浅海底边界动力过程与物质交换研究

浅海底边界动力过程是能量分配、颗粒物输运和水—底边界物质交换的关键环节,深入研究浅海底边界动力过程是提高环境容纳量预测能力的重要前提。分析了国内外该研究方向的进展和现状,提出在黄海中部和长江口外两个典型海区,以集成先进设备的海床基观测平台和水体要素连续观测的研究策略,获得底边界流场结构、水体和底边界湍流混合特征、底耗散动力学参数、底颗粒物浓度和梯度变化等规律,建立潮汐、层化、海浪等不同动力条件下底边界动力过程参数化方案,研究沉积物启动、沉降等动力学规律,以数值模式探讨海底拖曳力变化对潮流和环流结构的影响;了解颗粒物组成的季节变化及对起动、再悬浮、絮凝等动力过程的影响,以颗粒物输运模型研究中国近海沉积物源汇分布;以同位素示踪研究底界面交换对动力过程的响应。为解决面临的2个科学问题:①中国近海底边界能量耗散在能量分配中的作用;②中国近海底边界动力过程、颗粒物输运与物质交换的多时空尺度变化规律,奠定基础。

航空发动机动叶积垢数值模拟研究

基于NASA公布的Stage 36叶型及进气道数据,利用DPM离散相对ash,CaCO3及Al2O3颗粒不同粒径、颗粒入射速度等条件对颗粒运动轨迹及叶片壁面颗粒沉积速率进行研究。颗粒直径增大、材料密度增加、低入射速度情况下将造成压气机叶片表面的颗粒物沉积速率逐渐加剧。叶片压力面区域相对于吸力面积垢沉积率较大,叶根区域相对于叶尖区域更容易产生积垢。

Kinematic Characteristics and Thermophoretic Deposition of Inhalable Particles in Turbulent Duct Flow

The kinematical characteristics and thermophoretic deposition of inhalable particles with the diameters of 0-2.5μm （hereafter referred to as PM2.5） suspended in turbulent air flow in a rectangular duct with temperature distribution were experimentally studied. Particle dynamics analyzer （PDA） was used for the on-line measurement of particle motion and particle concentration distribution in the cross-sections of the duct. The influences of the parameters such as the ratio of the bulk air temperature to the cold wall temperature and the air flow rate in the duct on the kinematical characteristics and the deposition efficiencies of PM2.5 were investigated. The experimental re- sults show that the deposition efficiencies of PM2.5 mainly depend on the temperature difference between the air and the cold wail, wffile the air flow rate and the particlecon^centration almost affect hardly tile clep0si-tion-effi ciency. The radial force thermophoresis to push PM2.5 to the cold wail is found the key factor for PM2.5 deposition.Based on the experimental results, an empirical modified Romay correlation for the calculation of thermophoretic deposition efficiency of PM2.5 is presenlext. The empirical correlation agrees reasonably well with the experimental data.

Effect of auxiliary ventilations on diesel particulate matter dispersion inside a dead-end entry

Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. This paper used computational fluid dynamics(CFD) method to study the effect of four auxiliary ventilation systems on DPM distribution in a dead-end entry with loading operation. The auxiliary ventilation systems considered include: blower fan and tubing; exhaust fan and tubing, jet fan, and push–pull system. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of the loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup of local ventilation. It can also be used for selection of DPM control strategies and DPM annual training for underground miners.

Performance of a high-rate anammox reactor under high hydraulic loadings: Physicochemical properties, microbial structure and process kinetics

In this study, a lab-scale upflow anaerobic sludge blanket(UASB) reactor was applied to studying the high-rate nitrogen removal of granule-based anammox process. The nitrogen removal rate(NRR) finally improved to 15.77 kg/m3/d by shortening hydraulic retention time(HRT) to 1.06 h. Well-shaped red anammox granules were extensively enriched inside the reactor. The results of nitrogen removal kinetics indicated that the present bioreactor has great nitrogen removal potential, because the maximum rate of substrate utilization(Umax) predicted by Stover-Kincannon model is suggested as 55.68 kg/(m3·d). Analysis of the microbial community showed that the anammox genus Candidatus Kuenenia dominated the bacterial communities. The relative abundance of Candidatus Kuenenia rose from 12.29% to 36.95% after progressively shorter HRT and higher influent substrate concentrations, illustrating the stability of nitrogen removal performance and biomass enrichment offered by the UASB in carrying out high-rate anammox process.

Magnetic Characteristics of Surface Sediments of Liaodong Bay, China

Analysis of magnetic properties of marine surface sediments has been gradually proved to be one of the effective means for researching the source of marine sediments. In this paper, samples from 39 sites in Liaodong Bay were collected to analyze the magnetic characteristics of the surface sediments. Magnetic study indicated that the surface sediments of the Liaodong Bay are char- acterized by magnetite. In the middle and eastern part and the southwest comer of the Bay, the main magnetic grains were coarse multi- domain and pseudo-single-domain particles, while in other areas single-domain and pseudo-single-domain particles constitute the majority. Based on grain size and environmental magnetism data, the content of magnetic minerals has a positive correlation with the hydrodynamic environment when the magnetic mineral domain is finer. However, the content of magnetic minerals is in a complex relationship with the hydrodynamic environment in the coarse magnetic domain of magnetic minerals found in central Liaodong Bay and places outside the Fuzhou Bay, implying that the strong hydrodynamic environment accelerates the sedimentation of coarse magnetic minerals. Based on geographic pattern of magnetic properties, it can be inferred that the main provenance of the surface sediments of the Liaodong Bay is the surrounding rivers, and the comparative analysis indicates that Yellow River substances maybe also exist in the bay.

煤矿井下通风防尘控制技术研究与应用

中国在煤矿安全领域取得了显著进步,但煤矿井下的粉尘问题仍然是影响工作安全和健康的关键因素。本文深入探讨了煤矿井下的通风防尘控制技术,旨在通过科学研究和实践应用,为改善井下工作环境提供有力支持。结合工程实践,我们运用了流体动力学与颗粒物运动理论,对井下风量分布、防尘设备布局等关键控制技术进行了系统研究。研究结果显示,通过优化通风系统配置和科学布局防尘设备,可以有效降低井下粉尘浓度,从而显著提升矿工的工作环境质量。此外,我们还提出了煤粉尘综合治理策略,包括优化矿井开采布局、改进采矿工序,以及综合应用湿式打孔、高压喷雾等防尘措施,从源头上减少粉尘产生,进一步增强防尘效果。这些研究成果和控制策略在实验应用中取得了良好效果,对于推动我国煤矿健康生产具有重要意义。