多喷嘴气—液两相喷射过程的试验

近年来国内外学者在气—液喷射技术方面开展了大量的工作,但这些研究采用的工作蒸汽主要是干饱和蒸汽和过热蒸汽,关于湿蒸汽的研究较少,然而在实际工业中,相当一部分低压蒸汽是具有一定干度的湿蒸汽。为此,设计以湿蒸汽为工作蒸汽试验台,采用一种多喷嘴结构的汽液喷射器作为试验元件,对气—液两相喷射过程进行试验研究,得到不同蒸汽干度下,喷射器内的压力变化及蒸汽压力和低温水温度对喷射器内气、液两相混合均匀程度的影响。结果表明,蒸汽干度未明显影响混合室内的压力分布规律;水喷嘴出口处压力和混合室圆柱段入口处压力均在某蒸汽压力时达到极小值,且该蒸汽压力值大于喷射器的最佳蒸汽压力;提高蒸汽压力或增大低温水温度有助于混合室内气、液两相流体混合均匀。     

联合湿蒸汽流量、干度测量装置在稠油热采中的应用

介绍一种应用于稠油热采中的湿蒸汽流量、干度测量装置的原理、组成及系统软件功能。该装置基于两相流测量方法,解决了传统单相流测量湿蒸汽流量、干度误差大的问题。     

蒸汽质量在线测量技术及其在注汽锅炉中的应用

鉴于油田开发中蒸汽吞吐和蒸汽驱的当前状况,提出了一种油田注汽锅炉蒸汽质量在线测量的新思路、新技术,采取测量相关辅助参数法,经过大量实验分析,揭示出注汽锅炉的多个运行参数与蒸汽干度之间的内在变化关联,实现了注汽锅炉蒸汽干度、压力和流量等重要参数的在线测量,并且设计、开发了智能控制系统,自动追踪参数变化,调节控制信号,使锅炉蒸汽维持在设定的较高干度值范围内,提高了锅炉燃烧的稳定程度,保证了注汽质量。     

一种新蒸汽汽轮机两相重要区域热能高效优化方法

为了保证汽轮机经济安全运行,建立湿区热性质模型,精确地计算湿蒸汽的饱和温度、饱和压力及湿蒸汽的干度等是必要的。提出了以比焓和比熵为变量的饱和温度和饱和蒸气压力优化等式,用于计算蒸汽汽轮机湿区重要区域饱和水与饱和水蒸气热性质以及湿蒸汽的干度,其计算过程避免了耗时的迭代,减少占机时间,数值计算误差满足热循环和蒸汽轮机对数值一致性要求。其中,饱和温度等式可以替换IAPWS推荐的复杂饱和温度等式,优化两相重要区域的热动力学性质计算。     

蒸汽等干度分配监测装置的研究与应用

针对辽河油田实际生产中蒸汽干度均匀分配的难题,研发了一种蒸汽等干度分配监测装置。该监测装置由蒸汽等干度分配器、流量调节器、蒸汽多参数实时监测仪及GPRS远程数据传输系统组成,采用了一体化撬装方式,实现了蒸汽等干度分配、蒸汽流量精确控制、蒸汽参数实时监测的生产目的。     

油田注汽锅炉蒸汽干度控制方法研究

注汽锅炉是用于在稠油开采过程中向稠油层注入高压蒸汽的注蒸汽稠油热采的关键设备,而蒸汽干度是检测油田注汽锅炉的重要指标,直接影响稠油热采的效果。注汽锅炉的蒸汽干度控制影响因素中最主要的就是人为因素,对油田注汽锅炉的运行产生不利影响,同时,直接影响了稠油热采的效果。因此,对油田注汽锅炉蒸汽干度控制方法研究正向着自动化控制的方向迈进。本文简单介绍了油田注汽锅炉蒸汽干度控制的现状,重点分析了注汽锅炉蒸汽干度控制的重要指标,提出了干度控制的方法,即模糊控制方法和预测控制方法。     

油田注汽锅炉蒸汽干度控制系统解决方案

基于注汽锅炉工艺特点、研究现行的关于汽水两相流干度的各种计量方法后,经反复实验比较,最终采用电导率测量、PID最优控制算法,结合工业自动化控制技术,研发出注汽锅炉蒸汽干度控制系统解决方案.通过测量注汽锅炉进水、炉水电导率等参数数据,调整燃料供给控制信号,改变火量大小,实现蒸汽千度的自动调节控制.     

稠油注汽锅炉蒸汽干度测控装置的应用

介绍了应用蒸汽干度自动测控装置,实现蒸汽干度的实时检测与自动控制,效益显著。     

光纤传感干度测量仪研制

运用光纤传感技术研制的干度测量仪．通过水汽两相流在光学界面上不同折射率具有的不同反应．直接得出干度变化的响应值。从理论上分析了干度测量仪的工作原理，并实验证明可以连续、在线测量，可在高温、高压的狭窄空间工作。     

注汽锅炉蒸汽干度的模糊前馈-反馈控制

为了实现注汽锅炉蒸汽干度的高质量控制，设计了一个基于模糊逻辑的前馈-反馈干度控制系统。该系统采用基于Takagi-Sugeno（T—S）模糊模型的多步预测器对蒸汽干度进行预测，并将其预测输出作为系统反馈信号。来自水流量的前馈控制量与主回路控制量相乘，形成相乘型前馈-反馈控制以实现水火量的自动跟踪。同时在控制结构中引入非线性跟踪-微分器以增强系统的抗干扰能力。应用结果表明，该干度控制系统具有良好的控制效果。     

Energy metering system for high quality saturated steam

For accurate measurement of steam flow rate, the dryness fraction has to be included in the flow rate calculation; the dryness fraction is also a parameter that often needs to be monitored for effective process control and for condition monitoring of the plant. It is notoriously difficult, however, to measure dryness fraction easily and accurately. In this paper, an energy metering system which measures the steam quality, mass flow rate and thus the energy of the steam is proposed and tested. The system consists of a separator and condensate flowmeter followed by a steam flowmeter; the output signals of these devices are fed into a microcomputer which contains the characteristics of the devices and formulations for steam properties. Testing of the energy metering system showed that the average differences between the displayed output of the system and the values obtained using a condensate weightank was about 0.22% for the dryness fraction and 1.05% for the saturated steam flow rate.     

NUMERICAL SIMULATION OF WET STEAM CONDENSING FLOW WITH AN EULERIAN／EULERIAN MODEL

Wet steam condensing flow in low-pressure steam turbine leads to efficiency losses and blade erosions. In order to investigate this problem by numerical approach, an Eulerian/Eulerian model has been developed, in which the wet steam is regarded as mixture comprising two coupled systems: the vapor phase and the liquid phase. These two systems are both described by conservation equations. High resolution TVD scheme is employed to capture condensing phenomena in wet steam flow. This model has been validated by numerical simulations of condensing flows in 1D and 2D nozzles. Compared with experimental data, a good agreement is observed. This Eulerian/Eulerian model can be extended to 3D calculation of condensing flow.     

Measurement of steam flow rates using a clamp-on ultrasonic flowmeter with various wetness fractions

Most of the heat in industrial plants is supplied by steam. To minimize energy waste, measuring the steam flow rates in existing pipes is important. Clamp-on ultrasonic flowmeters are used for this purpose, for which the sensors are attached to the pipe wall. However, flow conditions that can be used are limited because the signal-to-noise ratio of the ultrasonic signal in a steam flow is low. Furthermore, the steam wetness increases with heat losses, which may affect measurement results. Therefore, flow rate measurements in wet steam flows using clamp-on ultrasonic flowmeters have not been fully established. In this study, steam flow rates with various wetness fractions and system pressures were measured using a laboratory-made clamp-on ultrasonic flowmeter. The results show that flow rates in wet steam could be determined within a 10% error under general conditions in a steam piping system, although the conversion factor from line-average to area-average velocities was calibrated in superheated conditions, and the speed of sound in saturated conditions at each pressure was used. However, the error of the flow rates tended to increase with the wetness fraction and was biased toward positive values. The speed of sound and liquid volume fraction were evaluated at different wetness fractions. The flow rate error due to the change in sound speed was less than 1%, and 1.2% of the flow rates were overestimated owing to the liquid volume fraction. The velocity distribution in wet steam was considered different from that in the superheated steam owing to the existence of the liquid phase, and the change in velocity profile may lead to an overestimation of the steam flow rates in the wet steam condition.     

核能海水淡化源蒸汽质量流量的测量与新的密度补偿式

本采用汽液两相流均相流动的模型,分析了涡街流量计在核能海水淡化源汽的捏流量测量中的适用性,并结合低压和蒸汽的热物理性质,论述了涡街流量计测量低压饱和蒸汽质量流量的误差一蒸汽干度之间关系。给出了一个用于低压饱和蒸汽质量流量测量的变系数密度补偿式和该补偿式的特色。     

经验模态分解中虚假模态分量消除法

基于能量原理,提出经验模态分解(EMD)中虚假模态分量消除方法.在正常采样的条件下,分析信号EMD分解误差与虚假模态分量的关系,讨论虚假模态分量的性质.从EMD分解的完备性角度考虑在虚假模态存在情况下能量不守恒,给出模态函数消除法,从EMD分解结果中剔出虚假模态分量,消除信号经验模态分解误差.其有效性在所给例子中得到证实.     

压水堆核电站湿蒸汽透平的研究与制造

本文就核电站湿蒸汽透平和常规电站透平的特点作了比较。指出湿蒸汽透平的蒸汽膨胀过程对设计及制造带来了诸如叶片受侵蚀、功率损失及叶片庞大等问题。特别在高压缸中,高密度湿蒸汽引起的侵蚀问题的尚待解决。在引进技术和设备的同时,也必须通过自己的科研工作才能掌握技术。为此,应积极开展湿蒸汽与水滴测量技术的基本研究,必须进行湿蒸汽膨胀的模拟试验以及湿蒸汽透平模型试验,以便在此基础上建立核电站湿蒸汽透平的正确设计计算方法。     

双背压凝汽器抽空气管路改进的可行性研究

国内安装的600MW、1000MN超临界、亚临界凝汽式机组,汽轮机为三缸四排汽汽轮机,配套的是双背压凝汽器。为了响应国家节能要求,对凝汽器高低背压设计原理及存在的问题进行分析,对所采用的抽空气管路进行分析,提出技改方案和安全风险控制要求,为各电力公司的节能工作提供了理论依据,同时使双背压凝汽器的设计更加完善。     

干式加工技术切削刀具的研究

干式加工技术的发展在很大程度上要依赖于切削刀具的开发与应用。本文正是在干式加工的基础上,主要从刀具材料、涂层及几何形状等方面分析影响切削刀具性能的因素,总结了不同加工条件下切削刀具的应用。