特大型灯泡贯流式机组机电安装技术难点

通过桥巩水电站工程建设实践,分析特大型灯泡贯流式机组机电安装中的技术难点:①尾水管里衬、座环、导水机构的吊装变形和焊接变形以及浇筑混凝土引起的尾水管里衬、座环变形;②发电机组合轴承和水轮机径向导轴承间隙调整。介绍克服这些技术难点的工艺措施:缩短起吊部件滞空时间,加大起吊部件整体刚度是减少吊装变形的有效方法;改进焊接工艺是减少焊接变形的有效方法;分层、分步浇筑混凝土并注意浇筑速度是控制混凝土浇筑变形的有效方法。正确估计组合轴承和水轮机径向导轴承在静止和运行状态间隙变化量是调整轴承间隙的重要依据。该工艺措施为提高我国大型灯泡贯流机组的设计、制造和安装水平提供了宝贵的经验。     

灯泡贯流泵机组变频装置特点与节能分析

根据南水北调工程中灯泡贯流泵采用变频调速的实际情况,分析了贯流泵在稳态和起动过程的负载特性和转矩特性,针对灯泡式大型同步电动机的特性选择变频装置的控制策略,通过励磁装置与变频装置的组合简化电动机的结构,以淮阴三站为例分析变频装置的技术特点。最后,对灯泡贯流泵的变速运行节能效果和不同转速下的变频装置与电动机损耗进行了分析,为采用变频装置的贯流泵经济运行提出了建议。     

Microstructure optimization of fuel electrodes for high-efficiency reversible proton ceramic cells

Reversible protonic ceramic cells (R-PCCs) are efficient energy storage and conversion devices that can operate in two modes, namely, in the fuel cell mode for the conversion of fuel to electricity, and in the electrolysis (EC) mode for the EC of water into hydrogen and oxygen. Fuel electrode is a critical component of fuel-electrode-supported R-PCCs, and its pore structure directly affects the electrochemical performance of the R-PCCs, but it has not been fully studied yet. Herein, the pore structure of Ni–BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ (Ni–BZCYYb) fuel electrodes was systematically modulated by varying the weight ratio (0, 5, 10, and 15 wt.%) of the pore-former added to Ni–BZCYYb, and the electrochemical performance characteristics in the fuel cell and EC modes were investigated. The cell with 10 wt.% pore-former in the Ni–BZCYYb electrode achieved a remarkable peak power density of 540.7 mW cm⁻² and a high current density of –2.28 A cm⁻² at 1.3 V at 700°C in the fuel cell and EC modes, respectively, and showing excellent durability for over 100 h. These results further highlight the critical role of the microstructure of fuel electrodes, which can be modified to achieve exceptional performance, particularly in EC operations.     

新型复合式露点间接蒸发冷却空调机组的试验研究

分析新型复合式露点间接蒸发冷却空调机组的芯体构造和工作原理。选择高湿度地区代表城市——福州,在7月份,对新型复合式露点间接蒸发冷却空调机组的工作电流和电压、机组风压、湿球效率、二/一次风量比、淋水量、耗水量等性能参数进行实际测试。结果表明:复合式露点间接蒸发冷却空调机组二/一次风量比为0.95时,机组的平均湿球效率为103%,机组在200L/h的淋水量下运行10min,需要消耗1.2L的水。将机组应用于一个室内模拟1kW发热源的房间,测试得到了机组运行的实际效果,并提出机组优化的试验参考。     

相思木浆用于文化用纸生产时的滤水性能和留着性能

对来自印度尼西亚的相思木 (Acacia)浆与混合阔叶木浆和来自北欧的桦木浆进行对比分析 ,以期获得用于文化用纸生产时湿部的潜在滤水、留着性能及相关的手抄片性能 ,这些性能比较均基于恒定的抗张强度水平。相思木浆被证明拥有在文化用纸生产中至关重要的光散射能力、湿部成形和填料留着能力方面的优越性。需要改进的地方是 :它的滤水速率和湿纸幅强度较低 ,这些将是现代高速纸机湿部的瓶颈所在。相比之下 ,桦木浆具有较快的滤水速率和较高的湿部固含量 ,但其留着性能还有待改进     

灯泡贯流式水轮机在小流量工况下的内流特性分析

为了研究灯泡贯流式水轮机在小流量工况下的内流特性,以某水电站贯流式水轮机为研究对象,利用RNG k-ε湍流模型对全流道进行数值计算,分析在小流量工况下尾水管恢复系数和全流道流动情况,并定量分析水轮机部分过流部件的压力脉动情况。结果表明：在小流量工况下当电站水头和导叶开度不匹配时,尾水管的恢复系数减小,当尾水管恢复系数减小2%~3%时,机组效率降低1%;受转轮主流区和尾水管死水区的相互作用,在尾水管边壁会形成漩涡结构,有明显的回流且在边壁存在高速流体;在小流量工况下,机组主要受低频压力脉动影响,转轮进口处的主频是由在转轮转动和导叶提供机组环量时产生的,在尾水管中主要受频率为0.2 Hz的低频压力脉动影响,压力脉动系数沿尾水管出口方向依次增大,最大为1.75%。     

福州软土固结状态初步分析

利用卡氏作图法可求取土层的前期固结压力Pc,结合计算出的土层自重压力Po,可获得土层的超固结比OCR.在收集有关资料的基础上,对福州软土的前期固结压力和超固结比进行数理统计和对比分析,进而对各层软土的固结状态作出评价和分析.     

A study on an optimal approach temperature control strategy of condensing water temperature for energy saving

An optimal approach temperature (OAT) control strategy is proposed for resetting the condensing water temperature hourly, so to maximize the performance of the combined water chiller and cooling tower system. A system performance factor is introduced for evaluation of the system performance. A regression function is presented for the calculation of an optimal condensing water temperature at each hour of air-conditioning operation. The parameters in the regression function include the ambient wet bulb temperature, the chiller load ratio at the hour, and a dimensionless relative efficiency of chiller and cooling tower. The regression function has an R² close to 1 compared to the computed results. When applied to two cities in Taiwan, the OAT control strategy has a potential to save energy more than 4% on an annual basis. The OAT control strategy is most advantageous when applied to regions with large seasonal variation of wet bulb temperature.     

谈对修复贾谊故居工程的理解

该文对长沙贾谊故居的修复工程设计构想进行了介绍。     

渗硼-等温淬火复合强化工艺在冷镦模上的应用

铜螺钉冷镦模具在服役过程中承受着多种压缩应力、疲劳应力以及冲击胀力、摩擦力，致使模具容易产生疲劳崩裂及型腔表面磨损、拉毛及擦伤等早期失效问题。针对以上问题，本文采用了渗硼-等温淬火复合强化热处理工艺，使冷镦凹模具有了表面高硬度、高耐磨性与基体具有高强度、高韧性的完美结合，故可使模具使用寿命比常规热处理工艺提高20倍以上。