共查询到20条相似文献,搜索用时 78 毫秒
1.
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
2.
3.
Investigation of the mechanical behavior of a flexible solid metal seal for a cryogenic butterfly valve 总被引:1,自引:0,他引:1
Ahn Jun Tae Lee Kyung Chul Lee Kwon Hee Han Seung Ho 《Journal of Mechanical Science and Technology》2011,25(9):2393-2400
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. 相似文献
4.
5.
The increase in common rail pressure can lead to increased cavitation inside the injector, resulting in degradation of injector performance and reduced life. The paper investigates the effect of the pressure block structure parameters (initial flow area around the ball valve) on the velocity field, pressure field, fuel gas phase volume fraction and drain rate of the control valve. The relationship between the initial flow area around the ball valve on the cavitation strength and unloading rate inside the valve was revealed. The results show that both the reduction of the flow area around the ball valve and the increase of the cavitation intensity inhibit the rate of oil discharge from the control valve. The reduction of the fuel flow area inhibits the expansion of the low-pressure region (0–1 MPa) within the flow layer, thus limiting the development of cavitation. The reduction of the cavitation area increases the fuel flow rate, however, the increase in flow rate increases the cavitation phenomenon, and these changes form a cycle (Reviewer 5. comment 2). The increase in cavitation inhibits the control valve pressure relief rate more significantly than the decrease in the initial flow area around the ball valve. Based on this, a stepped-pressure block model is proposed. The stepped pressure block model can effectively reduce the cavitation strength near the seal and enhance the oil discharge rate of the control valve. The study can provide a reference for the engineering optimization design of high-pressure common rail injector control valves. 相似文献
6.
7.
在简要介绍了液化天然气(LNG)重型商用车相关知识的基础上,对我国液化天然气行业情况和目前国内外开发、使用情况进行了阐述,通过对其社会、经济效益的分析,总结了该类车型在节能环保、安全经济等方面的突出优势,预测必将有更为广阔的发展前景和市场需求.同时,对加快发展LNG重型商用车提出建议. 相似文献
8.
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
9.
10.
《Pump Industry Analyst》2003,2003(8):3-4
Qatar Petroleum and ConocoPhillips are to develop Qatargas 3, a large-scale liquefied natural gas (LNG) project in Qatar servicing the US natural gas market.This is a short news story only. Visit www.worldpumps.com for the latest pump industry news 相似文献
11.
With the growing interest in liquefied natural gas (LNG) in the energy market, Coriolis mass flowmeters have been applied to many applications in the distribution of LNG. Since Coriolis flowmeters are normally calibrated at around room temperatures, measurements for LNG at cryogenic temperatures present a challenging condition. Firstly, a theoretical analysis for Coriolis mass flow sensors is provided considering the major changes of material properties (Young’s modulus and thermal expansion) at cryogenic temperatures. Then, a practical approach which can be used to correct the flow calibration factor obtained at a reference condition is presented. Finally, flow test results obtained from NIST’s cryogenic calibration facility are provided. Based on the results, it can be concluded that if a Coriolis flowmeter is calibrated at a reference condition and the flow calibration factor is corrected considering the non-linearity of Young’s modulus and thermal expansion change with temperature, it can still provide very accurate mass flow measurement even at cryogenic temperatures. 相似文献
12.
球阀作为高压天然气输送管道的主要设备,其内漏时的喷流气体会产生声发射信号,通过研究该声发射信号特征规律将有助于阀门内漏流量量化检测。针对这一问题,进行了天然气输送管道球阀内漏发声机理和检测试验研究,分析了阀门内漏声发射现象产生的机理和内漏流量检测评价方法。在此基础上,应用声发射检测系统对3种不同尺寸内漏球阀进行了检测试验,通过试验分析了球阀在不同内漏流量下的声发射信号频谱特征分布规律,并采用小波包分析方法进行信号特征参数(信息熵、均方根、频域峰值)提取。拟合特征参数与内漏流量关系曲线,采用R~2(确定系数)指标对曲线拟合程度进行评价,评价结果表明,采用均方根值(root mean square,简称RMS)的曲线拟合程度最高(R2为0.979),可以用于天然气输送管道球阀内漏流量的量化检测。 相似文献
13.
14.
《Pump Industry Analyst》2003,2003(12):2-3
ChevronTexaco Corp plans to construct a US$650 million offshore liquefied natural gas (LNG) receiving and regasification terminal, to be located 13 km off the coast of Baja California, Mexico. 相似文献
15.
16.
液压锥阀内部流场的三维仿真计算及可视化分析 总被引:3,自引:1,他引:2
计算机技术的不断发展和各种计算流体动力学(CFD)计算方法的广泛应用,为深入了解液压阀内部流体的流动状态提供了方便。运用CFD通用软件F luent,以实际液压锥阀为模型,对阀芯在不同开口度、不同半锥角以及不同流量下的流动特性进行了三维仿真计算,并对可视化图形进行了分析。对锥阀的流量系数及阀芯上的压强分布和液动力的计算表明仿真结果与理论计算结果基本一致,为锥阀的优化设计提供了理论依据。 相似文献
17.
Flowmeters and control valves are important components of flow measurement and control in heating, ventilating, and air conditioning (HVAC) system, which directly or indirectly impact building room comfort and energy costs. Valves as resistance components produce differential pressure which in turn can be used for flow measurement. This paper studies the function among valve opening position, pressure difference and flowrate of a new designed butterfly valve. The flow model of the butterfly valve is established based on the Bernoulli equation, the discharge coefficient C under different valve opening conditions are studied by CFD simulations and verified by experiments. The simulation results show that the discharge coefficient C reached a stable value of 0.67–0.70 as Reynolds number exceeded 5000, and the permanent pressure loss ratio is range from 0.95 to 0.37 corresponding to opening range from 10° to 70°. The correctness of the simulation results of C is verified by experiments, in which C is about 0.60. With the corrected values obtained from experiments, the simulation results are instructive to practice. The new designed butterfly valve flowmeter can be used efficiently in HVAC system, especially in variable air volume (VAV) air conditioning system. And the work of this paper offers a reference for other types of valve flowmeters in fluid control processes. 相似文献
18.
乳化液泵属于多柱塞阀配流往复式容积泵,以进、排液阀完成配流任务,实践中为了达到流量调节目的往往采用变频驱动技术。采用线性可变差动变压器(Linear Variable Differential Transformer,LVDT)位移传感器测量了进、排液阀阀芯和柱塞位移规律,并同步采集了泵出口处的压力数据。试验结果显示:排液阀阀芯在不同曲轴转速下的行程是变化的,且均未达到由限位结构决定的限位高度;排液阀阀芯在开启过程中存在着抖动,这种开启行程中的反向运动是由泵出口处的压力脉动导致;进、排液阀开启过程均存在滞后,而排液阀关闭滞后不明显,进液阀关闭滞后随着曲轴转速的下降而缓解。为了降低这类泵曲轴转速降低时引发的压力脉动加剧现象,可考虑采用主动控制进液阀启闭时刻的方式实现流量调节目的。 相似文献
19.
大型液化天然气(LNG)低温子母储罐属于三类重大承压特种设备,一旦发生事故往往会酿成灾难性事故。由于结构上的原因,无法对其进行内部检验即国家规定的全面检验,国外尚无该检验经验可借鉴。针对上述问题,论述了研发的大型LNG低温子母储罐不开罐非常规检验技术。实践证明,此检验技术完全能够起到和满足对大型LNG低温子母储罐全面检验的效果和要求。 相似文献
20.
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