检索结果-内蒙古大学图书馆

Enhancing the thermal performance of different types of heat exchangers with fins: A comprehensive review

International Communications in Heat and Mass Transfer 2025年 166卷

作者： Rashid, Farhan Lafta Alkhekany, Zainab Abdul Karim Kurji, Hayder J. Ahmad, Shabbir Chibani, Atef Kezzar, Mohamed Hammoodi, Karrar A. Kadhim, Saif Ali Haddad, Mohammed Amin Nassim Agyekum, Ephraim Bonah Petroleum Engineering Department College of Engineering University of Kerbala Karbala56001 Iraq College of Engineering University of Warith Al-Anbiyaa Karbala56001 Iraq Mechanical Engineering Department College of Engineering University of Kerbala Karbala56001 Iraq Graduate Program of Ocean Engineering School of Engineering Universidade Federal do Rio Grande Italia Avenue km 8 Rio Grande96201-900 Brazil Institute of Geophysics and Geomatics China University of Geosciences Wuhan430074 China Research Center in Industrial Technologies CRTI P.O.Box 64 Cheraga Algiers16014 Algeria Mechanical Engineering Department University of 20 Aout 1955 El Hadaiek Road B. O. 26 Skikda21000 Algeria Technology Department Faculty of Technology 20 Aout 1955 University of Skikda PO Box 26 Skikda21000 Algeria Department College of Engineering University of Al Maarif Al Anbar31001 Iraq College of Mechanical Engineering University of Technology-Iraq Baghdad Iraq LMSEA Mechanical Engineering Department National Polytechnic School of Constantine Constantine25000 Algeria Department of Nuclear and Renewable Energy Ural Federal University Named after the First President of Russia Boris Yeltsin 19 Mira Street Ekaterinburg620002 Russia Western Caspian University 31 Istiglaliyyat Street BakuAZ1001 Azerbaijan Istanbul Okan University Tuzla Campus Tuzla Istanbul34959 Turkey Tashkent State University of Economics Islam Karimov Street 49 Tashkent City100066 Uzbekistan

Heat exchangers are critical for thermal energy management efficiency in aerospace, automotive, food processing, and energy sector operations. This thorough study analyzes the thermal performance upgrades for different heat exchanger systems, particularly fins. Finned heat exchangers—including shell-and-tube, double-pipe, and compact types—enhance heat transfer through advanced geometries and manufacturing. Shell-and-tube heat exchangers (STHXs) perform well in cross-flow and phase-change but face maintenance and cost challenges. Double-pipe heat exchangers (DPHEs) improve performance but often have higher pressure drops and limited real-world testing. Compact heat exchangers (CHE) are space-efficient and benefit from additive manufacturing but face fabrication complexity and scalability issues and need further optimization and material innovation. The review analyzes new methods that optimize heat transfer performance using modern fin shapes, including rectangle-shaped fins, triangles, trapezoids, pin fins, and wavy fins. According to test results, these alternative fin designs lead to enhanced heat transfer rates and maintainable pressure drop levels. Scientific research has validated wavy fins as heat transfer performers because they enhance the Nusselt number to 28 % above circular tubes. Using ten longitudinal and wavy fins demonstrated maximum performance capabilities by reaching an overall response value of 1.33 in DPHEs. Future academic research moves toward designing compound heat exchangers from different materials while investigating novel performance-enhancing alternatives for thermal management systems in multiple applications. The review is a key reference to bridge gaps between heat exchanger design and optimization methods. © 2024

关键词： Fins (heat exchange)

来源：评论

学校读者我要写书评

暂无评论

Coarse-Grid Selection Using Simulated Annealing

arXiv

引用

arXiv 2021年

作者： Zaman, Tareq U. MacLachlan, Scott P. Olson, Luke N. West, Matt Scientific Computing Program Memorial University of Newfoundland NL Canada Department of Mathematics and Statistics Memorial University of Newfoundland NL Canada Department of Computer Science University of Illinois at Urbana-Champaign IL United States Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign IL United States

Multilevel techniques are efficient approaches for solving the large linear systems that arise from discretized partial differential equations and other problems. While geometric multigrid requires detailed knowledge about the underlying problem and its discretization, algebraic multigrid aims to be less intrusive, requiring less knowledge about the origin of the linear system. A key step in algebraic multigrid is the choice of the coarse/fine partitioning, aiming to balance the convergence of the iteration with its cost. In work by MacLachlan and Saad [1], a constrained combinatorial optimization problem is used to define the "best" coarse grid within the setting of a two-level reduction-based algebraic multigrid method and is shown to be NP-complete. Here, we develop a new coarsening algorithm based on simulated annealing to approximate solutions to this problem, which yields improved results over the greedy algorithm developed previously. We present numerical results for test problems on both structured and unstructured meshes, demonstrating the ability to exploit knowledge about the underlying grid structure if it is available. © 2021, CC BY.

关键词： Simulated annealing

来源：评论

学校读者我要写书评

暂无评论

Extreme Learning Machine Based-Shear Stress Model of Magnetorheological Fluid for a Valve Design 6th

Extreme Learning Machine Based-Shear Stress Model of Magneto...

引用

6th International Conference and Exhibition on Sustainable Energy and Advanced Materials, ICE-SEAM 2019

作者： Bahiuddin, Irfan Fatah, Abdul Yasser Abd Mazlan, Saiful Amri Imaduddin, Fitrian Ariff, Mohd Hatta Mohammed Utami, Dewi Nazmi, Nurhazimah Malaysia-Japan International Institute of Technology Universiti Teknologi Malaysia Jalan Sultan Yahya Petra Kuala Lumpur Wilayah Persekutuan Kuala Lumpur54100 Malaysia Department of Mechanical Engineering Vocational College Universitas Gadjah Mada Jl. Yacaranda Sekip Unit IV Yogyakarta Daerah Istimewa Yogyakarta55281 Indonesia Razak Faculty of Technology and Informatics Universiti Teknologi Malaysia Kuala Lumpur Malaysia Mechanical Engineering Program Faculty of Engineering Universitas Sebelas Maret Jl. Ir. Sutami 36 A Kentingan SurakartaCentral Java57126 Indonesia

ISBN: (纸本)9789811544804

Magnetorheological fluid (MRF) models are important tools in the design of the material based-valve in a damper. Although Bingham Plastic and polynomial models are quite widely employed, these data-driven models have disadvantages in term of the accuracy and narrow applicable operating conditions, including magnetic field and shear rate. Therefore, this paper aims to utilize an extreme learning machine (ELM) based-shear stress model to design an magnetorheological (MR) valve. Firstly, an MRF model of MRF 132DG is built using rotational rheometer test results. Secondly, the model is employed to model a meandering MR valve drop pressure utilizing the known design parameters and a finite element magnetic method (FEMM) results. The comparison of the steady state pressure between the simulation and experimental results (in literature) has shown a good agreement in term of the pattern and accuracy with error of less than 3%. In summary, ELM has shown its potential to model MRF behavior while employing it to an MR device. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Extreme learning machine Machine learning Magnetorheological fluids Meandering magnetorheological valve

来源：评论

学校读者我要写书评

暂无评论

Surface state induced velocity transition for layered carbon nanotube films under transverse penetration loading

引用

Composite Structures 2025年 369卷

作者： Wang, Pengfei Wang, Wenshuai Tian, Jie Song, Zhenhua Xu, Songlin CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei230027 China Department of Aeronautics and Astronautics College of Intelligent Robotics and Advanced Manufacturing Fudan University Shanghai200433 China Engineering and Materials Science Experiment Center University of Science and Technology of China Hefei230027 China

Carbon nanotube (CNT) films, consisting of entangled two-dimensional networks, exhibit prominent surface-dependent characteristics. Lubricants have been recognized as an effective strategy for reducing interfacial friction. However, experimental evidence indicates that lubricants unexpectedly increased the interfacial friction, demonstrating a counterintuitive velocity-dependent behavior. To elucidate the anomalous interfacial dynamics, experimental and computational methodologies were employed to systematically investigate the transverse penetrating behaviors of CNT films with different interface states and loading velocities. Experimental results indicate that the lubricant exhibits a decreasing trend at lower relative velocities, but transitions from decreasing to strengthening behavior as penetration velocity increases. The proposed equation reveals that the strengthening mechanism is not solely velocity-dependent but is jointly governed by the load magnitude and surface conditions. The high specific surface area of CNT films induces enhanced interface states and pronounced velocity-dependent characteristics, which collectively govern the fracture pattern observed in films subjected to distinct surface stress conditions. Deciphering the lubricant-induced velocity-transition mechanisms in CNT films yields new theoretical insights into interface-governed penetration behavior, while establishing material design principles for engineering impact-resistant membranes with tunable energy dissipation pathways. © 2025 Elsevier Ltd

关键词： Carbon films

来源：评论

学校读者我要写书评

暂无评论

Design of the Playskin Airtm: A user-controlled, soft pneumatic exoskeleton

Design of the Playskin Airtm: A user-controlled, soft pneuma...

引用

2019 Design of Medical Devices Conference, DMD 2019

作者： Li, Bai Greenspan, Ben Mascitelli, Thomas Raccuglia, Michael Denner, Kayleigh Duda, Raymond Lobo, Michele A. Physical Therapy Department and Biomechanics and Movement Science Program University of Delaware NewarkDE United States Mechanical Engineering Department University of Delaware NewarkDE United States Biomedical Engineering Program University of Delaware NewarkDE United States

ISBN: (纸本)9780791841037

Many children have an upper extremity disability leaving them unable to explore the environment around them. Hard exoskeletons can provide support to lift a child’s arms up against gravity, but these devices are generally large and obtrusive leading to low adherence. Children often prefer to have limited arm function rather than wearing such a device. Our lab has previously designed a passive soft exoskeleton to lift children’s arms, but this did not allow for user control and was limited in the length and weight of arm it could support. Building off of this research, we have created the preliminary design for a user-controlled pneumatic soft exoskeleton that may allow users to independently raise and lower their arms. Copyright © 2019 ASME

关键词： Pneumatics

来源：评论

学校读者我要写书评

暂无评论

Some improvements on the one-step inverse isogeometric analysis by proposing a multistep inverse isogeometric methodology in sheet metal stamping processes

arXiv

引用

arXiv 2020年

作者： Reza Isazadeh, Amir Shamloofard, Mansoor Assempour, Ahmad Center of Excellence in Design Robotics and Automation Department of Mechanical Engineering Sharif University of Technology Azadi Avenue P.O. Box 11365-9567 Tehran Iran

The isogeometric methodology has been successfully implemented in one-step inverse analysis of sheet metal stamping processes. However, these models are not capable of analyzing forming processes that require severe deformation and several forming stages. This paper presents a multistep inverse isogeometric methodology to enhance the precision of one-step models in predictions of the initial blank, strain distributions, and drawability of the formed parts. This methodology deals with the minimization of potential energy, deformation theory of plasticity, and considering membrane elements. The presented methodology utilizes the NURBS basis functions to create the final, middle, and blank geometries and also to analyze sheet metal deformation. The characteristics of the applied formulations make it possible to simultaneously observe the effects of changing part parameters on its formability. One advantage of this approach is that the linear system of governing equations is solved without concerning about the convergence. Besides, the presented methodology can successfully generate the middle geometry and to restrict the movements of physical nodes along the middle surface, by presenting a new NURBS-based mapping and sliding constraint technique. The performance of the presented model is experimentally and numerically evaluated under two classical problems, including the forming of a rectangular box and a two-step drawing of a circular cup. Results comparisons indicate the credibility of the presented model in prediction of forming parameters at a low computation time. Copyright © 2020, The Authors. All rights reserved.

关键词： Potential energy

来源：评论

学校读者我要写书评

暂无评论

Study of stinging nettle fibers as a reinforcing of composite materials based on its growing region 1

Study of stinging nettle fibers as a reinforcing of composit...

引用

1st International Conference on Design, Energy, Materials and Manufacture, ICDEMM 2018

作者： Suryawan, I.G.P.A. Suardana, N.P.G. Winaya, I.N.S. Suyasa, I.W.B. Lokantara, I.P. Department of Mechanical Engineering Udayana University Kampus Bukit Jimbaran Bali Indonesia Doctoral Program of Enviromental Science Udayana University Bali Denpasar Indonesia Doctoral Program of Engineering Science Udayana University Bali Denpasar Indonesia

Stinging nettle is a perennial herbaceous plant belonging to the Urticaceae family, In Bali Indonesia called jelatang. This species is considered a weed in intensive agriculture as its fast vegetative growth and high densities enable increased spread and soil coverage. In Tabanan Bali Indonesia several places to grow are in Denbantas altitude 200-500 meters and in Bedugul altitude 1000 -1500 meters above sea level. Nettle fibers are natural fibers that can be utilized as reinforcement for composite materials. Natural fibers have been used worldwide as a potential replacement for glass fiber reinforced composites, over the last few years has been applied in the automotive sector, aircraft interior and interior of the building. Properties of the natural fiber is lighter, easier to handle, not abrasive, and low cost. The objective of this study was to compare the composition and the tensile strength of the fiber nettle based growing areas from Bedugul and Denbantas. The method used is a fiber tensile test equipment, fourier transformer infrared red (FTIR), thermo-gravimetric analysis (TGA) and scanning electron microscope (SEM). From the research of nettle fibers that stinging nettle from Denbantas has a better tensile strength than Bedugul nettle. The TGA test the visible fiber from Denbantas is superior when used as a composite reinforcement. © Published under licence by IOP Publishing Ltd.

关键词： Scanning electron microscopy

来源：评论

学校读者我要写书评

暂无评论

Chemistry across multiple phases (CAMP) version 1.0: An integrated multi-phase chemistry model

arXiv

引用

arXiv 2021年

作者： Dawson, Matthew L. Guzman, Christian Curtis, Jeffrey H. Acosta, Mario Zhu, Shupeng Dabdub, Donald Conley, Andrew West, Matthew Riemer, Nicole Jorba, Oriol Barcelona Supercomputing Center Barcelona Spain Department of Atmospheric Sciences University of Illinois at Urbana-Champaign UrbanaIL United States Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Atmospheric Chemistry Observations and Modeling Laboratory National Center for Atmospheric Research BoulderCO United States Advanced Power and Energy Program University of California IrvineCA United States Department of Mechanical and Aerospace Engineering University of California IrvineCA United States

A flexible treatment for gas- and aerosol-phase chemical processes has been developed for models of diverse scale, from box models up to global models. At the core of this novel framework is an"abstracted aerosol representation" that allows a given chemical mechanism to be solved in atmospheric models with different aerosol representations (e.g., sectional, modal, or particle-resolved). This is accomplished by treating aerosols as a collection of condensed phases that are implemented according to the aerosol representation of the host model. The framework also allows multiple chemical processes (e.g., gas- and aerosol-phase chemical reactions, emissions, deposition, photolysis, and mass-transfer) to be solved simultaneously as a single system. The flexibility of the model is achieved by (1) using an object-oriented design that facilitates extensibility to new types of chemical processes and to new ways of representing aerosol systems;(2) runtime model configuration using JSON input files that permits making changes to any part of the chemical mechanism without recompiling the model;this widely used, human-readable format allows entire gas- and aerosol-phase chemical mechanisms to be described with as much complexity as necessary;and (3) automated comprehensive testing that ensures stability of the code as new functionality is introduced. Together, these design choices enable users to build a customized multiphase mechanism, without having to handle pre-processors, solvers or compilers. Removing these hurdles makes this type of modeling accessible to a much wider community, including modelers, experimentalists, and educators. This new treatment compiles as a stand-alone library and has been deployed in the particle-resolved PartMC model and in the MONARCH chemical weather prediction system for use at regional and global scales. Results from the initial deployment to box models of different complexity and MONARCH will be discussed, along with future extension to more

关键词： Aerosols

来源：评论

学校读者我要写书评

暂无评论

Detection and Location Estimation of Object in Unmanned Aerial Vehicle using Single Camera and GPS

Detection and Location Estimation of Object in Unmanned Aeri...

引用

Power, Control and Computing Technologies (ICPC2T), Conference on

作者： Snehil Sanyal Shashank Bhushan K Sivayazi Department of Mechanical Engineering Defence Institute of Advanced Technology Pune India Center for Artificial Intelligence & Robotics (CAIR) Defence Research & Development Organization (DRDO) Bengaluru India

ISBN: (数字)9781728149974

ISBN: (纸本)9781728149981

It is important for an Unmanned Aerial Vehicle (UAV) to detect any object in its view. This enables the UAV to locate the object with respect to itself and is required for locking and tracking the object. Object detection and location estimation makes the UAV capable of manipulating the environment as well as to follow the target. In the present work, object detection has been carried out using You Only Look Once (YOLO) to detect the object in the image stream of the Robot Operating System (ROS) bag file. The GPS information of the UAV is used to further calculate the GPS coordinates of the object. The images are acquired using a single monocular camera.

关键词： Cameras Object detection Global Positioning System Drones Three-dimensional displays Estimation

来源：评论

学校读者我要写书评

暂无评论

Dynamics and domain randomized gait modulation with bezier curves for sim-to-real legged locomotion

arXiv

引用

arXiv 2020年

作者： Rahme, Maurice Abraham, Ian Elwin, Matthew L. Murphey, Todd D. Department of Mechanical Engineering Northwestern University EvanstonIL60208 United States Robotics Institute Carnegie Mellon University PittsburghPA15213 Corresponding United States

We present a sim-to-real framework that uses dynamics and domain randomized offline reinforcement learning to enhance open-loop gaits for legged robots, allowing them to traverse uneven terrain without sensing foot impacts. Our approach, D2-Randomized Gait Modulation with Bezier Curves (D2-GMBC), uses augmented random search with randomized dynamics and terrain to train, in simulation, a policy that modifies the parameters and output of an open-loop Bezier curve gait generator for quadrupedal robots. The policy, using only inertial measurements, enables the robot to traverse unknown rough terrain, even when the robot’s physical parameters do not match the open-loop model. We compare the resulting policy to hand-tuned Bezier Curve gaits and to policies trained without randomization, both in simulation and on a real quadrupedal robot. With D2-GMBC, across a variety of experiments on unobserved and unknown uneven terrain, the robot walks significantly farther than with either hand-tuned gaits or gaits learned without domain randomization. Additionally, using D2-GMBC, the robot can walk laterally and rotate while on the rough terrain, even though it was trained only for forward walking. Copyright © 2020, The Authors. All rights reserved.

关键词： Modulation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：