Browsing by Author "Ugbeh, Judith"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Open Access Assessment of HEFA, ATJ, GTL-S8 and Farnesane as alternative jet fuels based on their water shedding characteristics(Cranfield University, 2022-06-24 10:09) Ugbeh, JudithPrevious studies have shown that impurities like surfactants in jet fuel have impacted the performance of coalescer filters. Therefore, aircraft maintenance schedules require an additional operation which is commonly known as water sumping. Normally after bulk fuel transfers, fuels are allowed to settle in tanks and sumping is carried out to remove free water. Water settling tests can indirectly measure surfactants in jet fuels, yet there is no reliable data that focuses on the water settling rate of alternative jet fuels that comply with or are very similar to the Jet A-1 specification. Additionally, the influence of the jet fuel composition on the rate of water-shedding is still unknown. Therefore, there is a need for a reliable study to fill this lack of knowledge. In this work, the water settling rate of five different jet fuels made to different national standards in comparison to conventional Jet A-1 fuel was evaluated. GTL S-8, HEFA and ATJ has been identified as potential/alternative candidates for ASTM D7566 certified jet fuels.Item Open Access Characterization of water droplets size distribution in aviation turbine fuel: Ultrasonic homogeniser vs. High shear speed mixer(Cranfield University, 2022-06-24 10:10) Ugbeh, JudithPumps, pressure drops across fittings, and flight operations (such as turning manoeuvres, take-off, and landing) are some of the many sources of turbulence mixing and shearing in aircraft fuel systems, therefore, making it an inevitable condition. Literature established that shearing conditions would influence the droplets and droplets size distribution in oil/water emulsion. So, low intensity shearing conditions could be beneficial as it promotes droplet coalescence, which could be a driving force for a weak emulsion. However, to date no experimental data shows the influence homogenising intensity and total water content has on dispersed water droplet size distribution (DSD) in aviation fuel. Therefore, to expand knowledge of improving quantification to the measurements of dispersed water droplets in aviation fuel, this study characterizes dispersed water droplets in aviation turbine fuel, varying available laboratory homogenising gadget and water content. Results presented shows that droplet count increases with water concentration and shearing effect. To provide more statistical evidence, kurtosis and skew values was calculated from the extrapolated data and compared with data from a hexanol/water mixture given that hexanol is likely to form a stable emulsion. Experimental results shows that the higher the homogenising intensity the more stable the emulsion is likely to be with a higher kurtosis and skew value close to that for the hexanol/water mixture.Item Open Access Effects of particulate contamination and jet fuel chemistry on the nucleation of water and ice in aircraft fuel systems(Cranfield University, 2018-11-27 10:51) Ugbeh, Judith3MT presented at the 2018 Defence and Security Doctoral Symposium.The contamination and behaviour of water in aircraft fuel systems remains a significant area of global research interest following several aircraft incidents. Water and particulates in fuel may lead to ice formation. The resulting ice formed may eventually block the fuel filters and feed pipes creating safety problems.In order to engineer a lasting solution to the problem of ice in jet fuel it is important to identify precisely the conditions and features that may exacerbate this phenomenon.This work will give a detailed account of the recent advances and technologies in the literature indicating conditions that might lead to the nucleation of water and ice in aircraft fuel systems. It will develop awareness of the key complexities associated with jet fuel chemistry. Furthermore, the work identifies the significant knowledge gaps that exist in the literature highlighting routes to be investigated for future research.Item Open Access Investigation of Water Droplet Size Distribution in Conventional and Sustainable Aviation Turbine Fuels(Cranfield University, 2022-06-24 10:13) Ugbeh, Judith; Carpenter, Mark; Okeke, NonsoWater droplet size variation has been established in the literature as an important variable that influences the behaviour and characteristics of water in fuel emulsion. However, with the growing demand for sustainable aviation fuels (SAF), no data is available that shows how these fuels will affect dispersed water droplets’ size and frequency distribution. To address this lack of knowledge, this study explores and presents experimental results on the characterization of dispersed water droplets in alternative fuel and conventional Jet A-1 fuel under dynamic conditions. The alternative fuels comprised of two fully synthetic fuels, two fuels synthesised from bio-derived materials and one bio-derived fuel. The data and statistics presented reveal that water droplet frequency and size distribution are sensitive to changes in fuel composition. Observations show that the evident transition of the droplet’s percentile over time in the cumulative frequency distribution could be attributed to droplets coalescence to form larger droplets. Mean droplet diameters between 3 and 6 µm were observed for all the fuels tested. With further analysis based on recommendations proposed in this work, the data may assist in providing insight to filter manufacturers.Item Open Access The impact of sustainable aviation fuels on aircraft fuel line ice formation and pump performance(Cranfield University, 2023-02-01 10:51) Ugbeh, Judith; Carpenter, MarkA recirculating fuel test rig capable of cooling fuel from ambient to -30 °C within 4 hours was built by Airbus to simulate conditions in an aircraft wing tank and allow characterisation of ice accretion. The key characteristic was the pressure drop across an inline fuel strainer for the different SAF explored but visual analysis of ice accretion on the strainer mesh (filters used in protecting fuel feed pumps) was also performed for individual experimental runs for comparison. Measurements revealed that 100% conventional fuel exhibited a higher propensity to strainer blockage compared to the SAF tested. However, all SAF blends behaved differently as the blending ratio with Jet A-1 fuel had an impact on the pressure differential at different temperatures. Data from this work are essential to establish confidence in the safe operation of future aircraft fuel systems that will potentially be compatible with 100 % SAF.