Haowei Hu^1,2,*, Qi Wang¹, Xinnuo Chen¹, Qin Li³, Mu Du⁴, Dong Niu^5,*

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1245-1259, 2024, DOI:10.32604/fhmt.2024.054223

Abstract To investigate the microscopic mechanism underlying the influence of surface-chemical gradient on heat and mass recovery, a molecular dynamics model including droplet condensation and transport process has been developed to examine heat and mass recovery performance. This work aimed at identify optimal conditions for enhancing heat and mass recovery through the combination of wettability gradient and nanopore transport. For comprehensive analysis, the structure in the simulation was categorized into three distinct groups: a homogeneous structure, a small wettability gradient, and a large wettability gradient. The homogeneous surface demonstrated low efficiency in heat and mass transfer, More >

Zhenzhen Liu, Hua Zhang^*, Zilong Wang, Yugang Zhao

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1087-1105, 2024, DOI:10.32604/fhmt.2024.053851

Abstract The exploration of performance and prediction of environmentally friendly refrigerant physical properties represents a critical endeavor. Equilibrium molecular dynamics simulations were employed to investigate the density and transport properties of propane and ethane at ultra-low temperatures under evaporative pressure conditions. The results of the density simulation of the evaporation conditions of the blends proved the validity of the simulation method. Under identical temperature and pressure conditions, increasing the proportion of R170 in the refrigerant blends leads to a density decrease while the temperature range in which the gas-liquid phase transition occurs is lower. The analysis More >

Liang Yi, Zhiqiang Lei, Zhisheng Xu, Yaolong Yin, Houlin Ying^*

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 977-996, 2024, DOI:10.32604/fhmt.2024.053688

Abstract This paper explores the smoke flow characteristics in tunnel fires, giving a particular emphasis on the effects of different distances between the smoke outlets and the fire source. It examines the smoke behavior under different conditions, including variations in heat release rates, exhaust volumetric flow rates, spacing between smoke outlets, and the longitudinal fire source positions. Results indicate that altering the fire source positions and the smoke outlets in the tunnel leads to variations in the properties of smoke flow both the fire source upstream and downstream; the distance between fire source and smoke outlet… More > Graphic Abstract

Bo Zhang¹, Yunxie Huang², Peilin Cui², Zhiguo Wang¹, Duo Ding¹, Zhenhai Pan³, Zhenyu Liu^2,*

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 997-1016, 2024, DOI:10.32604/fhmt.2024.053592

Abstract The high surface area of porous media enhances its efficacy for evaporative cooling, however, the evaporation of pure substances often encounters issues including local overheating and unstable heat transfer. To address these challenges, a volume of fluid (VOF) model integrated with a species transport model was developed to predict the evaporation processes of ternary mixtures (water, glycerol, and 1,2-propylene glycol) in porous ceramics in this study. It reveals that the synergistic effects of thermal conduction and convective heat transfer significantly influence the mixtures evaporation, causing the fluctuations in evaporation rates. The obtained result shows a More >

Matiewos Mekonen Abera^1,2,*, Venkata Ramayya Ancha¹, Balewgize Amare¹, L. Syam Sundar³, Kotturu V. V. Chandra Mouli⁴, Sambasivam Sangaraju⁵

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1043-1070, 2024, DOI:10.32604/fhmt.2024.049525

Abstract This study is focused on the simulation and optimization of packed-bed solar thermal energy storage by using sand as a storage material and hot-water is used as a heat transfer fluid and storage as well. The analysis has been done by using the COMSOL multi-physics software and used to compute an optimization charging time of the storage. Parameters that control this optimization are storage height, storage diameter, heat transfer fluid flow rate, and sand bed particle size. The result of COMSOL multi-physics optimized thermal storage has been validated with Taguchi method. Accordingly, the optimized parameters… More >

Guowei Feng¹, Qing Li^2,3, Yang Wang^1,*, Nan Lin⁴, Sixi Zha¹, Hang Dong¹, Ping Chen⁵, Minjun Zheng⁶

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2139-2161, 2024, DOI:10.32604/fdmp.2024.053941

Abstract High-density polyethylene (HDPE) pipes have gradually become the first choice for gas networks because of their excellent characteristics. As the use of pipes increases, there will unavoidably be a significant amount of waste generated when the pipes cease their operation life, which, if improperly handled, might result in major environmental contamination issues. In this study, the thermal degradation of polyethylene materials is simulated for different pressures (10, 50, 100, and 150 MPa) and temperatures (2300, 2500, 2700, and 2900 K) in the framework of Reactive Force Field (ReaxFF) molecular dynamics simulation. The main gas products,… More >

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

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

Xin Guan^*, Yuqi Xie, Shuaijie Wang, Mingyang Li, Shiwei Wu

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2045-2058, 2024, DOI:10.32604/fdmp.2024.049671

Abstract The effects of the erosion present on the leading edge of a wind turbine airfoil (DU 96-W-180) on its aerodynamic performances have been investigated numerically in the framework of a SST k–ω turbulence model based on the Reynolds Averaged Navier-Stokes equations (RANS). The results indicate that when sand-induced holes and small pits are involved as leading edge wear features, they have a minimal influence on the lift and drag coefficients of the airfoil. However, if delamination occurs in the same airfoil region, it significantly impacts the lift and resistance characteristics of the airfoil. Specifically, as More >

Hong Dong¹, Xiding Gao^2,*, Xinqi Zhang¹, Qian Wang^1,3, Haipeng Xu¹, Binrui Wang², Chengguo Gao¹, Kaiwen Luo², Hengyi Jiang²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 1971-1991, 2024, DOI:10.32604/fdmp.2024.049406

Abstract CO₂ pre-injection during hydraulic fracturing is an important method for the development of medium to deep heavy oil reservoirs. It reduces the interfacial tension and viscosity of crude oil, enhances its flowability, maintains reservoir pressure, and increases reservoir drainage capacity. Taking the Badaowan Formation as an example, in this study a detailed three-dimensional geomechanical model based on static data from well logging interpretations is elaborated, which can take into account both vertical and horizontal geological variations and mechanical characteristics. A comprehensive analysis of the impact of key construction parameters on Pre-CO₂ based fracturing (such as cluster More >

Cyril Enault^*

Revue Internationale de Géomatique, Vol.33, pp. 273-293, 2024, DOI:10.32604/rig.2024.053490

Abstract La question environnementale est devenue un enjeu majeur de société dans les pays occidentaux et principalement en France. L’Ile de France est aujourd’hui au cœur de cette nouvelle politique de maitrise de l’expansion des agglomérations. Aussi l’étalement urbain et plus particulièrement sa mesure et son évaluation actuelle et future présente un véritable enjeu de société. L’exploration de l’étalement urbain est donc au cœur de la géographie et de l’Economie Géographique depuis le début des années 1980, période où s’amorcent les grands développements du périurbain. Fort de ces enjeux, cet article s’intéresse à la question de… More > Graphic Abstract