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  • Open Access

    ARTICLE

    Investigations on High-Speed Flash Boiling Atomization of Fuel Based on Numerical Simulations

    Wei Zhong1, Zhenfang Xin2, Lihua Wang1,*, Haiping Liu2

    CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1427-1453, 2024, DOI:10.32604/cmes.2023.031271

    Abstract Flash boiling atomization (FBA) is a promising approach for enhancing spray atomization, which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pressure. However, when the outlet speed of the nozzle exceeds 400 m/s, investigating high-speed flash boiling atomization (HFBA) becomes quite challenging. This difficulty arises from the involvement of many complex physical processes and the requirement for a very fine mesh in numerical simulations. In this study, an HFBA model for gasoline direct injection (GDI) is established. This model incorporates primary and secondary atomization, as well as vaporization and… More >

  • Open Access

    ARTICLE

    Optimization of Gas-Flooding Fracturing Development in Ultra-Low Permeability Reservoirs

    Lifeng Liu1, Menghe Shi2, Jianhui Wang3, Wendong Wang2,*, Yuliang Su2, Xinyu Zhuang2

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 595-607, 2024, DOI:10.32604/fdmp.2023.041962

    Abstract Ultra-low permeability reservoirs are characterized by small pore throats and poor physical properties, which are at the root of well-known problems related to injection and production. In this study, a gas injection flooding approach is analyzed in the framework of numerical simulations. In particular, the sequence and timing of fracture channeling and the related impact on production are considered for horizontal wells with different fracture morphologies. Useful data and information are provided about the regulation of gas channeling and possible strategies to delay gas channeling and optimize the gas injection volume and fracture parameters. It is shown that in order… More >

  • Open Access

    ARTICLE

    A New Heat Transfer Model for Multi-Gradient Drilling with Hollow Sphere Injection

    Jiangshuai Wang1,*, Chuchu Cai1, Pan Fu2,3, Jun Li4,5, Hongwei Yang4, Song Deng1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 537-546, 2024, DOI:10.32604/fdmp.2023.030430

    Abstract Multi-gradient drilling is a new offshore drilling method. The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure. In this study, a new heat transfer model is proposed by which the variable mass flow is properly taken into account. Using this model, the effects of the main factors influencing the wellbore temperature are analyzed. The results indicate that at the position where the separation injection device is installed, the temperature increase of the fluid in the drill pipe is mitigated due… More >

  • Open Access

    ARTICLE

    NUMERICAL INVESTIGATIONS ON COMBUSTION AND EMISSION CHARACTERISTICS IN A DIRECT INJECTION DIESEL ENGINE AT ELEVATED FUEL TEMPERATURES

    Manimaran Renganathan, Thundil Karuppa Raj Rajagopal*

    Frontiers in Heat and Mass Transfer, Vol.4, No.1, pp. 1-11, 2013, DOI:10.5098/hmt.v4.1.3008

    Abstract In this work, fuel spray parameters are studied by varying the fuel temperature. To overcome the tedious experimental task, a 3-D Computational Fluid Dynamics methodology is adopted by injecting fuel at specified temperatures of 313 K, 353 K and 393 K. The validation is accomplished after the optimal spatial and temporal steps of discretization are found out. At a fuel temperature of 313 K, advancing the injection timing from 6 deg bTDC to 20 deg bTDC increases cylinder peak pressure from 79.8 bar to 90.9 bar. Relation between the emission characteristics and spray SMD and temperature is studied. More >

  • Open Access

    ARTICLE

    CFD MODELLING AND VALIDATION OF COMBUSTION IN DIRECT INJECTION COMPRESSION IGNITION ENGINE FUELLED WITH JATROPHA OIL BLENDS WITH DIESEL

    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 >

  • Open Access

    ARTICLE

    COMPUTATIONAL STUDIES OF SWIRL RATIO AND INJECTION TIMING ON ATOMIZATION IN A DIRECT INJECTION DIESEL ENGINE

    Renganathan Manimarana, Rajagopal Thundil Karuppa Rajb,*

    Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-9, 2014, DOI:10.5098/hmt.5.2

    Abstract Diesel engine combustion modeling presents a challenging task with the formation and breakup of spray into droplets. In this work, 3D-CFD computations are performed to understand the behaviour of spray droplet diameter and temperature during the combustion by varying the swirl ratio and injection timing. After the validation and grid and time independency tests, it is found that increase in swirl ratio from 1.4 to 4.1 results in peak pressure rise of 8 bar and an advancement of injection timing from 6 deg bTDC to 20 deg bTDC results in increase of peak pressure by 15 %. More >

  • Open Access

    ARTICLE

    Numerical Simulation of Asphaltene Precipitation and Deposition during Natural Gas and CO2 Injection

    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

    Numerical Simulation of Asphaltene Precipitation and Deposition during Natural Gas and CO<sub>2</sub> Injection

  • Open Access

    ARTICLE

    NATURAL CONVECTION ON A POROUS VERTICAL PLATE IN A DOUBLY STRATIFIED NON-DARCY POROUS MEDIUM

    D. Srinivasacharyaa,*, A.J. Chamkhab, O. Surendera, A.M. Rashadc,d

    Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.19

    Abstract The aim of the present article is to analyze the influence of thermal and mass stratification on natural convection heat and mass transfer over a porous vertical plate with uniform and constant wall temperature and concentration in porous medium. The Brinkman-Forchheimer based model is employed to describe the flow in the porous medium. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms by pseudo-similarity variables. The resulting system of nonlinear, coupled partial differential equations is then solved numerically. The influence of pertinent parameters on the dimensionless velocity, temperature, concentration, heat and mass transfer coefficients… More >

  • Open Access

    ARTICLE

    Mathematical Study of MHD Micropolar Fluid Flow with Radiation and Dissipative Impacts over a Permeable Stretching Sheet: Slip Effects Phenomena

    Pudhari Srilatha1, Ahmed M. Hassan2, B. Shankar Goud3,*, E. Ranjit Kumar4

    Frontiers in Heat and Mass Transfer, Vol.21, pp. 539-562, 2023, DOI:10.32604/fhmt.2023.043023

    Abstract The purpose of this research is to investigate the influence that slip boundary conditions have on the rate of heat and mass transfer by examining the behavior of micropolar MHD flow across a porous stretching sheet. In addition to this, the impacts of thermal radiation and viscous dissipation are taken into account. With the use of various computing strategies, numerical results have been produced. Similarity transformation was utilized in order to convert the partial differential equations (PDEs) that regulated energy, rotational momentum, concentration, and momentum into ordinary differential equations (ODEs). As compared to earlier published research, MATLAB inbuilt solver solution… More > Graphic Abstract

    Mathematical Study of MHD Micropolar Fluid Flow with Radiation and Dissipative Impacts over a Permeable Stretching Sheet: Slip Effects Phenomena

  • Open Access

    ARTICLE

    UREA-WATER DROPLET PHASE CHANGE AND REACTION MODELLING: MULTI-COMPONENT EVAPORATION APPROACH

    Viraj S. Shirodkar*

    Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.5

    Abstract Urea-water solution droplet evaporation is modelled using multi-component droplet evaporation approach. The heat and mass transfer process of a multi-component droplet is implemented in the Langrangian framework through a custom code in ANSYS-Fluent R15. The evaporation process is defined by a convection-diffusion controlled model which includes the effect of Stefan flow. A rapid mixing model assumption is used for the droplet internal physics. The code is tested on a single multi-component droplet and the predicted evaporation rates at different ambient temperatures are compared with the experimental data in the literature. The approach is used to model the injection of urea-water… More >

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