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排序方式: 共有3286条查询结果,搜索用时 15 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(2):1306-1318
The effective and efficient utilization of low-calorific value (LCV) gases has gained increasing attention in scientific research and industrial fields. In this study, the combustion characteristics of three LCV gases in practical devices are analyzed by using a nonadiabatic perfectly stirred reactor model. The complete steady-state solution in the temperature-residence time parameter space is obtained with arc-length continuation. The stable operation region is quantified by the eigenvalue analysis. The transition of solution curves is quantified with heat loss coefficient. Five key system parameters are systematically investigated on their effects on stability limits. With the combustion performance being quantified by a combustion state index, a combustion state regulation method is proposed to find the optimal regulation path of system parameters. Active subspace method is further applied to shorten the regulation step by identifying the active direction. The proposed method and findings are useful for optimal regulation of burning LCV gases in industrial burners. 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(48):20999-21012
Micro-combustor is a portable power device that can provide energy efficiently, heat recirculating is considered to be an important factor affecting the combustion process. For enhancing the heat recirculating and improving the combustion stability, we proposed a heat-recirculating micro-combustor embedded with porous media, and the numerical simulation was carried out by CFD software. In this paper, the effect of porous media materials, thickness and inlet conditions (equivalence ratio, inlet velocity) on the temperature distribution and exhaust species in the micro combustor are investigated. The results showed that compared with the micro combustor without embedded porous media (MCNPM), micro-combustor embedded with porous media (MCEPM) can improve the temperature uniformity distribution in the radial direction and strengthen the preheating capacity. However, it is found that the embedding thickness of porous media should be reasonably arranged. Setting the thickness of porous media to 15 mm, the combustor can obtain excellent comprehensive capacity of steady combustion and heat recirculating. Compared the thermal performance of Al2O3, SiC, and ZrO2 porous media materials, indicating that SiC due to its strong thermal conductivity, its combustion stabilization and heat recirculating capacity are obviously better than that of Al2O3 and ZrO2. With the porous media embedded in the micro combustor, the combustion has a tempering limit of more than 10 m/s, and the flame is blown out of the porous media area over 100 m/s. The reasonable equivalence ratio of CH4/air combustion should be controlled within the range of 0.1–0.5, and “super-enthalpy combustion” can be realized. 相似文献
3.
对菱镁矿在固体燃料燃烧过程中的固硫特性进行了理论研究,所得结论对进一步将菱镁矿作为固体燃料燃烧过程中的固硫剂具有非常重要的意义。 相似文献
4.
S. ReppA. Sadiki C. SchneiderA. Hinz T. LandenfeldJ. Janicka 《International Journal of Heat and Mass Transfer》2002,45(6):1271-1285
This work aims to compare numerical results obtained by using the Monte Carlo composition-PDF method and a presumed-β-PDF in order to reveal their effects on the prediction of flow and scalar fields in swirling confined methane diffusion flame. Using the intrinsic low dimensional manifolds method for modelling the chemistry and a second moment closure for the turbulence, it is shown that both PDF-methods provide a similar accuracy level of the prediction of mean quantities. While the presumed-β-PDF performs using reasonable computational efforts, the Monte Carlo-PDF allows to capture well the turbulence-chemistry interaction and strong finite-chemistry effects such as local extinction. 相似文献
5.
6.
Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant .The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area( SSA) on the minimal ignition temperature ,combustion temperature and final product of porous Ni-Ti SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM) and laser diffraction.The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA. 相似文献
7.
Two-phase (B2+L12) nickel aluminide intermetallic compounds were synthesized by the pressure-assisted volume combustion synthesis (CS). The production and characterization of the samples containing NiAl+Ni3Al were investigated. Aluminum (99% pure, 15 μm) and carbonyl nickel (99.8 pure, 4-7 μm) powders were used. The production of intermetallic compound was carried out at 1050 °C under 150 MPa uniaxial pressure in open air atmosphere in an electrical resistance furnace for 60 min. The formation temperature of intermetallic compound was determined by differential scanning calorimeter (DSC) analysis, and exothermic temperature of powder mixture was determined as 653 °C. The characterization of samples was confirmed by optical microscope, SEM and XRD analysis. It was observed that the structure of compound has very low porosity and the formation of NiAl was completed successfully. The relative density of test materials measured according to Archimedes’ principle was 98.04%. The microhardness of test materials was about 351 HVN1. 相似文献
8.
The operating conditions of this study are close to the typical operating conditions of flue gas desulfurization system in coal-fired power plants. The aim of this study is to investigate the absorption kinetics of SO2 and NO from simulated flue gas into an aqueous solution of acidic sodium chlorite using a bench-scale spraying column. The range of absorption rates measured in this study is between 1.91×10?11 and 9.59×10?10?mol?s?1?cm?2. The range of rate constants measured in this study is between 1.32×107 and 1.21×108?(L?mol?1)1.9?s?1, and the average rate constant is 6.16×107?(L?mol?1)1.9?s?1. The activation energy and frequency factor are 129 Kcal/mol (53.97 KJ/mol) and 6.93×1016?[(L/mol)1.9/s], respectively. 相似文献
9.
As an alternative to previously developed catalytic FeCrAlloy fibre mat burners based on perovskite catalysts, new catalytic burners have been developed based on Pd catalyst on lantana-stabilised Al2O3 and different fibre structures (NIT100A, NIT100S and NIT200S by ACOTECH NV). All development steps are considered, shifting from catalyst preparation (based on combustion synthesis of γ-Al2O3) to the optimisation of lantana and Pd loadings, from the definitions of the best catalyst-deposition conditions (washcoating) to the catalytic burners performances, determined in an ad hoc developed combustion chamber. The results show almost half pollutants emissions and better performance compared to various non-catalytic counterparts, especially as far as CO and NOx emissions are concerned. Some flame instability problems were though registered, especially for one of the catalytic burner mattresses employed, at low specific power inputs and excesses of air (<375 kW/m2 and <12%, respectively). Further, PdO/Pd transition is shown to influence the dynamic behaviour of the catalytic burners. 相似文献
10.
介绍了低旋流进气直喷燃烧系统应用于195柴油机的试验结果,着重探讨了燃烧室结构尺寸和供油系统主要参数对柴油机性能和燃烧放热规律的影响。研究表明,这种燃烧系统应用于小缸径直喷柴油机具有良好的推广前景。 相似文献