Alexander A. Fedorets¹, Eduard E. Kolmakov¹, Leonid A. Dombrovsky^1,2,3,*

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 1-14, 2024, DOI:10.32604/fhmt.2024.049335 - 21 March 2024

Abstract New experimental results, which are important for the potential use of small levitating droplets as biochemical microreactors, are reported. It is shown that the combination of infrared heating and reduced evaporation of saline water under the droplet cluster is sufficient to produce equilibrium saltwater droplets over a wide temperature range. The resulting universal dependence of droplet size on temperature simplifies the choice of optimal conditions for generating stable droplet clusters with droplets of the desired size. A physical analysis of the experimental results on the equilibrium size of saltwater droplets makes it possible to separate More > Graphic Abstract

Fayi Yan^*, Xuejian Pei, He Lu, Shuzhen Zong

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 287-304, 2024, DOI:10.32604/fhmt.2023.045038 - 21 March 2024

Abstract As compact and efficient heat exchange equipment, helically coiled tube-in-tube heat exchangers (HCTT heat exchangers) are widely used in many industrial processes. However, the thermal-hydraulic research of liquefied natural gas (LNG) as the working fluid in HCTT heat exchangers is rarely reported. In this paper, the characteristics of HCTT heat exchangers, in which LNG flows in the inner tube and ethylene glycol-water solution flows in the outer tube, are studied by numerical simulations. The influences of heat transfer characteristics and pressure drops of the HCTT heat transfers are studied by changing the initial flow velocity,… More >

Zongjun Yin^*, Rong Su, Hui Xu

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 487-504, 2024, DOI:10.32604/fdmp.2023.042631 - 12 January 2024

Abstract In this study, numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics (level-set method). Four flow patterns, namely “drop flow”, “jet flow”, “squeeze flow”, and “co-flow”, have been obtained for different flow velocity ratios, channel diameter ratios, density ratios, viscosity ratios, and surface tension. The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly, and the associated droplet generation process has been critically discussed considering the related frequency, diameter, and pinch-off length. In particular, it is shown that the More > Graphic Abstract

Jun Xu¹, Kai Bi¹, Yibin Lu^2,*, Tiantian Wang^2,3, Hang Zhang², Zeyuan Zheng³, Fushan Shi³, Yaxin Zheng³, Xiaoying Li², Jingping Yang³

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2727-2748, 2024, DOI:10.32604/cmes.2023.031341 - 15 December 2023

Abstract The spread and removal of pollution sources, namely, cough-released droplets in three different areas (front, middle, and rear areas) of a fully-loaded passenger car in a high-speed train under different fresh air flow volume were studied using computational fluid dynamics (CFD) method. In addition, the structure of indoor flow fields was also analysed. The results show that the large eddies are more stable and flow faster in the air supply under Mode 2 (fresh air volume: 2200 m³/h) compared to Mode 1 (fresh air volume: 1100 m³/h). By analysing the spreading process of droplets sprayed at different locations… More >

Yongchun Liu^1,*, Ni Qiao², Yanli Yang³, Yanchun Li¹, Chunxiao He¹, Siyang Wang¹, Chengcheng Liu¹, Ruixia Lei¹, Wang Li⁴, Wenwen Gao⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 383-400, 2024, DOI:10.32604/fdmp.2023.041928 - 14 December 2023

Abstract A silylated melamine sponge (SMS) was prepared by two simple steps, namely, immersion and dehydration of a melamine sponge coated with methyltrichlorosilane. The silylated structure of SMS was characterized by FT-IR (Fourier-transform infrared) spectroscopy, SEM (Scanning electron microscopy) and in terms of water contact angles. Its oil-water absorption and separation capacities were measured by FT-IR and UV-visible spectrophotometry. The experimental results have shown that oligomeric silanol covalently bonds by Si−N onto the surface of melamine sponge skeletons. SMS has shown superhydrophobicity with a water contact angle exceeding 150° ± 1°, a better separation efficiency with regard to More >

Ying Zhang^1,*, Weiming Niu², Leibing Yan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.1, pp. 885-902, 2024, DOI:10.32604/cmes.2023.029234 - 22 September 2023

Abstract In this paper, we consider mobile edge computing (MEC) networks against proactive eavesdropping. To maximize the transmission rate, IRS assisted UAV communications are applied. We take the joint design of the trajectory of UAV, the transmitting beamforming of users, and the phase shift matrix of IRS. The original problem is strong non-convex and difficult to solve. We first propose two basic modes of the proactive eavesdropper, and obtain the closed-form solution for the boundary conditions of the two modes. Then we transform the original problem into an equivalent one and propose an alternating optimization (AO) More >

Sheng Lan¹, Fei Yang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-1, 2023, DOI:10.32604/icces.2023.09077

Abstract Non-autoclaved concrete pipe piles are gaining attention as an environmentally friendly alternative to autoclaved concrete pipe piles. The purpose of this study was to investigate the changes in the impact resistance of a non-autoclaved concrete pipe pile with the addition of rubber. To this end, various volume fractions of rubber particles were used to replace the fine sand in the non-autoclaved pipe pile concrete (0%, 5%, 10% and 15%). Additionally, the axial impact resistance of rubber modified non-autoclaved concrete pipe pile was studied from the concrete materials and pipe pile components through quasi-static, dynamic compression… More >

Ali Alshahrani¹, Ahmad Adel Abu-Shareha^2,*, Qusai Y. Shambour², Basil Al-Kasasbeh¹

CMC-Computers, Materials & Continua, Vol.77, No.2, pp. 1679-1698, 2023, DOI:10.32604/cmc.2023.043545 - 29 November 2023

Abstract Active queue management (AQM) methods manage the queued packets at the router buffer, prevent buffer congestion, and stabilize the network performance. The bursty nature of the traffic passing by the network routers and the slake behavior of the existing AQM methods leads to unnecessary packet dropping. This paper proposes a fully adaptive active queue management (AAQM) method to maintain stable network performance, avoid congestion and packet loss, and eliminate unnecessary packet dropping. The proposed AAQM method is based on load and queue length indicators and uses an adaptive mechanism to adjust the dropping probability based… More >

Mainak Bhaumik¹, Anirban Sur^2,*, Kavita Dhanawade³

Frontiers in Heat and Mass Transfer, Vol.21, pp. 467-486, 2023, DOI:10.32604/fhmt.2023.044605 - 30 November 2023

Abstract Pin fins are widely used in applications where effective heat transfer is crucial. Their compact design, high surface area, and efficient heat transfer characteristics make them a practical choice for many thermal management applications. But for a high heat transfer rate and lightweight application, aerofoil shape pin fins are a good option. This work focuses on an experimental model analysis of pin-fins with aerofoil shapes. The results were evaluated between perforation, no perforation, inline, and staggered fin configurations. Aluminum is used to make the pin fins array. The experiment is carried out inside a wind… More >

Sikandar Khan¹, Khalid Saeed¹, Muhammad Faran Majeed^2,*, Salman A. AlQahtani³, Khursheed Aurangzeb³, Muhammad Shahid Anwar^4,*

CMC-Computers, Materials & Continua, Vol.77, No.1, pp. 1303-1323, 2023, DOI:10.32604/cmc.2023.039697 - 31 October 2023

Abstract Delay Tolerant Networks (DTNs) have the major problem of message delay in the network due to a lack of end-to-end connectivity between the nodes, especially when the nodes are mobile. The nodes in DTNs have limited buffer storage for storing delayed messages. This instantaneous sharing of data creates a low buffer/shortage problem. Consequently, buffer congestion would occur and there would be no more space available in the buffer for the upcoming messages. To address this problem a buffer management policy is proposed named “A Novel and Proficient Buffer Management Technique (NPBMT) for the Internet of… More >