Zhen Zhong^*, Yadong Li, Yuxuan Zhao, Pengfei Ju

Sound & Vibration, Vol.57, pp. 15-27, 2023, DOI:10.32604/sv.2023.041954 - 07 September 2023

Abstract Bent-housing motor is the most widely used directional drilling tool, but it often encounters the problem of high friction when sliding drilling in horizontal wells. In this paper, a mathematical model is proposed to simulate slide drilling with a friction reduction tool of axial vibration. A term called dynamic effective tractoring force (DETF) is defined and used to evaluate friction reduction effectiveness. The factors influencing the DETF are studied, and the tool placement optimization problem is investigated. The study finds that the drilling rate of penetration (ROP) can lower the DETF but does not change… More >

Xin Wang^1,3, Ying Yan^1,3, Hongmei Ji^1,3,*, Xiaowu Li^1,2,*

Journal of Renewable Materials, Vol.11, No.8, pp. 3297-3308, 2023, DOI:10.32604/jrm.2023.027066 - 26 June 2023

Abstract As an essential renewable mineral resource, mollusk shells can be used as handicrafts, building materials, adsorbents, etc. However, there are few reports on the wear resistance of their structures. The Vicker’s hardness and friction, and wear resistance of different microstructures in mollusk shells were comparatively studied in the present work. The hardness of prismatic structures is lower than that of cross-lamellar and nacreous structures. However, the experimental results of sliding tests indicate that the prismatic structure exhibits the best anti-wear ability compared with foliated, crossed-lamellar, and nacreous structures. The anti-wear and hardness do not present More > Graphic Abstract

O. M. Oyewola^a,b,* , M. O. Petinrin^a , and H. O. Sanusi^a

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-8, 2023, DOI:10.5098/hmt.20.16

Abstract The flow and heat transfer behaviour of channels with dimples and protrusions of spherical and piriform shapes was numerically explored by solving the Navier-Stokes and energy equations with a CFD software, the ANSYS Fluent 19.3, in the range of Reynolds numbers from 8,500 to 59,000. The values of the Nusselt number and friction factors were estimated and the non-dimensional Performance Evaluation Criterion (PEC) was determined to measure the thermal-hydraulic performance. The results reveal that the piriform protruded channel demonstrated a higher thermal performance with Nusselt number values of 36%, 15%, 23%, and 9% than the… More >

R. Selvam^1,*, L. Ganesh Babu², Joji Thomas³, R. Prakash¹, T. Karthikeyan¹, T. Maridurai⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 569-577, 2023, DOI:10.32604/fdmp.2022.022187 - 29 September 2022

Abstract Hybrid materials collected from organic and inorganic sources, which are traditionally used as brake lining materials, generally include fly ash, cashew shell powder, phenolic resins, aluminium wool, barites, lime powder, carbon powder and copper powder. The present research focuses on the specific effects produced by fly ash and aims to provide useful indications for the replacement of asbestos due to the health hazards caused by the related fibers. Furthermore, the financial implications related to the use of large-volume use of fly ash, lime stone and cashew shell powder, readily available in most countries in the More > Graphic Abstract

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 711-722, 2023, DOI:10.32604/fdmp.2022.021651 - 29 September 2022

Abstract The thermo-hydraulic properties of circular tubes with a twisted tape inside (used accordingly to induce turbulence and enhance heat transfer through the tube wall) are described for Reynolds Numbers ranging from 830 to 1990. Tapes twisted with the three distinct twist ratios are considered, namely, 6, 4.4 and 3. Air is used as the working fluid in several tests. For the sake of comparison, the standard tube with no insert is also examined. It is shown that in the presence of the twisted tape, the ‘frictional factor’, ‘Nusselt Number’ and the ‘thermal performance factor’ are More >

Saixuan Chen¹, Jie Yang^1,*, Guohua Cui¹, Fuzhou Niu², Baiqiang Yao¹, Yu Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 2021-2039, 2023, DOI:10.32604/cmes.2022.022669 - 20 September 2022

Abstract This paper proposes a zero-moment control torque compensation technique. After compensating the gravity and friction of the robot, it must overcome a small inertial force to move in compliance with the external force. The principle of torque balance was used to realise the zero-moment dragging and teaching function of the lightweight collaborative robot. The robot parameter identification based on the least square method was used to accurately identify the robot torque sensitivity and friction parameters. When the robot joint rotates at a low speed, it can approximately satisfy the torque balance equation. The experiment uses More >

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 501-511, 2023, DOI:10.32604/fdmp.2022.021502 - 29 August 2022

Abstract The thermal behavior of pipes with a twisted tape inside (used to enhance heat transfer through the tube wall) is studied in the laminar flow regime. Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–2000. It is found that in such conditions the ‘Nusselt Number’ (Nu) gradually increases with reducing the tape twist ratio, whereas the friction factor is detrimentally affected by the presence of the tape (as witnessed by the comparison with the companion case where a plain tube is considered). In particular, it is shown that More >

Shuai Wang, Zhihong Yu^*, Wenjie Zhang, Dongxu Zhao, Aorigele

Phyton-International Journal of Experimental Botany, Vol.91, No.11, pp. 2559-2582, 2022, DOI:10.32604/phyton.2022.021354 - 12 July 2022

Abstract

Sunflower (Helianthus annuus L.) is one of the four major oil crops in the world and has high economic value. However, the lack of discrete element method (DEM) models and parameters for sunflower seeds hinders the application of DEM for computer simulation in the key working processes of sunflower seed sowing and harvesting. The present study was conducted on two varieties of sunflower, and the DEM model of sunflower seeds was established by using 3D scanning technology based on the distribution of triaxial dimensions and volumes of the geometric model of sunflower seeds. Similarly, the physical

… More >

Rida Tazi¹, Adil Echchelh¹, Mohammed El Ganaoui², Aouatif Saad^3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1631-1638, 2022, DOI:10.32604/fdmp.2022.021975 - 27 June 2022

Abstract Unlike most fluids, granular materials include coexisting solid, liquid or gaseous regions, which produce a rich variety of complex flows. Dense flows of grains driven by gravity down inclines occur in nature and in industrialprocesses. To describe the granular flow on an inclined surface, several studies were carried out. We can cite in particular the description of Saint-Venant which considers a dry granular flow, without cohesion and it only takes into account the substance-substrate friction, this model proposes a simplified form of the granular flow, which depends on the one side on the angle of… More >

T. Khatir^1,2, M. Bouchetara², K. Derrar², M. Djafri³, S. Khatir⁴, M. Abdel Wahab^5,6,*

CMC-Computers, Materials & Continua, Vol.72, No.2, pp. 2259-2273, 2022, DOI:10.32604/cmc.2022.020879 - 29 March 2022

Abstract Braking efficiency is characterized by reduced braking time and distance, and therefore passenger safety depends on the design of the braking system. During the braking of a vehicle, the braking system must dissipate the kinetic energy by transforming it into heat energy. A too high temperature can lead to an almost total loss of braking efficiency. An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface. Heat transfer and temperature gradient, not to forget the vehicle's travel environment (high speed, heavy load, and steeply… More >