Quanbin Ba^1,2, Yanbao Liu^1,2,*, Zhigang Zhang^1,2, Wei Xiong^1,2, Kai Shen^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 697-710, 2021, DOI:10.32604/fdmp.2021.014762

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 >

Xulan Wang^1,*, 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

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 >

Huali Guo^*, Zhilong Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 745-757, 2021, DOI:10.32604/fdmp.2021.014651

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 >

Yulin Jiang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 759-772, 2021, DOI:10.32604/fdmp.2021.014470

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 >

Dan Tian^1,*, Danni Yu², Chunhui He³

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 711-720, 2021, DOI:10.32604/fdmp.2021.014290

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 >

Sheng Liu¹, Ling Leng², Wenjie Zhou², Lei Shi^2,*

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 >

Dehui Tong^1,2, Shunshun Qin^1,2, Jingguo Lin^1,2, Jingyang Sun³, Yuping Hu^3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 773-787, 2021, DOI:10.32604/fdmp.2021.013425

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 >

Hao Dou^1,2,*, Hongxia Liu^1,2, Feng Wang^1,2, Yanli Sun^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 629-638, 2021, DOI:10.32604/fdmp.2021.015612

Abstract Electrospinning is a versatile and popular method for the fabrication of ultrafine fibers and many parameters in electrospinning can be adjusted when ideal micro/nanofibers are required. In particular, the selection of a proper solvent condition is a fundamental and crucial step to produce electrospun ultrafine fibers. In this study, a commonly used biomaterial, polylactic acid (PLA), was dissolved in 7 different solvents and PLA micro/nanofibers were prepared by electrospinning. The morphology, porosity, mechanical property and static contact angle were characterized to determine the quality of the obtained product. The results show that different solvent conditions have a significant effect on… More >

Yanpu Chao¹, Hao Yi^2,3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 587-595, 2021, DOI:10.32604/fdmp.2021.015478

Abstract Many liquid metals have a high boiling point, strong electrical conductivity, high thermal conductivity, and non-toxic properties, which make them ideal targets for applications in different fields such as optics, microcircuits, electronic switches, micro-electromechanical System (MEMS) devices and 3D printing manufacturing. However, owing to the generally high surface tension of these liquids, achieving uniform micro-droplets is often a challenge due to the inherent difficulties in controlling their size and shape. In this study, a gallium indium alloy (GaIn_24.5) has been used in combination with a pneumatic drop-on-demand (DOD) injection technology to carry out a series of experiments. The micro-droplet forming… More >

Jianqiang Xiong^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 555-567, 2021, DOI:10.32604/fdmp.2021.015429

Abstract A robust optimization design method is proposed to investigate the influence of the hook position on the vertical vibration (bending) of an automobile exhaust system. A block diagram for the robustness analysis of the exhaust system is initially constructed from the major affecting factors. Secondly, the second-order inertia force is set as the vibration excitation source of the exhaust system and the displacement of four hooks of the exhaust system is selected as the variable factor. Then tests are carried out to investigate the resulting vertical bending considering four influencing factors and three levels of analysis. Finally, a variance analysis… More >