New alternative jet fuels have provided many advantages in the aviation industry, especially in terms of economics and environment. However, fuel–seal compatibility is one of the major issues that restricts alternative fuel advancement into the market. Thus, to help understand and solve the problem, this study examines the swelling effect of prepared and non-prepared O-rings in different fuels and aromatic species. Stress relaxation experiments were carried out to evaluate seal compatibility under compression, which mimics engine operation conditions. Seals were compressed and immersed in a variety of fuels and their blends for about 90h while maintaining a constant temperature 30°C and constant compression force of 25% seal thickness. The two types of elastomers investigated were fluorosilicone and nitrile O-rings, which are predominantly used in the aviation industry. Meanwhile, three different fuels and aromatic species were utilised as the variables in the experiments. The fuels used were Jet-A1, SPK and SHJFCS, while the aromatic species added were propyl benzene, tetralin and p-xylene. The swelling effects were determined from the P/Po value. Results indicate that Jet-A1 has the highest swelling effect, followed by SHJFCS and SPK. It was observed that the higher the percentage of aromatics in fuel, the higher the rate of swelling. Furthermore, prepared seals had a lower swelling rate than did non-prepared seals. Meanwhile, the intensity of the swelling effect in the Jet-A1-SHJFCS blends was in the order of 60/40, 85/15 and 50/50 blend. The work done in this study will aid in the selection of suitable aromatic species in future fuels. The novelty of this research lies in the determination of the appropriate amount of aromatic content as well as the selection of type of aromatic and its mixture fuel. Moreover, the various proportions of fuel blends with aromatic are investigated. The primary aim of this study is to understand the behaviour of prepared and non-prepared seals, and their compatibility with alternative fuels.

中文翻译：

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燃料、芳烃和制备方法对密封膨胀的影响

新的替代喷气燃料为航空业提供了许多优势，特别是在经济和环境方面。然而，燃料密封兼容性是限制替代燃料进入市场的主要问题之一。因此，为了帮助理解和解决问题，本研究检验了制备和未制备的 O 形圈在不同燃料和芳烃中的膨胀效应。进行应力松弛实验以评估模拟发动机运行条件的压缩下的密封相容性。密封件被压缩并浸入各种燃料及其混合物中约 90 小时，同时保持 30°C 的恒温和 25% 密封厚度的恒定压缩力。研究的两种弹性体是氟硅橡胶和丁腈 O 形圈，主要用于航空工业。同时，三种不同的燃料和芳香物质被用作实验中的变量。使用的燃料是 Jet-A1、SPK 和 SHJFCS，而添加的芳烃物质是丙苯、四氢化萘和p-二甲苯。溶胀效果由 P/P 确定○价值。结果表明，Jet-A1 的溶胀效果最高，其次是 SHJFCS 和 SPK。据观察，燃料中芳烃的百分比越高，溶胀率越高。此外，制备的密封件比未制备的密封件具有更低的膨胀率。同时，Jet-A1-SHJFCS 共混物的溶胀效果强度依次为 60/40、85/15 和 50/50 共混物。本研究中所做的工作将有助于在未来的燃料中选择合适的芳烃种类。本研究的新颖之处在于芳烃含量适宜量的确定以及芳烃种类及其混合燃料的选择。此外，还研究了各种比例的芳烃混合燃料。本研究的主要目的是了解准备好的和未准备好的海豹的行为，