爆炸切割气举负压解卡工艺技术的应用

近年来随着油田进入开发后期,井况不断恶化,井筒内结盐、结蜡、出砂等现象严重,部分井因生产层压力低,上部套漏点压力高,封隔器受上下层及井筒内液柱重力双重压力影响,井下封隔器解封无效造成大修现象日益增加。此类问题既延长了作业施工周期又增加了作业成本。爆炸切割气举负压解卡工艺技术通过备注切割后形成的通道,将井筒内的液注由气体携带掏空,在降低封隔器所受负荷的同时达到成功解卡的目的,为井下作业解卡工艺技术拓展了新的途径。     

混合燃气爆炸极限计算方法探讨

爆炸极限是表征可燃气体爆炸特性的重要参数,掌握混合燃气的爆炸极限是防止混合燃气爆炸的关键。阐述了确定混合可燃气体爆炸极限的意义;将混合燃气分成3种情况,并对每种情况下混合燃气爆炸极限的计算方法进行了分析探讨,最后探究了可燃气体含量很低的混合气体易燃性的判定方法。     

油田井下套管爆炸环焊技术研究

通过局部环焊技术对油田井下破损套管进行修复，得出简便可行的数学模型方程，选取切合实际的边界条件求解，求出了有工程应用价值的参数：装药量。     

液压胀管器在蓬莱油田A井的应用

液压胀管器是一种关键工具,被广泛用于修复套管的井下作业中。本文旨在介绍液压胀管器的工作原理、操作过程以及在蓬莱油田A井的实际应用效果。通过对其在井下作业中的使用情况进行分析,探讨了液压胀管器在修复套管方面的优势和效率,优化套损修复的措施,提高井下作业修井作业施工的质量。研究结果表明,在蓬莱油田A井的实际应用中,液压胀管器在套管修复方面发挥了重要作用,为该油田的生产提供了可靠的技术支持。     

高压力气体发生器低温点火性能

研究了气体发生剂性能、点火孔面积和排气孔面积等对高压力气体发生器低温点火性能的影响。研究结果表明,气体发生剂和点火孔是影响高压力气体发生器的主要因素,选用燃速较快的气体发生剂和较大的点火孔面积可以有效控制高压力气体发生器低温点火的稳定性。     

套管爆炸整形工艺研究

针对井底复杂情况下的套管变形现象,利用爆炸整形工艺技术进行变形套管的修复.介绍这种技术的原理、几个参数设计以及施工工艺过程,表现出这种技术优于当前广泛应用的机械修套技术,并提出将机械修套技术与爆炸修套技术相结合,更加有效地为油田现场进行服务.     

耐烃类火灾钢结构防火涂料耐爆炸性能试验研究

采用自制的建筑构件涂层可燃气体爆炸试验装置对超薄型防火涂层、厚型防火涂层进行了防爆炸性能测试。结果表明:当含量为9.5%、10%甲烷气体爆炸后,甲烷浓度瞬间降低,箱内温度瞬时上升到70℃,压力最大变化2 kPa,但超薄型防火涂层在该爆炸场景中无破损;而当燃气浓度为9.5%时,厚型防火涂料在试验过程中可能会产生裂纹、剥落。     

激波诱导下瓦斯浓度对煤尘爆炸压力的影响

运用水平管道气体-粉尘爆炸装置,研究了激波诱导下瓦斯浓度对煤尘爆炸压力的影响,并对多次平行实验的结果进行分析。通过对爆炸压力、爆炸压力上升速率和最小点火能的分析,得出结论,在爆炸下限以下,甲烷的存在增加了煤尘爆炸压力和爆炸压力上升速率,并且降低了煤尘爆炸的最小点火能。     

确定混合燃气爆炸极限的重要意义及计算方法

阐述了确定混合燃气爆炸极限的重要意义;分析了混合燃气爆炸极限的计算方法,探究了低含量可燃气体混合物火灾危险性类别的判定方法,指出了相关标准中存在的盲区,提出了制定相关计算混合燃气爆炸极限的企业标准的建议。     

浅谈石油井变形套管爆炸整形修复技术

随着我国经济和科学技术的发展,在资源开发方面也进行得越来越多.对石油的开采也一直在增多.而随着对油田的不断开发,石油井套管变形出现得越来越多,不仅仅存在变形现象,还有一些损坏现象,这些问题都会影响到油井的产量,还有进行开采时需要采用的措施.因此,近年来对石油井变形套管的修复措施越来越受到重视,本文就是对石油井变形套管的爆炸修复措施进行讨论.     

压装PBX炸药DDT管实验初始反应演化过程分析

在DDT管中采用惰性模拟材料研究电点火头和黑火药产生的初始压力对惰性模拟材料点火端面的影响;采用高速摄像机记录了DDT管内HMX基压装PBX炸药的燃烧发光过程;分析了压装PBX炸药DDT管实验初始反应演化过程。结果表明,电点火头和黑火药产生的初始压力会引起邻近脆性炸药端面裂纹形成和局部破坏,炸药燃烧的火焰沿炸药基体裂纹和炸药与管壁之间的缝隙中传播,压装PBX炸药初始反应演化与缝隙对流燃烧过程密切相关。     

Ignition and combustion of pyrotechnic compositions based on microsized and ultra-nanosized aluminum particles in a moist medium in a two-zone gas generator

This paper presents the results of an experimental study of the ignition and combustion of pyrotechnic compositions based on microsized and ultra-nanosized aluminum particles in a model two-zone gas generator using water as oxidizer. The flow of combustion products from the gas generator was video recorded, and the condensed products sampled behind the nozzle exit were studied by chemical and particle-size analyses. It was found that the replacement of microsized aluminum particles by ultra-nanosized particles in the samples led to a ≈17% decrease in the active aluminum content in the condensed phase, a 10–15% increase in the efficiency of the process in the gas generator (completeness of conversion of the pyrotechnic composition to combustion products), and a factor of about three decrease in the ignition delay.     

炭黑尾气在生产中的回收利用

针对炭黑尾气水分高、着火点高、易爆燃的特性,在炭黑尾气利用时,要解决稳定燃烧、预热煤气、平衡尾气压力及防止炭黑滤袋泄漏等问题。结合实际生产中炭黑尾气的成分,采取了相应的安全措施,完善了炭黑系统和锅炉系统衔接的各项指标,取得了较为显著的经济效益。     

Ignition and combustion of pyrotechnic compositions based on micro- and nanoparticles of aluminum diboride in air flow in a two-zone combustion chamber

This paper presents the experimental study of ignition and combustion of micro- and nanoparticles of aluminum diboride as part of pyrotechnic energy-saturated compositions in a gas generator with an air afterburner chamber and the thermodynamic calculations of combustion of pyrotechnic compositions based on aluminum diboride in air. The discharge of the combustion products from the afterburner chamber is recorded on video. It is shown that replacing micron aluminum diboride by powdered diboride with a mass-average diameter of particles equal to ≈270 nm in the pyrotechnic composition and increasing the pressure in the afterburner chamber cause the combustion efficiency in air to increase by 5–20%.     

Experimental Investigation on Laser Ignition and Combustion Characteristics of NEPE Propellant

The ignition and combustion property of solid propellant is the main content in internal ballistic research, which has a great significance for propulsion application and combustion mechanism. In this study, the detailed gas‐phase reaction mechanism of Nitrate Ester Plasticized Polyether Propellant (NEPE) was developed. It is helpful to understand the intricate processes of solid‐propellant combustion. The factors which may have influences on ignition delay time and temperature distribution of propellant surface was analyzed by laser ignition experiment. Using high‐speed camera and an infrared thermometer, the ignition and combustion process and the surface temperature distribution of NEPE propellant under laser irradiation were measured. Laser heat flux, ambient pressure and initial temperature of NEPE propellant have an influence on the ignition delay time and the surface temperature. Results show that the ignition delay time decreases with the increase of laser heat flux, ambient pressure and initial temperature of NEPE propellant. At the same time, with the increase of laser heat flux, the influences of ambient pressure and initial temperature on the ignition delay time decrease. Besides, laser irradiation, ambient pressure and initial temperature have significant influences on the surface temperature distribution of the propellant.     

催化燃烧中表面反应-气相反应间相互作用及其对均质压燃发动机着火特性的影响

通过对微元管中甲烷在铂表面的催化燃烧过程的数值计算,分析了当混合气入口压力很高时气相反应对整个催化燃烧过程的影响;通过敏感度分析,找出了对异相着火及气相着火起主要作用的基元反应步.结果表明,在异相着火过程中起主要作用的基元反应步为甲烷与氧气在催化剂表面的吸附反应及氧气的解吸反应,在气相着火过程中起主要作用的基元反应步为OH·及水的吸附与解吸反应.对活塞顶涂有铂催化剂的均质压燃（HCCI）发动机的燃烧过程进行了数值模拟,分析了催化效应及关键表面反应基元步对HCCI发动机着火时刻以及燃烧过程中中间组分的影响,结果表明,催化反应能促进混合气的着火,缩短着火延迟时间,对HCCI发动机着火时刻起主要影响的表面反应为OH·及水的吸附与解吸反应.     

Combustion characteristics of a direct-injection engine fueled with natural gas-hydrogen blends under different ignition timings

In this paper, combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas-hydrogen blends under various ignition timings and lean mixture condition were investigated. The results show that the ignition timing has significant influence on engine performance, combustion and emissions. The time intervals between the end of fuel injection and ignition timing are very sensitive to direct-injection gas engine combustion. The turbulence in combustion chamber generated by the fuel jet maintains high and relatively strong mixture stratification is presented when decreasing the time intervals between the end of injection and the ignition timing, giving fast burning rate, high brake mean effective pressure, high thermal efficiency and short combustion durations. For specific ignition timing, the brake mean effective pressure and the effective thermal efficiency increase and combustion durations decrease with the increase of hydrogen fraction in natural gas. Exhaust HC concentration decreases and exhaust NO_x concentration increase with advancing the ignition timing while the exhaust CO gives little variation under various ignition timings.     

Mathematical Simulation of Airbag Inflation by Low Temperature Gas Generator Products

A mathematical model is described analyzing the processes during the combustion of a solid propellant gas generator for airbags. Results on parameter variations are presented. For porous and granulate charges the dynamic parameters of the gas flow and the progress of the ignition of the propellant are determined.     

An investigation into propane homogeneous charge compression ignition (HCCI) engine operation with residual gas trapping

Propane is available commercially for use in conventional internal combustion engines as an alternative fuel for gasoline. However, its application in the developing homogeneous charge compression ignition (HCCI) engines requires various approaches such as high compression ratios and/or inlet charge heating to achieve auto ignition. The approach documented here utilizes the trapping of internal residual gas (as used before in gasoline controlled auto ignition engines), to lower the thermal requirements for the auto ignition process. In the present work, with a moderate engine compression ratio the achievable engine load range was controlled by the degree of internal trapping of exhaust gas supplemented by inlet charge heating. Increasing the compression ratio decreased the inlet temperature requirements; however, it also resulted in higher pressure rise rates. Varying the inlet valve timing affects the combustion phasing which can help to decrease the maximum pressure rise rates. NOx emissions were characteristically low due to the nature of homogeneous combustion.     

Effects of NTO Oxidizer Temperature and Pressure on Hypergolic Ignition Delay and Life Time of UDMH Organic Gel Droplet

Organic gel propellants are promising candidates for a variety of rocket motor and scramjet applications, since they are intrinsically safe and provide high performance. It is well known that organic gel fuel droplets exhibit distinct combustion characteristics compared with conventional liquid fuel droplets, and furthermore an understanding of the ignition delay and lifetime of these droplets is critical to the improvement of combustor design. In this work, investigations of the combustion of unsymmetrical dimethylhydrazine (UDMH) organic gel droplets in different nitrogen tetroxide (NTO) oxidizing atmospheres were conducted using two sets of experimental apparatus. The combustion characteristics under different conditions of temperature and pressure were compared and analyzed based on the flame shapes observed during experimentation. From these trials, an unsteady combustion model was developed and used for the numerical simulation of spray‐sized UDMH organic gel droplet combustion in an NTO atmosphere. The hypergolic ignition and burning characteristics of the organic gel droplets under conditions simulating either engine startup or steady state combustion were compared, and changes in ignition delay and droplet lifetime with ambient temperature and pressure were analyzed. The experimental and numerical results show that the UDMH organic gel droplets exhibit periodic swell‐burst behavior following the formation of an elastic film at the droplet surface. Each droplet burst results in fuel vapor ejection and flame distortion, the intensity of which declines with increasing ambient pressure. However, the swell‐burst period is extended with increasing ambient pressure, which results in potential flameout. Under conditions of low temperature and pressure similar to those at engine startup, the ignition delay and lifetime of spray‐sized gel droplets decrease with increasing temperature or pressure, although there is a sharp increase in droplet lifetime when the ambient pressure reaches a critical value associated with flameout. The ignition delay was found to be a rate‐limited phenomenon linked to the droplet heating rate. The proportion of ignition delay and droplet lifetime due to droplet heating‐up decreased with increasing temperature or decreasing pressure. Conversely, at high temperatures and pressures simulating the engine’s steady state operating conditions, the droplets were observed to flameout after several swell‐burst periods and both ignition delay and lifetime decreased monotonically with increasing temperature or pressure. The ignition delay time was determined to be rate‐limited by gas phase chemical reactions and contributed very little to the overall droplet lifetime compared with the engine startup condition.