Nine sets of fin parameter combinations, including a plain tube control group, were modeled. Simulations were performed under steady-state conditions using the EWT Realizable k-epsilon turbulence model, with benzene and water as working fluids, while accounting for temperature-dependent thermophysical properties. Flow field distribution, temperature profile, Nusselt number, and pressure drop in the shell side of the heat exchanger were analyzed. Response surface methodology was employed to systematically evaluate the coupled effects of fin height and fin spacing on thermal performance. The results indicate that annular fins significantly enhance heat transfer by inducing secondary flow and disrupting the thermal boundary layer. Compared to the smooth tube, the finned tubes increased the Nusselt number (Nu) by up to 28.6% and the total heat transfer rate by 13.55%, while the pressure drop (Delta P) increased by approximately 9.81% to 16.5%. The analysis revealed that fin height is the dominant factor affecting performance, whereas fin spacing plays a regulatory role. As the fins became taller or denser, the temperature field evolved from stable stratification to intense mixing and eventually to local disorder. The study identified an optimal parameter range for engineering applications. A fin height of 2-3 mm combined with a spacing of 10-15 mm achieves the best balance between heat transfer enhancement and flow resistance. Specifically, the combination of h = 3 mm and s = 10 mm yielded the highest Energy Efficiency Coefficient (EEC) of 1.567. This configuration is recommended for large-flow, pressure-drop-sensitive systems, such as those found in petrochemical plants or long-distance heat transmission applications.

To improve energy savings and emission reduction in industrial heating furnaces, this study investigated the impact of various molar fractions of hydrogen on natural gas combustion and compared the results of the Non-Premixed Combustion Model with the Eddy Dissipation Combustion Model. Initially, natural gas combustion in an industrial heating furnace was investigated experimentally, and these results were used as boundary conditions for CFD simulations. The diffusion flame and combustion characteristics of natural gas were simulated using both the non-premixed combustion model and the Eddy Dissipation Combustion Model. The results indicated that the Non-Premixed Combustion Model provided simulations more consistent with experimental data, within acceptable error margins, thus validating the accuracy of the numerical simulations. Additionally, to analyze the impact of hydrogen doping on the performance of an industrial gas heater, four gas mixtures with varying hydrogen contents (15% H2, 30% H2, 45% H2, and 60% H2) were studied while maintaining constant fuel inlet temperature and flow rate. The results demonstrate that the Non-Premixed Combustion Model more accurately simulates complex flue gas flow and chemical reactions during combustion. Moreover, hydrogen-doped natural gas significantly reduces CO and CO2 emissions compared to pure natural gas combustion. Specifically, at 60% hydrogen content, CO and CO2 levels decrease by 70% and 37.5%, respectively, while NO emissions increase proportionally; at this hydrogen content, NO concentration in the furnace chamber rises by 155%.

借助Fluent软件分析了旋流器锥角、溢流管插入深度和入口尺寸对分离器分离效率和压降的影响.结果表明:综合考虑分离效率和压降,锥角为10°、溢流管插入深度为24 mm、入口尺寸为10 mm×21 mm的旋流器,对直径为5μm的颗粒分离效果最好.

本文以线上线下混合式"金课"建设为目标,以《工程流体力学》课程为例,探讨工科专业基础课程的线上线下混合教学模式,对在线课程建设、教学资源及线上线下教学实践进行了探讨,并与现代信息技术有效融合,设计和实施符合混合式教学过程及课程特点的评价考核机制,突出以学生为中心的课程理念,顺应时代发展和人才培养要求.

基于叶素动量理论对水平轴潮流能水轮机叶片外形进行设计,并结合Wilson方法修正计算模型,采用Matlab软件对叶片进行优化计算,得到优化后的弦长和扭角.通过坐标转换得到优化后翼型的三维坐标,将得到的坐标导入SolidWorks软件中建立叶片的三维模型.最后通过Fluent软件对设计的水轮机在不同尖速比下进行三维数值模拟.计算结果表明,设计的水轮机在水流速度为0.8 m/s,叶尖速比为3时,捕能系数能取得较大值,且水轮机无回流现象,具有良好的水动力特性.

为了提高横轴水轮机发电装置能量利用率,采用CFD方法研究了水轮机外围导流罩的增速性能,比较了有、无导流罩情况下水轮机的流场特性.选取导流罩入口角度、出口角度、导流罩间距3个因素,每个因素选取4个水平,对16种方案下的横轴水轮机力矩系数及能量利用率进行对比分析.结果 表明,导流罩在一定程度上增大了来流的速度,水平段中心处速度可增大至原来的2倍左右;导流罩结构参数对横轴水轮机能量利用率影响的大小依次为:出口角度、间距、入口角度;其中导流罩出口角度和间距对能量利用率影响较为明显,而入口角度对其影响较小;当导流罩间距为1.4倍水轮机旋转直径时,其能量利用率达到最大.

本文基于当前课程思政建设的社会大背景,从教学内容、教学方法等方面,比较具体地阐述了《工程力学》课程思政的实施方法,为工程力学思政教学提供了一定参考.

《工程流体力学》课程主要阐述流体平衡和运动的基本规律及其有关的基本概念、基本理论、基本计算方法和基本实验技能.要求学生不仅要掌握流体力学相关知识和理论,还要学习流体力学中蕴含的唯物主义哲学思想及科学精神等思想政治教育相关内容.文章以上海海洋大学《工程流体力学》课程为例,探讨《工程流体力学》课程中所蕴含的思政教育内容以及德育实施情况.

A circular particle settling in a confined vertical channel with static fluid is investigated by lattice Boltzmann method, the effect of density ratio on the particle motion and flow pattern is discussed. It shows that the particle starting from an initial position off-center displays various moving modes accompanied by different flow patterns for 1.003 ≤ γ ≤ 5.0: when γ < 1.1, the particle is finally in a stable equilibrium near the centerline and settles uniformly with a symmetrical flow, but there are different modes before reaching the centerline at different density ratios, a monotonic approach appears at γ ≤ 1.005 and an transient overshoot appears at 1.005 < γ < 1.1; When γ = 1.1, a weak oscillation appears in the particle moving but the flow is almost symmetrical, it is in a critical state of the particle moving from stable equilibrium with a transient overshoot to oscillation; When 1.1 < γ ≤ 3.0, the particle oscillates regularly around the centerline with the uniform amplitude and frequency, and it turns into irregularity for γ > 3.0. Meanwhile the rotation of the particle depends on the distance from a wall; it rolls up the closer wall and stops at centerline.

本文针对当前普通高校理论力学讲授学时大量减少的问题,根据多年的教学实践,从教材、教学内容、教学方法和教学手段等方面,归纳总结了普通高校理论力学少学时教学的几点切实可行的教改措施,为理论力学的教学提供建设性意见和建议.

Based on the horizontal ocean generation,the motion of blade airfoil is simulated based on the Reynolds averaged Navier-Stokes equations,with various attack angle from 0°～26°.By analyzing and comparing the results,the value of the lift drag ratio can be effectively improved within a certain range by increasing the attack angle.However,when lift coefficient reaches the maximum,lift-drag ratio and the energy harvesting efficiency do not reach the maximum.The rule is also verified that the root cause of stalling phenomenon on airfoil is the separation of boundary layer.The pressure difference between suction and pressure side is bigger,providing a higher lift coefficient,which is mainly from in the first half of the hydrofoil.In addition,the laws of the other hydrodynamic characteristics with various attack angle are considered,including flow field and pressure distribution.Thus,it provides theoretical references for designing the efficient ocean-conversion blades.

文章探讨基于CAI进行学生雷诺实验的教学改革,在分析雷诺实验的基本原理和教学要求的基础上,对教学方法、教学工具等方面进行了一系列改进措施.改进后的雷诺实验教学有助于学生对原理的理解,提高了实验效率和计算准确度,优化了实验教学效果,提升了学生满意度.

在卧式水轮机带动永磁同步发电机发电过程中,功率性能反映了系统的发电效率。针对水轮机发电系统功率性能的研究中,建立发电系统数学方程困难的问题,提出了联合仿真方法。首先利用Gambit对水轮机进行建模,将模型导入Fluent软件后,对水动力性能进行计算,以获得海洋能作用在水轮机主轴上的转矩值。然后在Matlab/Simulink里建立发电系统模型,调用仿真计算得到的转矩数据,驱动发电机发电。实验结果表明,联合仿真研究方法可以模拟海洋能作用在水轮机主轴上的转矩值情况,并获得由转矩值带动发电机发电的功率特性,并保证了发电系统的功率性能。

围绕力学课程群建设主题,以上海海洋大学机制专业为例,本文在完善教学教材体系建设、设计课程内容技巧、关注质量目标达成度、优化考核方法等方面进行了广泛的探讨,以促进力学学科全面发展,并与机制专业培养目标设紧密结合,使力学真正融合到专业学科的建设中,以此提升力学学科在教学中的核心地位,促进二者的共同协调发展.

针对某种卧式浪流轮机获能效率较低的问题,提出对卧式浪流轮机加装导流罩,起到聚流增速的效果。在Gambit里对所设计的导流罩、水轮机以及两者组成的系统进行建模并且划分网格,用CFD软件(Fluent)建立数学模型,对导流罩主要参数进行仿真研究。分别对导流罩的长度以及开口张角进行分析,并且对比有无导流罩卧式浪流轮机获能效率的状况;仿真结果表明,加装导流罩使卧式浪流轮机水动力学性能更好,获能效率更高,并且得出导流罩主要参数尺寸。

The preparation of concrete specimen occupies an important position in the concrete technology research.The automatic prep-aration system was studied in order to meet the different needs of small scale specimen preparation in the research field.On the basis of analyzing the concrete preparation process,the function of concrete specimen automatic preparation system was divided,the overall and part model was constructed,different scale specimen preparation was achieved by changing mould.Based on the research of the concrete specimen preparation system,the precision and efficiency of the civil engineering concrete specimen preparation is improved,to provide help and support to the research of concrete material.

通过对三种伞布料的迎风风阻系数风洞试验,得到了各工况下不同布料的风阻系数值.对三种布料风阻系数实验结果进行研究,得到三种布料的风阻系数随风力变化的变化规律,结合上海市区东南方向南汇新城的年均风速的情况,依据风阻系数的实验结果,找到三种布料中最适合做抗风伞的布料是EVA.该实验方法可以作为测定雨伞布料风阻系数的测试方法.

Based on the engineering practice of the experimental tea-ching courses in fluid mechanics as the object, in order to promote the teaching quality, the method of combining CFD simulation and test methods, process steps is presented with examples, in order to enhance students understanding of the course and application, and promote the cultivation of students' innovative ability.

基于教师教学评价和学生学习效果评价两层面,分析了高校教学质量评价方案以及指标因素,给出了评价包含的指标体系与分类,为高校教学质量评价的改革与完善、评价指标的构建提供支持与参考.

为推进海洋可再生能源的发展与利用,提高海洋能捕获机构的效率,以水平轴式海洋能捕获机构为对象,结合计算流体力学原理,利用RNG k-ε来模拟机构流场的湍流流动,给出了机构有限元网格划分方式,通过计算机仿真模拟分析优化机构叶片布置数量.在此基础上,以不同来流攻角方向对机构叶片特性进行分析,分析了不同攻角情况下的流场状态,给出了攻角变化范围,并讨论给出了分析结果.