Environmental effects on the mechanical properties of E-glass and S-glass fiber epoxy composite ring specimens used in aircraft fuel pipes

An experimental investigation was performed in predicting the consequences of the exposure to seawater and moisture absorption on the mechanical properties of two different GFRE pipe rings made of E-glass and S-glass fiber and utilized in aircraft fuel pipe line system. Filament winded tubular composite pipe rings were immersed in seawater for two, four and six months, respectively and their moisture absorption was noted. The outcomes exhibit a remarkable decrease in fatigue life for saturated GFRE sample rings. In contrast, a water absorption up to 40% of the maximum content exhibited no impact. The tests revealed debonding and cracks in the fiber and matrix interphase in the case of samples immersed in seawater on a long-term basis, although the applied mechanical load was zero.

Aircraft Fuel Thermal Management System and Flight Thermal Endurance

An aircraft thermal management model was created in which fuel is circulated through the heat dissipating components for cooling purposes. A fraction of this fuel is then fed to the engine for combustion, while the excess is cooled by rejecting heat to the ambient and returned to the tank. The thermal management system was designed with the intent of controlling the heat dissipating surface temperature, ensuring a certain heat removal rate, while safeguarding the physical integrity of the fuel. The time variation of the fuel temperature and heat transfer rates was calculated. It was observed that for a constant heat dissipating surface temperature, the heated fuel temperature increased, and the heat removal capacity degraded over time. Conversely, for a specified heat removal rate, both the heat dissipating surface temperature and heated fuel temperature increased during the flight. Lastly, when the maximum fuel temperature was specified, both the heat dissipating surface temperature and heat removal rate decreased over time. In all cases, the time taken for these variables to hit the user-defined threshold values was recorded. A detailed sensitivity analysis was also presented highlighting the critical importance of the fuel recirculation rate on the performance of the thermal management system.

A Study on Sustainable Consumption of Fuel—An Estimation Method of Aircraft

Though the development of China’s civil aviation and the improvement of control ability have strengthened the safety operation and support ability effectively, the airlines are under the pressure of operation costs due to the increase of aircraft fuel price. With the development of optimization controlling methods in flight management systems, it becomes increasingly challenging to cut down flight fuel consumption by control the flight status of the aircraft. Therefore, the airlines both at home and abroad mainly rely on the accurate estimation of aircraft fuel to reduce fuel consumption, and further reduce its carbon emission. The airlines have to take various potential factors into consideration and load more fuel to cope with possible negative situation during the flight. Therefore, the fuel for emergency use is called PBCF (Performance-Based Contingency Fuel). The existing PBCF forecasting method used by China Airlines is not accurate, which fails to take into account various influencing factors. This paper aims to find a method that could predict PBCF more accurately than the existing methods for China Airlines.This paper takes China Eastern Airlines as an example. The experimental data of flight fuel of China Eastern Airlines Co, Ltd. were collected to find out the relevant parameters affecting the fuel consumption, which is followed by the establishment of the LSTM neural network through the parameters and collected data. Finally, through the established neural network model, the PBCF addition required by the airline with different influencing factors is output. It can be seen from the results that the all the four models are available for the accurate prediction of fuel consumption. The amount of data of A319 is much larger than that of A320 and A330, which leads to higher accuracy of the model trained by A319. The study contributes to the calculation methods in the fuel-saving project, and helps the practitioners to learn about a particular fuel calculation method. The study brought insights for practitioners to achieve the goal of low carbon emission and further contributed to their progress towards circular economy.

Characterisation of Microstructure and Mechanical Properties of Linear Friction Welded α+β Titanium Alloy to Nitinol

A variable area nozzle integrated into the design of a high-bypass-ratio turbofan engine effectively saves up to 10% in aircraft fuel consumption. Additionally, noise emissions can be lowered at airports during take-off and landing by having better control of the nozzle diameter. Shape memory capabilities of Nitinol alloys could be availed in the form of actuators in the construction of such a nozzle. However, these Nitinol actuators must be joined to Ti-6Al-4V, a prominent alloy making up most of the rest of the nozzle. Because of the huge differences in the physical and metallurgical properties of these alloys, fusion welding is not as effective as solid-state welding. In the current study, a linear friction welding process was adopted to join Ti-6Al-4V to Nitinol successfully. The effect of friction welding on the evolution of weld macro and microstructures; hardness and tensile properties were studied and discussed. The macrostructure of Ti-6Al-4V and Nitinol’s dissimilar joint revealed flash formation mainly on the Ti-6Al-4V side due to its reduced flow strength at high temperatures. Optical microstructures revealed fine grains in Ti-6Al-4V immediately adjacent to the interface due to dynamic recrystallisation and strain hardening effects. In contrast, Nitinol remained mostly unaffected. An intermetallic compound (Ti2Ni) was seen to have formed at the interface due to the extreme rubbing action, and these adversely influenced the tensile strength and elongation values of the joints.