丁醇燃烧机理及时发动机使用性能影响的研究

发布时间：2018-07-10 06:22

本文选题：丁醇 + 燃烧机理　；参考：《东北林业大学》2016年博士论文

【摘要】：丁醇作为汽车代用燃料对实现在用汽车的“节能减排”具有重大的现实意义,可以有效缓解化石能源日益枯竭的危机,同时减少汽车排放对大气环境的污染,符合当前国家能源的发展战略；同时可以降低国内原油对外依存度,有利于缓解国家的能源安全问题。本文以丁醇为研究对象,总结了丁醇作为车用燃料的应用进展,分析了丁醇燃烧的化学反应动力学机理；利用定容燃烧弹进行了不同燃烧边界条件对丁醇燃烧特性的影响研究,对93号汽油与丁醇燃烧特性的差异进行了比较；通过发动机台架试验分析了丁醇/汽油混合燃料对发动机使用性能的影响；在低温舱内进行了丁醇/汽油混合燃料的低温冷起动试验,分析了常规和非常规排放物的排放特性及其生成机理；应用生命周期理论对车用燃料丁醇的能量平衡和温室气体排放进行了定量分析。基于Dagaut等人提出的C1-C4化学物质的氧化机理,利用Chemkin软件构建丁醇化学反应动力学模型,结合来自Goos, Burcat和Ruscic等人的热力学数据库,利用Chemkin软件的射流搅拌反应器模块,模拟了预混无火焰环境下丁醇氧化并计算了均匀氧化产物的浓度；应用对冲流扩散火焰模块,模拟了非预混火焰环境下丁醇燃烧特性并计算了燃烧产物的浓度；为了对模拟结果进行更深入的分析,分别对丁醇的氧化、燃烧进行了反应路径分析和敏感性分析。研究结果表明,在给定的条件下,丁醇主要通过H原子提取反应进行消耗,生成燃料自由基分子,随后分解成较小的碳氢化合物和含氧组分；丁醇分子中的羟基部分直接生成了甲醛、乙醛和丁醛等含氧组分,这些含氧组分是丁醇燃烧非常规排放物的主要成分。根据试验中所采用的定容燃烧弹台架运行机制,结合发动机实际燃烧时的放热规律,基于构建的准维双区燃烧模型,确定了丁醇混合气浓度、定容燃烧弹初始压力和初始温度3个边界条件,获得了丁醇燃烧持续期、燃烧延迟时间、燃烧压力、燃烧温度、燃烧放热量等燃烧特性的影响规律,比较了汽油与丁醇燃烧特性的差异；利用丁醇和汽油燃烧的化学反应机理,从理论上对燃烧特性的试验结果进行了分析。研究结果表明,丁醇的燃烧特性非常接近汽油的燃烧特性,但丁醇的燃烧持续期以及着火延迟时间均有所延长,丁醇总的放热量稍高于汽油,但放热速率慢于汽油。选取汽油、不同体积比的丁醇/汽油混合燃料等5种试验燃料,进行了发动机全负荷以及转速为2000r/min和2500r/min部分负荷特性试验,获得了5种试验燃料对发动机动力性、经济性和排放性能的影响规律。研究结果表明,与汽油相比,在发动机上燃烧丁醇/汽油混合燃料的动力性和燃油经济性没有明显下降；在全负荷工况下,随着转速的增加,NOx的排放先增加后减少但始终高于汽油,HC和CO的排放减少并始终低于汽油；部分负荷工况下,丁醇在混合燃料中体积比越大,NO、的排放越多,HC和CO的排放越少。在低温舱内进行发动机台架试验,用尾气分析仪对发动机排气中的HC和CO进行了测量和分析,并采用气相色谱和液相色谱法,对CH2O、CH3CHO等非常规排放物进行了测量和分析；获得了丁醇／汽油混合燃料在-7℃时冷起动及怠速暖机最初120s内的常规及非常规排放特性,结合丁醇化学反应动力学模型对排放物的生成机理进行了分析。研究结果表明,在冷起动的最初120 s内,随着燃料中丁醇体积比的增大,HC排放量和CO排放量逐步减少,每种燃料的HC和CO排放量均是先增加后减少；对于非常规污染物,随着燃油中丁醇体积分数从10%增加到30%,乙烯排放体积分数提高37%,甲醛排放量增加67.6%,乙醛排放量增加69.9%,苯排放量减少40.5%,甲烷排放体积分数减少16%,乙炔排放体积分数减少12.5%。以丁醇替代常规车用燃料为研究对象,构建了丁醇的生命周期系统模型,以汽油生命周期原料生产到车辆使用的能源消耗和环境排放指标为评价基准,对车用丁醇燃料的能源消耗和温室气体排放进行了定量分析,从生命周期角度对丁醇作为汽车代用燃料产生的环境影响进行系统评价。研究结果表明,以玉米为原料生产丁醇完全替代汽油作为燃料,可以有效降低能源消耗和温室气体排放,净能量盈余为9.65MJ/kg,能量比为1.18；副产品按照不同的分配方案,玉米丁醇生命周期温室气体排放量与同等热值汽油相比可以减少26%～49.5%。本文的研究成果可为丁醇作为汽车代用燃料的应用奠定理论分析和试验研究基础,为丁醇燃烧机理研究提供有益的参考,并对在寒区使用丁醇作为代用燃料具有一定的借鉴价值。
[Abstract]:As a substitute fuel for automobile, butanol is of great practical significance to the realization of "energy saving and emission reduction" in automobile. It can effectively alleviate the increasingly exhausted crisis of fossil energy and reduce the pollution of automobile emission to the atmosphere. It is in line with the current national energy development strategy; meanwhile, it can reduce the external dependence of domestic crude oil, which is beneficial to the domestic oil. Taking butanol as the research object, this paper summarizes the application progress of butanol as a vehicle fuel, analyzes the chemical reaction kinetics mechanism of butanol combustion, and studies the combustion characteristics of butanol with different combustion boundary conditions with constant volume combustion bomb, and the combustion characteristics of No. 93 gasoline and butanol. The difference was compared. The effect of butanol / gasoline mixed fuel on engine performance was analyzed by engine bench test. The cold start test of butanol / gasoline mixed fuel in cryogenic tank was carried out in low temperature tank. The emission characteristics and formation mechanism of conventional and unconventional emissions were analyzed, and the life cycle theory was applied to the vehicle. The energy balance of fuel butanol and the emission of greenhouse gas were quantitatively analyzed. Based on the oxidation mechanism of C1-C4 chemical substances proposed by Dagaut et al., the kinetic model of butanol chemical reaction was constructed by Chemkin software, and the thermodynamic data base from Goos, Burcat and Ruscic was combined with the jet mixing reactor model of Chemkin software. Block, simulated the oxidation of butanol in the premixed non flame environment and calculated the concentration of the homogeneous oxidation product. The combustion characteristics of butanol in the non premixed flame environment were simulated and the concentration of the combustion products was calculated by using the hedging flow diffusion flame module. The simulation results were further analyzed and the combustion of butanol was carried out respectively. Reaction path analysis and sensitivity analysis show that under given conditions, butanol is consumed mainly by H atom extraction, producing fuel free radicals, then decomposing into smaller hydrocarbons and oxygen containing components, and the hydroxyl groups of butanol molecules are directly connected to the oxygen containing components, such as formaldehyde, acetaldehyde and butyral. Some oxygen components are the main components of the unconventional emission of butanol combustion. According to the operating mechanism of the fixed volume combustion projectile used in the test and the law of the heat release during the actual combustion of the engine, based on the constructed quasi dimensional two zone combustion model, the concentration of butanol mixture, the initial pressure and the initial temperature of the fixed volume combustion bomb are 3 boundary strips. The effects of combustion characteristics such as combustion duration, combustion delay, combustion pressure, combustion temperature and combustion heat discharge were obtained. The difference of combustion characteristics between gasoline and butanol was compared. The experimental results of combustion characteristics were analyzed theoretically by the chemical reaction mechanism of butanol and gasoline combustion. The results showed that the results of the combustion characteristics were analyzed. The combustion characteristics of butanol are very close to the combustion characteristics of gasoline, but the duration of combustion and the delay time of butanol are prolonged, and the total heat release of butanol is slightly higher than that of gasoline, but the exothermic rate is slower than that of gasoline. 5 kinds of Test fuels, such as gasoline, butanol / gasoline mixed fuel with different volume ratio, are used to carry out the full load of the engine and the full load of the engine. The effect of 5 Test fuels on engine power, economy and emission performance was obtained with the speed of 2000r/min and 2500r/min partial load characteristics. The results showed that the power and fuel economy of combustion of butanol / gasoline blended fuel on the engine did not decrease obviously compared with gasoline. As the speed increases, the emission of NOx increases first and then decreases but is always higher than that of gasoline, and the emission of HC and CO decreases and is always lower than that of gasoline; the larger the volume ratio of butanol in the mixed fuel, the more the emission of NO, the less the emission of HC and CO, and the engine bench test in the cryogenic tank, and the exhaust analyzer to the engine row in the low temperature tank. The HC and CO in gas were measured and analyzed. The unconventional emissions of CH2O and CH3CHO were measured and analyzed by gas chromatography and liquid chromatography. The conventional and unconventional emission characteristics of butanol / gasoline mixed fuel in the initial 120s of cold starting and idle speed warmer at -7 were obtained, and the chemical reaction kinetics model of butanol was combined with the chemical reaction model of butanol. The formation mechanism of the emission was analyzed. The results showed that, with the increase of butanol volume ratio in the initial 120 s, the HC emission and CO emission decreased gradually, and the HC and CO emissions of each fuel increased first and then decreased; for unconventional pollutants, the volume fraction of butanol in fuel increased from 10%. With the addition of 30%, the volume fraction of ethylene emissions increased by 37%, formaldehyde emission increased by 67.6%, acetaldehyde emission increased by 69.9%, benzene emission reduced by 40.5%, methane emission volume fraction decreased by 16%, acetylene volume fraction reduced by 12.5%. and butanol replaced conventional vehicle fuel as the research object, and the life cycle system model of butanol was constructed, with gasoline life. The energy consumption and environmental emission indicators used for vehicle production to vehicles are evaluated as the benchmark, and the energy consumption and greenhouse gas emissions of butanol fuel are quantitatively analyzed. The environmental impact of butanol as an automobile substitute fuel is systematically evaluated from the life cycle point of view. The results show that corn is the raw material. The total substitution of butanol as fuel can effectively reduce energy consumption and greenhouse gas emissions. The net energy surplus is 9.65MJ/kg and the energy ratio is 1.18. According to the different distribution schemes, the results of the study on the greenhouse gas emissions from the butanol life cycle and the same calorific gasoline can be reduced by 26% to 49.5%. in accordance with the different distribution schemes. As the basis of theoretical analysis and experimental research, butanol provides a useful reference for the study of butanol combustion mechanism, and has a certain reference value for the use of butanol in cold region as a substitute fuel.
【学位授予单位】：东北林业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：U464

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