阀杆旋转角度启闭的撑拢式阀门密封结构

介绍了一种适用于球阀、蝶阀和旋塞阀的阀杆旋转角度启闭的撑拢式阀门密封结构。此种结构已获得发明专利(专利号：00111674．6)。     

阀杆倾角对角座阀流量特性影响的数值研究

采用计算流体动力学方法研究阀杆倾角对角座阀流量特性的影响。分别采用数值模拟和实验测试,获得了在不同阀门进出口压差条件下,阀杆倾角为45°,55°和60°时阀内介质体积流量,对比验证了数值计算的准确性。在此基础上,对不同阀杆倾角条件下阀内的流场和阀门的通流能力进行分析。结果表明阀内的最高流速及速度场分布对阀门的通流能力具有重要影响：当阀杆倾角为45°时,阀内介质的流速最高,流量系数最大,流阻系数最小;阀杆倾角处于45°～60°范围时,随着角度的增加,角座阀的流量系数随之降低,流阻系数相应增加。对于该流道结构的角座阀,阀杆倾角推荐采用45°～50°的设计范围。     

旋塞阀设计计算中的几个问题

旋塞阀设计计算中的几个问题河北省唐县阀门厂尹占民就现有阀门设计资料中有关旋塞阀的设计计算提出几点质疑，给出具体运算的结果供参考。１．旋塞通道孔平均宽度Ｂ取旋塞的平均直径ｄ与公称通径相等，按梯形通道孔的平均宽度Ｂ与高度ｈ之比为１∶２．５，则通道孔面积Ｆ...     

NK阀阀板的运动解析

分析了煤气系统中主流隔断装置的缺陷,提出了NK阀结构,分析了此阀门的启闭过程,确定了阀板的运动要求.阀板的运动由两部分组成:一部分是直线运动,密封圈与阀座分离,确保阀板上的密封圈与阀座的密封面完全无摩擦;另一部分是旋转运动,实现阀门的全开,加大流通面积.NK阀阀板的运动解析为设计相应运动装置提供依据.     

固定球阀的设计与计算

介绍支撑板结构固定球阀设计原理、设计计算和强度校核。采用支撑板固定球结构,可以改善阀杆受力状态,阀杆转动时只承受扭矩而不承受弯矩。阀门启闭时扭矩减小,阀门使用寿命延长,适用于大口径高压固定球阀及全焊接固定球阀。     

锅炉给水泵最小流量调节阀结构设计与仿真

为了研究某新型给水泵最小流量调节阀的流场特性,利用CFD仿真技术对最小流量阀进行流场分析。对最小流量阀的迷宫碟片进行优化设计和试验,并对最小流量阀整体模型进行流通性能验证。分析结果表明,迷宫流道能够很好地实现降压和控速要求,阀门整体流通性能良好,满足工况需求。     

阀口形状对套筒调节阀调控特性的影响

为了满足管道系统调节性能的要求,本文基于计算流体力学(CFD),研究了阀口节流截面形状对套筒调节阀调控的影响。讨论了椭圆型阀口、V型阀口和扇形阀口3种类型的节流阀。结果表明,流道的几何形状对流量系数影响很大;V形阀口具有类似的等百分比流量特性;扇形阀口具有类似的线性流动特性。相对特性随截面形状的变化而变化。在小开口时,阀门的内部流动更为复杂。阀芯附近的能量损失相对较大。     

四通换向旋塞阀的研制

四通换向旋塞阀是流量计量系统的重要装备,为打破国外垄断,开展了对四通换向旋塞阀的研制.本文详细介绍了四通换向旋塞阀的主阀结构、操作器结构、压力泄放装置、滑片密封工艺等,通过气压密封、动作灵活性以及流通能力等试验,验证了四通换向旋塞阀的良好性能,同时表明产品符合相关标准和规范,满足用户使用要求,达到了国际同类阀门产品的技...     

大口径高温高压Y形截止阀的设计

介绍了Y形截止阀的结构特点和阀门流道的结构设计,计算了介质通过截止阀时的流阻及压降,分析了流道形式和流通面积等对压降的影响,论证了流体在阀门流道中的速度变化形态以及阀门设计的合理性.     

阀门启闭件双密封装置

介绍一种具有大小两个启闭件并以快慢两阶段方式关闭阀门启闭件的密封装置。该密封装置是一种分别在大小两个启闭件上均装有环形橡胶密封圈和环形金属密封圈的双密封装置,在阀门关闭时,阀板上的环形橡胶密封圈与阀座先接触形成一道密封;在环形橡胶密封圈被稍微压缩后,阀板上的环形金属密封圈再与阀座接触又形成一道密封并承受整个启闭件上的压力;而环形橡胶密封圈良好的弹性变形减轻了启闭件关闭件时的冲击力,具有一定的消声减震性。     

双阀座止动式旋塞阀设计及接触应力分析

针对目前常用的旋塞阀容易发生转动失效的问题设计了一种双阀座止动式旋塞阀。该旋塞阀在发生井喷关闭后,可有效减小旋塞阀球形阀芯和阀座之间的接触应力,减少球形阀芯的变形,从而使旋塞阀开启转动力矩变小,并能保证其密封的可靠性,有效解决了旋塞阀容易发生转动失效的问题;另外还通过建立球形阀芯和阀座接触的力学模型和ansys有限元分析软件分别对旋塞阀工作时球形阀芯和阀座的接触应力进行了理论计算和有限元分析。     

基于COMSOL液压节流阀内部流场数值模拟研究

针对不同开度下U型节流阀内部流场的变化,基于软件COMSOL Multiphysics建立CFD数值计算模型,得到了节流阀内部流场的速度、压力分布等随着阀口开度变化的特性云图。研究结果表明：节流口处压力下降梯度较大,并出现局部低压区。阀内流体速度在经过阀口处急剧变化,阀口附近流速达到最大,并沿流体流动方向形成一个空心锥形高速射流区域。即流体出口端射流出射方向倾斜指向出口,另一过流面中流体出射方向指向阀座,并沿阀体壁面流动。此外,随着阀口开度减小,阀口处速度大小和阀口附近压力几乎不变,但是节流口流体出射方向角度变大。     

直通单座调节阀柱塞式阀芯型线设计方法

对调节阀的结构特性进行研究,推导出已知固有流量特性调节阀相对的缩流面积和涡流面积之比等于其相对流量系数。根据相似性原理,假设具有相同固有流量特性的不同规格调节阀其相对流通面积随相对开度的变化规律是相似的,并据此给出了一种柱塞式阀芯型线的解析设计方法。根据该方法所设计的阀芯型线的数值模拟流量特性与固有流量特性的偏差符合IEC 60534-2-4的规定,可见该设计方法减轻了调节阀阀芯型线设计过程中通过流量试验反复修正阀芯型线的工作量,具有一定的推广价值。     

方钻杆旋塞阀转动失效的理论分析与仿真

方钻杆旋塞阀在高压环境下使用时存在阀球转不动的现象,最主要的原因是旋塞阀密封接触造成的摩擦力矩过大。本文对摩擦力矩进行了计算,同时利用ABAQUS仿真的方法获得了高压下方钻杆旋塞阀的密封接触分析结果,两种方法得到的结果基本吻合。建立了一套利用有限元来分析高压旋塞阀密封接触问题的方法。     

Evaluation of loss coefficient for an end plug with side holes in dual-cooled annular nuclear fuel

The Korea Atomic Energy Research Institute (KAERI) has been developing a dual-cooled annular fuel for a power uprate of 20% in an optimized pressurized water reactor (PWR) in Korea, OPR1000. The dual-cooled annular fuel is configured to allow coolant flow through the inner channel as well as the outer channel. Several thermal-hydraulic issues exist for the application of dual-cooled annular fuel to OPR1000. One is the hypothetical event of inner channel blockage because the inner channel is an isolated flow channel without the coolant mixing between the neighboring flow channels. The inner channel blockage could cause a departure from nucleate boiling (DNB) in the inner channel that eventually results in fuel failure. A long lower end plug for the annular fuel was invented to provide flow holes by perforating the side surface of the end plug body. The side holes in the lower end plug are expected to supply a minimum coolant in the inner channel to prevent the DNB occurrence in the event of partial or even complete blockage of the inner channel entrance. But due to the very unusual shape of the lower end plug, it is difficult to estimate the flow resistance of the side flow holes using empirical equations available in the open literature. An experiment and computational fluid dynamics (CFD) analysis were performed to investigate the bypass flow through the side holes of the end plug in the case of complete entrance blockage of the inner channel. The form loss coefficient in the side holes was also estimated using the pressure drop along the bypass flow path.     

玻璃纤维增强塑料浮动球阀密封性能分析

采用玻璃纤维增强塑料(GFRP)制作的球阀,具有强度高、密度小、耐酸碱腐蚀等优点,已逐步取代金属球阀应用在氯碱化工管道中。以DN50 GFRP浮动球阀为研究对象,分析常压下旋塞预紧力、密封件摩擦因数和密封面宽度对其密封性能的影响,并探究阀球推荐工作压力和GFRP浮动球阀整体设计参数对密封性能影响的主次顺序。结果表明：GFRP浮动球阀最高工作压力不应超过3 MPa,在常压环境下,需施加550 N以上的旋塞预紧力才能保证球阀正常密封;增大密封面摩擦因数可提高其密封性能,当密封面摩擦因数达到0.2时,密封面上最低密封比压最接近临界密封比压,材料利用率最高;随密封面宽度增加,最大密封比压呈先减小后增大的趋势,综合考虑球阀的使用寿命和材料利用率,该阀座的最佳密封面宽度为8.65 mm;密封面宽度对GFRP浮动球阀密封性能影响最大,其次为旋塞预紧力,密封件摩擦因数的影响最小。     

Flow analysis in a return channel of a multi-stage centrifugal pump

Flow recirculation is an unpleasant and even hazardous phenomenon that can cause mechanical damage in turbomachinery and has to be prevented during their operations. We numerically studied the effects of return channel blade curvature on reducing the recirculation of flow inside the return channel vanes of a multi-stage centrifugal pump. Computational fluid dynamics (CFD) analyses were performed for a wide range of volumetric flow rates. The standard k-ε turbulence model was adopted as the turbulence model, and the impeller rotation simulated employing the Multiple reference frames (MRF) method. First, a baseline model together with five different modified geometries for return channel was studied and compared using a two-stage pump framework. The results reveal that decreasing the curvature of the return channel blade makes smooth streamlines and eliminates the flow recirculation inside the return channels. As the second part, two return channels with the highest pump performance were selected to be used in the simulation of a multistage pump. The simulations of the multi-stage pump show that the flow inside the baseline return channel includes considerable areas of flow recirculation, while the modified return channels again have attached flow stream. It is concluded that the return channels with the smooth curvatures and outlet blade angles above 90° remove the flow recirculation inside the return channels, resulting in higher pump efficiencies.     

A study on the force balance of an unbalanced globe valve

A pneumatic control valve is a piping element that controls the volumetric flow rate and pressure of a fluid; it is necessary to analyze the characteristics of the forces with respect to the opening of the valve in order to evaluate its operating performance. The forces occurring during operation are: resisting force and actuator force, where the load resistance is mostly affected by the fluid pressure difference of the valve. In this study, a force balance equation derived from the equilibrium relationship between the resisting force and the actuator force of an unbalanced globe valve is proposed, and the force balance equations are used to model the dynamic equations of a pneumatic unbalanced globe valve installed in nuclear power plants. A CFD analysis is also carried out to evaluate the pressure distribution and forces acting on the top and bottom planes of the valve plug. The results of this analysis have been verified through experimentation. This study has shown that the fluid pressure difference between the inlet and outlet of the valve, measured from the force balance equation of an unbalanced valve, should actually be examined with the fluid-pressure difference between the top and bottom side of the valve plug.     

液压支架用电液换向阀的动态特征及流场特性仿真分析

为了提高液压支架的机械控制能力,利用电液换向阀完成支架控制箱动作控制。该文采用流体动力学仿真了电液换向阀的动态特征及流场特性。研究结果表明:当时间到达0.14 s时二级阀芯发生运动,出口流量快速增大至一个峰值状态;随着阀芯到达一个稳定运动状态后,换向阀也达到1013 L/min的稳定出口流量。换向阀在高压大流量系统内工作时将会快速到达峰值压力,产生液压冲击作用并使支架立柱受到破坏。当流体由阀套流至阀芯时因为过流断面的面积会迅速降低,使压力下降4.1 MPa,形成压力集中损失的区域,同时在阀芯的主流道区域还会形成均匀的压力分布状态。从阀口的下游最初进入阀芯的主通道位置时将达到最大流速,等于109 m/s,表明该部位形成了最小的过流面积。