Chenxi Xiu^1,2,*, Xihua Chu²

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2305-2338, 2024, DOI:10.32604/cmes.2023.030194

Abstract This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials. By utilizing this model, the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information. The microstructures under consideration can be classified into three categories: a medium-dense microstructure, a dense microstructure consisting of one-sized particles, and a dense microstructure consisting of two-sized particles. Subsequently, the Cosserat elastoplastic model, along with its finite element formulation, is derived using the extended Drucker-Prager yield criteria. To investigate failure behaviors, numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element (UEL)… More >

A. Najjaran^*, Ak. Najjaran, A. Fotoohabadi, A.R. Shiri

Frontiers in Heat and Mass Transfer, Vol.4, No.1, pp. 1-5, 2013, DOI:10.5098/hmt.v4.1.3003

Abstract In this paper, the aim is obtaining convection coefficient of human body. This field of study is essential in study of ventilation systems, astronauts’ clothes and any other fields in which human body is the main concern. At first a 3D human body has been designed by unstructured grids. Feet and hands are stretched completely in considered sample. Two postures (standing and supine) are considered for body. Soles and the back of entire body are considered in contact with the ground respectively in these postures. Other parts of human body are exposed to surrounding air. The heat transfer and the… More >

Shigenao Maruyama^a, Masud Behnia^b, Masasazumi Chisaki^c, Takuma Kogawa^c,*, Junnosuke Okajima^a, Atsuki Komiya^a

Frontiers in Heat and Mass Transfer, Vol.4, No.2, pp. 1-6, 2013, DOI:10.5098/hmt.v4.2.3002

Abstract The diffusion process of deep seawater drawn up by a vertical pipe deployed in the ocean is investigated. This vertical pipe is based on the principal of perpetual salt fountain. Numerical simulations of seawater upwelling from the pipe are performed based on experiments conducted in the Mariana trench region. Two turbulence modeling approaches were examined: k-ε model and Large Eddy Simulations (LES). The results in both models show that diffusion of the deep seawater diffusion after ejection from the pipe. The LES results show a 50% lower vertical penetration compared to the k-ε model as well as well as predicting… More >

Suripeddi Srinivas^a , Akshay Gupta^b,*, Ashish Kumar Kandoi^b

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-12, 2014, DOI:10.5098/hmt.5.21

Abstract The present work deals with the flow and thermal analysis of nanofluid in the wavy channels. The governing flow equations are solved numerically using CFD package assuming single phase approach. To study the effect of the concentration and size variation of the nanoparticle, the concentration and size are varied from 0% - 5% and 25 nm - 100 nm respectively over the Reynolds number range of 250-1500 for Au-water nanofluid. The effect on heat transfer enhancement because of corrugation of wavy channel is analyzed on four different shapes (sinusoidal, triangular, trapezoidal and square) channels. The effect of amplitude of the… More >

Edoardo Gino Macchi^* , Giovanni Braschi, Mario Gallati

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.20

Abstract Radiofrequency thermal ablation (RFTA) is a medical procedure currently widely adopted for liver tumors treatment. Its outcome is strongly influenced by temperature distribution near the RF applicator therefore continuous measurements are required both to validate RFTA numerical models and to better control the outcome of the procedure. The space-time evolution of the thermal field during RFTA on ex vivo porcine liver tissue has been measured by infrared thermal imaging in different experimental setups. A three-dimensional simulation of the whole experiment reproduces all the features of the thermal field measurements and validates the proposed measurement methodology. More >

Manoj Kr. Triveni^* , Dipak Sen, RajSekhar Panua

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.12

Abstract A numerical investigation has been performed for heat transfer analysis in a right-angled triangular enclosure filled with water. The side wall of the enclosure is maintained at high temperature compare to the base wall while hypotenuse is kept thermally insulated. Two - dimensional steady-state continuity, momentum and energy equations along with the boussinesq approximation are solved by finite volume method using commercial available software, FLUENT 6.3. The computational results are shown in terms of isotherms, streamlines and velocity contour for Rayleigh number (10⁵ ≤ Ra ≤ 10⁷ ). The heat transfer is presented in terms of local and average Nusselt… More >

Biswajit De^*, Rajsekhar Panua

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-6, 2014, DOI:10.5098/hmt.5.7

Abstract This paper presents a pre-mixed combustion model for diesel and Jatropha oil blends combustion studies. Jatropha oil blends are considered as a mixture of diesel and Jatropha oil. CFD package, FLUENT 6.3 is used for modeling the complex combustion phenomenon in compression ignition engine. The experiments are carried out on a single cylinder, four strokes, water cooled direct injection compression ignition engine at compression ratio of 17.5 at full load condition at constant speed of 1500 rpm fuelled with diesel and jatropha oil blends with diesel. The numerical model is solved by considering pressure based, implicit and unsteady solver and… More >

Tian Li^1,2,*, Hao Liang¹, Zerui Xiang², Jiye Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 463-473, 2024, DOI:10.32604/fdmp.2023.043618

Abstract A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains. Using the shear stress transport (SST) k-ω turbulence model, the effect of various vortex generator types on the aerodynamic characteristics of an ICE2 (Inter-city Electricity) train has been investigated. The results indicate that the vortex generators with wider triangle, trapezoid, and micro-ramp arranged on the surface of the tail car can significantly change the distribution of surface pressure and affect the vorticity intensity in the wake. This alteration effectively reduces the resistance of the tail car. Meanwhile, the micro-ramp vortex generator with its… More > Graphic Abstract

Yongwei Duan, Zhaopeng Zhu, Hui He^*, Gaoliang Xuan, Xuemeng Yu

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 349-364, 2024, DOI:10.32604/fdmp.2023.042659

Abstract The gas-water two-phase flow occurring as a result of fracturing fluid flowback phenomena is known to impact significantly the productivity of shale gas well. In this work, this two-phase flow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model (EDFM). This model assumes the region outside the stimulated reservoir volume (SRV) as a single-medium while the SRV region itself is described using a double-medium strategy which can account for the fluid exchange between the matrix and the micro-fractures. The shale gas adsorption, desorption, diffusion, gas slippage effect, fracture stress sensitivity, and… More >

Shasha Feng^*, Yi Liao, Weixin Liu, Jianwen Dai, Mingying Xie, Li Li

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 275-292, 2024, DOI:10.32604/fdmp.2023.041825

Abstract Asphaltene deposition is a significant problem during gas injection processes, as it can block the porous medium, the wellbore, and the involved facilities, significantly impacting reservoir productivity and ultimate oil recovery. Only a few studies have investigated the numerical modeling of this potential effect in porous media. This study focuses on asphaltene deposition due to natural gas and CO₂ injection. Predictions of the effect of gas injection on asphaltene deposition behavior have been made using a 3D numerical simulation model. The results indicate that the injection of natural gas exacerbates asphaltene deposition, leading to a significant reduction in permeability near… More > Graphic Abstract