Louay Abd Al-Azez Mahdi, Mohammed A. Fayad, Miqdam T. Chaichan^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.9, pp. 2201-2214, 2023, DOI:10.32604/fdmp.2023.027166

Abstract A theoretical study based on the Penalty factor (PF) method by Cavallini et al. is conducted to show that the pressure drop occurring in a wire-on-tube heat exchanger can be converted into a temperature difference for two types of refrigerants R-134a and R-600a typically used for charging refrigerators and freezers. The following conditions are considered: stratified or stratified-wavy flow condensation occurring inside the smooth tube of a wire-on-tube condenser with diameter 3.25, 4.83, and 6.299 mm, condensation temperatures 35°C, 45°C, and 54.4°C and cover refrigerant mass flow rate spanning the interval from 1 to 7 kg/hr. The results show that the… More > Graphic Abstract

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.18, No.1, pp. 1-13, 2022, DOI:10.5098/hmt.18.2

Abstract This study numerically investigates pressure loss, heat transfer and thermal efficiency in round tube heat exchangers attached with various types of Vrings. A typical type A V-ring is compared with two types of modified V-rings (type B and C). The impacts of blockage ratios, b/D = 0.05, 0.10, 0.15 and 0.20 for all V-ring types in the turbulent region are discussed (Re = 3000 – 20,000). Flow directions in the round pipe attached with the V-rings are varied. The V-apex setting downstream is referred to as “V-Downstream, while the V-apex setting upstream is referred to as “V-Upstream”. The flow and… More >

Mohamed Shaimi^* , Rabha Khatyr, Jaafar Khalid Naciri

Frontiers in Heat and Mass Transfer, Vol.20, No.1, pp. 1-14, 2023, DOI:10.5098/hmt.20.23

Abstract This paper presents an exact analytical solution to the extended Graetz problem in microchannels and microtubes, including axial heat conduction, viscous dissipation, and rarefaction effects for an imposed constant wall temperature. The flow in the microchannel or microtube is assumed to be hydrodynamically fully developed. At the same time, the first-order slip-velocity and temperature jump models represent the wall boundary conditions. The energy equation is solved analytically, and the solution is obtained in terms of Kummer functions with expansion constants directly determined from explicit expressions. The local and fully developed Nusselt numbers are calculated in terms of the Péclet number,… More >

Ameer Abed Jaddoa^* , Karema Assi Hamad, Arshad Abdul Jaleil Hameed

Frontiers in Heat and Mass Transfer, Vol.20, No.1, pp. 1-9, 2023, DOI:10.5098/hmt.20.18

Abstract In the Heat Transfer process, many innovations were introduced aiming to obtain the most optimum behavior of the cooling process using nanofluids as coolant liquids. These nanofluids have gained much attention in cooling systems due to their special rheological and thermal performance. In this work, an experimental evaluation is conducted for nanofluids Al₂O₃, SiO₂, CuO, ZnO, and TiO₂ nanoparticles applied to a mini-channel. The nanofluid particles were entirely spread out in purified water (size of 15 nm) before being passed to the heat sink through a confined inflow channel. The obtained results showed that the achieved improvement rates are 25%,20%,… More >

Hussein Al-Gburi^*, Akeel Abbas Mohammed, Audai Hussein Al-Abbas

Frontiers in Heat and Mass Transfer, Vol.20, No.1, pp. 1-7, 2023, DOI:10.5098/hmt.20.17

Abstract Transferring thermal energy efficiently necessitates utilizing a heat exchanger capable of producing the full thermal power of the energy supply at lowest possible cost and time. Therefore, in the present investigation, the impact of corrugated helical coil concentric tube-in-tube heat exchanger on the thermal performance is investigated experimentally. As a continuous in our issue of heat exchanger, the corrugated helical tube-in-tube is carried out and compared with smooth helical tube-in-tube for free convection heat transfer. The set-up of the experimental apparatus are designed and utilized to be appropriate for the cooling and heating systems of working fluid. The impacts of… More >

Ruidong Wu¹, Guowei Wang^2,3,4,*, Zhixing Yang¹, Ruiquan Liao^2,3,4, Yang Cheng^2,3,4

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.8, pp. 2053-2066, 2023, DOI:10.32604/fdmp.2023.026301

Abstract An experimental analysis has been conducted to study the process of fluid accumulation for different borehole trajectories. More specifically, five heel angles have been experimentally realized to simulate the borehole trajectory of the sloping section of the formation. The fluid-carrying capacity, pressure drop and fluid discharge volatility have been investigated for these conditions and, accordingly, the relationship between heel angle and wellbore pressure drop fluid-carrying capacity has been determined. The results show that while the reasonable roll angle can increase the pressure loss in the wellbore, it is beneficial to drainage. In terms of pressure loss and liquid-carrying capacity, when… More > Graphic Abstract

Oleg R. Kuzichkin^1,*, Muneam Hussein Ali², Ayad F. Alkaim³, Lis M. Yapanto⁴, Gabdrakhman H. Valiev⁵, L. S. Abdullah⁶, Mustafa M. Kadhim⁷

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.4, pp. 1039-1048, 2022, DOI:10.32604/fdmp.2022.019532

Abstract A systematic study of two-phase (water-air) currents in open channels (water-air) has been conducted by means of experiments and numerical simulations. A dedicated device has been designed and manufactured on purpose. The numerical simulations have been based on the solution of a system of mass, momentum and energy balance equations for a two-phase fluid. The effect of different influential parameters has been explored, namely, velocity and dimensions of the channel, surface pressure and tension. More >

M. Narendra Kumar^1,*, S. Manoj Kumar², G. C. Vijayakumar¹, K. Kadirgama^3,4, M. Samykano⁵, Krishna Venkatesh¹, H. B. Murlidhara¹

Energy Engineering, Vol.119, No.1, pp. 201-217, 2022, DOI:10.32604/EE.2022.016597

Abstract This study computationally investigates the hydrodynamics of different serpentine flow field designs for redox flow batteries, which considers the Poiseuille flow in the flow channel and the Darcy flow porous substrate. Computational Fluid Dynamics (CFD) results of the in-house developed code based on Finite Volume Method (FVM) for conventional serpentine flow field (CSFF) agreed well with those obtained via experiment. The deviation for pressure drop was less than 5.1% for all the flow rates, thus proving the present CFD analysis’s validity on the modified variation of serpentine flow fields. Modified serpentine flow field-2 (MSFF2) design provided least pressure drop across… More >

Mingjun Du^1,2, Jiaqiang Jing^1,*, Xinqiang Xiong³, Bingbing Lang², Xuan Wang², Shiying Shi^4,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.1, pp. 81-91, 2022, DOI:10.32604/fdmp.2022.016640

Abstract Transportation of heavy oil by the so-called water-ring technique is a very promising method by which pressure drop and pollution can be significantly reduced. Dedicated experiments have been carried out by changing the phase’s density, viscosity, velocity and interfacial tension to systematically analyze the characteristics of the water ring. On the basis of such experimental data, a mathematical model for pressure drop prediction has been introduced. This research shows that as long as the density of oil and water remains the same, a concentric water ring can effectively be formed. In such conditions, the oil-water viscosity difference has little effect… More >

Xinke Yang¹, Shanzhi Shi¹, Hui Zhang¹, Yuzhe Yang^2,3, Zilong Liu^2,3, Ruiquan Liao^2,3,*, Joseph X. F. Ribeiro⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.2, pp. 371-383, 2021, DOI:10.32604/fdmp.2021.011486

Abstract The accurate prediction of the pressure distribution of highly viscous fluids in wellbores and pipelines is of great significance for heavy oil production and transportation. The flow behavior of high-viscosity fluids is quite different with respect to that of low-viscosity fluids. Currently, the performances of existing pressure-drop models seem to be relatively limited when they are applied to high-viscosity fluids. In this study, a gas-liquid two-phase flow experiment has been carried out using a 60 mm ID horizontal pipe with air and white oil. The experimental results indicate that viscosity exerts a significant influence on the liquid holdup and pressure… More >