烘干炉风道导流板的优化设计

采用有限元仿真分析软件ANSYS，利用其参数化分析、计算语言APDL，对热风烘干炉进行参数化建模，并用计算流体动力学FLOTRAN完成了各种设计方案的数值计算，同时利用APDL语言的计算控制和结果提取功能以及循环迭代算法，成功地模拟了烘干炉内在不同尺寸和位置的导流板作用下的流场，最后取得使烘箱内部流场分布均匀时所对应导流板的尺寸和位置作为设计的依据。     

动力锂电池悬浮烘箱风速场特性分析与结构优化

为提升动力锂电池悬浮烘箱的干燥性能,探究烘箱内风速场的匀流特性,以中部进风式悬浮烘箱为模型,对其风室风速场进行数值模拟分析,通过量化指标评价各风刀出口的风速均匀性.在特定工况下展开试验并验证了数值模拟结果的准确性.针对风室内气流发展紊乱和各风刀出口风速分布不均的现象,对烘箱结构进行优化设计.结果 表明,烘箱内涡流现象减弱,气流发展平稳.各风刀出口的平均风速值均方差减小,风速分布均达到了不均匀系数＜5％的良好评价指标,整体风刀出口风速的平均不均匀系数由6.9％降至1.5％,气流整体分布均匀性得到明显改善.研究结果可为新型烘箱的设计与生产提供理论依据.     

改善离心风机进口气流的试验研究

在对离心风机静止模型的进口流场分析的基础上，通过用导流板进行试验，得到了最佳位置。然后用导流圈在已知性能的风机上进行测试，效率明显提高。     

单板干燥室配风管速度均匀性的优化研究

喷气式单板干燥室的气流分配不均是影响单板干燥质量的主要因素。通过对配风管气流分配特性的实验和仿真研究,提出了一种导流板设计方案。通过对导流板中心孔间距、板厚、安装位置和孔径对配风管气流均匀性的影响进行分析,优化了导流板的设计参数。结果表明:相对于无导流板的配风管,导流板中心孔间距为45mm时,配风管的气流分配效果提升了41%;板厚为8mm,安装位置在分配管的2/5处时,配风均匀度分别提高了66%和67%;孔径为12mm时,气流分配效果提升了87%。     

翼型导流板对风机盘管进风均匀性改进的研究

采用翼型导流板对某三代核电机组安全壳冷却机组风机盘管进风均匀性的改善进行了研究。提出了在盘管迎风面安装与竖直方向成一定夹角导流板的改进方案,采用数值模拟的方法分析其流场,依据GB/T14294-2008定量分析了改进方案对盘管迎风面进风均匀性的改善,筛选出了满足国标要求的改进方案。对筛选出的改进方案在原风机盘管上进行了实施,并对改进方案实施后风机盘管的迎风面进风均匀性进行了测量和定量分析。研究结果表明:在风机盘管迎风面安装与竖直方向有一定夹角的导流板可以提高风机盘管迎风面上的断面风速均匀度对于文中的研究对象,在风机盘管迎风侧安装与竖直方向30°夹角的导流板后,风机盘管迎风面上的断面风速均匀度为86%,满足国标要求。     

矿井通风系统风流流动数值模拟研究

以山西煤炭进出口集团韩家洼煤矿为例,分析其工程概况,对通风系统可靠性进行评价,通过理论分析、数值模拟的研究方法对矿井通风系统风流流动、风速、风量及负压进行模拟。研究表明:正常情况下,在总回风巷中,巷道的风速最大,在长度较小的联络巷风速较小,有毒有害气体量小,无瓦斯突出的危险,风量除了与风速大小有关,还与巷道的端面大小有关,其与风速无明显的函数关系;调节风门异常时,巷道风速增加量大,通风系统中的其他巷道受此影响风速也有所增加;风压异常时,风机负压减小量与风速大小、风量大小关系成函数对应关系。工程实测表明,数值模拟各巷道风量和风速研究结果与矿上实测结果相符,数值模拟可对通风系统进行评价。     

引进三十万吨合成氨设备主换热器导流片（器）导流性能的试验研究

本文对引进三十万吨合成氨设备中主换热器－板翅式换热器导流片的导流性能进行了大量试验研究，分析了影响流片导流性能的主要因素。通过对试验结果的分析与讨论，为改善板坡式换热器内部的物流分配及优化板坡式换热器的设计提供了依据。     

CFD在生物反应器结构优化改进上的应用

降低微藻生物质积累成本是解决微藻生物柴油技术产业化发展的关键技术之一。气浮开发式跑道池光生物反应器是最具被运用于大规模培养潜力的反应器之一。文中借助计算流体动力学(CFD)对影响微藻生物质积累的反应器结构和尺寸进行优化改进,研究了进气口位置设计和添加导流板结构对反应器流场分布的影响。模拟计算结果表明:添加导流板结构和将进气口位置对称设置在反应器长度方向的拐弯处都能较好地改善反应器流场分布,提高平均速度,降低死去比例,有助于微藻生物质积累;添加导流板的平均速度比无导流板时提高了14.6%,死区比例为无导流板时的5.7%。     

基于网络的矿井通风安全监测研究

为了研究矿井通风安全监测系统所涉及的关键问题,做了以下相关分析研究:通过对风速传感器测得数据进行分析,得出了传感器所处巷道截面的平均风速;通过对巷道截面风速进行仿真研究,得出了不同截面尺寸下巷道截面风速的分布图;通过网络互相关联的影响因素对巷道故障点进行分析,得出了矿井通风安全监测评估方法。     

压缩机出口处导流板的模拟与改进

针对压缩机出口处导流板内流场的不均匀性,提出了几种导流板改进的方法来削弱漩涡的影响,提高均匀性。改进的方法为:添加短导流板、改变导流板的几何安装角、切割导流板以及降低导流板的弯曲度。借助Fluent软件对导流板改进前后的流动进行数值模拟,结果表明:降低导流板弯曲度或添加一半的导流板,均对漩涡削弱明显,效果好,其余方法的效果较差。     

Study on the design of ball valve based on elastic ring valve seat structure and fluid characteristics and fatigue strength

Aimed at the technical problems such as the influence of granular medium on spring pre-tightening force sealing, a new ball valve based on elastic ring valve seat structure is studied. The spring plate type valve seat structure is designed to cooperate with the ball core for sealing, and the blade spring coil is used to cooperate with the ball core for sealing in the spring plate type valve seat structure. Wherein the supporting back ring supports the blade leaf spring on the outer side to enhance and protect the role of the blade spring coil. The design without the spring cavity avoids the problem of sealing failure caused by medium entering into the spring cavity and affecting the compression spring, and avoids the situation that the valve seat can be sealed with the ball core by pre-tightening the compression spring, thus avoiding the problem of sealing failure caused by the valve seat sticking on the valve body. The mechanical and flow characteristics are studied and analyzed by the ball valve characteristic test system. The stem torque, unbalance torque, flow characteristics and flow coefficient variation at different nominal diameters are analyzed. The seal allowable squeeze stress and seal surface pressure are analyzed, and the seal is stable and reliable with the seal pressure meeting the seal design criteria. The fluid dynamics simulation analyzes the velocity, pressure and flow traces of the fluid flowing through the ball valve under three opening degrees: fully closed, half open and fully open, the maximum velocity-pressure and opening degree variation curves of the inlet and outlet, the maximum velocity-pressure and opening degree variation curves of the inlet and outlet under different nominal diameters and the flow resistance coefficient curves. Static strength analysis was done for the ball core and spring plate seat structure to obtain the stress, displacement, strain and safety factor. The fatigue strength of the ball spool and spring-loaded plate seat structure was analyzed, and the total number of lives (cycles) and load factors were obtained, and the results show that the fatigue strength of the ball spool and spring-loaded plate seat structure is safe and the fatigue strength meets the requirements. Ball valve pressure test, low pressure sealing test and high pressure sealing test, valve body strength and ball valve sealing performance all meet the requirements.     

高温蝶阀筋板设置对阀座强度的影响及分析

基于大型通用有限元软件ANSYS,分别对筋板在垂直及倾斜放置时的高温蝶阀阀座进行数值模拟和加载分析,获得了高温蝶阀阀座的径向、周向、轴向和MISES等效应力场情况,对两种阀座的承载能力进行了对比和分析,为高温蝶阀的结构优化和安全选型提供参考依据。     

风速校验器原理、误差及校准参数的确定

风速校验器作为一种现场校准用自动气象站风速传感器的标准仪器,已在我国气象计量部门推广使用.为确保风速传感器现场校准的准确、可靠.本文将从风速校验器的工作原理、误差来源和风速校准参数的确定方法等方面加以介绍.     

电热热风循环干燥炉新型炉体结构解析

新型炉体结构是指炉体侧板为薄钢板弯曲成型，板块式组合结构，而原结构为整体钢结构构架，内外侧用钢板覆盖。另外，加热系统均分为几个加热单元，加热腔嵌在炉体内。而原结构为一个加热单元放置在炉顶中部，统一加热。新型结构对比旧式结构最大的优点就是节省钢材、加热均匀、降低噪音。     

Development of aspect dummy considering seat dimension factor

The HPM-I dummy that was used to design car seats was developed by referring to human body dimension data in the 1960s, not to reflect changes of body sizes in accordance with time flow. Also, the HPM-I dummy that was made of one plate of a back rest could not express various kinds of postures. Thereafter, HPM-II, which had three back rests, was developed, but it could not consider various kinds of seat dimension factors by body size of 50th percentile male. We developed not only a 5th percentile female model but also 95th percentile male model to make use of them for automobile seat design and rating. The study developed the HARB model, HPM-II model, and CAD model of each percentile based on 50th percentile male HPM-II dummy.     

冲压座椅强度与疲劳有限元仿真

结合力学基本概念,对某冲压座椅的失效原因进行了仿真分析。首先应用圣维南原理等力学概念对冲压座椅几何模型进行简化,然后结合计算力学理论采用商业软件对座椅进行底板强度和靠背疲劳仿真分析。仿真结果表明,冲压座椅装配孔的改进改善了局部区域的应力分布。     

某舰炮基座灵敏度分析与轻量化设计

为实现某舰炮基座的轻量化设计,基于有限元理论和结构优化理论,分析了舰炮基座在极限工况下的结构响应。在此基础上,基于尺寸优化理论和灵敏度分析理论,完成了舰炮基座的灵敏度分析和轻量化设计,得到了舰炮基座中质量灵敏度较大的板件厚度。优化前后的分析结果表明,优化后舰炮基座的重量降低13.2%,最大应力为160.6 MPa,优化后的舰炮基座满足设计要求,达到轻量化的目的。     

单座调节阀耐水冲击数学模型

在调节阀中,介质的流速以冲击力的形式对阀内件产生很大的损伤。经过分析单座调节阀的工作状态,把单座调节阀的工作状态简化为孔板节流过程。通过使用动量方程、伯努利方程和连续性方程建立单座调节阀耐水冲击的数学模型,得到不同开度下,单座调节阀所受到的冲击力。     

Numerical analysis of a radiant drying oven for web applications

During the manufacture of prepregs (composite material made of resin with fiber reinforcement), for the electronics industry, solvent evaporation and product heating are important aspects of the production process. A mathematical model is presented to describe convective and infra-red radiant heating and solvent evaporation from a web (product being processed before being finished as prepreg) in a solvent removal oven. Differential equations are used to model the mass and energy transfers occurring within the oven. Radiation enclosure theory is employed to describe the infrared heat transfer within the oven and use is made of a solvent evaporation model from the literature. Results of temperature distributions in the heated plate (oven component), the web and the air/solvent mixture; the convective and radiant heat transfer rates to the web, the web solvent concentration and the effects of varying the web velocity, heater temperature, heater size and inlet air temperature are in agreement with theory. The results yielded good agreement with a similar study in the literature. Careful analysis of the results of computer simulations under different conditions, such as presented in this study, can be expected to lead to better design decisions prior to building an infra-red oven for web applications.     

Human response of vertical and pitch motion to vertical vibration on whole body according to sitting posture

When a whole body is exposed to vertical vibration, the body??s asymmetric shape affects the response to translational and rotational motion. The degree of asymmetry of a body on a seat is affected by posture. In our study, sixteen male subjects sitting on a seat were used to obtain a response to vertical vibration over a frequency range of 3 to 40 Hz. Two kinds of magnitude of the vibration at each frequency were applied (0.224 m/s² and 0.708 m/s² RMS). Without a backrest, three kinds of sitting postures (average thigh contact P1, supported thigh contact P2, and minimum thigh contact P3) were set by adjusting the height of the footrest and by using an inclined seat pan. The vertical and rotational responses were measured using a force plate mounted on a rigid seat. The apparent eccentric mass (AEM) is defined in this study as rotational response of body to vertical whole body vibration exposure. In the result, the AEM of P2 posture was bigger than that of P1 and P3 posture, especially in a frequency range of 20 to 40 Hz where idle vibration of the passenger vehicle exists. The apparent mass (AM) was even changed by the three kinds of sitting posture, but the difference was not as much as in the case of the AEM. The bigger difference of the AEM is assumed that the sitting posture mainly affects the asymmetry of the fore-and-aft direction, which is more strongly correlated with the rotational pitch response.