Effect of heat loss on the syngas production by fuel-rich combustion in a divergent two-layer burner

The effect of heat loss on the syngas production from partial combustion of fuel-rich in a divergent two-layer burner is numerically studied using two-dimensional model with detailed kinetics GRI-Mech 1.2. Both the radiation and wall heat losses to the surrounding are considered in the computations. It is shown that two types heat losses have different effects on the syngas production. The radiation heat loss has significant effect on the syngas temperature and the syngas temperature is dropped as radiation heat loss is increased, but it has neglected effect on the reforming efficiency and methane conversion efficiency. The wall heat loss has a comprehensive effect on the syngas production. The wall heat loss not only reduces the conversion efficiency, but also significantly decreases the syngas temperature. The effect of wall heat loss becomes weak as the equivalence is increased. The reforming efficiency drops from 0.440 to 0.424 for equivalence ratio of 2 and mixture velocity of 0.17 m/s for the predictions between adiabatic wall and non-adiabatic conditions.     

渐变刚度板簧式轻卡悬架阻尼参数仿真设计

为了有效提高渐变刚度钢板弹簧式轻型卡车的乘坐舒适性,根据弹簧受力与刚度和变形之间的关系,利用等频原理,建立了渐变刚度钢板弹簧力学特性解析计算模型,并利用钢板弹簧加载-卸载试验对所建立的模型的正确性进行了验证。基于1/2车辆行驶振动模型,利用MATLAB的Simulink工具箱,建立了考虑渐变刚度钢板弹簧力学特性的轻卡行驶振动仿真分析模型。最后,以人体振动舒适性最佳为目标,利用多岛遗传算法,建立了轻卡悬架系统阻尼参数仿真设计方法,并利用实车试验对所建立的轻卡悬架系统阻尼参数仿真设计方法的正确性进行了验证。上述研究为渐变刚度钢板弹簧式轻卡悬架系统参数的设计提供了有效参考。     

基于英飞凌TC275的整车控制器CCP协议底层驱动开发

针对以英飞凌TC275单片机为平台的整车控制器,进行控制器局域网络标定协议(controller area network calibration protocol,CCP)底层驱动程序的开发。依据CCP的需求开发了英飞凌TC275的控制器局域网络(controller area network,CAN)模块、系统定时器(system timer,STM)模块和FLASH模块的底层驱动程序,实现CCP标定系统的通信连接、数据上传、数据下载、数据存储等功能。为验证系统的性能,进行整车控制器的实际测试,测试结果表明:所开发的基于TC275单片机的CCP底层驱动程序能够实现CCP的功能要求。     

Tunable Fe/N co-doped 3D porous graphene with high density Fe-Nx sites as the efficient bifunctional oxygen electrocatalyst for Zn-air batteries

Nitrogen-doped transition metal materials display promising potential as bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, Fe/N co-doped three-dimensional (3D) porous graphene (FeN-3D-PG) is prepared via a template method using sodium alginate as the carbon source and low polymerization degree melamine resin as the nitrogen source. The low polymerization degree melamine resin can form complexes with Fe³⁺ in the aqueous solution and further forms high density Fe-N_x active sites during pyrolysis. Meanwhile, the formed 3D porous structure efficiently promotes the uniform distribution of Fe-N_x active sites. The FeN-3D-PG catalyst exhibits pH-independent ORR activity. For OER, the catalyst possesses a low over potential (370 mV at 10 mA cm⁻²) in alkaline electrolyte. The Zn-air batteries (ZABs) using FeN-3D-PG as cathode exhibits a power density up to 212 mW cm⁻², a high specific capacity of 651 mAh g⁻¹, and the charge-discharge stability of 80 h. This work provides new sight to transition metal materials based ZABs with excellent performance.     

Enhanced photocatalytic activity of nonstoichiometric crystalline TaO2F and Ta2O5 with carbon coating

Pure and carbon-coated tantalum-based oxides photocatalysts were synthesized via the mesocrystalline precursor transformation method by annealing pure and polydopamine-coated (NH₄)₂Ta₂O₃F₆ mesocrystals in Ar. The oxygen-poor atmosphere thermal annealing process assisted the formation of nonstoichiometric TaO₂F mesocrystals with more F and Ta₂O₅ nanorods with oxygen vacancies and the associated lower valence state Ta ions (Ta⁴⁺). Furthermore, the carbon coating, decomposed from coated polydopamine, helped to control their particle size within 100 nm by isolating the connection of (NH₄)₂Ta₂O₃F₆ subunits. Hence, as-synthesized products, particularly carbon-coated Ta₂O₅ nanosheets, owning large surface area (67.6 m² g^?1), fine particle size (<100 nm), excellent electronic conductivity, decreased bandgap energy, enhanced and extended absorption in the visible range, exhibited preferable photocatalytic activity in the photodegradation of methylene blue, reaching a 76.54 % and 41.71 % removal under ultraviolet and visible light illumination, suggesting a promising candidate for wide-range responsive photocatalytic applications.     

Effects of particle sizes on performances of the multi-zone steam generator using waste heat in a bio-oil steam reforming hydrogen production system

Hydrogen production by bio-oil steam reforming is an advanced production technology. It is a good method of coupling waste heat utilization with bio-oil steam reforming to produce hydrogen, which increases the cleaning ability of the bio-oil steam reforming system. A multi-zone steam generator using waste heat has been proposed, which can produce the heat source and steam source of the hydrogen system. The DEM model of the multi-zone steam generator was set up. The model has been used to investigate the effects of particle sizes (40 mm–80 mm). With increasing particle size, the flow index and the flow uniformity gradually decrease, the vertical velocity gradient increases in the area on both side with the zone steam generator, and the vertical velocity fluctuation amplitude gradually increases. So, the hydrogen production decreases from the particle size increasing.     

Modified La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes with the infiltration of Er0.4Bi1.6O3 for intermediate-temperature solid oxide fuel cells

Aiming to lower the activation energy and expedite the oxygen reduction reaction (ORR) process of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) cathodes for application in intermediate-temperature solid oxide fuel cells (IT-SOFCs), Er_0.4Bi_1.6O₃ (ESB) modified LSCF was prepared by infiltrating using organic solvents. The infiltration of ESB dramatically reduces the polarization resistances of LSCF cathodes (from 0.27 to 0.11 Ω cm² at 700 °C, from 0.58 to 0.25 Ω cm² at 650 °C), and lowers their activation energy (from 100.28 to 97.15 kJ mol^?1). Also, ESB makes the rate-limiting step of LSCF cathodes at high frequency change from the charge transfer process on the cathode to the adsorption and diffusion of oxygen on cathode surface. The single cell with ESB infiltrated LSCF cathodes shows a peak power density of 469 mW cm^?2 at 700 °C using humid hydrogen and air as fuels and oxidants, respectively, as well as a good short-term stability for 50 h.     

Effect of grain size on the electrical performance of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ solid electrolytes with addition of NiO

In order to clarify the effect of grain size on the electrical performance of BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ (BZCYYb) solid electrolytes with addition of NiO, microcrystalline (~1.5?µm) and ultrafine-grained (~280?nm) BZCYYb electrolytes (with 1?wt% NiO) were fabricated by the conventional and two-step sintering method, respectively. The results show that compared with microcrystalline electrolytes, the ultrafine-grained electrolytes have similar grain-interior conductivities, but much lower grain-boundary conductivities, illustrating that the grain boundary is not conducive for ionic transport. As a result, the electrical conductivity of microcrystalline electrolytes (1.9?×?10^?2 S?cm^?1 at 600?°C in wet air) is higher than that of ultrafine-grained electrolytes (1.1?×?10^?2 S?cm^?1 at 600?°C in wet air). In addition, the OCV (open-circuit voltage) values of electrolyte-supported single cells show that the undesired electronic conduction exists in the electrolytes due to the BaY₂NiO₅ impurity formed by the reaction of NiO and BZCYYb. The ultrafine-grained electrolytes show lower OCV values than that of microcrystalline ones, due to the prolonged electronic transport paths. Therefore, large-grained or grain boundary-free microstructure are necessary for improving the electrical performance of BZCYYb electrolytes.     

Heat transfer trait simulation of H finned tube in ventilation methane oxidation steam generator for hydrogen production

With the steam obtained by the energy released from ventilation air methane oxidation, the hydrogen production through gasification method is considered more commercial. In order to constrain the steam parameter fluctuation, the shunt honeycomb ceramics are adopted to fill between the heat exchange tubes. However, transient heat transfer characteristics of this kind of heat exchanger have not been fully studied. This paper carried out a numerical simulation study on the transient heat transfer characteristics of H finned tube under periodic reverse-flow conditions. Results show that the existence of shunt honeycomb ceramics enhances the effect of radiation. Gas flow direction reversing destructs the original boundary layer, achieving a sudden rise of the convective heat flux in the new upstream. It takes about 12s to form a new relative stable boundary layer. The apparent heat transfer coefficient achieves a maximum of 108.77 W m⁻² K⁻¹ and an average of 99.1 W m⁻² K⁻¹.     

酶联合挤压豌豆蛋白肽的分离工艺

本文旨在应用响应曲面实验设计优化酶联合挤压豌豆蛋白酶解条件,以期得到最优的抗氧化肽和准确的酶解预测模型,并分离得到具有高自由基清除率的豌豆蛋白抗氧化肽。以含水量为30%的豌豆蛋为原料,以O_2~-.清除率为评价指标,利用响应曲面设计优化中性蛋白酶挤出物的酶解条件,得出酶解最佳条件为:加酶量12.23%、温度40.23℃、pH 6.99、底物浓度6.92%。在此条件下,O_2~-.清除率为75.93%。采用透析和高效液相相结合的方法,对酶解产物进行分离及分子量的确定。分离得到小于1 ku、1~3.5 ku、3.5~7 ku和大于7 ku的酶解液。经测定发现分子量小于1 ku的酶解液抗氧化活性最强,达78.31%,其分子量集中在200~800 u左右,为2~8肽。经验证,所建模型预测准确可靠,酶解产物抗氧化性高,可为相关生产和工艺产品开发提供参考价值。透析可显著提高肽的自由基清除率。