共查询到20条相似文献,搜索用时 187 毫秒
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本文介绍同时联用技术(如动态热机械仪与介电分析仪,差示扫描量热仪与光量热计联用),串联联用技术(如热分析与气相色谱、质谱和傅里叶变换红外光谱联用)及其应用。 相似文献
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邻氯苯亚甲基丙二腈(CS)作为催泪剂在各国反恐防暴装备中得到了广泛应用。实际使用时,燃烧和爆炸驱动分散CS形成气溶胶的同时会导致其分解。为提高CS的利用效率,有必要研究其热稳定性和热分解性能。本工作应用热重分析与差示扫描量热法(TGA/DSC)研究CS在不同升温速率时产生的热失重和热效应现象,并与傅里叶变换红外光谱法(FTIR)联用对逸出气体进行分析;用热裂解与气相色谱-质谱(PY-GC/MS)技术研究CS在350~650 ℃的热分解性能。实验发现:CS在96 ℃附近熔融;310 ℃附近沸腾;450~550 ℃之间发生首次热分解,热分解产物与温度有着密切关系,550 ℃的分解产物有4 种;650 ℃的热分解程度加深,分解产物多达 10 种。因此,建议CS与烟火剂混合使用时,烟火剂的燃烧温度以不超过450 ℃为宜。 相似文献
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加压热重分析仪 总被引:1,自引:0,他引:1
王双祥 《仪器仪表与分析监测》1998,(2):23-25
加压热重分析仪王双群熊源泉孙晨亮(东南大学热能所210096)东南大学热能所长期从事煤的清洁燃烧和发电技术研究,了解加压工况下煤热解过程对研究煤的加压燃烧和气化特性有十分重要的作用,国内外暂无相应分仪器产品,为此,我们自行研制了加压热重分析仪。1加压... 相似文献
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用差热(DTA)-热重(TGA)分析技术研究了一水硫酸锂脱水及固-固相变的非等温动力学,由不同升温速率下,差热-热重曲线计算了一水硫酸锂脱水及固-固相变过程的表观活化能和反应级数,并对几种热分析处理动力学数据的结果进行了比较,表明几种方法结果一致。 相似文献
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利用比表面积测试仪(BET )和电子扫描电镜(SEM )对纳米铁粉表面特性进行测定,利用热重分析仪(TGA)对50nm、100nm、500nm和20000nm铁粉在10℃· min-1、20℃· min-1、30℃· min-1和40℃· min-1升温速率下进行了热分析实验,得到纳米铁粉的表面微观结构、差示扫描量热曲线(DSC )和热重曲线(T G ),结果发现:粒径为50nm和100nm的铁粉在较低的温度下可能发生了相变,相变温度区间为260~350℃,而粒径为500nm和20000nm的铁粉在燃烧过程中则没有发生熔融,纳米金属粒径越小,越容易熔化。 相似文献
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热重分析中逸出气体的傅里叶变换红外光谱测量 总被引:5,自引:0,他引:5
随着傅里叶变换红外光谱技术的迅速发展,一些新的联用技术不断涌现并日趋成熟。本文旨在介绍热重分析-傅里叶变换红外光谱(TGA-FTIR)的联机方法、数据处理及结果表示,并以几个实例说明其应用。 相似文献
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热分析技术是在程序控温和一定气氛下,测量物质的某种物理性质与温度或时间变化等关系的一种方法技术手段,能够准确、快速的测量物质的变化,在纳米碳材料表征中有重要的应用。本文将简要阐述热分析及其联用技术在纳米碳材料表征方面的应用进展和研究成果,结果表明它们为纳米碳材料的耐氧化性、热稳定性、表面氧化度、不同形态碳含量、热分解机理等分析的探索提出了切实可行的研究途径,同时结合笔者在这方面的一些工作对热分析技术的具体应用进行了详述,最后对热分析及其联用技术在纳米碳材料表征中的应用做了重要的前景展望。 相似文献
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Characteristics of self-excited combustion oscillation are experimentally studied using confined premixed flames stabilized
by a rearward-facing step. A new idea to suppress combustion oscillation was applied to the flames. The characteristics of
unsteady combustion were examined, which is driven by forced pulsating mixture supply that can modulate its amplitude and
frequency. The self-excited combustion oscillation having weaker flow velocity fluctuation intensity than that of the forced
pulsating supply can be suppressed by the method. The effects of the forced pulsation amplitude and frequency on controlling
self-excited combustion oscillations were also investigated comparing with the steady mixture supply. The unsteady combustion
used in this experiment plays an important role in controlling self-excited combustion oscillations, and it also exhibits
desirable performances, from a practical point of view, such as high combustion load and reduced pollutant emissions of nitric
oxide. 相似文献
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Seonghyeon Seo 《Journal of Mechanical Science and Technology》2003,17(6):906-913
Lean premixed combustion has been considered as one of the promising solutions for the reduction of NOx emissions from gas
turbines. However, unstable combustion of lean premixed flow becomes a real challenge on the way to design a reliable, highly
efficient dry low NOx gas turbine combustor. Contrary to a conventional diffusion type combustion system, characteristics
of premixed combustion significantly depend on a premixing degree of combusting flow. Combustion behavior in terms of stability
has been studied in a model gas turbine combustor burning natural gas and air. Incompleteness of premixing is identified as
significant perturbation source for inducing unstable combustion. Application of a simple convection time lag theory can only
predict instability modes but cannot determine whether instability occurs or not. Low frequency perturbations are observed
at the onset of instability and believed to initiate the coupling between heat release rate and pressure fluctuations. 相似文献
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The objective of this paper is to characterize dynamic pressure traces measured at self-excited combustion instabilities occurring
in two combustion systems of different hardware. One system is a model lean premixed gas turbine combustor and the other a
fullscale bipropellant liquid rocket thrust chamber. It is commonly observed in both systems that low frequency waves at around
300Hz are first excited at the onset of combustion instabilities and after a short duration, the instability mode becomes
coupled to the resonant acoustic modes of the combustion chamber, the first longitudinal mode for the lean premixed combustor
and the first tangential mode for the rocket thrust chamber. Low frequency waves seem to get excited at first since flame
shows the higher heat release response on the lower frequency perturbations with the smaller phase differences between heat
release and pressure fluctuations. Nonlinear time series analysis of pressure traces reveals that even stable combustion might
have chaotic behavior with the positive maximum Lyapunov exponent. Also, pressure fluctuations under combustion instabilities
reach a limit cycle or quasi-periodic oscillations at the very similar run conditions, which manifest that a self-excited
high frequency instability has strong nonlinear characteristics. 相似文献
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光纤燃烧传感器研制中的关键技术 总被引:1,自引:1,他引:1
总结了光纤燃烧传感器(FOCS)研制过程中的关键技术,包括传感器探头、光纤及滤光片、光探测器、数据采集及信号处理系统的设计和制作中的问题,并对其相应的解决方法进行了探讨。 相似文献
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围绕汽油机的节能和排放问题,本文主要从结构和进气组织等方面,概述了被称为第三种燃烧方式的汽油缸内直喷(GDI)的发展和研究。 相似文献
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研究了直喷式柴油机瞬态工况壁面温度对燃烧噪声的影响机理。开展内燃机瞬态工况测试技术和测试方法研究,通过对瞬态与稳态过程的壁面温度差异的研究分析,从气体动力载荷和高频压力振荡两方面分析研究瞬态噪声与稳态噪声产生差异的机理。瞬态工况壁面温度高于同负荷同转速的稳态工况。壁面温度的差异导致两种工况下滞燃期的改变,影响燃烧压力和缸内压力升高率以及压力高频振荡的频率和幅值。结果表明,瞬态与稳态工况壁面温度的差异影响到动力载荷与压力高频振荡,是两种工况下燃烧噪声产生差异的主要二级影响因素之一。 相似文献
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相比于TiC、TiB2单相陶瓷,TiC—TiB2复合陶瓷因具有高硬度、高断裂韧性及优异的耐磨性,目前已成为工程陶瓷的研究热点。本文基于对目前国内外TiC—TiB2复合陶瓷制备方法与力学性能的介绍,分析了反应物成分,反应物颗粒尺寸,压坯密度等因素对力学性能的影响,并且结合超重力下燃烧合成技术制备大尺寸、高致密、高硬度TiC—TiB2近共晶成分复合陶瓷研究结果,指出燃烧合成及其衍生技术现已成为制备TiC—TiB2复合陶瓷的研究热点,并且为获得高致密的细晶材料,TiC—TiB2复合陶夺发展趋势在于共晶系复合陶瓷。 相似文献
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This study presents the methodological aspects of combustion instability modeling and pro-vides the numerical results of the
model (sub-scale) combustion chamber, regarding geometrical dimensions and operating conditions, which are for determining
the combustion stability boundaries using the model chamber. An approach to determine the stability limits and acoustic characteristics
of injectors is described intensively. Procedures for extrapolation of the model operating parameters to the actual conditions
are presented, which allow the hot-fire test data to be presented by parameters of the combustion chamber pressure and mixture
(oxidizer/fuel) ratio, which are customary for designers. Tests with the model chamber, based on the suggested scaling method,
are far more cost-effective than with the actual (full-scale) chamber and useful for injector screening at the initial stage
of the combustor development in a viewpoint of combustion instabilities. 相似文献