Single droplet ignition and combustion of jet-A1, hydroprocessed vegetable oil and their blends in a drop tube furnace

• Autor(a) principal: Pacheco, Gonçalo de Sousa Pina Pernicha
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/10388
• topic: Combustão; Gota Isolada; Hvo; Ignição; Jet Fuel; Micro Explosão; Misturas; Puffing; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

The environmental impact and the dependence of fossil fuels in the aeronautical sector have promoted the demand for alternative and greener fuels. This is one of the main challenges for this sector in the near future. A possible solution in the near future might be the blending of biofuels with jet fuel, which would allow the use of greener fuels, and a reduction in the greenhouse gases and emissions without significant changes in the existing fleets of the companies, which means the development of a “drop in” fuel. In this context, this work examines the ignition and the combustion characteristics of single droplets of jet-A1 (JF), hydroprocessed vegetable oil (NExBTL) and their mixtures in a drop tube furnace (DTF). The objective of this work is to evaluate the influence of the fuel mixture composition on the fuel characteristics. Droplets with diameters of 155 ± 5 µm, produced by a commercial droplet generator, were injected into the DTF, whose wall temperature and oxygen concentration were controlled. Experiments were conducted for three temperatures (900, 1000 and 1100 ºC). The ignition and combustion of the droplets were evaluated through the images obtained with a high-speed camera coupled with a high magnification lens, and an edge detection algorithm. The images allowed for the observation of the burning phenomena, and data are reported for temporal evolution of droplet sizes and burning rates. The results revealed that the fuel mixtures followed the ?? 2 law, except the mixture with 75% JF for a DTF wall temperature of 1100 ºC. This was due to the occurrence of puffing and micro explosions, which enhanced the burning rates. In addition, it was observed that the mixtures with a higher content of JF present brighter flames, and higher burning rates.