GOALI: Transient Jets and Re-Ignition for Energy Efficiency Gains from Confined Combustion

智力优势：可燃燃料-空气混合物可以被有意或无意地点燃，由邻近燃烧事件产生的热反应气体的瞬时喷射，一股烟。这种重燃现象与普通的电火花或压缩点火事件有很大的不同。重燃是否发生，以及多快发生，取决于以不同速率发生的物理和化学过程的复杂相互作用：泡芙涡旋旋转、混合和燃料分子氧化。初步实验结果与气体运动预测结果很好地吻合，但也表明，再点火延迟时间取决于燃料-空气比，这在某种程度上尚无法解释。该项目将使用计算、实验和分析方法来研究混合残余或再注入燃烧气体和新鲜混合物的瞬态射流的再点火，建立常见气体燃料的再点火延迟时间，并确定其对关键参数的敏感性。计算模型将用于预测静止射流和流动射流中的泡芙涡动力学和反应混合物温度。实验将通过使用压力传感器、可视化和光学诊断来验证涡旋动力学，并测量穿越和静止射流的重新点燃延迟时间。然后将开发一个简化的数学模型，以仔细地解开气体混合和化学过程，并更准确地预测重新点燃。在其他类型的燃烧中得到验证的燃料氧化理论将被测试是否适用于射流再点火。与该项目合作的公司的科学家不仅会指导项目本身，还会指导博士候选人将研究成果应用于该公司。广泛影响：该项目将使喷气点燃燃烧方法成为可能，旨在大幅减少各种发电厂的燃料消耗和温室气体排放。该项目的成功有可能改变自工业革命以来燃料消耗的许多方式。它直接导致了新的燃烧方法，在飞机和发电发动机中产生压力提升。通过改造或重新设计带有增压燃烧室的发电燃气轮机和飞机喷气发动机，美国每年可节省约100亿美元的燃料和1亿吨的二氧化碳排放。该项目将使用一种称为波转子燃烧器的装置帮助开发增压燃烧技术。这种颠覆性技术还可以使创新的中小型发电机以及更高效的混合动力汽车和便携式电源装置成为可能。此外，该项目还使使用内燃机的卡车和机车的点火更加可靠，从而可以用更便宜的国内天然气燃料替代从进口石油中提炼的柴油。来自小型预室的瞬态射流可以在减少氮氧化物排放和避免柴油烟雾的同时实现天然气的一致点火。这项研究的结果将立即用于同时进行但单独的波转子燃烧室实验，并将简化模型纳入工业可用的设计规范中。博士候选人将协助行业合作伙伴开发波浪转子燃烧器原型，其初始目标是将每个燃气轮机的燃料消耗，碳排放和重量减少约20%。

Intellectual Merit: Combustible fuel-air mixtures can be ignited, intentionally or not, by a transient jet, a puff, of hot reactive gas from an adjacent combustion event. This re-ignition phenomenon differs greatly from common electric spark or compression ignition events. Whether or not, and how quickly, re-ignition occurs depends on a complex interaction of physical and chemical processes occurring at different rates: puff vortex spinning, mixing and fuel molecule oxidation. Preliminary experiments show good agreement with gas motion predictions, but also indicate that re-ignition delay time depends on the fuel-air ratio in a way that is as yet unexplained. This project will use computational, experimental, and analytical approaches to investigate re-ignition by transient jets that mix residual or re-injected combustion gases and fresh mixtures, establish the re-ignition delay time for common gaseous fuels, and determine their sensitivities to key parameters. Computational models will be used to predict puff vortex dynamics and reacting mixture temperature in stationary and traversing jets. Experiments will verify vortex dynamics and measure re-ignition delay times for traversing and stationary jets through the use of pressure sensors, visualization, and optical diagnostics. A simplified mathematical model will then be developed to carefully disentangle the gas mixing and chemical processes, and more accurately predict re-ignition. Fuel oxidation theory validated in other types of combustion will be tested for applicability to jet re-ignition. Scientists at a company partnering in this project will not only guide the project itself, but also mentor a doctoral candidate in applying the research findings at the company.Broad Impacts: This project will enable jet-ignited combustion approaches aimed at dramatic reductions in fuel consumption and greenhouse gas emissions in a wide range of power plants. The success of this project has the potential to transform many of the ways in which fuel has been consumed since the Industrial Revolution. It leads directly to novel combustion methods that create a pressure boost in aircraft and electric power generation engines. By retrofitting or redesigning power generation gas turbines and aircraft jet engines with pressure-boost combustors, the United States can save an estimated $10 billion dollars in fuel and 100 megatons of CO2 emissions each year. The project will help develop pressure-boost combustion technology using a device called a wave rotor combustor. This disruptive technology can also enable innovative medium- and small-scale power generators as well as more efficient hybrid vehicles and portable power units. Additionally, the project enables more reliable ignition in trucks and locomotives using internal combustion engines, allowing the substitution of less expensive, domestic gas fuels for diesel refined from imported petroleum. Transient jets from small pre-chambers can accomplish consistent ignition of natural gas while reducing nitrogen oxide emissions and avoiding diesel smoke. The results of this research will be immediately utilized in concurrent but separate wave rotor combustor experiments, with simplified models being incorporated into design codes usable by industry. The doctoral candidate will assist the industry partner in the development of a wave rotor combustor prototype, the initial goal of which is reducing fuel consumption, carbon emissions, and the weight of gas turbines by about 20% each.