Kaiyong Hu^1,2,*, Zhaoyi Chen¹, Yunqing Hu¹, Huan Sun¹, Zhili Sun¹, Tonghua Zou^1,3, Jinghong Ning¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2109-2126, 2024, DOI:10.32604/fdmp.2024.050773 - 23 August 2024

Abstract The current study focuses on spray cooling applied to the heat exchange components of a cooling tower. An optimization of such processes is attempted by assessing different spray flow rates and droplet sizes. For simplicity, the heat exchanger of the cooling tower is modeled as a horizontal round tube and a cooling tower spray cooling model is developed accordingly using a computational fluid dynamics (CFD) software. The study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube… More > Graphic Abstract

Ambareen Khan¹, Sher Afghan Khan², Mohammed Nishat Akhtar^1,*, Abdul Aabid^3,*, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2007-2028, 2024, DOI:10.32604/fdmp.2024.049368 - 23 August 2024

Abstract When better fuel-air mixing in the combustion chamber or a reduction in base drag are required in vehicles, rockets, and aeroplanes, the base pressure control is activated. Controlling the base pressure and drag is necessary in both scenarios. In this work, semi-circular ribs with varying diameters (2, 4, and 6 mm) positioned at six distinct positions (0.5D, 1D, 1.5D, 2D, 3D, and 4D) inside a square duct with a side of 15 mm are proposed as an efficient way to apply the passive control technique. In-depth research is done on optimising rib size for various More > Graphic Abstract

Vigneshvaran Sethuraman¹, Parvathy Rajendran^1,*, Sher Afghan Khan², Abdul Aabid³, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1847-1866, 2024, DOI:10.32604/fdmp.2024.049441 - 06 August 2024

Abstract This study deals with base pressure management in a duct for various values of the Mach number (M), namely, Mach number corresponding to sonic and four supersonic conditions. In addition to the Mach number, the nozzle pressure ratio (NPR), the area ratio, the rib dimension, and the duct length are influential parameters. The following specific values are examined at M = 1, 1.36, 1.64, and 2, and NPRs between 1.5 and 10. The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct. When the… More >

Yuanyuan Zhao¹, Fujian Zhao², Guohui Li³, Wei Xu^4,*, Xiuli Wang^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1883-1901, 2024, DOI:10.32604/fdmp.2024.047298 - 06 August 2024

Abstract Self-excited oscillating jets (SOJ) are used in several practical applications. Their performances are significantly affected by structural parameters and the target distance. In this study, a geometric model of the SOJ nozzle accounting for multiple structural parameters is introduced, then the related cavitation performances and the optimal target distance are investigated using a Large-Eddy Simulation (LES) approach. Results are also provided about an experiment, which was conducted to validate the simulation results. By analyzing the evolution of the vapor volume fraction at the nozzle outlet, a discussion is presented about the effect of the aforementioned… More >

Cheng-Yeh Li, Jui-Hsiang Kao^*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2277-2304, 2024, DOI:10.32604/cmes.2023.030215 - 15 December 2023

Abstract The performance of a water jet propulsion system is related to the inlet duct, rotor, stator, and nozzle. Generally, the flow inlet design must fit the bottom line of the hull, and the design of the inlet duct is often limited by stern space. The entire section, from the rotor to the nozzle through the stator, must be designed based on system integration in that the individual performance of these three components will influence each other. Particularly, the section from the rotor to the nozzle significantly impacts the performance of a water jet propulsion system.… More >

Zhigang Wang, Bin Zheng, Peidong Zhao, Baoli Wang, Fanyan Meng, Wenke Xu, Jian Meng^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 365-382, 2024, DOI:10.32604/fdmp.2023.030302 - 14 December 2023

Abstract Heavy-fuel engines are widely used in UAVs (Unmanned Autonomous Vehicles) because of their reliability and high-power density. In this study, a combustion model for an in-cylinder direct injection engine has been implemented using the AVL FIRE software. The effects of the angle of nozzle inclination on fuel evaporation, mixture distribution, and combustion in the engine cylinder have been systematically studied at 5500 r/min and considering full load cruise conditions. According to the results, as the angle of nozzle inclination increases, the maximum combustion explosion pressure in the cylinder first increases and then it decreases. When… More > Graphic Abstract

Yu Gao¹, Zhenqiang Xu^2,3,*, Kaixiang Shen^2,3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 179-192, 2024, DOI:10.32604/fdmp.2023.030499 - 08 November 2023

Abstract Hydraulic jetting is a form of fracturing that involves using a high-pressure jet of water to create fractures in the reservoir rock with a nozzle serving as the central component of the hydraulic sandblasting perforation tool. In this study, the flow behavior of the nozzle is simulated numerically in the framework of a SST k-ω turbulence model. The results show that the nozzle structure can significantly influence the jet performance and related cavitation effect. Through orthogonal experiments, the nozzle geometric parameters are optimized, and the following configuration is found accordingly: contraction angle 20°, contraction segment More >

Jingjing Gao, Xingkai Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 109-127, 2024, DOI:10.32604/fdmp.2023.030106 - 08 November 2023

Abstract A new approach and a new related distribution system are proposed to address the issue of uneven steam injection caused by the different suction capacities of the used wells during the application of steam “stimulation” methods for enhanced oil recovery. The new distribution system consists of a swirler, spiral dividing baffles, and critical flow nozzles. Numerical simulations are used to analyze the flow-field and degree of steam homogeneity obtained with such an approach. The results indicate that a higher inlet pressure leads to better results. Additionally, the internal flow field becomes more stable, and the More >

Jiefeng Wang¹, Eddie Yin Kwee Ng^2,*, Jianwu Li¹, Yanhao Cao¹, Yanan Huang¹, Liang Li^1,2,3,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 1-31, 2023, DOI:10.32604/fhmt.2023.045510 - 30 November 2023

Abstract The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling, such as the impingement cooling and the axial flow cooling. This asymmetrical property will affect the cooling performance in the blade leading edge, whereas such effects are not found in most of the studies on vortex cooling due to the neglect of the mainstream flow in the airfoil channel. This study involves the mainstream flow field and the rotational effects based on the profile of the GE E³ blade to reveal the mechanism of the asymmetrical flow structure… More > Graphic Abstract

Xin Li¹, Shaohan Zheng^1,2, Yuliang Zhang^1,*, Minfeng Lv³

Frontiers in Heat and Mass Transfer, Vol.21, pp. 245-264, 2023, DOI:10.32604/fhmt.2023.041778 - 30 November 2023

Abstract This article aims to reveal the transient thermal characteristics of the solid domain in a nozzle flowmeter when measuring fluids of varying temperatures. Based on finite element method, the transient numerical calculation of the thermal characteristics of each component of the nozzle flowmeter has been conducted. The research shows that: as the fluid passes through the flowmeter, the high heat flux area inside the nozzle flowmeter gradually transfer from the center of the nozzle to the inlet and outlet, as well as the pressure tapping points upstream and downstream; High thermal stress zones are present More >