首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Standing Wave Difference Method for Leak Detection in Pipeline Systems   总被引:2,自引:0,他引:2  
The current paper focuses on leakage detection in pipe systems by means of the standing wave difference method (SWDM) used for cable fault location in electrical engineering. This method is based on the generation of a steady-oscillatory flow in a pipe system, by the sinusoidal maneuver of a valve, and the analysis of the frequency response of the system for a certain range of oscillatory frequencies. The SWDM is applied to several configurations of pipe systems with different leak locations and sizes. A leak creates a resonance effect in the pressure signal with a secondary superimposed standing wave. The pressure measurement and the spectral analysis of the maximum pressure amplitude at the excitation site enable the identification of the leak frequencies and, consequently, the estimation of the leak approximate location. Practical difficulties of implementation of this technique in real life systems are discussed.  相似文献   

2.
This paper describes progress on a new technique to detect pipeline features and leaks using signal processing of a pressure wave measurement. Previous work (by the present authors) has shown that the analysis of pressure wave reflections in fluid pipe networks can be used to identify specific pipeline features such as open ends, closed ends, valves, junctions, and certain types of bends. It was demonstrated that by using an extension of cross-correlation analysis, the identification of features can be achieved using fewer sensors than are traditionally employed. The key to the effectiveness of the technique lies in the artificial generation of pressure waves using a solenoid valve, rather than relying upon natural sources of fluid excitation. This paper uses an enhanced signal processing technique to improve the detection of leaks. It is shown experimentally that features and leaks can be detected around a sharp bend and up to seven reflections from features/leaks can be detected, by which time the wave has traveled over 95?m. The testing determined the position of a leak to within an accuracy of 5%, even when the location of the reflection from a leak is itself dispersed over a certain distance and, therefore, does not cause an exact reflection of the wave.  相似文献   

3.
张传亮 《黑龙江冶金》2013,(5):34-35,37
针对化工生产中经常出现的泄漏问题,通过对带压堵漏技术的基本原理及技术特点的研究,提出了消除泄漏的有效措施。  相似文献   

4.
In water distribution systems, valves play a crucial role in system reliability and security by providing a shutoff function when it is necessary to isolate subsystems. In this paper failure of shutoff valves to close is considered. The failure impact is quantified in terms of the expanding subnetwork and the increased number of customers out of service. To evaluate a system-wide valve failure impact, three methods are suggested: segment–valve matrix, decision tree analysis, and simulation. The segment–valve matrix shows the propagation of failure through the network as valves fail to close. The decision tree enumerates all possible valve failure combinations and corresponding event probabilities. Because the complete enumeration can be unwieldy, simulation procedures are offered that approximate the enumeration results closely. The details of the methods are illustrated with the aid of an example.  相似文献   

5.
王春燕 《冶金动力》2007,(2):33-33,35
分析了真空管道止回阀发生的一起爆炸事故,认为其原因是止回阀外密封泄漏,且密封腔无安全装置,提出了相应防范措施消除了隐患。  相似文献   

6.
石油、天然气输送管道通常服役环境较恶劣:管道压力大、输送介质复杂,管道的安全问题日显突出,对管线钢屈强比提出更高要求.屈强比较高是长期困扰CSP流程生产管线钢的难题,运用数理统计方法对生产管线钢的过程工艺参数进行对比分析,查找影响屈强比的关键因素,并通过采取有效措施:调整化学成分、过程工艺参数,提高固溶强化效果,使其屈...  相似文献   

7.
应用蓄热燃烧技术改造传统均热炉燃烧系统,可以节约燃气的消耗率,提高炉内温度场的均匀性.文章通过数值模拟试验,研究了均热炉应用蓄热燃烧技术改造后炉内的流场和温度场,提出了优化改造方案.  相似文献   

8.
通过对现场实际情况的调研,建立了加热炉水梁的平面和三维实体模型,并利用ANSYS软件给出的有限元分析结果,确定了水梁产生裂纹的根本原因,即水梁的高度偏差和在高温交变载荷作用下的受力变形。最后,根据有限元的计算结果,将原焊接结构修改为三通方式,提高了焊缝质量.延长了水梁的使用寿命。  相似文献   

9.
邢福 《山西冶金》2010,33(5):50-53
详细分析了电解槽本体氧化铝漏料的5种原因和外围设备漏料的3种情况;介绍了成功的改进经验和解决问题的建议,对电解铝生产有重要的指导意义。  相似文献   

10.
In the present paper, the behavior of municipal solid waste incinerator ash in cement-based systems was simulated by spiking experiments on portland cement making use of pure compounds, including MgCl2, K2SO4, Zn(NO3)2, and NaNO2, which were selected based on the findings from previous investigation. A 24?1 fractional factorial design was used to arrange the program of experiments. The evolution of physical and mechanical properties as well as acid neutralization capacity with curing time was studied with the aid of statistical analysis. Based on the results from the present work, a model was developed for prediction of unconfined compressive strength and buffering capacity of incinerator ash?portland cement mixtures. The good agreement between predicted and measured values indicated that the behavior of incinerator ash in cementitious systems is largely to be ascribed to the four selected compounds.  相似文献   

11.
A robust approach for approximately solving reliability-based optimal design problems, for series structural systems, is developed. The approach reformulates the problems by replacing reliability terms with deterministic functions. The reformulated problems can be solved by existing semiinfinite optimization algorithms, producing solutions that are identical to those of the original problems, when the limit-state functions are affine, or when first-order reliability approximations are used. An important advantage of the approach is that the required reliability and optimization calculations are completely decoupled, allowing flexibility in the choice of the optimization algorithm and the reliability method. Three sets of examples demonstrate applications of the approach.  相似文献   

12.
A strategy for optimal nonlinear stochastic control of hysteretic systems with parametrically and∕or externally random excitations is proposed and illustrated with an example of a single-degree-of-freedom system. A hysteretic system subject to random excitation is first replaced by a nonlinear nonhysteretic stochastic system, from which an It? equation for the averaged total energy of the system as a 1D controlled diffusion process is derived by using the stochastic averaging method of energy envelope. For a given performance index, a Hamilton-Jacobi-Bellman equation is then established based on the stochastic dynamical programming principle and solved to yield the optimal control force. Finally, the statistics of the responses of uncontrolled and controlled systems and those of the optimal control force are predicted analytically. Comparison with the modified optimal polynomial controller indicates that the proposed strategy is more effective and efficient.  相似文献   

13.
Leak Detection in Pipes by Frequency Response Method   总被引:4,自引:0,他引:4  
The frequency response method is used to determine the location and rate of leakage in open loop piping systems. A steady-oscillatory flow, produced by the periodic opening and closing of a valve, is analyzed in the frequency domain by using the transfer matrix method, and a frequency response diagram at the valve is developed. For a system with leaks, this diagram has additional resonant pressure amplitude peaks (herein referred to as the secondary pressure amplitude peaks) that are lower than the resonant pressure amplitude peaks (herein called primary amplitude peaks) for the system with no leaks. Several piping systems are successfully analyzed for all practical values of the friction factor to detect and locate individual leaks of up to 0.5% of the mean discharge. The method, requiring the measurement of pressure and discharge fluctuations at only one location, has the potential to detect leaks in real-life pipe systems conveying different types of fluids, such as water, petroleum, and so on.  相似文献   

14.
本文从地下管道的种类和探测方法入手,重点介绍了电磁法,并简单地介绍了其他几种方法在管道测量中的应用。  相似文献   

15.
分析了汽轮机油封漏油、汽封漏汽的原因,提出了解决措施,实践证明了取得了良好效果。  相似文献   

16.
研究管道与土体之间相互作用对于管道防震减灾工作具有重要意义,为了研究地下管道所受应力的影响因素,通过改变管径、埋深、土体强度、摩擦系数建立了不同的模型。结果表明:相较于管径和管土间摩擦系数,管道埋深和土体强度对管道应力有较大影响,因此在施工过程中,除了埋深,更应注意管道地基土和回填土的选择。  相似文献   

17.
Eleven types of single circular biplane grids with different diameter (d) and mesh (M) were vertically and constantly oscillated inside a 2 L square jar. The velocity components were measured using a 2D laser doppler anemometer. The average root-mean-square turbulent velocity q′ values were found to be relatively constant at both vertical and horizontal points of measurement—a condition that could not be achieved in the case of impeller mixing. Since the mixing intensity was uniform within the jar, the average volume velocity gradient ? could be applied as the surrogate mixing intensity parameter. It was also found that q′ was linearly related to the vertical grid speed and grid physical characteristics, indicating that the mixing was easily controlled. The macro length scale (L) was calculated and was found to be constant and proportional to d or M, as it should be in the case of turbulent mixing. This study shows the potential of grids as the mixing devices that can be expected to produce an optimum mixing environment for the flocculation process.  相似文献   

18.
眼镜阀误动作是生产工艺系统重大危险源。从生产实际出发,说明系统工艺配置基本状况及误动作现象与危害,结合误动作工作机理分析了故障原因并采取了改进措施。  相似文献   

19.
李磊 《甘肃冶金》2005,27(2):54-55
QSL炉是采用国际先进的一步炼铅法进行铅冶炼,与QSL炉配套的余热锅炉在第3次开炉试车不足3个月的运行中发生两次漏水事故。本文就这一问题进行了原因分析。  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号