The pyrolysis of phenolic resin was studied in a single-pulse shock tube at high temperatures between 1100 K and 1800 K. Considering the very high temperature and short duration time in a shock tube, the heat transfer process of sample particles in high temperature gas was analyzed and the heat equilibrium conditions between the phenolic resin powder and the ambient high temperature gas was also discussed. The pyrolysis product distribution and the pyrolysis rate constants of phenolic resin were determined using gas chromatograph and mass spectrometry. The major pyrolysis products were identified as water, carbon monoxide, hydrogen, acetylene and benzene. The pyrolysis process was divided into the lower and higher temperature regions at the temperature of 1400 K. The different dependency relationships of the pyrolysis rate constant with temperature for the lower and higher temperature regions were obtained.

A method used for the study of thermal decomposition kinetics by peak analysis was developed. This method needs only a few eigenvalues of the thermogravimetric mass loss curves for the determination of kinetic parameters. A peak separation was performed to separate the thermal decomposition of phenolic resin into three stages according to the characteristic of the experimental differential mass loss curve. Kinetic parameters for each stage were determined using peak analysis method. A decomposition kinetic model, which was shown to accurately describe the decomposition process of phenolic resin, was obtained by the combination of these three stages.

The pyrolysis behavior of phenolic formaldehyde resin was studied in a shock tube at high temperatures between 1200K and 1800K.The major hydrocarbon products were identified as methane,ethene,acetylene,benzene and toluene.The variation of the major products distribution with pyrolysis temperature was obtained.It was found that the thermal decomposition of phenolic formaldehyde resin mainly took place at the methylene bridges at the temperatures below 1400K,while the cracking of aromatic framework became the major pyrolysis pathway at the temperatures above 1400K,which gave birth to large amount of acetylene.

The pyrolysis kinetics of phenolic-formaldehyde resin was studied at the temperature range from 1400 to 1700 K using a shock tube. Shock tube experiment can provide a rapid heating rate, which breaks through the limit of traditional heating rate. The major hydrocarbon products were identified as methane, ethene, acetylene and benzne. The effect of diffusion on the pyrolysis process was investigated through analyzing the reaction-diffusion process. It was found that in this experiment the reaction-diffusion process got constant rapidly, and the effect of diffusion was neglectable. The pyrolysis rate constant of phenolic resin under the pyrolysis mechanism of aromatic framework cracking was obtained for the first time.

JP-10 (exo-tetrahydrodicyclopentadiene, C10H16) ignition delay times were measured in a preheated shock tube. The vapor pressures of the JP-10 were measured directly by using a high-precision vacuum gauge, to remedy the difficulty in determining the gaseous concentrations of heavy hydrocarbon fuel arising from the adsorption on the wall in shock tube experiments. The whole variation of pressure and emission of the OH or CH radicals were observed in the ignition process by a pressure transducer and a photomultiplier with a monochromator. The emission of the OH or CH radicals was used to identify the time to ignition. Experiments were performed over the pressure range of 151-556 kPa, temperature range of 1000-2100 K, fuel concentrations of 0.1%-0.55% mole fraction, and stoichiometric ratios of 0.25, 0.5, 1.0 and 2.0. The experimental results show that for the lower and higher temperature ranges, there are different dependency relationships of the ignition time on the temperature and the concentrations of JP-10 and oxygen.

On the basis of the ignition experiments of JP10 and kerosene, experimentswere carried out to study the effect of silane addition on ignitioncharacteristics of these two typical heavy hydrocarbon fuels behindreflected shock waves over the temperature range of 880$\sim$1800K and pressurerange of 0.16~0.53MPa.A longer observation time is required as the ignition time increases at thelower temperature region. The shock tube worked under conditions for atailored interface, resulting in an observation time of about 7ms, and thelower temperature bound of experiments was extended in the current study.The uncertainty in the concentration of the fuel vapor due to the adsorptionof the fuel vapor on the shock tube wall is one of the largest sources oferrors in ignition time measurements of heavy hydrocarbon fuels, thus thegaseous concentrations of JP10 and kerosene were determined in the shocktube by measuring the gas pressure with a high-precision vacuum gaugecombined with gas chromatography. Since kerosene is a complex mixture ofmany hydrocarbon components, the adsorption content of differentcomponents differs, so the gas composition different from the liquidcomposition. In the present study, a simulant modified fuel for kerosene wasprepared by adding some heavy hydrocarbon components into the originalkerosene in proportion to the adsorption content to compensate the loss inthe gas phase through the adsorption. To minimize the degree of adsorptionand increase the test fuel vapor pressure, the shock tube was preheated andmaintained at 70 C throughout the experiments. The conditions behindthe reflected shock were calculated from the incident shock speed using theone-dimensional shock relations. A quartz window was installed on thesidewall very close to the endplate of the driven section to monitor theemission from the ignition process in the reflected shock region. Theemission focused through a lens was detected by using a photomultiplierafter passing through a monochromator centered at the emission line of OHradical at 306.5nm as a marker to identify the instant of ignition.When the molar ratio of the added silane with the fuel was in the range of10%$\sim$15{%}, the corresponding mass ratio was 2%~3{%}, a significantreduction in the ignition delay time was observed experimentally. Anincrease of the additionof silane shortened the ignition delay for JP10 at the lower endof temperature range studied. Specifically, the ignition time for JP10decreased from 3.7 to 0.87ms at 1100K and from 0.17 to 0.10ms at1500K. By contrast, the addition of silane shortened the ignition delay for kerosenethroughout the temperature range considered. Specifically, the ignition timefor kerosene decreased from 3.6 to 0.91ms at 1000K and from 0.75to 0.16ms at 1220K. The results presented herein are useful for the engine design andfuel selection in supersonic combustion researches, and also can be used tovalidate chemical kinetics models of heavy hydrocarbon fuel combustion withsilane addition.

On the basis of the ignition experiments of JP-10 and kerosene in shock tube,the experiments of effect of enhancers,nitromethane and dichlormethane, on ignition characteristics of JP-10 and kerosene were performed.Under conditions for a tailored interface in a preheated shock tube,the experimental time of about 7 ms was obtained.The whole variation of the OH radical emission at 306.5nm was observed in the ignition process by a monochromator with a photomultiplier,to identify the time to ignition.When the molar ratio of the added enhancer with the fuel accounted for 10%～20%,correspondingly the mass ratio was 5%～12%,a significant reduction in ignition time was observed experimentally.Specifically,at 1100K the addition of 10% mole ratio of CH3NO2 produced a 70% reduction in the ignition time for JP-10.The ignition time of kerosene were shortened effectively,when 10%～15% mole ratio of CH3NO2 was added,correspondingly the mass ratio was 5%～6%.Specifically,at 1000K the ignition time for kerosene decreased by 50%.

在JP-10点火延时的激波管实验中,JP-10在激波管壁的吸附导致气相浓度的不确定是测量结果分散的主要原因之一.利用精确测定的吸附曲线确定了实验时JP-10真实的气相浓度,解决了高碳数碳氢燃料点火延时激波管实验时管壁吸附影响燃料气相浓度确定的困难.实验显示JP-10的吸附符合Langmuir吸附等温关系.

In shock tube measurements of the JP-10 ignition delay time, the uncertainty of the gas concentration due to the adsorption of JP-10 in shock tube is one of the main reasons resulting in large scatter of measurement data. By measuring the adsorption curve accurately, the gas concentrations were determined, which overcomes the difficulty in determining the gas concentrations of heavier hydrocarbon fuels due to the adsorption on the wall in shock tube experiments. The present results of experiments show that the adsorption of JP-10 is in accord with Langmuir's adsorption isotherm.

A theoretical calculation is made of the nonequilibrium dissociation of the diatomic molecule with the vibration-dissociation coupling behind a strong shock wave front. The distinguishing feature of this work is to take the molecular fundamental parameters as the starting point for calculation. The master equation method is applied to study the coupling between vibrational excitation and dissociation. The vibrational transition probabilities are calculated with the SSH theory. In the neighborhood of the dissociation limit, the multi-quantum transitions are taken into account and the effect of atom recombination is considered. In a O-2-Ar mixture, the variation of many of the physical quantities of O-2 molecule behind a primary shock front with time are calculated out, such as the vibrational energy level distribution, the vibrational relaxation time, the dissociation incubation time, the dissociation product concentration and the dissociation rate coefficient. The calculated results are found to be in a good agreement with those experimental data given by Camac and Wray, respectively. It is demonstrated in the calculation that a quasi-steady state emerges at the late stage after the shock passage during which the vibrational energy level distribution persists almost constant, Park's model underestimates the nonequilibrium dissociation rate coefficient and Hansen's model overestimates the nonequilibrium dissociation rate coefficient.

在单脉冲激波管上,研究了1,2-二氯乙烷的热裂解.实验的激波条件为:温度区间1020 K＜T＜1190 K, 压力: P=0.12 MPa,实验时间τ=0.5 ms;实验气体为1,2-二氯乙烷稀释于Ar气中(3.95 mmol/L).以4-甲基-1-环己烯作为对比速率法实验的内标物,用4-甲基-1-环己烯开环反应的速率常数k=1015.3exp(-33400/T) s-1,以及从其产物的浓度推定出实验温度.经激波加热后的实验气体的终产物用气相色谱分析出主要成分为C2H3Cl,指示出主要反应通道为β消去反应.如把所有产物C2H3Cl都归于β消去反应,则可推定出表观之反应速率常数k1a=5.0×1013exp(-30000/T) s-1.对于由C-Cl键断键反应引发的链反应的可能影响做了分析研究.用了一种简便分析可推知在实验的温度范围内的低端(1020 K)链反应的影响可以忽略,而在其高端(1190 K)链反应将给出10%的终产物C2H3Cl的附加浓度,获得真实的β消去反应速率常数则必须把这部分予以扣除.经过这样的校正之后,最后得到CH2ClCH2Clβ消去反应速率常数为k1c=2.3×1013exp(-29200/T) s-1.

利用反射激波加热使试验气体电离,继之以强稀疏波快速冷却,构成一种新的激波管方法,并测定了在氩气氛中钠离子与电子三体复合速率系数.由于稀疏波冷却速度达106 K/s,电离过程处于非平衡状态.选用氨基钠作为向实验体系中引入钠离子的源物质.用压电传感器和Langmuir静电探针分别监测反射激波后5区压力和离子浓度变化.稀疏波的冷却过程被视为绝热的.分析了探针工作状态,引入了探针鞘层内的弹性散射修正.测定了在800～2600K温度范围内以惰性气体氩为碰撞第三体的钠离子与电子电离复合速率系数kr＝3.43×10-14T-3.77cm6s-1.

The ionization kinetics of sodium diluted in argon is studied in a shock tube, in which the test gas mixture is ionized by a reflected shock wave and subsequently quenched by a strong rarefaction wave. A Langmuir electrostatic probe is used to monitor the variation of the ion number density at the reflection shock wave region. The working state of the probe is in the near fi-ee fall region and a correction for reduction of the probe current due to elastic scattering in the probe sheath is introduced. At the temperature range of 800 to 2600 K and in the ambience of argon gas, the three-body recombination rate coefficient of the sodium ion with electron is determined: 3.43 x 10(-14)T(-3.77) cm(6).s(-1).

在单脉冲激波管中,进行了二乙硫醚的高温裂解动力学的实验研究.由实验结果得出二乙硫醚的主要裂解通道,以及生成主要裂解产物C2H4在1000K-1150K温度范围内的表观反应速率常数.裂解机理是关键反应C4H10Sk→2C2H4+H2S,测得表观速率常数k=9.55×在1014exp(-(30199/T))s-1.

For measuring the temperature of reservoir gas in the detonation driven shock tunnel (DDST) directly, argon is used as the driven gas with small amount of CF4 added as reagent to produce the temperature indicator C2 F4 based on a kinetic analysis of the thermal decomposition during the shock process. By using a high speed one-way valve connected directly to the shock tunneljust ahead of the entrance of the nozzle, a sarnpling system is constructed to sample the reservoir gas to a gas chromatography. The experimental results show that the sampling technique suggested here is available and the chemical temperature scale determined is convenient. The effects of condensation water on the wall of the driven section, as we use the oxyhydrogen detonation as the driven gas, are also discussed.

Perfluoropropylene C3F6 has been decomposed in presence of scavenger H2 in single pulse shock tube. The products CH4, C2F4, CF3H and C 2F3H are obtained and used as a measure of the rate of the cleavage of the vingl - methyl C - C bond in C3F6 C 3F6 → CF3 + C2F3 The rate expression for this reaction has been found to be k(C3F 6→CF3 + C2F3) = 10 (17.4±0.2)exp(- 355300 ± 8360/RT)s-1 (1090K < T < 1190K) The results are consistent with a bond dissociation energy for primary vinyl C - CF3 bond in perfluoropropylene of 355.3 kJ/mol. The formation enthalpy of C3F6, ΔHf 0(C3F6) = -1078.4 kJ/mol is obtained.

This report describes a new method for measuring the temperature of the gas behind the reflected shock wave in shock tube, corresponding to the reservoir temperature of a shock tunnel, based on the chemical reaction of small amount of CF 4 premixed in the test gas. The final product C 2 F 4 is used as the temperature indicator, which is sampled and detected by a gas chromatography in the experiment. The detected concentration of C 2 F 4 is correlated to the temperature of the reflected shock wave with the initial pressure P 1 and test time τ as parameters in the temperature range 3 300 K< T <5 600 K, pressure range 5 kPa< P 1 <12 kPa and τ≅0.4 ms.

发展了测定电离复合速率常数的一种新的激波管方法.在这一方法中使用反射激波加热预混气体使之电离,相继用可控制的强稀疏波使之快速冷却,冷却速度很快,可达106K/s, 使之在冷却过程中,电离远离平衡态.用压电传感器和Langmuir探针监测状态变化历程和离子浓度,并可获得过程中所有的状态参数.测定了NO+ + e 电离复合速率常数.实验表明这一方法简易可靠.