Laminar Burning Velocity Measurements Over Wide-Ranging Temperatures and Pressures for Renewable and Conventional Fuels

可再生燃料和传统燃料在宽温度和压力范围内的层流燃烧速度测量

• 批准号: EP/H031197/1
• 负责人: C Stone
• 金额: $ 17.74万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FH031197%2F1
• 关键词: Laminar; Burning; Velocity; Measurements; Over

Laminar burning velocity measurements are needed for models that assist development of clean and efficient combustion in engines, boilers and furnaces, and for the validation of laminar burning velocity models. Our laminar burning velocity measurements are made in a spherical vessel with central ignition, so that a spherical flame front forms and propagates radially. During combustion the pressure rises and the unburned gas ahead of the flame front is compressed isentropically. So, from a single experiment, laminar burning velocity data are obtained for a sequence of linked temperatures and pressures. By varying the initial temperature and pressure the effects of pressure and temperature can be decoupled, and correlations generated for the effect of temperature and pressure on the laminar burning velocity. The schlieren system can detect the onset of cellularity (even when the flame is larger than the 40 mm diameter windows) so that we can avoid using data that violates our smooth flame front assumption. This builds on earlier work at Oxford over 16 years that has led to 3 innovations:+ Free-fall experiments to eliminate the effect of buoyancy.+ A multi-zone combustion model for data analysis, so that the effect of dissociation and the temperature gradient in the burned gas (typically 500 K) is incorporated into the analysis of flame front position and pressure rise.+ The use of 'real residuals' by retaining part of the previous combustion event as residuals, as opposed to the conventional approach of using a fixed composition N2/CO2 mixture to represent the residuals.Our facility has a comprehensive LabView interface for setting-up the experimental conditions and data logging. This system also ensures that condensation of either fuel or water vapour (in the residuals or as a diluent) is avoided. A schlieren system with a high speed video camera records early flame growth and cellularity (the departure from a smooth flame front, if it occurs). The experimental data are analysed by MATLAB routines that incorporate: image processing (of the schlieren system data), a multi-zone combustion model, and experimental pressure data; the code also combines data from multiple experiments in order to generate correlations for the laminar burning velocity. Initial conditions can be up to 450 K and 4 bar (final pressure limit of 35 bar), with combustion data obtained up to 30 bar and an unburned gas temperature of 650 K. Liquid fuels (or diluents such as water) can be added by a Hamilton precision glass syringe which is controlled by a syringe actuator. This facility and software are readily adaptable for testing different fuels.The combustion of fuels from renewable sources and their performance when combined with conventional fuels is very important. In 2008 the UK crude oil consumption was 78.7 Mt (~20% gasoline) - BP Statistical Review of World Energy; June 2009. EU legislation requires bio-fuel to become a minimum 5.75% of the total fuel consumption in 2010. Gasoline vehicles can mostly operate on a 10% ethanol 90% gasoline (E10) blend with no adverse effects. But, to exploit the potentially higher octane rating of E10 and its different combustion in engines, laminar burning velocity data for ethanol and its mixtures are needed. Ethanol is mostly simply made from the fermentation of sugars, but competition with food use means that second generation or cellulosic-ethanol needs to be exploited. Ethanol has been produced from cellulose for over 100 years, but there is now a rapid increase in the commercialisation of the process (http://en.wikipedia.org/wiki/Cellulosic_ethanol). Gaseous fuels from renewable sources depend on the processing route. The anaerobic digestion of waste (by mesophilic bacteria) produces biogas (which is 60-70%CH4, and 40-30%CO2), whilst pyrolysis of waste or biomass produces syngas (a partial oxidation process that gives typically 40% CO, 25% H2, 20% H2O, 15% CO2).

层流燃烧速度的测量是必要的模型，帮助开发清洁和有效的燃烧在发动机，锅炉和熔炉，并验证层流燃烧速度模型。我们的层流燃烧速度的测量是在一个球形容器与中心点火，使一个球形火焰前锋的形成和传播径向。在燃烧过程中，压力上升，火焰前缘之前的未燃烧气体被等熵压缩。因此，从一个单一的实验，层流燃烧速度的数据得到了一系列的链接的温度和压力。通过改变初始温度和压力，可以解耦压力和温度的影响，并生成温度和压力对层流燃烧速度的影响的关联式。纹影系统可以检测到细胞的开始（即使当火焰大于40 mm直径的窗口），这样我们就可以避免使用违反我们的平滑火焰前锋假设的数据。这建立在牛津大学16年来的早期工作的基础上，导致了3项创新：+自由落体实验，以消除浮力的影响。用于数据分析的多区燃烧模型，因此燃烧气体中的分解效应和温度梯度（通常为500 K）被纳入火焰前沿位置和压力上升的分析中。+使用“真实的残留物”，将之前燃烧事件的一部分保留为残留物，而不是使用固定成分的N2/CO2混合物来表示残留物的传统方法。我们的设备具有全面的LabView界面，用于设置实验条件和数据记录。该系统还确保避免燃料或水蒸气（残留物中或作为稀释剂）的冷凝。带有高速摄像机的纹影系统记录了早期火焰生长和细胞结构（如果发生，则偏离平滑的火焰前缘）。实验数据进行分析MATLAB例程，其中包括：图像处理（纹影系统数据），多区燃烧模型，和实验压力数据;代码还结合了多个实验的数据，以生成相关的层流燃烧速度。初始条件可高达450 K和4 bar（最终压力极限为35 bar），燃烧数据可高达30 bar，未燃烧气体温度为650 K。液体燃料（或稀释剂如水）可以通过由注射器致动器控制的汉密尔顿精密玻璃注射器添加。该设备和软件可随时适用于测试不同的燃料。可再生能源燃料的燃烧及其与传统燃料混合时的性能非常重要。2008年，英国原油消费量为7870万吨（约20%为汽油）-《BP世界能源统计评论》; 2009年6月。欧盟立法要求生物燃料在2010年至少占总燃料消耗量的5.75%。汽油车大多可以使用10%乙醇90%汽油（E10）混合物，没有不利影响。但是，为了利用E10潜在的更高辛烷值及其在发动机中的不同燃烧，需要乙醇及其混合物的层流燃烧速度数据。乙醇主要是由糖发酵而成，但与食品用途的竞争意味着需要开发第二代或纤维素乙醇。从纤维素生产乙醇已经有100多年的历史，但是现在该方法的商业化正在迅速增加（http：//en.wikipedia.org/wiki/Cellulosic_ethanol）。来自可再生资源的气体燃料取决于加工路线。废物的厌氧消化（通过嗜温细菌）产生沼气（其为60-70%CH4和40-30%CO2），而废物或生物质的热解产生合成气（部分氧化过程，通常产生40%CO，25%H2，20%H2O，15%CO2）。

项目成果

Constant Volume Measurements of Laminar Burning Velocity ? Comparison between Constant Pressure and Pressure-Rise Measurements

层流燃烧速度的恒定体积测量？

• 作者: Nathan Hinton (Author)

Aqueous ethanol laminar burning velocity measurements using constant volume bomb methods

• DOI: 10.1016/j.fuel.2017.10.113
• 发表时间: 2018-02-15
• 期刊: FUEL
• 影响因子: 7.4
• 作者: Hinton, N.;Stone, R.;Olm, Carsten
• 通讯作者: Olm, Carsten

Laminar burning velocity measurements in constant volume vessels - Reconciliation of flame front imaging and pressure rise methods

• DOI: 10.1016/j.fuel.2017.09.031
• 发表时间: 2018-01-01
• 期刊: FUEL
• 影响因子: 7.4
• 作者: Hinton, Nathan;Stone, Richard;Cracknell, Roger
• 通讯作者: Cracknell, Roger