基于COSMOS/FloWorks的割炬电极冷却水道优化

COSMOS/FloWorks是完全整合至SolidWorks且易学易用的流体分析软件。文中使用COSMOS/FloWorks对一种等离子割炬的电极冷却水道进行仿真分析,从而发现此冷却水道存在的问题是前内壁面冷却水流速偏低,直角拐弯处出现最小流速。通过减少经过前内壁面处的冷却水的流通截面面积,在直角拐弯处开圆角可解决上述问题。     

圆管内部流场的有限元解析

应用COSMOS/FloWorks软件模拟圆管中的流场得到出口速度,并与理论值进行比较。结果显示,应用COSMOS/FloWorks软件模拟圆管内部流场是可靠的。为COSMOS/FloWorks软件在流体理论研究中的应用提供了参考。     

液压锥阀的有限元分析及优化设计

在三维CAD软件SolidWorks中创建液压锥阀的三维模型，用有限元分析软件COSMOS／FloWorks，对其进行静态分析，掌握锥阀阀腔内流体的流场流速分布及压力场分布的情况，并根据有限元的计算结果，以阀心的优化设计为例，介绍了用有限元对锥阀的优化设计过程。     

液压锥阀的有限元分析及优化设计

在三维CAD软件SolidWorks中创建液压锥阀的三维模型，用有限元分析软件COSMOS／Flo Works对其进行静态分析，掌握锥阀阀腔内流体的流场流速分布及压力场分布的情况。并根据有限元的计算结果，以阀芯的优化设计为例．介绍了对锥阀用有限元进行优化设计的过程。     

硅微弹簧-滑块摩擦力测试结构静力学分析

为了研究微机械摩擦问题，设计了一组硅微弹簧摩擦力测试结构，并对其进行了静力学分析，导出系统弹性系数的计算方法，分析了强度及应力分布特点。对比ANSYS仿真结果，分析了两种分析方法的差异原因，得出微结构中拉簧测试微结构力学性能影响最大，弯簧根部应力最大，而拉簧直角拐弯处应力最大。     

干式螺杆压缩机壳体水夹层换热性能分析

针对带有水夹层壳体的干式螺杆压缩机,腔体内的温度控制是决定压缩机可靠性的关键要素,为了进一步验证水夹层结构的合理性,准确控制进水量,推导了等熵压缩过程中壳体内壁面温度分布计算方法,得到壳体内壁面瞬态及稳态温度分布;建立了冷却水对壳体内壁面的换热计算模型,得到了在不同温度下水夹层冷却效果变化曲线,从而得到了螺杆压缩机壳体...     

发动机汽缸盖冷却水套的CFD分析与仿真研究

以汽车1.6升四缸汽油发动机为研究对象,利用UG软件建立了其冷却水套的几何模型,并进行了必要的简化处理。后用FLUENT的前处理软件GAMBIT,对冷却水套模型划分网格,再用FLUENT软件,对冷却水套的流场进行了数值模拟及结果分析。仿真结果表明冷却水套的设计较合理,基本达到设计要求的冷却效果,尚有需要优化之处,例如：冷却水套内的流速较小,温度分布不很均匀,若再改进,将有更好冷却效果。     

COSMOS/M有限元与数据库的数据传输

利用Delphi编程语言实现COSMOS／M有限元程序与Paradox数据库之间数据传输，以开发活塞稳态温度场参数化有限元软件为例，说明了实现数据传输的相关方法和步骤。     

氨冷凝器传热管腐蚀泄漏分析

通过对冷却水、传热管以及垢层的分析检验，发现氨冷凝器传热管泄漏是由冷却水对金属的电化学腐蚀引起的。水垢与锈垢的形成导致传热管内壁金属受到垢下腐蚀，垢下腐蚀对金属材料的穿进速度大，形成凹坑以至穿孔。另外，传热管原始内表面粗糙不平整，不清洁加速了腐蚀与成垢，原材料的非金属夹杂物存在降低材料抗腐蚀的能力，最后针对这一案例提出防护措施。     

振动打桩机偏心块的参数研究与有限元分析

以激振力为10t的振动打桩机激振器为例．针对常用的几种半圆式偏心块结构．从理论上获得其结构参数．并运用Solid Works机械设计软件建立模型．在此基础上使用有限元分析软件COSMOS/Work对其进行结构分析和有限元计算．得到弯角武偏心块比直角式偏心块承受的应力小．在恒定离心力作用下刚度和安全系数太装配弯角偏心块强度和承载能力最好．并便于拆装和移运等结论，为改进设计和现场使用提供了理论依据。     

Flow near the meniscus of a pressure-driven water slug in microchannels

Micro-PIV system with a high speed CCD camera is used to measure the flow field near the advancing meniscus of a water slug in microchannels. Image shifting technique combined with meniscus detecting technique is proposed to measure the relative velocity of the liquid near the meniscus in a moving reference frame. The proposed method is applied to an advancing front of a slug in microchannels with rectangular cross section. In the case of hydrophilic channel, strong flow from the center to the side wall along the meniscus occurs, while in the case of the hydrophobic channel, the fluid flows in the opposite direction. Further, the velocity near the side wall is higher than the center region velocity, exhibiting the characteristics of a strong shear-driven flow. This phenomenon is explained to be due to the existence of small gaps between the slug and the channel wall at each capillary corner so that the gas flows through the gaps inducing high shear on the slug surface. Simulation of the shape of a static droplet inside a cubic cell obtained by using the Surface Evolver program is supportive of the existence of the gap at the rectangular capillary corners. The flow fields in the circular capillary, in which no such gap exists, are also measured. The results show that a similar flow pattern to that of the hydrophilic rectangular capillary (i.e., center-to-wall flow) is always exhibited regardless of the wettability of the channel wall, which is also indicative of the validity of the above-mentioned assertion.     

Numerical simulation of fluid flow and heat transfer in a plasma spray gun

A computational fluid dynamics (CFD) simulation for analyzing fluid flow patterns in a plasma spray gun is presented in this study. It is coupled with a heat transfer simulation of the plasma spray gun. Based on CFD and heat transfer theory, the numerical model of the nozzle in the plasma spray gun is developed, and the coupled simulation of the flow fluid and heat transfer is carried out with the semi-implicit method for pressure-linked equations (SIMPLE) method. Local turbulence, which will lead to appearance of a static-water region, is found at the front corner of the cooling channel in the nozzle. The locations insufficiently cooled are found in the wall near the heat source and in the gasket in the rear of the nozzle. Then, cooling processes with different parameters of cooling water are analyzed. The optimal velocity and direction of cooling water, which efficiently cool the nozzle and improve the service life of the plasma jet, are obtained .     

Numerical simulation of fluid flow and heat transfer in a plasma spray gun

A computational fluid dynamics (CFD) simulation for analyzing fluid flow patterns in a plasma spray gun is presented in this study. It is coupled with a heat transfer simulation of the plasma spray gun. Based on CFD and heat transfer theory, the numerical model of the nozzle in the plasma spray gun is developed, and the coupled simulation of the flow fluid and heat transfer is carried out with the semi-implicit method for pressure-linked equations (SIMPLE) method. Local turbulence, which will lead to appearance of a static-water region, is found at the front corner of the cooling channel in the nozzle. The locations insufficiently cooled are found in the wall near the heat source and in the gasket in the rear of the nozzle. Then, cooling processes with different parameters of cooling water are analyzed. The optimal velocity and direction of cooling water, which efficiently cool the nozzle and improve the service life of the plasma jet, are obtained .     

基于COSMOS/M有限元的二次开发

以COSMOS／M有限元程序为基础，运用有限元程序语言进行二次开发，建立了内燃机活塞的有限元计算模型，同时运用Delphi语言编制了数据输入输出接口，并在4105，490型柴油机活塞的温度场，及其影响因素的定量分析中进行了应用，为活塞的优化设计提供了高效、便捷的计算工具。     

高锰钢前导轮铸造工艺模拟及优化

高锰钢前导轮内腔结构复杂,需要合理的铸造工艺以避免填内部产生铸造缺陷。为此,采用商业软件ProCAST对导轮轴孔处设一个明冒口的单冒口工艺（SR）和两个明冒口的双冒口艺艺（DR）进行缺陷预测、计算发现,单冒口工艺（SR）的缺陷形成倾向低于双冒口的工艺（DR）。进而,通过调整单冒口工艺（SR）的冷铁形状、位置及增大轮缘处暗冒口体积．提出优化工艺M1;在M1基础上,通过减小轴孔处明冒口体积,并加大该处冒口保温砖厚度,提出优化工艺M2,模拟计算表明,采用M1和M2工艺均可消除导轮轮缘处的缩孔缩松缺陷;以M2的热裂倾向最小,热裂纹主要出现在前导轮内腔垂直拐角处和轴孔附近。     

发动机水套冷却性能分析

利用数值模拟对某汽油机的冷却水套进行了冷却性能研究,对原机冷却水套内冷却水的流场分布、冷却水套内壁面换热系数和压力损失进行了分析.计算结果表明:该汽油机冷却水套总体分布合理,设置的8个分水孔各自取到不同的作用;通过大孔B1、B2的流体用于冷却鼻梁区等重点区域,其它孔主要用来将绕流缸体的冷却水引入缸盖,对缸盖冷却起补充作...     

降雨环境下车身表面水相分布特性

本文建立了汽车外流场空气动力学数值计算模型，结合Lagrangian discrete phase model和Eulerian wall film model两种方法模拟了水相的生成和发展过程。在此基础上，开展不同降雨强度、不同车速条件下的车身表面水相生成计算，研究影响水相分布变化的因素。研究结果表明：在一定的车速和降雨强度条件下，车身水相厚度逐渐增大，最终趋于稳定；当车速一定时，车头、前窗、后窗和侧窗区域水相厚度随降雨强度的增大而增大；当降雨强度一定时，车头、后窗和侧窗水相厚度随车速增大而增大，而前窗水相厚度随车速增大而减小。     

柴油机缸盖冷却水腔三维流动数值模拟分析

柴油机优良的冷却性能对提高其工作性能和气缸盖可靠性起着非常重要的作用。以某V型12缸水冷发动机的冷却水腔为研究对象,采用流体分析软件FLUENT对缸盖及其冷却水腔内的流动与传热进行数值模拟计算,得到冷却水在缸盖复杂水腔内的三维流场分布与进出水孔的流量,并详细分析了其流场、压力场、温度场及换热情况, 为该型柴油机气缸盖冷却水腔的结构优化设计提供一定的参考依据,从而提高内燃机的工作性能和气缸盖的可靠性。模拟计算结果表明:冷却水腔的流动均匀性可以达到该发动机的冷却要求;流经各缸的冷却液流量分配合理;“鼻梁区”冷却效果较好,且“流动死区”能满足冷却需求。通过对气缸盖内冷却液流动的优化,可以有效地提高整机及气缸盖的冷却效率。     

塑料异型材挤出模CAE技术及优化设计方法的研究

通过分析和计算模头内塑料熔体流动过程和定型模内型材冷却过程的数学模型、初始条件和边界条件,对这两个过程进行了数值模拟,获得了模头内熔体的速度场和定型模内型材的瞬态温度场。分别以模头流动的平衡性和定型模冷却的均匀性为优化目标,完成模头流道结构和定型模冷却水道的优化设计。结果表明,经优化设计后熔体流动的平衡性和冷却的均匀性都有显著提高,这对复杂型材挤出模的设计具有重要的理论意义和实际应用价值。     

An experimental study on the AC electroosmotic flow around a pair of electrodes in a microchannel

This paper presents an experimental study on the AC electroosmotic flow in a microchannel having a pair of rectangular electrodes on the bottom wall with narrow gap. The microchannel was made of PDMS (Polydimethylsiloxane) and the electrodes of ITO (Indium Tin Oxide). The electrodes were arranged such that the electric field is mainly perpendicular to the channel’s longitudinal direction, thus creating a transversal secondary flow. The primary flow was driven by a pressure force through the fluid-level difference on both reservoirs of the channel. To measure the velocity distributions around the electrodes, we used a micro-PTV (particle tracking velocimetry) technique. We find that on the surface of the electrodes the flow velocity caused by the AC electroosmosis is directed from the electrode edge toward the side wall of the channel, and the maximum crosswise velocity occurs at the frequency 120Hz. A smooth profile of the crosswise velocity component along a vertical line was successfully obtained from the present experimental technique, and it shows a flow reversal due to the mass conservation principle.