共查询到19条相似文献,搜索用时 171 毫秒
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研究了一种基于单片机控制的流量阀反馈控制系统,其对流量系数c及参数m进行计算,得到精确值,提高了流量阀的控制精度,对参数计算进行了理论分析,进行了硬件设计和软件设计,并且搭建了实验平台。 相似文献
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基于Fluent流场仿真软件,对某滑阀内部流场进行数值模拟和可视化研究。在相同计算条件下,分别对不同阀口开度下的三维模型进行稳态模拟仿真,得到滑阀内部流场的速度压力、流量特性以及流量系数的变化规律:在相同的压差条件下,随着阀口开度的增大,阀口处的最大速度、流场的最低压力、流量系数都随之降低。通过改变节流槽的形状进行仿真比较,得到流量系数与节流槽截面形状密切相关,在阀口开度相同的条件下,随着进出口压差的增大,半圆形节流槽滑阀的流量系数变化比较明显。研究为滑阀的优化提供了有效数据,并且对同类型产品的相关研究具有一定参考价值。 相似文献
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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。 相似文献
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Jun-Ho Bae Sung-Jin Kim Moon-Saeng Kim Chul Kim 《Journal of Mechanical Science and Technology》2011,25(9):2277-2284
The safety valves used in liquefied natural gas — floating production storage and offloading (LNG-FPSO) ships play an important
role in maintaining a fixed pressure by controlling the release of liquefied natural gas (LNG) from pipes in an LNG piping
system. Therefore, the discharge coefficient is regarded as the most important parameter influencing the valve performance.
In order to satisfy the ship’s classification criteria, the discharge coefficient of the safety valve must usually be over
0.8. Despite the importance of a good understanding of the flow phenomena inside the safety valve for the improvement of the
discharge coefficient, the successful design of valves depends on experience and experiments in an industrial field. In this
study, a computational fluid dynamics (CFD) investigation was carried out with ANSYS-CFX software to observe the flow phenomena
inside the valve and to determine the discharge coefficients from changes in the valve lift, which is the distance between
the exit of the nozzle and the lower part of the disc plate. The discharge coefficients obtained were also verified through
comparison with available experimental data. 相似文献
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爆破片与安全阀串联组合泄放特性 总被引:1,自引:0,他引:1
爆破片及安全阀串联组合泄放系数测定在国内标准及文献中还未见报道。建立了爆破片与安全阀串联组合泄放特性试验装置,研究了爆破片与安全阀之间不同接管长度、不同泄放压力下组合泄放装置泄放量及泄放系数。选用孔板流量计测量介质流量,选用反拱刻槽型爆破片及弹簧全启式安全阀。以单独安装安全阀泄放试验作为对比试验。结果表明,单独安装安全阀时,随着接管长度增加,泄放系数稍变小,但最小值为0.9。试验所用批次的爆破片和安全阀串联组合时,泄放系数在0.78~0.84之间,组合校正系数Kc在0.876~0.912范围内。 相似文献
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Young Joon An Byeong Jin Kim Byeong Rog Shin 《Journal of Mechanical Science and Technology》2008,22(10):1998-2005
A numerical analysis of three dimensional incompressible turbulent flows through high pressure drop control valves was carried
out by using a CFD-ACE code to develop anti-cavitation control valve used in LNG marine system. For this, numerical simulation
was performed on several models of control valve that have different orifice diameters of anti-trim and the size of valve
discharge. In this study, flow characteristics of control valves with complex flow fields including pressure drop, cavitation
effect and variation of flow coefficient as well as correlation of discharge coefficient were investigated and analyzed. Comparing
with conventional control valves, newly designed valves by using the CFD analysis showed an improved flow pattern with reduced
cavitation and an anticipated performance characteristic.
This paper was presented at the 9th Asian International Conference on Fluid Machinery (AICFM9), Jeju, Korea, October 16–19, 2007. 相似文献
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针对普通旋流器在矿井水的浓缩分离作业过程中,由于进料浓度低造成底流浓度低,导致底流产物后续处理困难的问题,提出一种间歇排料式浓缩旋流器.在旋流器底流口处串接浓缩斗并间歇关闭安装在浓缩斗排料口处的气动阀门,增加物料在浓缩斗内的浓缩时间,提升底流浓度,所得底流产物可直接经皮带机运输.通过数值模拟和对比试验探究物料在旋流器内的沉积情况和间歇排料式浓缩旋流器的浓缩性能,利用Dynamic?Mesh技术实现数值模拟过程中边界参数的改变.模拟结果表明,随着浓缩时间的增加,浓缩斗底部物料浓度明显升高,在进料浓度为4%的情况下,间歇排料周期大致为122?s;试验结果表明,间歇排料式浓缩旋流器底流浓度为73.57%,浓缩比为18.39,与常规排料式旋流器相比分别增加28.33%和7.08,浓缩性能显著提升. 相似文献
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A side orifice is an important type of hydraulic structure which is used widely in irrigation and waste management systems to divert desired discharges from a main channel or to distribute the flow within the basins. Circular pipes flowing partially full are often used in these systems, but existing predictive relations developed for rectangular channels result in significant error. In the present study, the flow through a side orifice in a circular open-channel is numerically simulated and validated to test the effect of different parameters on the discharge coefficient and propose an appropriate predictive equation. To minimize the number of required simulations and validations, a Response Surface Method-Central Composite Design (RSM-CCD) is employed. Results showed that the discharge coefficient is inversely related to the Froude number (Fr) and the ratio of the side orifice length to the approaching flow water depth. However, any increase in either the ratio of the orifice length to the main channel diameter or the ratio of the lower crest level to the orifice length will increase the discharge coefficient. A new equation is presented to determine the discharge coefficient of side orifice in a circular open-channel using RSM-CCD. The sensitivity analysis showed that all linear terms must considered in the equation but that the interaction terms can be dropped. The maximum error of the equation to predict the training and validation data are 1% and 2% respectively. 相似文献
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Unexpected variations in spring characteristics could affect the performance of discharge control valves. In this study, a novel experimental procedure was used to quantify the effects of the spring's elasticity coefficient and unloaded spring length on water delivery by the discharge control valve. Based on an average sensitivity index reflecting the performance of a given structure, the hydraulic behavior of the discharge control valve was quantified. The results indicate that the valve was sensitive to the unloaded spring length, especially when it was slightly smaller than its nominal value. The discharge control valve performance was affected no more than about 16% by ± 4% variation in spring elasticity. In general, spring elasticity variations affect the valve of the smaller design discharge more than that designed for a higher discharge value. The outcome of this study should help design and fabricate discharge control valves to enhance their performance. 相似文献