Optimisation of hydrogen and/or Ammonia based fuel utilisation in Gas Turbines

遵循欧洲绿色协议设定的目标，以及英国承诺到2035年完全由清洁能源供电的承诺，碳中和以及如何实现这一目标的话题已成为许多政治议程的中心议题。2021年，发电量约占英国温室气体(GHG)总排放量的20%，成为第二大单一来源。因此，如果要实现雄心勃勃的净零目标，该行业的脱碳至关重要。在过去的十年里，氢作为零碳能源载体的应用引起了人们的极大兴趣。然而，氢的燃烧行为与传统化石燃料非常不同。氢的反应特性意味着较低的火焰稳定性、较高的NOx排放、极大地改变热声行为以及增加闪回和自燃的风险，因此使得在当前的稀薄预混(DLE)系统中利用高比例的氢非常具有挑战性。原始设备制造商正在投入大量的研发资源来开发氢气燃烧能力高达100%的DLE系统。受到特别关注的主要部件之一是燃气轮机燃烧室及其辅助部件。旋流器湿表面的粗糙度会影响轴向速度、热释放、NOx排放和操作极限。因此，应从设计阶段一直到制造和后处理仔细考虑表面粗糙度。考虑到氢的回闪风险增加，了解粗糙度对边界层闪回(BLF)的影响是最重要的。学生进行的研究将集中在对粗糙度影响的数值模拟上。为了更好地了解粗糙度引起的流场变化(速度剖面、旋涡数、回流区的变化)，模拟将与等温流的实验反应进行验证。还将进行粗糙度对氢气火焰影响的实验工作。这些发现将能够告知原始设备制造商AM部件的天气表面处理，如抛光或人为增加粗糙度，以改善透平机械部件的性能，特别是在BLF、排放和火焰稳定性方面。

Following the goals set by the European Green Deal and the UK's commitment to be powered entirely by clean energy by 2035, the topic of carbon neutrality and how to reach it has found centre stage in many political agendas. In 2021, electricity generation accounted for ~20% of total UK greenhouse gas (GHG) emissions making it the second largest single source. Decarbonising this sector is therefore vitally important if the ambitious net-zero goals are to be met. The use of hydrogen as a zero-carbon energy vector has gained significant interest in the past decade. The combustion behaviour of hydrogen is however very different to that of conventional fossil fuels. Hydrogen's reactive characteristics imply lower flame stability, higher NOx emissions, greatly modified thermoacoustic behaviours and enhanced risks of flashback and auto-ignition and therefore makes utilising high percentages of hydrogen in current lean premixed (DLE) systems very challenging. OEMs are investing significant R&D resources into the development of DLE systems capable of hydrogen-firing up to 100%. One of the main components receiving particular attention being gas turbine combustors and their auxiliary parts. The roughness of swirler wetted surfaces can affect axial velocities, heat release, NOx emissions and operability limits. Surface roughness should therefore be considered carefully starting from the design stage all the way through to manufacturing and post processing. Understanding the effect of roughness on boundary layer flashback (BLF) is of prime interest given hydrogen's increased risk of flashback.Research carried out by the student will focus on numerically modelling roughness effects. Simulations will be validated against experimental reacting an isothermal flow with the aim of better understanding roughness induced changes on the flow field (changes in velocity profiles, Swirl number, recirculation zones). Experimental work on the effect of roughness on H2 flames will also be performed. Findings will be able to inform OEMs on weather surface treatments of AM parts, such as polishing or artificially increasing roughness, are needed in turbomachinery components to improve performance particularly with regards to BLF, emissions and flame stability.