微涡喷发动机离心甩油盘环形折流燃烧室的设计与实验研究

微涡喷发动机是低成本的结构简单的燃气涡轮动力装置,特别适合于推动巡航导弹、(雷达)假目标、轻型直升机、无人侦察机和航空靶机。离心甩油盘环形折流燃烧室由于具有燃油雾化质量好,轴向长度短,高空性能好等优点,很适合作为微涡喷发动机动力装置的燃烧室。本文主要研究了离心甩油盘环形折流燃烧室的气动热力学参数和几何参数的设计,并通过实验研究验证参数设计的合理性。

高速微涡活性污泥法提高氧利用效率的研究

概述了高速微涡活性污泥法的工艺特点,并对该法提高氧的转移及利用效率进行了研究和机理分析.

CFD数值模拟在微涡絮凝中的应用

传统的絮凝理论是基于层流的条件得到的结果,而实际絮凝反应中,流体的流态是以湍流占优势的,不存在整体和恒定不变的速度梯度,因此微涡絮凝较传统絮凝更为复杂,其内部流态分布对絮体的形成具有重要作用,但目前试验无法获取其流态分布。随着计算机硬件的更新,计算能力不断提高,许多学者开始使用CFD数值模拟对种种复杂的实际问题进行计算模拟,以湍动能k、湍动能耗散率ε、涡旋速度梯度、涡旋尺寸作为评价指标,对微涡絮凝进行研究。

微涡喷发动机主轴内冷通道传热数值研究

对推力为100 N,转速为1×105r/min的微型涡喷发动机BUAA100的特点进行了介绍,然后对该发动机的主轴内冷通道基于Navier-Stokes方程和能量方程建立了计算模型,采用迭代法解决了前螺母简易离心泵进口边界条件和通道下游边界流动、换热相互耦合的问题,进行了数值模拟研究.给出的主轴内冷通道、简易离心泵创新设计方案和数值研究方法,可供其它微发研究参考.

100N推力级微小型涡喷发动机数字式电子控制器研究

建立了100N推力级微小型涡喷发动机模型,应用鲁棒控制算法进行了控制器软、硬件系统开发设计;提出了全新的仿真方法,用该方法对控制器进行了仿真,取得了良好的效果。电子控制器不仅具备等转速调节功能,且有足够的逻辑、多种控制监测和保护功能,完全符合多功能FADEC控制的要求。

微小型涡喷发动机进气畸变压力场测试及数值仿真分析

基于某微小型涡喷发动机平台,开展发动机进气总压畸变压力场测试,将试验结果与经校验的数值仿真计算结果进行对照,确定了该试验方法的可行性。通过对进气道渐缩段的数值仿真,探讨了微小型涡喷发动机尺寸效应所带来的二次畸变的影响。结果表明:该测量方法能够较好地评估小型涡喷发动机的抗畸变能力;进气渐缩段对进入压气机的畸变存在较大影响,能降低60%左右上游传递来的畸变。为今后微小型涡喷发动机抗畸变能力测试分析提供理论参考。

2006-2015年内蒙古锡林浩特刈割草原碳水通量观测数据集

草原生态系统是世界上分布最广泛的植被类型之一,具有重要的生态服务功能,对全球碳水循环发挥着重要作用。刈割作为内蒙古草地常见的利用方式,其会对草原生态系统结构与功能均产生深刻的影响。但目前关于刈割对草原生态系统碳水循环过程影响机制尚不清晰。缺乏长期、连续的通量观测数据是重要原因之一。按照ChinaFLUX标准数据处理方法,我们收集整理了2006–2015年内蒙古锡林浩特温性典型草原生态系统碳水通量和常规气象数据。本数据集提供的长期涡度通量观测数据,不仅为研究刈割利用下草原生态系统碳水通量的时间动态过程及调控机理提供了坚实的数据基础,同时也对优化该区域草地利用管理及评估刈割对我国北方草原碳汇功能的影响具有重要价值。

农村饮用水供给一体化样机开发试验研究

以混凝、沉淀、过滤为主要工艺开发了一种农村饮用水供给一体化样机,以聚合氯化铝为混凝剂,考察了进水流量和加药量对处理效果的影响,其出水水质(以浊度为主要分析指标)可满足国家规定的要求,且该装置的建造费用较传统的工艺组合低,吨水处理费用只有0.31元。该装置采用的工艺可以用于以地表水为水源的农村地区供水处理,对于与本试验所采用水源水质差别较大的地区或以地下水为水源的地区的给水处理,尚需做相关的适应性研究。

CAUSALITY DIAGRAM BASED SAFETY ANALYSIS OF MICRO TURBOJET ENGINE

An improved safety analysis based on the causality diagram for the complex system of micro aero-engines is presented.The study is examined by using the causality diagram in analytical failure cases due to rupture or pentration in the receiver of micro turbojet engine casing,and the comparisons are also made with the results from the traditional fault tree analysis.Experimental results show two main advantages：（1）Quantitative analysis which is more reliable for the failure analysis in jet engines can be produced by the causality diagram analysis;（2）Graphical representation of causality diagram is easier to apply in real test cases and more effective for the safety assessment.

耿井水厂脉冲澄清池和虹吸滤池的改造

耿井水厂是由原来的脉冲澄清池改造完成的。改造后,池型由立管式微涡反应器、小网格反应池、斜管式沉淀池、V型滤池组成。处理能力比改造前提高了10%,出厂水质量低于1.0NTU,达到国家新的水质标准CJ/T2006《生活饮用水卫生标准》的要求。

微小型涡喷转子结构热工作稳定性分析及试验验证

针对某型微小型涡喷发动机高速转子进行结构热工作稳定性分析,采取高精度整体动平衡、热态动平衡检查以及必要的结构阻尼和隔热冷却处理进行试验验证.结果表明:转子不平衡量减小,在合适外阻尼作用下转子持续稳定,后轴承隔热屏的安装使转子支承测点平均温度降低,减少了转子支承的热量输入,减轻了热流对支承刚度以及阻尼的影响,改善了发动机转子结构热工作稳定性,提升了发动机整机稳定性和安全性.

给水常规处理及强化混凝工艺中试装置的设计及运行

为提高合肥市居民饮用水的水质,根据本地原水的水质特征,我们设计和制作一套中试水处理装置,主要由常规水处理工艺和微涡强化混凝工艺构成。设计的常规水处理工艺包括机械混凝、斜管沉淀和石英砂过滤。设计的强化混凝工艺主要包括改造常规机械搅拌桨板和增设管道网格反应器两方面。实验结果表明:相对于传统工艺,强化混凝有较好的处理效果,形成矾花密实易沉降,能减轻滤池负担并且反应时间缩短。

Effects analysis on catalytic combustion characteristic of hydrogen/air in micro turbine engine by fuzzy grey relation method

In order to enhance catalytic combustion efficiency, a premixed hydrogen /air combustion model of the micro turbine engine is established under different excess air ratio, inlet velocity and heat transfer coefficient. And effects of inlet velocity, excess air coefficient and heat transfer coefficient on the catalytic combustion efficiency of the hydrogen have been analyzed by the FLUENT with CHEMKIN reaction mechanisms and the fuzzy grey relation theory. It is showed that inlet velocity has a more intuitive influence on the catalytic combustion efficiency of the hydrogen. A higher efficiency can be obtained with a lower inlet velocity. The optimum excess air coefficient is in the range of 0.94 to 1.0, the catalytic combustion efficiency of the hydrogen will be declined if the excess air coefficient exceeded 1.0. The effect of heat transfer coefficient on the catalytic combustion efficiency of the hydrogen mainly embodies in the case of the excess air coefficient exceeded 1.0, however, the effect will be declined if the heat transfer coefficient exceeded 4.0. The fuzzy grey relation degrees of the inlet velocity, heat transfer coefficient and excess air coefficient on the catalytic combustion efficiency of the hydrogen are 0.640945, 0.633214 and 0.547892 respectively.

预紧力与粗糙度对拉杆弯曲振动特性影响的研究

微小型涡喷发动机的离心叶轮轴向长度相比转轴长度不可忽略,可将其看作拉杆转子结构。为研究该拉杆转子结构的弯曲振动特性,建立了包含连接面的简支梁数学模型,应用结合面接触分形理论,推导了预紧力、粗糙度对拉杆弯曲振动特性的数学关系。通过算例研究,得出了预紧力、粗糙度对拉杆弯曲振动特性的影响趋势。结果表明:连接面所需的最小预紧力随着粗糙度的增加呈指数增长;仅考虑连接面刚度变化的情况下,拉杆固有频率与对数坐标下的预紧力之间呈S型曲线关系,粗糙度值越大,S曲线的潜伏期越长;同时考虑预紧力对连接面刚度和拉杆抗弯刚度的影响,当粗糙度较小时,拉杆固有频率随预紧力上升而上升;粗糙度较大或预紧力较大时,拉杆固有频率随预紧力上升而下降。

Organizing Filament of Small Amplitude Scroll Waves

We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory. In particular for the excitable media with equal diffusion, we obtain a close system for the motion of the filament. With an example of the Oregonator model, our results are in good agreement with those simulated by Winfree.

3D optical vortices generated by micro-optical elements and its novel applications

In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communication

Experimental investigation on control and reduction of vibration induced by fluid flow in turbine governing valve

Governing valve is the necessary passage through which steam enters into the steam turbine. The instability of the gas flow inside valve is the main reason that can induce the valve vibration, especially the valve rod vibration. In order to reduce the vibration and improve the performance of the governing valve such as the security and economy of the steam turbine, we try to find the method by experimental investigation. As to commonly used governing valve such as ball governing valve in this paper, a number of micro pressure sensors that have high frequencies and nice dynamic capability are employed successfully. The micro sensors are inserted directly in key positions of the valve, such as positions of valve seat throat, valve disc top and so on. The collection and measurement of many different working conditions are carried out and the conclusion of the valve instability is obtained. Therefore, vibration induced by fluid flow is controlled and reduced by means of regulating operation conditions and valve structure. Meanwhile, by numerical simulation of ball governing valve, valve disc adhered flow and asymmetric collision force are considered as main factor to cause oscillation under the condition of small lift as well as small and middle pressure ratio.

Wind Energy Generation Potential in Union Hidalgo, Mexico： A Preliminary Study

Union Hidalgo municipality in Oaxaca State, Mexico, is located in an area with attractive wind potential. For this reason, this paper presents a preliminary study of the technical feasibility of wind power generation in Union Hidalgo, by a micro-study with a higher resolution than that used in Wind Resource Atlas of Oaxaea, published in April 2004. In this work, the wind map of Union Hidalgo was generated using the micro-scale model WAsP 9.1, with a resolution of 50 meters. Wind speed and direction data recorded at 15 m and 32 m agl （above ground level） over four years and seven months in a surface anemometer station were used. With Class 7 wind patterns, the results show values that justify the installation of wind turbines to produce electricity in the area. Estimated capacity factors （55% on average） are comparable with those obtained in wind power plants already operating in areas near Union Hidalgo and sites with high wind potential in other parts of the world. The topography of the study area is predominantly flat, and together with the directional behavior of the wind, which comes from the NNW 44% of the time, this favors the introduction of wind power plants in the area.

Analysis of micro vortex metallization and introduction of evaluation factor in mixing process

To improve the mixing efficiency in water purification or wastewater treatment process and understand the mechanism of mass transfer,and a suitable evaluation factor is introduced to evaluate the efficiency of mixing process.The diffusion mass transfer under turbulent condition is investigated based on dynamic and mathematical analysis.The results indicate that submicroscopic diffusion is the rate-limiting step in mass transfer,and the inertia effect of micro vortex causes the phase mixing.An excellent efficiency can be obtained by controlling the scale of micro vortex within millimeter.Furthermore,a new indicator named mixing factor(IH)is proposed to evaluate the efficiency of mixing processes,which is more feasible than conventional evaluation methods,because of its connection of mixing extent with energy consumption.

Robust Adaptive Pitch Control of Floating Wind Turbines

In this paper, a modified sliding-mode adaptive controller is derived to achieve stability and output regulation for a class of dynamical systems represented by a non-homogeneous differential equation with unknown time-varying coefficients and unknown force function. In this scheme, the control law is constructed in terms of estimated values for the bounds of the unknown coefficients, where these values are continuously updated by adaptive laws to ensure asymptotic convergence to zero for the output function. The proposed controller is applied to solve the problem of pitch angle regulation for a floating wind turbine with dynamic uncertainty and external disturbances. Numerical simulations are performed to demonstrate the validity of the designed controller to achieve the desired pitch angle for the floating turbine＇s body.