Jaimon Dennis Quadros¹, Sher Afghan Khan², Abdul Aabid^3,*, Muneer Baig³

CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.3, pp. 2331-2352, 2023, DOI:10.32604/cmes.2023.028925

Abstract The application of abruptly enlarged flows to adjust the drag of aerodynamic vehicles using machine learning models has not been investigated previously. The process variables (Mach number (M), nozzle pressure ratio (η), area ratio (α), and length to diameter ratio (γ )) were numerically explored to address several aspects of this process, namely base pressure (β) and base pressure with cavity (β_cav). In this work, the optimal base pressure is determined using the PCA-BAS-ENN based algorithm to modify the base pressure presetting accuracy, thereby regulating the base drag required for smooth flow of aerodynamic vehicles. Based on the identical dataset,… More > Graphic Abstract

Stepan Konev¹, Victor A. Eremeyev^2,3, Hamid M. Sedighi^4,5,*, Leonid Igumnov², Anatoly Bragov², Aleksandr Konstantinov², Ayaulym Kuanyshova¹, Ivan Sergeichev¹

CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.3, pp. 2149-2161, 2023, DOI:10.32604/cmes.2023.028179

Abstract This article presents the results of experimental studies concerning the dynamic deformation and failure of a unidirectional carbon fiber reinforced plastic (T700/LY113) under compression. The test samples were manufactured through the filament winding of flat plates. To establish the strain rate dependencies of the strength and elastic modulus of the material, dynamic tests were carried out using a drop tower, the Split Hopkinson Pressure Bar method, and standard static tests. The samples were loaded both along and perpendicular to the direction of the reinforcing fiber. The applicability of the obtained samples for static and dynamic tests was confirmed through finite… More >

Abdourahamane Salifou Adam¹, Hatem Mrad¹, Haykel Marouani^2,*, Yasser Fouad³

CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.3, pp. 2845-2865, 2023, DOI:10.32604/cmes.2023.030777

Abstract A high percentage of failure in pump elements originates from fatigue. This study focuses on the discharge section behavior, made of ductile iron, under dynamic load. An experimental protocol is established to collect the strain under pressurization and depressurization tests at specific locations. These experimental results are used to formulate the ultimate pressure expression function of the strain and the lateral surface of the discharge section and to validate finite element modeling. Fe-Safe is then used to assess the fatigue life cycle using different types of fatigue criteria (Coffin-Manson, Morrow, Goodman, and Soderberg). When the pressure is under 3000 PSI,… More >

Vijayakumar Thulasi, R. Thundil Karuppa Raj^*

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-9, 2018, DOI:10.5098/hmt.10.33

Abstract Diethyl ether is one of the potential alternative fuels for the high speed compression ignition engines that can replace the existing neat diesel fuel. It is well known that the combustion characteristic of a compression ignition engine is highly influenced by the fuel spray structure formed during the injection process. In this paper the spray structure formation for the diethyl ether fuel is studied numerically, using the discrete phase model and it is compared with the neat diesel fuel. The spray is investigated in a constant volume chamber maintained at 30 bar pressure. The fuel is injected into the chamber… More >

AlemKarima^a,*, Sahel Djamel^b , Nemdili Ali^c, Ameur Houari^d

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-7, 2018, DOI:10.5098/hmt.10.27

Abstract In the present paper, the effects of a new baffle design on the efficiency of a tubular heat exchanger are numerically investigated. It concerns butterfly baffles inserted in a cylindrical tube heat exchanger. We focus on the influence of the shape of baffles, the space between baffles (pitch ratio, PR) and the baffle size (i.e. the blockage ratio, BR) on the heat transfer and flow characteristics. Three geometrical configurations with different PRs are realized (PR = 1, 2 and 4) and five others with different blockage ratios (BR = 0.1, 0.2, 0.3, 0.4 and 0.5). The investigations are achieved for… More >

Ralph Eismann^a,† , Robert Adams^b

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.4

Abstract Convergence of numerical schemes for pipe network analysis requires continuous modelling of pressure losses in the transition region between laminar and turbulent regions. Several existing correlations for the friction factor of straight pipes and helical tubes are presented. Based on these correlations a new explicit correlation for helical tubes with arbitrary surface roughness is derived. The friction factor is expressed as a continuous function of the Reynolds number covering laminar, transitional, and turbulent flow regions. Potential sources of error are also discussed, including the effects of tube deformation caused by the bending process. More >

Fatemeh Rezaei^1,2,*, Milan Gaff^1,3,4,*, Róbert Nemeth⁵, Jerzy Smardzewski⁶, Peter Niemz⁷, Haitao Li^8,9, Anil Kumar Sethy^1,10, Luigi Todaro¹¹, Gourav Kamboj¹, Sumanta Das¹, Roberto Corleto¹, Gianluca Ditommaso¹, Miklós Bak⁵

Journal of Renewable Materials, Vol.11, No.8, pp. 3277-3296, 2023, DOI:10.32604/jrm.2023.028352

Abstract The performance of engineered wood products is highly associated with proper bonding and an efficient cutting method. This paper investigates the influence of CO₂ laser cutting on the wetting properties, the modified chemical component of the laser-cut surface, and the strength and adhesive penetration near the bondline. Beechwood is cut by the laser with varying processing parameters, cutting speeds, gas pressures, and focal point positions. The laser-cut samples were divided into two groups, sanded and non-sanded samples. Polyvinyl acetate adhesive (PVAc) was used to bond the groups of laser-cut samples. After assembly with cold pressing, the tensile shear test was… More >

Shihong Xiao^1,2,*, Shichao Zhou^1,*, Linlin Yue¹, Xianyou He¹, Maolin Xiang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2549-2567, 2023, DOI:10.32604/fdmp.2023.025063

Abstract In this study, the pressure compensation mechanism of a reducer bellows is analyzed. This device is typically used to reduce the size of undersea instruments and improve related pressure resistance and sealing capabilities. Here, its axial stiffness is studied through a multi-fold approach based on theory, simulations and experiments. The results indicate that the mechanical strength of the reducer bellows, together with the oil volume and temperature are the main factors influencing its performances. In particular, the wall thickness, wave number, middle distance, and wave height are the most influential parameters. For a certain type of reducer bellows, the compensation… More >

Fengping Li¹, Dong Sun^1,*, Qiaolin Zhang^1,2,3, Hairong Chen^1,2,3, István Bíró^2,3, Zhiyi Zheng⁴, Yaodong Gu^1,*

Molecular & Cellular Biomechanics, Vol.20, No.1, pp. 35-47, 2023, DOI:10.32604/mcb.2023.041016

Abstract Background: A children’s backpack is one of the important school supplies for school-age children. Long-term excessive weight can cause spinal deformity that cannot be reversed. This study compared a double helical spring decompression structure backpack (DHSB) with a traditional backpack (TB) to explore the optimization of decompression devices on upper body pressure. The finite element (FE) method was then used to explore the simulation of lumbar stress with different backpacks, in order to prove that DHSB can reduce the influence of backpack weight on lumbar vertebrae, avoid the occurrence of muscle discomfort and spinal deformity in children; Methods: 18 male… More > Graphic Abstract

Yasushi Koito^a,*

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.26

Abstract This paper describes extended numerical analyses on vapor pressure distribution in a centered-wick ultra-thin heat pipe. Analyses were conducted by using a three-dimensional model developed by the author. Numerical results were obtained changing design parameters and operating conditions of the heat pipe. Discussion was made on the heat transfer limit as well as the vapor pressure drop. Moreover, a simple method was also presented to evaluate the vapor pressure drop in the ultra-thin heat pipe. Calculated results with the simple method agreed in 10 % with the three-dimensional numerical results. More >