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Subsonic Transport Aircraft
Published in G. Daniel Brewer, Hydrogen Aircraft Technology, 2017
Aircraft fuel systems include all the fuel-oriented systems which connect with either the fuel containment system or the engines. These systems, illustrated schematically in the diagram of Figure 4–39, consist of engine fuel supply, fueling/defueling, fuel cross-feed and transfer, pressurization/venting, and jettisoning. In purpose and basic function these systems for LH2-fueled aircraft are identical with those of conventionally fueled aircraft, viz., to supply fuel according to a specified flow/pressure schedule to the engines. In details, however, there are significant differences.
Experimental investigation of fuel properties and engine operation with natural and synthetic antioxidants added to biodiesel
Published in Biofuels, 2023
Gediz Uğuz, Abdülvahap Çakmak, Carlos da Silva Bento, Nalan Türköz Karakullukçu
Biodiesel comprises large quantities of unsaturated fatty acid methyl esters. This state faciliates vulnerable phenomena such as autoxidation for biodiesel [18] which decreases the storage life of fuels and negatively affects them. Also, oxidation products (e.g. aldehydes, organic acids, alkanes, ketones and various polymers) can form easily. These products cause challenges such as corrosion of the fuel system components (including the fuel tank, pump, filter, fuel line and injectors), injector blockages, and filtration problems [19]. Furthermore, autoxidation of biodiesel can adversely affect fuel properties, especially its viscosity and acid value [20]. For this reason, the determination and improvement of the oxidation stability of biodiesel are important for storage and engine efficiency [21]. Oxidation stability is one of the principal factors used in biodiesel quality control. Antioxidants are specific chemicals that inhibit the oxidation process. Although it is impossible to completely stop biodiesel degradation due to autoxidation, it can be substantially slowed by adding antioxidants [22].
Pressure Control of High Pressure Tubing Based on Fluid Mechanics
Published in IETE Journal of Research, 2023
Yuhong Tao, Zhixin Wang, Shengang Cai, Zhile Xia
In the high-pressure fuel system, the fuel goes in and out of the oil pipe intermittently through the high-pressure oil pump. This intermittent working process will cause the pressure inside the high-pressure oil pipe to produce violent shock, which will seriously affect the working efficiency of the engine. Therefore, it is of great practical significance to study pressure control in high pressure tubing.
Advanced abrasive-based nano-finishing processes: challenges, principles and recent applications
Published in Materials and Manufacturing Processes, 2022
Manjesh Kumar, Anupam Alok, Vikash Kumar, Manas Das
To deal with these problems, a magnetorheological polishing fluid (MRPF) was created to finish different materials, varying from ceramics to the toughest metals.[29] MRPFs are mediums that react to an external magnetic field with a drastic rheological behavior shift.[30–32] An MR fluid is actually a freely streaming liquid without a magnetic field, but its viscosity could be enhanced by two times in a relatively small amount of timespan (milliseconds) and displays solid-like properties.[33,34] Shear yield stress may characterize a fluid’s strength. Furthermore, the viscosity shift is gradual and flexible, i.e. post extracting the magnetic field, the MRPF will reverse back to a free streaming media. Utilizing these MR fluid properties, MRPF instruments have silent and fast-response interactions between electronic controllers and mechanical devices[35–37]. Therefore, researchers and industrialists showed great attention to MRPFs and their uses. MRP fluid science is now an essential element of smart materials. Traditional MRP fluids are non-colloidal collections of a few microns with magnetizable particles in low-permeability liquids.[38,39] MR fluid devices include composite structures, hydraulic valves, brakes, seals, clutches, dampers, polishing devices[40] (for polishing specimens like balls of bearing, micro-channel, bearing, tube, barrel, capillary tube, micro/macro gear, biomedical implant, injector nozzle, mold, rail fuel system, pump rotor, micro-hole and optics) and tactile sensor.[41,42] The various kinds of advanced polishing methods have been established by various authors, including MR finishing,[29] MR jet polishing,[43] and MR abrasive flow finishing,[44] where forces are produced throughout the polishing procedure could be conveniently manipulated. Initially, most experiments and advance practices are focused on electro-rheological (ER) fluids, which are located simultaneously with MR fluids. While ER fluids suggest enormous possibilities in several ways, however, they include the aforementioned drawbacks: relatively lower yield strength, vulnerability to particular constituents (e.g. water), large electrical demand, fairly small operating temperature length. MRPFs yield strength is higher than ER fluids, having tolerance capacity to particular constituents, use the lesser power supply, comparatively broad operating temperature length. MRPFs have been extensively used in engineering fields, including automotive, gym instruments, aircraft and polishing devices in recent years.