Najiba Hasan Hamad^1,*, Ranj Sirwan Abdullah², Ahmed Mohammed Adham²

Energy Engineering, Vol.123, No.1, 2026, DOI:10.32604/ee.2025.073377 - 27 December 2025

Abstract Coiled tube heat exchangers are widely preferred in shell structures due to their superior heat transfer performance, driven by favorable flow characteristics. This study investigates the effect of modifying coil and shell configurations on heat transfer efficiency. Two key enhancements were examined: adding fins to the outer coil surface and integrating longitudinal slots within a hollowed shell. These modifications promote turbulence and extend heat transfer duration, thereby improving performance. However, they also introduce challenges, including increased pressure loss and manufacturing complexity. Numerical simulations were conducted using ANSYS Fluent 2024R1 under identical boundary conditions. With a… More > Graphic Abstract

Adel Saad Assiri^1,2,*

CMC-Computers, Materials & Continua, Vol.86, No.1, pp. 1-21, 2026, DOI:10.32604/cmc.2025.069826 - 10 November 2025

Abstract Customer churn is the rate at which customers discontinue doing business with a company over a given time period. It is an essential measure for businesses to monitor high churn rates, as they often indicate underlying issues with services, products, or customer experience, resulting in considerable income loss. Prediction of customer churn is a crucial task aimed at retaining customers and maintaining revenue growth. Traditional machine learning (ML) models often struggle to capture complex temporal dependencies in client behavior data. To address this, an optimized deep learning (DL) approach using a Regularized Bidirectional Long Short-Term… More >

Xiaoyan Zhuo¹, Yukun Ji¹, Yatao Ren^1,*, Xuehui Wang², Hong Qi¹

Frontiers in Heat and Mass Transfer, Vol.23, No.6, pp. 1701-1720, 2025, DOI:10.32604/fhmt.2025.074045 - 31 December 2025

Abstract Flow and heat transfer characteristics during droplet impact on hot walls are pivotal for elucidating the mechanisms of spray cooling and exploring pathways for heat transfer enhancement. When the wall temperature exceeds the Leidenfrost point, a vapor film forms between the droplet and the wall, rendering the heat transfer process highly complex. Furthermore, for droplet impact on curved walls, the presence of curvature introduces additional factors that modify the spreading behavior of the droplet and necessitate in-depth analysis. Therefore, this work investigates the flow and heat transfer dynamics of droplet impact on hot planes and… More >

Shuo Wang^1,2,*, Huiming Wang^1,2, Ying Zhang^1,2, Zhiqiang Zhang^1,3, Li Jia^1,2

Frontiers in Heat and Mass Transfer, Vol.23, No.6, pp. 1721-1740, 2025, DOI:10.32604/fhmt.2025.073226 - 31 December 2025

Abstract This experimental investigation was conducted on the flow boiling performance of refrigerant R134a in two types of parallel microchannels: sintered porous microchannels (PP-MCs) and smooth parallel microchannels (SP-MCs). The tests were performed under controlled conditions including an inlet subcooling of 5 ± 0.2°C, saturation temperature of 33°C, mass fluxes of 346 and 485 kg/m²·s, and a range of heat fluxes. Key findings reveal that the sintered porous microstructure significantly enhances bubble nucleation, reducing the wall superheat required for the onset of nucleate boiling (ONB) to only 0.13°C compared to 2.2°C in smooth channels. The porous structure… More >

Noor Moneer Basher¹, Omar Rafae Alomar^1,*, Omar Mohammed Ali², Diyar Abdullah Ahmed³

Frontiers in Heat and Mass Transfer, Vol.23, No.6, pp. 2001-2024, 2025, DOI:10.32604/fhmt.2025.066997 - 31 December 2025

Abstract The energy consumption of a Split air conditioning unit (ACU) inside a building is extremely large, and efforts to decrease this issue are ongoing. The current work aims to experimentally investigate the thermal performance of ACU using an external cooling-water loop for pre-cooling the condenser to improve the efficiency and to reduce energy consumption by reducing refrigerant temperature before entering the condenser, thereby reducing the coefficient of performance. The experiments are performed on ACU with and without using an external cooling-water loop under different climate conditions. By using the experimental data, the systems’ performances for… More >

Pooja Yadav^1,*, Ramin Farnood², Vivek Kumar^1,*

Journal of Polymer Materials, Vol.42, No.4, pp. 1181-1197, 2025, DOI:10.32604/jpm.2025.072564 - 26 December 2025

Abstract Heavy metal contamination in water sources is a widespread global concern, particularly in developing nations, with various treatment approaches under extensive scientific investigation. In the present study, we fabricated electrospun composite polyvinylidene fluoride (PVDF) nanofibrous membranes exhibiting hierarchical surface roughness and superhydrophobicity for the removal of heavy metal ions via vacuum membrane distillation (VMD) process. The membranes were prepared by incorporating optimized dosing of silica nanoparticles, followed by a two-step membrane modification approach. These membranes exhibited notable characteristics, including elevated water contact angle (152.8 ± 3.2°), increased liquid entry pressure (127 ± 6 kPa), and… More > Graphic Abstract

Xiulong Yao¹, Mengge Yu^1,*, Jiali Liu², Qian Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.11, pp. 2795-2814, 2025, DOI:10.32604/fdmp.2025.072708 - 01 December 2025

Abstract High-speed trains operating in freezing rain are highly susceptible to severe ice accretion in the pantograph region, which compromises both power transmission efficiency and dynamic performance. To elucidate the underlying mechanisms of this phenomenon, an Euler–Euler multiphase flow model was employed to simulate droplet impingement and collection on the pantograph surface, while a glaze-ice formation model incorporating wall film dynamics was used to capture the subsequent growth of ice. The effects of key parameters—including liquid water content, ambient temperature, train velocity, and droplet diameter—on the amount and morphology of ice were systematically investigated. The results More >

Zhaoqi Li, Xuan Liu, Hengkong Zhao, Zhen Zhang^*, Yan Li

The International Conference on Computational & Experimental Engineering and Sciences, Vol.33, No.4, pp. 1-1, 2025, DOI:10.32604/icces.2025.012239

Abstract The growing use of ultra-thick composite laminates in aerospace structures demands a deeper understanding of their unique damage mechanisms under tensile loading, which differ significantly from those of thin laminates. This study introduces a novel 3D progressive damage model combining solid elements, the LaRC05 3D failure criterion (enhanced with through-thickness in-situ strengthening effects), and a mixed-mode cohesive zone model (CZM) to predict interlaminar delamination. The model captures the interaction between in-plane damage and through-thickness failure modes in open-hole ultra-thick composites, and addresses stress redistribution, localized buckling, delamination migration, and in-situ strength enhancement. Mesh sensitivity analysis… More >

Xinlong Wang¹, Xiaohang Qu¹, Chuandong Lin^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.33, No.1, pp. 1-1, 2025, DOI:10.32604/icces.2025.011311

Abstract The lattice Boltzmann method (LBM) has been extensively utilized in various fields, including the droplet dynamics [1–4]. At present, significant challenges persist in accurately resolving interfacial dynamics during droplet collisions—including deformation [5], breakup process [6] and capturing microscale details [7] of contact line motion during droplet-wall interactions. In this work, the non-orthogonal multiple relaxation time lattice Boltzmann method is used to study droplets impacting superhydrophobic walls with different characteristic of surface protrusion. The horizontal displacement, maximum spreading length, and the contact time are probed in the process of droplet collisions under various conditions of Weber More >

Alexander A. Fedorets¹, Eduard E. Kolmakov¹, Anna V. Nasyrova¹, Dmitry N. Medvedev¹, Vyacheslav O. Mayorov², Vladimir Yu. Levashov², Leonid A. Dombrovsky^1,3,*

Frontiers in Heat and Mass Transfer, Vol.23, No.4, pp. 1091-1102, 2025, DOI:10.32604/fhmt.2025.068244 - 29 August 2025

Abstract A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere. The laboratory setup is based on converting a generated droplet jet of complex structure into a directed flow of evaporating droplets falling in a vertical tube. Images of falling droplets captured by a high-speed camera through a window in the vertical channel wall are used to determine the sizes and velocities of individual droplets. The computational modeling of droplet motion and evaporation proved useful at all stages of the experimental… More >