段塞流气塞破裂后管线压降特性

在气液两相流动中,气塞形成后可能会由于地形变化、输送设备、或其他人为因素引发破裂,引发流体的流动状态变化及压力波动。为了深入了解段塞流流动过程中气塞破裂机理,建立了段塞流流动过程中气塞破裂的物理数学模型,以气液两相流流动参数和管线几何尺寸为研究对象,对气液两相流气塞破裂所引发的压力波动进行分析。结果表明:其他条件相同时,相同长度气塞破裂引发的气塞上游管线压力降低的幅度随上游管线持液率的增大而逐渐增大,随管道直径、液塞尺寸、混合物流速的增大而逐渐减小。     

弛放气压力波动引起高压蒸汽压力递减的原因分析及应对措施

分析了塔里木大型化肥装置因一段炉燃料气系统压力波动,导致高压蒸汽压力从10.7 MPa递减下降至8.92 MPa,并使整个系统接近高压蒸汽跳车的原因：①弛放气设定压力降低导致放空阀打开;②高压用户用汽量增加;③高压废锅产汽量下降。结果表明,通过提高一段炉温度、调整高压合成氨系统负荷、调整高压蒸汽透平抽气量、增加快装锅炉...     

脉冲式密相气力输送水平管中的料栓行为

探讨了聚丙烯颗粒在脉冲式密相气力输送水平管中的料栓行为. 结果表明在一定操作气速下,料栓的长短变化有规律,料栓的运动速度随其长度而变;栓长为1 m左右的聚丙烯颗粒由栓状流向沙丘流型转变的料气速度之比为0.7~0.8,出现在操作气速5 m/s左右;单个料栓的压力梯度与其长度有关,沿单个料栓的压力梯度和截面固含量随气速而变;料栓压降与操作气速无关.     

油气混输泵的研究与发展

多相混输泵是多相混输技术的核心,国外各公司、科研机构都投入大量的人力财力进行研究。分析了气液两相流动的主要计算模型,简要综述国内外混输泵的发展情况以及各种油气混输泵的结构和工作原理。与传统泵相比,油气混输泵具有十分广阔的前景。     

GLCC多相流量计扩大气相流量计量程的探索与实践

气田使用GLCC多相流量计来对单井的油气水产量进行测试计量,在实际使用中发现,气相流量计量程偏小,部分井在大油嘴下的产量超量程,导致无法计量。为解决此问题,气田探索通过扩大气相流量计的量程,来达到使设备满足测试计量需求的目的。文章总结了从三个方面的具体探索过程,以及实际检验结果。     

Solution Method for Countercurrent Plug Flow Models of Multicomponent Gas Separation by Permeation

Abstract

A simple solution method was developed for the countercurrent ideal plug flow model of multicomponent gas separation by permeation that is commonly applied to hollow fiber membrane modules. The solution method is independent of the number of components in the feed gas. The result is an implicit function in a single variable defined as the stage cut. The function is readily solved by the method of damped successive substitution. The method was tested for three cases from the literature and found to be insensitive to the initial guess for stage cuts less than 60%.     

瞬态压力分析法检测城镇燃气管道泄漏

提出一种针对城镇短距燃气管网的局部管道泄漏检测方法。文中建立了简化的管道泄漏模型,通过数值模拟检测燃气管道破损引起的流场瞬态压力脉动,对压力脉动信号分析实现泄漏识别。分析结果表明,在泄漏发生前管道内流场均匀,没有出现强烈的压力脉动;当发生泄漏时,泄漏口产生高速射流而引起局部流场不均匀,产生随时间变化的压力扰动,扰动的传播使整个管道内流场出现强烈的压力脉动。对流场瞬态压力信号进行FFT分析发现,在数值模拟条件下的泄漏引起一种固定模式的扰动,其频率约为42.4 Hz。     

海上油气田硫化氢处理技术

硫化氢是天然气中常见的成分,具有很强的毒性与腐蚀性,必须处理以满足生产安全与销售要求。首先介绍了硫化氢的危害,然后分析了目前海上油气田硫化氢处理常用的处理方法的特点,主要为外输至陆地处理,海上处理与回注地层的方法。最后提出海上油气田选择硫化氢处理方法时要综合考虑技术、经济等因素。     

水平管段塞流持液率的波动特性

气液两相段塞流是液塞和长气泡在空间和时间上的交替,在流动过程中表现出间歇性和不稳定性.今对水平管中段塞流持液率的波动特性进行了分析.结果表明:在同一折算液速下,随着折算气速的增加,段塞单元的平均持液率和液膜持液率先快速下降再缓慢下降,而液塞持液率先缓慢下降再快速下降.段塞流持液率的概率密度分布为双峰分布,高持液率峰对应于液塞区,低持液率峰对应于液膜区;概率密度函数中较完好的峰所对应的持液率与光滑分层液膜区和液塞区的平均持液率相一致.     

Analysis of Multiphase Flow and Heat Transfer: Pressure Buildup in an Unsaturated Porous Slab Exposed to Hot Gas

This study develops a mathematical model for coupled heat and mass transfer in an unsaturated porous slab exposed to a flowing hot gas. Effects of the initial saturation conditions on associated variables, i.e., total pressure, temperature, moisture content, and multiphase flow, are studied. The Newton-Raphson method based on a finite volume technique is applied. This study emphasizes the influence of initial saturation level and gravitational effect in heat and multiphase flow phenomena associated with this system. Gravity enhances the downward flow of liquid within the porous slab. Pressure buildup occurs near the interface between the wet and the dry zone. However, it appears that the order of magnitude to the total pressure is small. This study explains the fundamental mechanism of multiphase flow that involves heat and mass transfer in a heated unsaturated porous slab.     

Analysis of Multiphase Flow and Heat Transfer: Pressure Buildup in an Unsaturated Porous Slab Exposed to Hot Gas

This study develops a mathematical model for coupled heat and mass transfer in an unsaturated porous slab exposed to a flowing hot gas. Effects of the initial saturation conditions on associated variables, i.e., total pressure, temperature, moisture content, and multiphase flow, are studied. The Newton-Raphson method based on a finite volume technique is applied. This study emphasizes the influence of initial saturation level and gravitational effect in heat and multiphase flow phenomena associated with this system. Gravity enhances the downward flow of liquid within the porous slab. Pressure buildup occurs near the interface between the wet and the dry zone. However, it appears that the order of magnitude to the total pressure is small. This study explains the fundamental mechanism of multiphase flow that involves heat and mass transfer in a heated unsaturated porous slab.