压缩机环状阀流量系数数值研究

应用计算流体力学软件FLUENT对环状阀流场进行模拟,得到流量系数αv与气阀升程和阀座通道宽度比H/b的关系曲线.使用MATLAB拟合得到流量系数计算公式.计算公式清晰地反应了升程和阀座通道宽度对流量系数的影响情况,使得环状阀流量系数的计算方便、快捷.     

往复式压缩机网状阀有效通流面积研究

通过对往复式压缩机网状阀内气体流动特点的分析，把气流通过网状阀时的流动损失分为四个部分：阀座流动损失，气流通过气阀第一次和第二次转弯时流动损失及出口流动损失。通过对气阀的吹风试验，分别得到了各个部分流动损失系数与升程，阀座通道宽度比Ｈ／ｂ拉关系式，进而得到气阀的有效通流面积与Ｈ／ｂ的关系式，与现有的公式相比较，取得了满意的结果。     

球阀与阀组结构参数变化规律的分析研究

基于FLUENT软件的动网格技术,将湍流模型与多相流技术相结合,通过计算与分析球阀阀组的结构参数对转子泵出口球阀的运动特性及球阀内部流场特性的影响规律,给出了阀球运动参数的变化曲线和球阀内部流场的分布云图。阀座半锥角小于45°时,阀球速度、升程变化较大,阀隙最大流速较小且变化较快,大于45°时,阀球速度、升程、阀隙最大流速变化较接近。阀球上下表面压差随阀座半锥角的增大而增大,且阀座半锥角大于45°时,阀球上下表面压差随介质气液比的增大明显减小。阀座入口直径增大,阀球速度、升程及阀隙最大流速变小。阀球速度随时间函数呈现先增大后减小趋势;但当介质气液比增加到0.8、0.9时,阀球速度则呈现先减小后增大趋势;随介质气液比的增大,阀球速度、升程变化梯度和阀隙开度减小,阀隙最大流速增大。气液比小于0.5时,流量系数缓慢变化,超过0.5时,流量系数发生突变,甚至于在超过0.65以后,流量系数急剧变化超过1.0。     

基于fluent的环状阀流量系数数值计算

通过做气阀静态吹风实验,得到环状阀流量系数实验值。采用Fluent软件对环状阀流场进行数值模拟,得到流量系数模拟值。对模拟值与实验值做比较,其相对误差只有0．89％,表明模拟准确,得到一种新的环状阀流量系数计算方法。     

往复活塞式压缩机的直流阀

往复活塞式压缩机的工作过程,必须依靠气阀的作用来实现。因此,气阀的好坏对压缩机的工作性能及运转可靠性,有着特别重要的影响。 直流阀主要由阀片及阀体（作为阀座和升程限制器）两个零件所组成的一种气阀。 在直流阀中,阀片平面与阀座通道中的气流方向平行,如图1a）所示,而在非直流的气阀中,阀片平面与阀座通道中的气流方向垂直如图1b）所示。     

活塞式压缩机环状阀安全设计问题

本文认为:阀片冲击速度过大,会导致环状阀使用寿命过短。本文从限制阀片撞击阀座和升程限制器的冲击速度出发,给出了两个数学关系式,可以用来确定环状阀的阀片升程和气阀弹簧力等主要参数。当环状阀有关参数满足这两个数学关系时,可望阀片不因频繁撞击阀座和升程限制器而过早破坏。参考文献7。     

喷嘴挡板式压电气动微阀阀口密封宽度对流场特性影响的分析

为了探究喷嘴挡板式压电气动微阀阀口密封宽度对阀口流动特性的影响,应用CFD技术,采用SST k-ω湍流模型,对不同密封宽度下阀口的流动特性进行了数值模拟计算。结果发现,阀口端面密封宽度对压电气动微阀阀口的流动特性有显著的影响,选取合理的阀口端面密封宽度,可降低阀口的压力损失,提升气动微阀阀口的过流能力;同时发现微阀流量-压力系数不受阀口端面密封宽度的影响。该研究为阀口设计提供了重要参考。     

低流量引起截止／止回阀振动的减振方法

截止／止回阀具有截止阀和止回阀的两种功能。当流体以高速高压流动时,脉动对阀门的影响可以忽略。当流体压力波动和流量较小时,阀瓣将沿着阀杆上下滑动并撞击阀座,产生振动和噪音,甚至造成阀门的毁坏。新型截止／止回阀（图１、２）通过改变阀座和阀瓣间的流体通道,...     

气动流量阀阀座密封性能研究及结构优化

利用有限元软件ANSYS 建立气动流量阀阀座密封结构的二维轴对称模型,以流体渗透压力（Fluid Pressure-Penetration）的加载方式模拟阀座密封结构的介质压力负载,研究介质压力、预紧弹簧力、阀座结构参数等对阀座密封结构密封性能的影响。结果表明：弹簧力与最大有效密封压力及无介质压力最大等效应变呈正相关;密封面外径及斜面倾角与最大有效密封压力及无介质压力最大等效应变呈负相关;密封面内径不影响最大有效密封压力。利用正交试验对关键密封参数进行了优化,优化后最大有效密封介质压力提高了14.14%,提高了阀座密封结构密封性能,而最大等效应变仅增大1.87%,对密封结构寿命影响很小。     

单偏心蝶阀流量特性数值模拟及结构优化

利用FLUENT软件对DN400单偏心蝶阀原始方案进行全开时的流量分析,针对模拟结果总结出影响蝶阀流量系数的重要因素为蝶板、阀座、阀轴和压板结构。通过优化方案对影响流量系数的重要零部件进行结构优化,提升流体域体积,减小流通阻力,增大流量系数,以满足流量系数大于15 000的设计要求。研究结果为单偏心蝶阀设计提供了重要的参考依据。     

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.     

水压锥阀空化射流流场结构与流量特性的相关性研究

为了研究水压锥阀空化流场与流量特性的相关性,对两种阀座结构的水压锥阀内部的空化射流开展了三维动态流场仿真.结果表明,直角型锥阀和倒角型锥阀均在阀芯后沿存在分离流诱发的附着型空化,在阀口下游有漩涡空化;此外,倒角阀座流道内亦存在分离流现象并形成附着型空化.倒角型流道入口处的分离流造成流体的局部加速,对于0.6 mm开口度...     

Study on the design of control valve for U-shaped noise reduction cage and its fluid flow features and noise

In response to technical issues such as the ineffective noise reduction impact of balanced cage and single-seat control valves, the U-shaped noise reduction cage control valve is investigated and developed. In addition, its equal percentage flow properties and noise reduction impact are good, allowing it to effectively minimize the noise created by the change of fluid parameters of medium such as vapor, gas, and gas-liquid two-phase flow. The flow coefficient and flow properties were analyzed. The noise features of the medium air flow at small and large openings of 30% and 85% are simulated and analyzed, respectively. The pressure, velocity, and temperature of the inlet and outlet air, as well as the sound intensity maximum and sound power level maximum, are also analyzed with the opening curves. A small opening of 30% was selected, and the noise characteristics of cavitation generated by the medium water flow were simulated and analyzed. Together with the pressure and temperature change curves of the incoming water, the volume maxima and density minima of water are studied. The maximum sound intensity and sound power level of water are analyzed using the pressure and temperature curves of inlet water, as well as the cavitation coefficient and the degree of opening. The results of the trial for the pressure resistance of the valve body and the trial for the valve seat seal indicate that both the valve body strength and the valve seat seal meet the specifications. Comparing the noise trial results and simulation results reveals that the sound intensity and sound power level assessed by the trial and simulation are comparable, and the noise reduction impact of the control valve is positive.     

双浮动密封橡胶O形圈接触应力分析

针对双浮动密封橡胶O形圈接触过程应力的变化,建立双浮动密封二维轴对称非线性接触模型;利用有限元方法对O形圈进行应力计算,分析O形圈在不同压缩率、不同浮封座和浮动环的斜面角度及不同摩擦因数下的应力变化情况。结果表明:橡胶O形圈各应力最大值随压缩率的增加呈线性增大, O形圈内高应力分布区域随压缩率的增加而增大,并由接触部位附近向其中间位置扩散;摩擦因数对O形圈各应力影响很小,而浮封座和浮动环的斜面角度对O形圈等效应力和接触压力影响较大;随着浮封座斜面角的增加,等效应力总体趋于减小,接触压力先减小后缓慢增加,而剪切应力整体变化较小;随着浮动环斜面角的增加,等效应力、接触压力呈递增趋势,剪切应力曲线上下波动,但整体变化不明显。确定双浮动密封浮封座和浮动环斜面角度最优值,为双浮动密封结构设计提供了指导。     

浅析缸盖座圈凡尔线尺寸超差

介绍Mapal座圈刀具精镗某发动机进排气座圈的工艺过程;通过使用Mapal座圈导管刀具对发动机缸盖座圈凡尔线角度和宽度经常超差问题进行研究;根据密封带宽度角度其变化规律更改刀具调整的公差,进而提高刀具寿命。     

F级燃气轮机高压迷宫密封泄漏特性研究

以F级燃气轮机高压迷宫密封为研究对象,研究密封间隙、压比、密封齿厚对迷宫密封泄漏特性的影响规律,采用泄漏系数表征各种影响因素与密封泄漏量的函数关系。结果表明:相同压比条件下,密封间隙增大,泄漏系数增大,且增大的趋势变大;相同密封间隙下,随着压比提高,泄漏系数近似线性的增大;相同间隙和压比下,随着齿厚的减小,泄漏系数减小。     

弹簧组弹性阀座结构分析

弹簧组弹性阀座可以分阀前、阀后以及双面密封三种形式。这三种密封形式虽然很相似,但是密封特点差别很大,应用条件和场所各不相同。针对固定球阀弹簧组弹性阀座的三种密封形式,进行详细介绍。为弹簧组弹性阀座的密封形式的选取提供依据。     

Investigation of the mechanical behavior of a flexible solid metal seal for a cryogenic butterfly valve

Seat tightness at the fully shut position should be a consideration in the development of a butterfly valve for use in a liquefied natural gas (LNG) vessel. A flexible solid metal seal offers sufficient tightness of the butterfly valve and meets the specifications for cryogenic temperature. In the present study, characteristics for a cryogenic butterfly valve, such as the flow coefficient and the pressure loss coefficient, were estimated by numerical fluid analysis carried out to simulate 3-D flow and to study performance as it was affected by the opening angles of the valve disc. A design criterion to ensure the seat tightness of the butterfly valve at the fully shut position was proposed, in which the contact pressure between the metal seal and the valve disc would be compared with the fluid pressure. Numerical structural analysis showed that the contact pressure can be calculated by simulation of the frictional contact behavior on the surface of the metal seal and the valve disc. As a result, an adequate flexibility of the metal seal and the valve disc was required in order to accomplish a contact pressure that would be high enough to satisfy the seat tightness requirement. Under cryogenic temperature, thermal shrinkage caused the metal seal to adhere closely to the valve disc periphery at both sides and raised the contact pressure to a relatively high value, though there was no contact across a small area at the center position, which is susceptible to leakage. An additional displacement of the metal seal and the valve disc appeared at an operating fluid pressure of 6.9 bar and produced sufficient contact pressure at the no-contact area. This was verified by experimental leakage tests performed at room and cryogenic temperatures.     

航空发动机石墨圆周密封接触特性分析

基于结构受力分析,利用ANSYS分析某型在役航空发动机石墨圆周密封的接触特性,研究不同工况参数对密封环最高温度、最大变形、最大应力及接触压力作用规律。结果表明:石墨圆周密封环主密封面应力分布比较均匀,密封环接头处应力最大,这与应用时接头处磨损较重的实际情况相符;辅助密封面和密封跑道应力分布均匀,密封座端面应力沿径向呈梯度分布,最大应力位于密封座靠近密封跑道边缘处;随滑动速度的增大,密封环主密封面最高温度增大,而最大变形、最大应力和接触压力表现为先减小后增大;石墨密封环主密封面最高温度、最大变形、最大应力和接触压力随密封压差增大而增大。