“…However, amorphous boron molecules do not appear as a reticular structure in SEM images. 34 Therefore, it can be basically confirmed that reticular structures in the deposition sample are boron carbide.Figure 16.SEM micrographs of the deposition sample on the injector panel. (a) Low-magnification micrograph of the sample, (b) high-magnification micrograph of the sample.…”
Section: Experimental Eesults and Discussionmentioning
confidence: 75%
“…However, amorphous boron molecules do not appear as a reticular structure in SEM images. 34 Therefore, it can be basically confirmed that reticular structures in the deposition sample are boron carbide.…”
Section: Microanalysis Of Boron Nanoparticles Combustion Behaviormentioning
Nano-sized energetic particle as fuel additives is of great significance for liquid hydrocarbon fuels that will exhibit high-density and high-calorific value in high-speed propulsion systems. An experimental investigation has been conducted to determine the propulsive and combustion behavior of hydrocarbon fuels containing boron nanoparticles. In this study, nano-sized boron particles with average diameter of 20 nm are added into the basic fuel JP-10 and quadricyclane, respectively. They are then referred as slurry fuels and burned in the rocket combustor using pure oxygen as the oxidizer. With a wide range of excess oxidizer coefficients, three parameters characterizing the propulsion performance are employed to evaluate the effect of boron nanoparticles on hydrocarbon fuels. It is found that the boron-based slurry fuel showed superior density specific impulse. It is increased by 1.18% and 1.44% when the addition of boron particles with 10% mass fraction are added into the basic fuel JP-10 and quadricyclane, respectively. Combustion depositions of the boron-based slurry fuel located at different positions are then collected for deep analysis by means of the energy dispersive spectrometer, X-ray diffractometer, and scanning electron microscope. Comprehensive microanalysis results demonstrate that boron particles first combine with the C-element in the hydrocarbon fuel to form the boron carbide with a reticular structure, and then the boron carbide oxidizes to form block-shaped boron oxide. However, the surface boron oxide hindered the further reaction of the internal boron carbide, which limits the energy release of the boron particles and ultimately leads to the unsatisfactory combustion efficiency of the slurry fuel.
“…However, amorphous boron molecules do not appear as a reticular structure in SEM images. 34 Therefore, it can be basically confirmed that reticular structures in the deposition sample are boron carbide.Figure 16.SEM micrographs of the deposition sample on the injector panel. (a) Low-magnification micrograph of the sample, (b) high-magnification micrograph of the sample.…”
Section: Experimental Eesults and Discussionmentioning
confidence: 75%
“…However, amorphous boron molecules do not appear as a reticular structure in SEM images. 34 Therefore, it can be basically confirmed that reticular structures in the deposition sample are boron carbide.…”
Section: Microanalysis Of Boron Nanoparticles Combustion Behaviormentioning
Nano-sized energetic particle as fuel additives is of great significance for liquid hydrocarbon fuels that will exhibit high-density and high-calorific value in high-speed propulsion systems. An experimental investigation has been conducted to determine the propulsive and combustion behavior of hydrocarbon fuels containing boron nanoparticles. In this study, nano-sized boron particles with average diameter of 20 nm are added into the basic fuel JP-10 and quadricyclane, respectively. They are then referred as slurry fuels and burned in the rocket combustor using pure oxygen as the oxidizer. With a wide range of excess oxidizer coefficients, three parameters characterizing the propulsion performance are employed to evaluate the effect of boron nanoparticles on hydrocarbon fuels. It is found that the boron-based slurry fuel showed superior density specific impulse. It is increased by 1.18% and 1.44% when the addition of boron particles with 10% mass fraction are added into the basic fuel JP-10 and quadricyclane, respectively. Combustion depositions of the boron-based slurry fuel located at different positions are then collected for deep analysis by means of the energy dispersive spectrometer, X-ray diffractometer, and scanning electron microscope. Comprehensive microanalysis results demonstrate that boron particles first combine with the C-element in the hydrocarbon fuel to form the boron carbide with a reticular structure, and then the boron carbide oxidizes to form block-shaped boron oxide. However, the surface boron oxide hindered the further reaction of the internal boron carbide, which limits the energy release of the boron particles and ultimately leads to the unsatisfactory combustion efficiency of the slurry fuel.
“…They reported a smooth burning of droplets for dilute suspension, while for the case of dense suspension, the liquid fuel was consumed first, and then the particles burned toward the end as a large agglomerate. More comprehensive results on the burning behavior of boron nanofuel droplets have been reported by Ojha et al 16,19,21 They studied the effect of morphology, 19 silane capping, 21 particle size, 16 and metal decoration on the burning behavior of boron-laden nanofuel droplets. 23 The results reported from the droplet combustion studies of boron-laden slurry/nanofuel are very encouraging due to multifold analysis by several researchers.…”
Section: Introductionmentioning
confidence: 93%
“…10 The studies on the ignition and combustion of single boron particles 11,12 dust clouds of boron injected into the post-flame region 13,14 and boron-loaded liquid fuel droplets have appeared in the open literature. 15,16 The initial studies performed to evaluate the combustion characteristics of boron loaded in liquid fuel were mainly through droplet combustion, where droplets were suspended on a single fiber. 8,11,17,18 A wide range of data has been reported on the effect of particle size, 19 solid particle loading, 18,20 and surfactant concentration 21 on the burning characteristics of slurry fuel droplets.…”
The characterization of atomized spray in terms of its structure, break-up, and droplet morphology is crucial to analyze an engine's performance. Therefore, in this study, the spray characteristics of boron-laden slurry fuels have been evaluated experimentally through a high-speed imaging technique. The rheological properties of the boron-loaded slurry fuels have been measured and their impact on the atomization behavior has been qualitatively analyzed. The spray cone angle, penetration length, sheet break-up length, ligament length, ligament diameter, and droplet diameter distribution are obtained by processing the time-sequences images. The experiments were performed at three atomizing air-to-liquid ratios (ALR). Spray characteristics of the fuel samples with various particle loadings (10%, 20%, and 30%) have been analyzed and compared with that of the pure Jet A-1. The obtained results were qualitatively analyzed with different non-dimensional parameters, such as Momentum flux ratio, Weber number, Ohensorge number, and Reynolds number. The results show that an increase in viscosity due to particle loading significantly affects the spray characteristics. However, a better atomization behavior of boron slurry fuel at higher ALR than low ALR, even with higher particle loading, has been observed. This is possibly due to the change in momentum flux ratio at higher atomizing air velocity.
“…The available volumetric fuel storage in any air-breathing propulsion system is limited. The production of high-density and high-energy-density hydrocarbon fuels offers certain advantages over currently available petroleum-based fuels [2].…”
Experiments of high temperature pyrolysis and soot formation analysis on JP-10, one of the representatives of fuels, were conducted in order to analyze its properties and help construct its chemical kinetic mechanism. High-temperature pyrolysis and fuel-rich oxidation experiments were carried out on JP-10 fuel under different conditions using two types of shock tube equipment (SPST and HPST). The pyrolysis experiments were carried out in two working conditions with JP-10 concentrations of 200 ppm and 500 ppm (in Ar). Quantitative analyses of JP-10 pyrolysis products were carried out using gas chromatography, and a total of eight small molecule products below C4 were detected. Among these eight products, methane, ethene, and acetylene were the three main products. In the fuel-rich oxidation experiments for soot formation analysis, a total of nine working conditions were designed, but soot formation was detected only under three of them. The soot induction delay time and soot yield of JP-10 were investigated using laser absorption measurement. The SYmax (the maximum amount of soot yield) and other relevant parameters were investigated under these three different working conditions. At a pressure of 3 bar and a temperature of 1884.10 K, the soot yield reached a maximum of 14.3. In addition to practical insights from these data, they were also useful for the construction and validation of the chemical kinetic mechanism of JP-10.
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