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Alternative Fuel Sources
Published in Michael Frank Hordeski, Hydrogen & Fuel Cells: Advances in Transportation and Power, 2020
Liquid hydrogen as a method for storing and transporting hydrogen can have several advantages over gases. The liquid form has a higher energy density and is easier to transport and handle. At atmospheric pressures, hydrogen is a liquid at −253°C (−423°F), which is only a few degrees above absolute zero. It must be stored in highly insulated tanks. Liquid hydrogen is a cryogenic fuel. Cryogenics is the study of low temperature physics. A beaker of liquid hydrogen at room temperature will boil as if it was on a hot stove. If the beaker of liquid hydrogen is spilled on the floor, it is vaporized and dissipates in a few seconds. If liquid hydrogen is poured on the hand, it would feel cool to the touch as it slides through the fingers. This is due to the thermal barrier that is provided by the skin. But, place a finger in a vessel containing liquid hydrogen and severe injury will occur in seconds because of the extremely cold temperature. In most accidents, the most serious concern would be a fuel fed fire or explosion. In this case, liquid hydrogen is generally considered to be a preferred fuel.
The Hydrogen Economy
Published in Michael Frank Hordeski, Alternative Fuels—The Future of Hydrogen, 2020
When hydrogen gas is liquefied, it needs to be cooled to −421.6° Fahrenheit, making liquid hydrogen a cryogenic fuel. Cryogenics is the study of low-temperature physics. A beaker of liquid hydrogen at room temperature will boil as if it was on a hot stove. If the beaker of liquid hydrogen is spilled on the floor, it is vaporized and dissipates in a few seconds. If liquid hydrogen is poured on the hand, it would feel cool to the touch as it slides through the fingers. This is due to the thermal barrier that is provided by the skin. But, place a finger in a vessel containing liquid hydrogen and severe injury will occur in seconds because of the extreme cold. This hydrogen fuel on board a vehicle would allow the use of a small, efficient fuel cell Stirling engine cryocooler system to provide air conditioning.
Research progress of lossless and safe storage technology for cryogenic liquid tanks
Published in International Journal of Green Energy, 2022
However, large/different structure civil cryogenic fuel storage tanks represented by LNG and LH2 have been widely used. The size, capacity and structure of existing storage tanks are quite different from traditional cryogenic storage tanks. In particular, LH2 is an extremely cryogenic liquid with extremely low latent heat of vaporization. This makes the two-phase flow and heat and mass transfer in large cryogenic storage tanks more severe and complex than traditional small storage tanks or large LNG storage tanks. The prediction error of lossless storage time by using existing calculation models is larger. Therefore, with the advent of hydrogen energy era, scholars need to focus on the stratification, rollover and self-pressurization of extremely cryogenic fuel tanks in complex storage and transportation environment. Through these studies, scholars need to obtain the law of gas-liquid two-phase flow, heat transfer and evaporation with storage and transportation time. On this basis, scholars should find a suitable model to predict the safe time of lossless storage and transportation so as to obtain an accurate prediction method of the lossless storage time. These studies are of great importance to the engineering community.
Investigation on thermo-mechanical performances of friction stir welding of aluminum alloys (AA6063)
Published in Welding International, 2022
Jogendra Kumar, Prasenjit Patra, Arpan Kumar Mondal, Rajesh Kumar Verma
The surface finish is better compared to other welding processes. It is widely used to manufacture rocket fuel tanks, civil aviation equipment, aerospace industry (wings), fuselages, cryogenic fuel tanks for space rockets, and military aircraft. The shipbuilder industry includes panels for decks floor, hulls and superstructure, helipads, and offshore accommodation structures. Automotive engine components, chassis, wheel rims, hydroformed tubes, tail lift for lorries, fuel tankers, motorcycles, and cycle frames [28–30]. Both metallic and non-metallic substances like plastic and multiple polymers can be welded using FSW [5]. After welding, the surface finish is much better than the traditional welding process. During welding, heat is generated by the effect of friction interfaces of the tool shoulder and the workpiece. It has been reported that the following equation is used for estimation of the frictional heat flow [31]:
Significance of fluid flow characteristics in the hydrogen-fuelled scramjet combustor using flame stabilisation analysis
Published in Australian Journal of Mechanical Engineering, 2021
The important prerequisite in this contemporary period of fossil energy is to reduce the exhaust gases without undergoing complex exhaust gas treatment phenomena. Compared to all other hydrocarbon fuels, hydrogen is the most energised and suitable alternate fuel for the range of 4–10 Mach number. In the mid nineteenth century, NASA had designed, fabricated and analysed the cooled scramjet engine with hydrogen as the fuel that demonstrated the thermal efficiency, structural integrity, engine system integration etc. (Voland et.al. 2006). It was also reported that the hydrogen can also be used as a cryogenic fuel to provide combustion chamber cooling (AlGarni 1996; Donohue et.al 1994; Cui, Yu, and Bao 2008; Amati et.al 2008). The other characteristics of Hydrogen fuel include rapid atomisation and vaporisation, faster dissipation rate. This account to the safety of passengers and crew members in case of hypersonic vehicle crushes (Halupovich et al. 1999; Rainey and Veziroglu 1992). The specific impulse of the hydrogen-fuelled scramjet engines is more when compared with other Hydro-carbon-fuelled engine having similar Mach number. Thereby, hydrogen is considered as the most important fuel for the future hypersonic vehicles. This enhanced thermal efficiency drawn the attention of researchers working in the similar domain (Cockrell et al. 2002; Moses et al. 2004).