Siti Nurul Akmal Yusof^a , Yutaka Asako^a,*,Mohammad Faghri^b , Lit Ken Tan^a , Nor Azwadi bin Che Sidik^a, Wan Mohd Arif bin Aziz Japar^a

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-5, 2019, DOI:10.5098/hmt.13.25

Abstract A numerical analysis for the effect of a cylinder diameter on the state quantities for the irreversible process in a piston-cylinder system was conducted using the LB1S model. The numerical method is based on the ALE method. The cylinder-diameter range of D=0.01 m to 0.10 m was chosen. The effect of the cylinder-diameter on the state quantities was slight in the single compression with the piston velocity of -10 m/s. The ratio of the average pressure to the pressure of the reversible process at the end of the first cycle ranged from 1.00023 to 1.00462 in the cyclic compression-expansion processes… More >

Louay Abd Al-Azez Mahdi, Mohammed A. Fayad, Miqdam T. Chaichan^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.9, pp. 2201-2214, 2023, DOI:10.32604/fdmp.2023.027166

Abstract A theoretical study based on the Penalty factor (PF) method by Cavallini et al. is conducted to show that the pressure drop occurring in a wire-on-tube heat exchanger can be converted into a temperature difference for two types of refrigerants R-134a and R-600a typically used for charging refrigerators and freezers. The following conditions are considered: stratified or stratified-wavy flow condensation occurring inside the smooth tube of a wire-on-tube condenser with diameter 3.25, 4.83, and 6.299 mm, condensation temperatures 35°C, 45°C, and 54.4°C and cover refrigerant mass flow rate spanning the interval from 1 to 7 kg/hr. The results show that the… More > Graphic Abstract

Jiawei Zhang^*, Qing Wang, Hongchun Huang, Haige Wang, Guodong Ji, Meng Cui, Hongyuan Zhang

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.9, pp. 2305-2314, 2023, DOI:10.32604/fdmp.2023.026304

Abstract Formation pressure is the key parameter for the analysis of wellbore safety. With increasing drilling depth, however, the behavior of this variable becomes increasingly complex. In this work, a 3D model of the formation pressure under uncertainty is presented. Moreover a relevant algorithm is elaborated. First, the logging data of regional key drilling wells are collected and a one-dimensional formation pressure profile along the well depth is determined. Then, a 3D model of regional formation pressure of the hierarchical group layer is defined by using the Kriging interpolation algorithm relying on a support vector machine (SVM) and the formation pressure… More >

Ravikan Nonkhuntod, Suchuan Yu^*

International Journal of Mental Health Promotion, Vol.25, No.5, pp. 613-626, 2023, DOI:10.32604/ijmhp.2023.025648

Abstract Due to peer pressure playing a crucial role in the decision to drink, people who have a more fragile temperament might be expected to be at higher risk. Moreover, many studies have investigated the influence of peer pressure on alcohol consumption, but few have examined the relationship between heavy drinking and peer pressure via a spatial autoregressive model (SAR) in low/middle-income countries, such as Thailand. This paper investigated the connection between heavy drinkers over the age of 15 years who drink more than or equal to 60 grams of unmixed alcohol at least once per month based on the Thai… More >

Pablo Saiz-Gonzalez^1,2, Daniel J. McDonough³, Wenxi Liu⁴, Zan Gao^1,*

International Journal of Mental Health Promotion, Vol.25, No.5, pp. 711-719, 2023, DOI:10.32604/ijmhp.2023.027530

Abstract Virtual reality (VR) seems to have the potential to provide opportunities to promote physical activity (PA) in a fun way. This paper aimed to examine the acute effects of three different virtual reality-based exercise bikes on young adults’ blood pressure (BP) and feelings compared to a traditional exercise cycling session. Four exercise sessions (immersive VR cycling, two non-immersive VR cycling, and traditional cycling) were completed by 36 young adults (22 females; M_age = 23.6 years). BP was measured immediately before and after each session using a BP cuff and exercise-induced feelings were assessed via an established survey immediately after each… More >

V. W. Bhatkar^a,*, Anirban Sur^b,*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-5, 2021, DOI:10.5098/hmt.17.12

Abstract A jet pump or an ejector uses primary fluid flow as motive fluid to entrained secondary fluid. In this paper, the main intention is to find suction flow rate, primary flow rate, secondary flow rate, loss factors and ejector efficiency for an applied pressure. The values of the different loss factors estimated are primary nozzle loss factor (Kp)=0.06, suction loss factor (Ks)=0.04-0.1, mixing loss factor (Km)=0.07-0.1 and diffuser loss factor (Kd)=0.0289. It is found that with the increase in pressure across the ejector, efficiency increases with increase in flow ratio and decrease in pressure ratio. More >

Wei Lin^a, Yongbin Zhang^b,*

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-4, 2022, DOI:10.5098/hmt.18.48

Abstract The cellular membrane of animal has the thickness normally between 5nm and 10nm and has the filtration nanopores with the diameters normally between 0.4nm and 1.2nm. The pressure drop and the critical power loss on the single nanopore for starting the wall slippage have been obtained. The wall slippage is sensitively raised with the pore radius reduction and has a linear dependence on the power loss on the pore. Without wall slippage, the water flow in the pore is much slower than the classical theory calculation; However it is far faster than the classical theory calculation for the wall slippage… More >

Ali Chitsazan^a , Georg Klepp^a, Mohammad Esmaeil Chitsazan^b, Birgit Glasmacher^c

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-6, 2022, DOI:10.5098/hmt.18.17

Abstract For the optimization of the impinging round jet, the pressure force coefficient and drying energy consumption on the moving curved surface are set as the objective functions to be minimized simultaneously. SHERPA search algorithm is used to search for the optimal point from multiple objective tradeoff study (Pareto Front) method. It is found that the pressure force coefficient on the impingement surface is highly dependent on the jet to surface distance and jet angle, while the drying energy consumption is highly dependent on the jet to jet spacing. Generally, the best design study during the multi-objective optimization is found at… More >

Ali Chitsazan^a, Georg Klepp^a, Birgit Glasmacher^b

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-9, 2022, DOI:10.5098/hmt.18.16

Abstract The effect of jet Reynolds number, jet exit angle, the nozzle to surface distance, jet to jet spacing on the heat transfer, and pressure force performance from multiple impinging round jets on a moving curved surface have been numerically evaluated. Two correlations are developed and validated for the average Nu number and the pressure force coefficient and the agreement between the CFD and correlations was reasonable. The surface motion effect becomes more pronounced on the Nu number distribution for low jet Re number, high jet to jet spacing, large jet to surface distance, and angled jets. The pressure force coefficient… More >

Ali Chitsazan^a , Georg Klepp^a, Birgit Glasmacher^b

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-7, 2022, DOI:10.5098/hmt.18.15

Abstract The effect of surface curvature, number of jets, number of jet rows, jet arrangement, crossflow, and surface motion on the heat transfer and pressure force performance from multiple impinging round jets on the moving flat and curved surface have been numerically evaluated. The more number of jets (more than three jets) has no significant effect on the average heat transfer rate. The more number of jet rows increases the strength of wall jets interference and crossflow effects and degrade the average heat transfer rates. There is a minor difference between inline and staggered arrangements on both moving flat and curved… More >