Home / Journals / FDMP / Vol.17, No.4, 2021
Table of Content
  • Open Access

    ARTICLE

    Optimizing the Exhaust System of Marine Diesel Engines to Improve Low-speed Performances and Cylinder Working Conditions

    Sheng Liu1, Ling Leng2, Wenjie Zhou2, Lei Shi2,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 683-695, 2021, DOI:10.32604/fdmp.2021.013575
    Abstract Proper design of exhaust systems in marine high-power turbocharged diesel engines can contribute to improve the low-speed performance of these engines and make the working conditions of the cylinders more uniform. Here a high-power marine 16-cylinder V-type turbocharged diesel engine is simulated using the GT-Power software. The results reveal the differences induced by different exhaust system structures, such as an 8-cylinder-in-pipe exhaust system with single/double superchargers and a 4-cylinder-in-pipe exhaust system with a single supercharger. After a comparative analysis, the 8-cylinder type with double superchargers is determined to be the optimal solution, and the structure of the exhaust system is… More >

  • Open Access

    ARTICLE

    Analysis of the Flow Field Characteristics Associated with the Dynamic Rock Breaking Process Induced by a Multi-Hole Combined External Rotary Bit

    Quanbin Ba1,2, Yanbao Liu1,2,*, Zhigang Zhang1,2, Wei Xiong1,2, Kai Shen1,2
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 697-710, 2021, DOI:10.32604/fdmp.2021.014762
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract The characteristics of the flow field associated with a multi-hole combined external rotary bit have been studied by means of numerical simulation in the framework of an RNG k-ε turbulence model, and compared with the results of dedicated rock breaking drilling experiments. The numerical results show that the nozzle velocity and dynamic pressure of the nozzle decrease with an increase in the jet distance, and the axial velocity of the nozzle decays regularly with an increase in the dimensionless jet distance. Moreover, the axial velocity related to the nozzle with inclination angle 20° and 30° can produce a higher hole… More >

  • Open Access

    ARTICLE

    Macromolecule’s Orientation in a Nanofiber by Bubble Electrospinning

    Dan Tian1,*, Danni Yu2, Chunhui He3
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 711-720, 2021, DOI:10.32604/fdmp.2021.014290
    (This article belongs to this Special Issue: Nanoscale Flow and Nanomaterial Fabrication)
    Abstract In the search for sustainable alternatives to harmful synthetic fibers, an increasing amount of research focuses on biomimicry and natural fibers. Sea silk is an exceptional textile material. It is a kind of natural silk produced using the long silky filaments secreted by a specific bivalve mollusk (Pinna nobilis); now at edge of extinction. This paper suggests a simple but effective way to prepare artificial sea silk from Mytilus edulis. A sea silk solution is prepared using a Mytilus edulis protein, and a polyvinyl alcohol (PVA) solution is mixed with the sea silk solution in order to produce artificial sea… More >

  • Open Access

    ARTICLE

    Haemodynamic Analysis of the Relationship between the Morphological Alterations of the Ascending Aorta and the Type A Aortic-Dissection Disease

    Qingzhuo Chi1, Huimin Chen1, Lizhong Mu1,*, Ying He1, Yong Luan2
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 721-743, 2021, DOI:10.32604/fdmp.2021.015200
    (This article belongs to this Special Issue: Bioheat Transfer in Micro and Macro Scales)
    Abstract Type A aortic dissection (AD) is one of the most serious cardiovascular diseases, whose risk predictors are controversial. The purpose of this research was to investigate how elongation accompanied by dilation of the ascending aorta (AAo) affects the relevant haemodynamic characteristics using image-based computational models. Five elongated AAos with different levels of dilation have been reconstructed based on the centerlines data of an elderly and an AD patient. Numerical simulations have been performed assuming an inflow waveform and a Windkessel model with three elements for all outflow boundaries. The numerical results have revealed that the elongation of AAo can disturb… More >

  • Open Access

    ARTICLE

    CFD Analysis and Optimization of an Engine with a Restrictor Valve in the Intake System

    Huali Guo*, Zhilong Zhang*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 745-757, 2021, DOI:10.32604/fdmp.2021.014651
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract In some competitions the rules clearly state that all participating cars must install a restrictor valve structure in the intake system of the engine. The intake air volume of the engine is considerably affected due to the existence of such a valve. Indeed, a small interface diameter through which gas flows can lead to considerable flow resistance and loss. In this study, a four-cylinder engine for FSC racing is analyzed using a combined method based on numerical simulation and experiments. The analysis reveals that the main factors affecting the intake air volume are the intake manifold and the volume of… More >

  • Open Access

    ARTICLE

    A New Processing Method for the Nonlinear Signals Produced by Electromagnetic Flowmeters in Conditions of Pipe Partial Filling

    Yulin Jiang*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 759-772, 2021, DOI:10.32604/fdmp.2021.014470
    (This article belongs to this Special Issue: Fluid Structure Interaction in Various Engineering Field)
    Abstract When a pipe is partially filled with a given working liquid, the relationship between the electromotive force (EMF) measured by the sensor (flowmeter) and the average velocity is nonlinear and non-monotonic. This relationship varies with the inclination of the pipe, the fluid density, the pipe wall friction coefficient, and other factors. Therefore, existing measurement methods cannot meet the accuracy requirements of many industrial applications. In this study, a new processing method is proposed by which the flow rate can be measured with an ordinary electromagnetic flowmeter even if the pipe is only partially filled. First, a B-spline curve fitting method… More >

  • Open Access

    ARTICLE

    Thermal Analysis of a Novel Oil Cooled Piston Using a Fluid-Solid Interaction Method

    Dehui Tong1,2, Shunshun Qin1,2, Jingguo Lin1,2, Jingyang Sun3, Yuping Hu3,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 773-787, 2021, DOI:10.32604/fdmp.2021.013425
    (This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)
    Abstract Thermal load has a vital influence on the normal operation and service life of diesel engines. In this study, the thermal load and oil-cooling effect on diesel engine pistons were investigated by means of computational fluid dynamics. In particular, the flow and heat transfer characteristics of the cooling gallery were determined during the oscillation of the piston. Moreover, the temperature field distribution of the piston with and without the cooling gallery were compared. The results revealed that the cooling gallery has a prominent effect on reducing the thermal load on the piston crown and piston lands. To fully understand the… More >

  • Open Access

    ARTICLE

    Mixed Convection in a Two-Sided Lid-Driven Square Cavity Filled with Different Types of Nanoparticles: A Comparative Study Assuming Nanoparticles with Different Shapes

    Mostafa Zaydan1, Mehdi Riahi1,2,*, Fateh Mebarek-Oudina3, Rachid Sehaqui1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 789-819, 2021, DOI:10.32604/fdmp.2021.015422
    (This article belongs to this Special Issue: Nano-Enhanced Heat Transfer)
    Abstract Steady, laminar mixed convection inside a lid-driven square cavity filled with nanofluid is investigated numerically. We consider the case where the right and left walls are moving downwards and upwards respectively and maintained at different temperatures while the other two horizontal ones are kept adiabatic and impermeable. The set of nonlinear coupled governing mass, momentum, and energy equations are solved using an extensively validated and a highly accurate finite difference method of fourth-order. Comparisons with previously conducted investigations on special configurations are performed and show an excellent agreement. Meanwhile, attention is focused on the heat transfer enhancement when different nano-particles:… More >

  • Open Access

    ARTICLE

    Thermo-Mechanical Analysis of the Sealing Performance of a Diesel-Engine Cylinder Gasket

    Xulan Wang1,*, Zezhong Chen1, Changzhen Liu1, Wei Ren2, Bo Wu1, Shude Ji1, Xiaofei Chen1, Shijie Wen1, Yonggang Hao1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 821-831, 2021, DOI:10.32604/fdmp.2021.014707
    (This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)
    Abstract Taking the combustor composite structure of a high-strength diesel engine as the main research object, dedicated tests have been conducted to verify the accuracy of three distinct cylinder gasket pressure simulation models. Using the measured cylinder gasket compression rebound curve, a gasket unit has been designed and manufactured. For this unit, the influence of the bolt pretension, cylinder body and cylinder head material on gasket sealing pressure has been investigated systematically in conditions of thermo-mechanical coupling. The results show that the bolt pretension force is one of the most important factors affecting the cylinder gasket sealing pressure. The change of… More >

  • Open Access

    ARTICLE

    A Research on the Flow Characteristics of a Splitter-Based Water Cooling System for Computer Boards

    Yukun Lv, Quanzhi Ge*, Zhuang Wei, Shuang Yang
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 833-844, 2021, DOI:10.32604/fdmp.2021.015082
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract The splitter is an important component of water-based cooling systems used to extract heat from computer boards. In the present study, the flow characteristics of a 16-splitter structure were numerically simulated and compared with experimental results to verify the reliability of the numerical simulation method. Accordingly, the concept of splitter structural coefficients was proposed. Based on the results of this study, we recommend a selection range of 5 ≤ k ≤ 6 for the structure factor k of the splitter; after optimization, the maximum deviation of the splitter outlet flow was reduced from the original value of 100% to 8.3%. More >

  • Open Access

    ARTICLE

    Coupled Effects of Heat and Moisture of Early-Age Concrete

    Yang Wang1, Hanxi Wang2,*, Linwei Yang1, Li Qian1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 845-857, 2021, DOI: 10.32604/fdmp.2021.015961
    Abstract In order to analyze the coupled influence of temperature and humidity on early-age concrete (including cement and copper tailings), a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations. In such a framework, the influence of hydration-released heat and water consumption are also taken into account. The results provided by such a model are verified by means of experiments and related sensor measurements. The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws. More >

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