective regime for different values of Reynolds number within the study zone. Constructal design was used to design the flow geometric. Two-dimensional unsteady laminar flow equations with buoyancy force were solved numerically using finite element technique implemented on ANSYS FLUENT software. The study showed an optimised arrangement of 50% difference in coefficient of drag and 10% difference in Nusselt number within the geometrical arrangement variation. The effect of geometric arrangement is pronounced at low Ri than at high… More >

Javed S. Shaikh^1,*, Krishna Kumar¹, Khizar A. Pathan², Sher A. Khan³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1637-1653, 2023, DOI:10.32604/fdmp.2023.025113

Abstract The complex fluid-dynamic instabilities and shock waves occurring along the surface of a two-dimensional wedge at high values of the Mach number are studied here through numerical solution of the governing equations. Moreover, a regression model is implemented to determine the pressure distribution for various Mach numbers and angles of incidence. The Mach number spans the interval from 1.5 to 12. The wedge angles (θ) are from 5° to 25°. The pressure ratio (P₂/P₁) is reported at various locations (x/L) along the 2D wedge. The results of the numerical simulations are compared with the regression model showing good agreement. More >

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 501-511, 2023, DOI:10.32604/fdmp.2022.021502

Abstract The thermal behavior of pipes with a twisted tape inside (used to enhance heat transfer through the tube wall) is studied in the laminar flow regime. Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–2000. It is found that in such conditions the ‘Nusselt Number’ (Nu) gradually increases with reducing the tape twist ratio, whereas the friction factor is detrimentally affected by the presence of the tape (as witnessed by the comparison with the companion case where a plain tube is considered). In particular, it is shown that the heat transfer efficiency can… More >

Li Lei¹, Jun An¹, Fushun Liang¹, Cheng Cheng¹, Naixiang Zhou², Yanhong Ning³, Jingzhi Zhang^1,4,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1037-1048, 2021, DOI:10.32604/fdmp.2021.016081

Abstract The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally studied. The test channel is a transparent quartz glass circular channel with an inner diameter of 6.68 mm. The working fluids are air and water and their superficial velocities range from 0.014 to 8.127 m/s and from 0.0238 to 0.556 m/s, respectively. The void fraction is determined using the flow pattern images captured by a high-speed camera, while quick closing valves are used for verification. Four flow patterns are analyzed in experiments: slug flow, bubbly flow, annular flow and stratified flow.… More >

Daoming Shen^1,*, Xia Zhang¹, Wei He¹, Jinhong Xia¹, Songtao Xue²

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.6, pp. 1259-1272, 2020, DOI:10.32604/fdmp.2020.010951

Abstract Experiments about heat transfer in the presence of a two-phase flow due to the condensation of a R1234yf refrigerant have been performed considering a smooth tube and two micro-fin tubes. The following experimental conditions have been considered: Condensation temperatures of 40°C, 43°C and 45°C, mass fluxes of 500–900 kg/(m² ·s), vapor qualities at the inlet and outlet of the heat transfer tube in the ranges 0.8–0.9 and 0.2–0.3, respectively. These tests have shown that: (1) The heat transfer coefficient increases with decreasing the condensation temperature and on increasing the mass flux; (2) The heat transfer coeffi- cient inside the micro-fin… More >

Bin Wang¹, Jing Zheng¹, Yuanyuan Yu^1,2, Runmin Lv¹, Changyue Xu^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 675-684, 2020, DOI:10.32604/fdmp.2020.09681

Abstract Rocket sleds belong to a category of large-scale test platforms running on the ground. The applications can be found in many fields, such as aerospace engineering, conventional weapons, and civil high-tech products. In the present work, shock-wave/rail-fasteners interaction is investigated numerically when the rocket sled is in supersonic flow conditions. Two typical rocket sled models are considered, i.e., an anti-D shaped version of the rocket sled and an axisymmetric slender-body variant. The dynamics for Mach number 2 have been simulated in the framework of a dynamic mesh method. The emerging shock waves can be categorized as head-shock, tailing-shock and reflected-shock.… More >