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Rocket kerosene plays an important role in the regenerative cooling process of rocket thrust chambers. Its thermal conductivity determines the cooling efficiency and the tendency to coke in rocket kerosene engines. In this paper, graphene nanoplatelets (GNPs) were introduced into rocket kerosene to improve its thermal conductivity. Molecular dynamics simulation was used to investigate the thermal conductivity of the composite system and its underlying thermal conductivity mechanism. Firstly, by studying the effect of the mass fraction of GNPs, it was found that, when the graphene mass fraction increases from 1.14% to 6.49%, the thermal conductivity of the composite system increases from 4.26% to 17.83%, which can be explained by the percolation theory. Secondly, the influence of the size of GNPs on the thermal conductivity of the composite system was studied. Basically, the thermal conductivity was found to increase by increasing the aspect ratio of GNPs, indicating that GNPs with a higher aspect ratio are more conducive to improving the thermal conductivity of rocket kerosene. By carefully analyzing the effect of the size of GNPs on thermal conductivity, it was concluded that the thermal conduction enhancement by adding GNPs is determined by the combined effect of the percolation theory and the Brownian motion. The results of the temperature effect study showed that the ratio of thermal conductivity to rocket kerosene increased from 1.16 to 1.26 and from 1.07 to 1.11 for the composite systems, with graphene sizes of 41.18 Å × 64.00 Å and 24.14 Å × 17.22 Å in the temperature range of 293 K to 343 K, respectively. It is further proved that the Brownian motion of GNPs has a non-negligible effect on the thermal conductivity of the composite system. This work provides microscopic insights into the thermal conduction mechanism of GNPs in nanofluids and will offer practical guidance for improving the thermal conductivity of rocket kerosene. [ABSTRACT FROM AUTHOR]

Adding drag reduction agent (DRA) to rocket kerosene is an effective way to reduce the pipeline resistance of rocket kerosene transportation systems. However, so far, there have been few research reports on the effect of DRA on the rheological properties of rocket kerosene solution, especially from a microscopic perspective. In this study, coarse-grained molecular dynamics simulations were conducted to investigate the rheological properties of rocket kerosene solutions with DRAs of different chain lengths and concentrations. The results showed that the viscosity of DRA—kerosene solution is generally higher than that of pure kerosene at a low shear rate, while with an increase in shear rate, the viscosity of DRA—kerosene solution decreases rapidly and finally tends to become similar to that of pure kerosene. The shear viscosity of DRA—kerosene solution increases with an increase in chain length and concentration of polymers. Through observing the morphologic change of DRA molecules and analyzing the radius of gyration and the mean-squared end-to-end distance of polymers, it was confirmed that the rheological properties of DRA—kerosene solutions are strongly related to the degree of entanglement of polymer chains. The simulation results provide microscopic insights into the rheological behavior of DRA—kerosene solutions and clarify the intrinsic relation between the morphologic change of polymer molecules and the rheological properties of DRA—kerosene solutions. [ABSTRACT FROM AUTHOR]

Fire hazard of liquid fuel exposed in oxygen-rich environment is significantly greater than that in air, which should be considered in the safety risk assessment of scenarios where oxygen and fuel coexist. To reveal the effect of oxygen concentration on fuel properties and combustion characteristics of liquid fuel, a series of experiments were conducted to measure the liquid-phase component, flash point, lower flammability limit, heat release rate and flame height of rocket kerosene at different oxygen concentrations. The results show that the flash point of rocket kerosene (with an average chemical formula of C 11.98 H 22.64) decreases nonlinearly with the increased oxygen concentrations, while the oxygen concentration has a great enhancement effect on the heat release rate and visible flame height of rocket kerosene pool fire. Prediction models of the flash point and lower flammability limit based on the Clausius-Clapeyron equation, Le Chatelier rule and decreasing temperature assumption, as well as empirical equations of the heat release rate and visible flame height, were derived for different oxygen concentrations in this work, providing a new comprehensive understanding of the effect of oxygen concentration on the rocket kerosene, and could be further applied to fire risk assessment in liquid fuel and oxygen coexisting scenarios. • The average chemical formula of rocket kerosene can be expressed as C 11.98 H 22.64. • Flash point of liquid fuels decreases with the increased oxygen concentrations. • Prediction model of flash point at different oxygen concentrations is derived. • Oxygen concentration has a great enhancement effect on the HRR and flame height. • Obtained equations can be used in risk analysis of fuel/O 2 coexisting scenarios. [ABSTRACT FROM AUTHOR]

A procedure for sensitive determination of rocket kerosene in water is described; it includes the dispersive liquid-liquid microextraction of analytes followed by their separation and determination by gas chromatography mass spectrometry in the mode of chromatogram registration against selected ions ( m/ z: 67, 81, 85, 95, 136, 137, 174, 183, and 193). The effect of the nature and volume of disperser and extraction solvents, salt additives, and the extraction duration on the efficiency of extraction of analytes is studied. The detectable concentration range is 0.005-0.05 mg/L. The detection limits ( S/ N = 3) of kerosene RG-1 and T-1 are 0.0015 and 0.0022 mg/L, respectively. The repeatability of the measurement results for the above range varies from 16 to 9% ( n = 3); the intermediate precision varies from 20 to 12% ( n = 5). [ABSTRACT FROM AUTHOR]

The components of rocket kerosene were determined by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCЧGC/TOFMS) under pre-defined analytical conditions. Qualitative analysis was performed by identification of the various groups of the compound on a structured chromatogram. Quantitative analysis was performed by estimating the areas of the respective characteristic peaks. It was found that the kerosene contained paraffins, monocyclic, bicyclic, and tricyclic alkanes, alkenes, and aromatic and oxygen-containing compounds. It was demonstrated that GCЧGC/TOFMS has obvious advantages over traditional methods for determining the components of rocket kerosene. [ABSTRACT FROM AUTHOR]

A method has been developed for determining rocket kerosene (RG-1 and T-1) in soil by static headspace analysis with subsequent gas chromatography-mass spectrometry analysis. It has been shown that the headspace analysis of a solid sample is the preferred approach to sample pretreatment compared with the ultrasonic extraction by methanol and the analysis of the equilibrium headspace collected above the extract. The effects of the temperature, the incubation time of the sample, and the moisture of the sample on the extraction and the sensitivity of the headspace determination of rocket kerosenes in soils of different nature have been considered. It has been found that 1 cm of the headspace collected above the sample at the temperature of 90°C for 20 min should be injected into a chromatograph (splitless injection mode) to determine the mass concentration of kerosenes in soil in the range of 50-500 mg kg. To determine the concentration in the range of 500-20000 mg kg, 0.1 cm of the headspace collected under similar conditions should be injected into a chromatograph (split mode, 1: 10). The repeatability of the measurements for the studied concentration ranges is 12-6% and the intermediate precision is 14.3-7.4%. The gas chromatography analysis takes 41 min. [ABSTRACT FROM AUTHOR]

Rocket kerosene (RK) is a new rocket propellant. Toxicity occurs if a high level of RK is inhaled. To study the toxicity of RK in lung and the mechanisms of RK-induced lung jury, a total of 72 male ICR mice (1.5 months, adult) were randomly assigned to the RK exposure group (RKEG) and normal control group (NCG). Mice were whole-body exposed to room air or aerosol of 18000 mg/m3 RK for 4 hours. Histopathological analysis was performed to evaluate the pulmonary lesions. Oxidative stress was assessed by assay of MDA, SOD, GSH-PX and TAOC. Inflammatory response was estimated by detecting inflammatory cell counts, TNF-α and IL-6 protein levels in serum. The results showed that after 2 to 6 hours of RK exposure, pulmonary vascular dilatation, congestion and edematous widening of the alveolar septum were noted. After 12 to 24 hours post-exposure, diffuse hemorrhage in alveolar space were found, along with the progressive pulmonary vascular dilatation and edematous widening of alveolar septum. During 3 to 7 days of RK-exposure, inflammatory cells were scattered in the lung tissue. The pathological alterations of the lung were alleviated after 14 days post-exposure, and showed significant improvement after 21 days post-exposure. After 30 days of RK exposure, the pathological changes in the lung tissue were nearly recovered except the local thickening of the alveolar wall. Compared with NCG, RK inhalation produced a significant increase of MDA levels and a significant decrease of SOD, GSH-Px and TAOC activity in the lung after 2 hours post-exposure (P<0.05). There were significant increases of TNF-α and IL-6 protein levels in serum of mice in RKEG after 2, 6 and 12 hours and 1, 4 and 7 days post-exposure compared with NCG (P<0.05). TNF-α protein levels had a sharp increase after 4 days of exposure. IL-6 protein level was increased at early phase of experiment and then gradually decreased along with the prolonged course of exposure. Considering that the RK-induced lung injury was through the oxidative stress, inhibition of oxidative stress after RK exposure may be urgently needed.