二维碳粒床中阴燃传播的数值模拟

本文对内部有受迫气流经过的二维碳粒填充床的阴燃，从点火开始到稳态传播整个过程进行了数值模拟。计算采用控制容积法，用ＰＩＳＯ算法求解。主要研究新鲜空气流动速度与阴燃波的传播速度和反应温度之间的关系，也探讨了正向阴燃与反向阴燃之间的异同。其结果为：在受迫气流经过的阴燃床中点火，将产生反向阴燃，且气流速度越大，阴燃波的传播速度越快，阴燃温度越高。在条件相同的情况下，反向阴燃的传播速度比正向阴燃的传播速度大；而反向阴燃的反应温度比正向阴燃的反应温度低。     

Surface shape development of the pitch lap under the loading of the conditioner in continuous polishing process

Continuous polishing using the pitch lap is a key process in finishing large flat optical elements. The optical elements’ surface figure is primarily dependent on the surface shape of the pitch lap, which is controlled by a large-size conditioner. However, underlying fundamentals of the process control is not yet clear, and it remains empirical and nondeterministic to date. In this study, a novel analysis model is proposed for exploring the surface shape development of the pitch lap under the conditioner loading. The analysis model divides the polishing time into a series of segments, in which the shape variation of the pitch lap due to viscoelastic creep is derived from the pressure distribution at the conditioner-lap contact interface. Further, a contact model of the lap and conditioner is built to obtain the pressure distribution at the interface, and a novel creep model is proposed for the viscoelastic behavior of the pitch lap under the pressure. The analysis model combined with the contact and viscoelastic models can be used to explore the pitch lap shape development under various conditions and hence reveal the underlying fundamentals of controlling the lap shape by the conditioner.     

响应曲面法优化磷石膏制备硫酸铵的工艺

为了优化磷石膏制备硫酸铵的工艺,采用磷石膏过筛和添加分散剂的方法来提高磷石膏中硫酸根的转化率.采用响应曲面法(RSM)分析了物料配比、反应温度、加料速度和分散剂用量对磷石膏中硫酸根转化率的影响,并建立了相应的预测方程,通过Matlab软件对方程求导并确定较优的工艺参数:硫酸钙与碳酸铵物质的量比为1.19,反应温度为44 ℃,加料速度为29 g/min,分散剂用量(分散剂质量占反应物总质量的质量分数)为1.3×10-3,相应的磷石膏中硫酸根转化率的预测值为96.4%.经实验证明:应用响应曲面法所得到的磷石膏转化工艺参数是可行的.     

SC型高效催化剂丙烯液相本体聚合

SC型高效催化剂是用无水MgCl_2、醇、蘸、TiCl_4以及添加剂制备的,SC型催化剂和A1Et_3助催化剂、Ph_2Si(OMe)_2外给电子体,用于丙烯液相本体聚合,丙烯在70℃聚合2h具有高效率(大于3万gPP/gCat),得到的聚丙烯等规度(大于98％)和堆密度(大于0.45g/cm~3)高,颗粒形态好,粒度分布窄,聚丙烯的MFR容易用氢调节。     

太湖流域不同种浮萍淀粉积累的研究

对在太湖采集的15株浮萍进行分子鉴定,从中筛选出3株高淀粉含量浮萍作为供试材料,对其生长培养基进行优化,并研究饥饿条件对其生长和淀粉积累的影响。结果表明:采集到的浮萍分布于5个种,分别为Lemna aequinoctialis,Lemna minor,Lemna turionfera,Spirodela polyrhiza,Landoltia punctata;与SH培养基相比,改良的培养基SH-1和SH-2均能显著促进浮萍的生长;在饥饿试验中,筛选的3种浮萍S.polyrhizza,L.aequinoctialis和L.punctata每周的生长速率(以鲜重计)分别为18.64,20.77和16.52g/m2,饥饿培养33 d后,淀粉含量分别达到20.6%,21.98%和24.30%,较饥饿前分别增加了73.4%,75.4%和137.5%。相较于S.polyrhiza和L.aequinoctialis,L.punctata在淀粉积累方面表现出一定的优势。     

Quantitative evaluation and factors of gas-wetness in gas/liquid/solid systems

After altering the wetness of porous media from preferentially liquid-wet to preferentially gas-wet, gas well production will increase greatly in gas condensate reservoirs. Since the gas-wet degree seriously affects the production, it has both theoretical and practical value to study quantitative measurement and effect factors for gas wettability. In the study, using the sessile drop and the captive bubble, the gas-wet quantitative evaluation methods and criteria have been put forward. Glass slides, treated by the fluorocarbon polymer Zonyl8740, were used as gas-wetness measurement substrates in order to eliminate the roughness effect. The calculation of slide surface free energy and slide/water interface free energy was determined by two models, respectively, Owens-Wendt and the captive bubble two-probe method. The results show that, if the solid surface free energy is less than solid/liquid interface free energy, the surface or the interface will be preferential gas-wetting, otherwise, non gas-wetting; with the decrease of surface free energy and interface free energy, the gas-wetting gets strong. Thus, it is effective to realize gas-wetness by lowering the value of surface free energy or surface tension.     

基于自适应遗传算法的协调控制系统优化

针对火电单元机组的协调控制系统,提出了一种基于自适应遗传算法的多变量鲁棒PID控制器参数寻优方法.以控制器设定点跟踪性能为优化目标,鲁棒性能为动态约束,采用具有自适应交叉概率和变异概率的遗传算法寻优PID控制器参数.仿真结果表明,与传统遗传算法寻优所得PID控制器相比,基于自适应遗传算法的鲁棒PID控制器具有良好的负荷...     

Combined constant speed control method for a wind generator equipped with hydraulic energy storage

A wind generator equipped with hydraulic energy storage (WG‐HES) uses hydraulic transmission systems instead of gearbox transmissions, thus eliminating high‐power converters and reducing the tower‐top cabin weight. When there is no wind or the wind speed is extremely low, the pressured oil released by accumulators is used to drive a motor to operate at a constant speed, thereby generating constant‐frequency power. However, few studies have examined the constant speed control characteristics for generating electricity using only an accumulator group. In this study, a combined constant speed (CCS) proportional–integral–derivative (PID) control method based on “variable displacement and throttling” is proposed, which includes two closed loops and one regulating loop. First, a simulation model of the CCS PID control method for a variable motor was established in the Simcenter Amesim program. The influence of different PID parameters on the anti‐interference ability of the constant speed control of the motor was analyzed under a given load step. Then, we obtained the range of control parameter values and a set of optimal values. Second, the effectiveness of the CCS control method and the accuracy of the simulation results were verified on a 600‐kW WG‐HES system prototype. The results verified that the CCS control method has good anti‐interference ability and can meet the requirements of constant speed control for a variable motor under the best PID parameters. These results can provide a basis for developing control strategies for WG‐HESs when there is no wind or at low wind speeds.     

小尺度受限空间内瓦斯爆燃的动态特性

为获得包括瓦斯爆燃点火初期、火焰加速、减速及二次加速过程中动态火焰微细结构及其与超压之间的相互关系,实验研究了小尺度受限空间内瓦斯爆燃火焰形状、火焰锋面位置、火焰速度及超压等动态特性.研究结果表明,在无障碍物条件下,火焰锋面光滑,火焰形状由"半球"状逐渐演变为"手指"状;而有障碍物条件下,火焰锋面出现明显褶皱和湍流现象,其火焰速度经历两次加速和一次减速过程,最大火焰速度达112m/s,与无障碍物条件下最大值相比增幅为124%;当火焰锋面经过障碍物后即将重新汇合时,出现8.5kPa的最大超压,与无障碍物条件下的最大值相比增幅为118%.     

发动机余热回收及利用专利技术现状及其发展趋势

围绕发动机余热回收及利用技术进行专利分析研究,对其专利布局情况和专利态势情况从专利申请量、专利申请类型、专利申请人区域分布等角度进行了宏观上的总体分析,以期通过对国内外的专利分析了解世界范围内发动机余热回收和利用技术的发展趋势,掌握国外相关企业在我国的专利布局情况,发现我国企业在技术研发中的优势或不足,供中国企业和研究院、所等寻找技术突破点及制定专利战略时参考。