"平滑式"阀控铅蓄电池

介绍一种"平滑式"阀控铅蓄电池,它是利用蓄电池槽结构设计来实现"平滑滤波"的理论,对改进群体蓄电池的性能又是一个创新,对消除阀控电池的"膨胀"、"干涸"等大有好处,最终能有效提高蓄电池的寿命,该技术已获得国家专利.     

隔板对阀控式铅酸蓄电池电解液"干涸”的影响

从隔板方面探讨了对VRLAB"干涸”问题的影响,分析了隔板的孔隙结构及状态,并提出了解决"干涸”问题隔板应采取的对策.     

制冷用水平管降膜蒸发器的研究进展及新技术

针对制冷系统中使用的水平管降膜蒸发器,进行了包括管间流型、管外绕流成膜特征、气流、表面传热系数等流动和换热机理的综述性报道,回顾了水平管降膜蒸发器的技术进展。在批判继承前人研究成果的基础上,提出了可以解决水平管降膜蒸发器内部流动稳定性、均匀性,有效避免局部干涸等难题的新型技术——带有导流和二次布液装置的水平管降膜蒸发器技术。     

Study on two-phase countercurrent flow and transport phenomenon in PEM of a direct methanol fuel cell

The direct methanol fuel cell (DMFC), which allows the direct use of an aqueous methanol solution as the fuel and air (O2) as the oxidant, is a further development of the proton exchange membrane fuel cell (PEMFC). It seems to be the most attractively al-ternative power source for environmentally benign vehicles in the 21st century in view of its all merits, such as its simplicity from systems point of view and its potential infra-structure capability for fuel distribution. The research on…     

振荡热管的热阻变化规律及烧干特性

振荡热管作为高效传热元件,在解决微小空间而热通量较高的元器件散热方面具有独特的优势。虽然振荡热管结构简单,但其内部运行规律多变复杂,目前还处于探索研究阶段。通过对实验结果的分析,得到随加热功率和充液率改变振荡热管的热阻变化规律,探讨了不同工况所对应的传热机理;同时还对振荡热管的烧干特性进行了分析和研究。所做工作为建立振荡热管理论模型、认识其传热规律提供参考。     

自然循环流动不稳定条件下的传热特性实验研究

为探究流动不稳定性机理,在低压自然循环系统中开展了一系列相关实验,分析了不同流量振荡模式下自然循环的沸腾传热机制及局部传热特性。实验表明：中、低热流密度下出现的较规则的周期性振荡由加热段内流动沸腾诱发,壁面过热度不会随流量振荡而大幅度变化;高热流密度下自然循环系统出现的周期性不规则振荡现象中,流动沸腾类型间的相互转变不是流量波动的唯一原因。大幅度的流量脉动可能在高热流密度下导致沸腾临界的发生,出口壁面出现间歇性干涸,局部传热系数下降的同时伴随壁温的短暂飞跃。随着热流密度的提高,自然循环系统可能出现持续性干涸。     

基于液膜蒸干模型的低压低流量环状流CHF理论研究

为对低压低流量下的环状流临界热流密度（CHF）进行预测,建立了考虑液膜蒸发、液滴沉积和夹带的液膜蒸干模型,并用已有的实验数据对其进行验证。计算结果表明：在实验参数范围内,CHF计算值与实验值相对偏差在25%以内,两者符合较好。以建立的环状流CHF模型为基础,研究了进口焓差、质量流速、管径和加热长度对CHF的影响。该模型能够有效地计算低压低流量环状流CHF和分析CHF随不同参数的变化趋势。     

Investigation of Break Location Effects on Thermal-Hydraulics during Intermediate Break Loss-of-Coolant Accident Experiments at ROSA-III

The rig of safety assessment (ROSA)-III facility is a volumetrically scaled (1/424) boiling water reactor (BWR/6) system with an electrically heated core designed for integral loss-of-coolant accident (LOCA) and emergency core cooling system (ECCS) tests. Break location effects on thermal-hydraulics during intermediate LOCAs were investigated by using four experiments at the ROSA-III, the 15 and 25% main recirculation pump suction line break (MRPS-B) experiments, the 21% single-ended jet pump drive line break (JPD-B) experiment and the 15% main steam line break (MSL-B) experiment. Water injection from the high pressure core spray (HPCS) was not used in any of the experiments. Failure of ECCS actuation by the high containment pressure was also assumed in the tests.

In the MRPS-B experiments, the discharge flow turned from low quality fluid to high quality fluid when the downcomer water level dropped to the main recirculation line outlet elevation, which suppressed coolant loss from the vessel and the core. In the JPD-B experiment, the jet pump drive nozzle was covered with low quality fluid and low quality fluid discharge continued even after the downcomer water level reached the jet pump suction elevation. Low quality fluid discharge ceased after the ADS actuation. It suggestes that the JPD-B LOCA has the possibility of causing larger and more severe core dryout and cladding temperature excursion than the MRPS-B LOCA. The MSL-B LOCA was characterized by mixture level swell in the downcomer and the core. The core mixture level swell resulted in the much later core dryout initiation than that in the MRPS-B LOCA, however, ECCS actuation was also delayed because of slow downcomer water level drop.     

Critical Heat Flux for Rod Bundle under High-Pressure,Low-Flow and Mixed Inlet Conditions

The authors have developed a new on-line corrosion product monitor (OCPM) to automatically measure the concentrations of corrosion products in PWR secondary water. The corrosion products of interest for this application are mainly iron and copper. The OCPM offers a number of outstanding features: (1) it measures trace metals on-line; (2) it allows simultaneous quantitative multi-element analysis; (3) its operation is fully automatic with an excellent lower detection limit; and (4) it is transportable and easy to operate. During its development stage, the OCPM was applied at an actual PWR plant and was able to successfully automatically analyze the concentrations of iron and other trace metals contained in the PWR secondary water, while maintaining operational stability without operator intervention for long periods of time. It was also shown that the use of this new system would greatly reduce the workload of plant water chemistry personnel, providing a better alternative to conventional chemical analysis methods. The OCPM is now being introduced into several PWR plants in Japan, with the objectives of conducting detailed studies of the corrosion product behavior in the plant systems and reducing the workload of plant personnel.     

Core Liquid Level Depression due to Manometric Effect during PWR Small Break LOCA

In the previous study, it is reported that the core collapsed liquid level was depressed nearly to the core bottom and the dryout of the core was observed in the early stage of the PWR cold leg small break loss-of-coolant accident (LOCA) experiment, The manometric effect due to the liquid seal formation in the loop seal and the difference of the liquid holdup between the steam generator (SG) upflow-side and downflow-side caused a depression of the core collapsed liquid level. The core liquid level was recovered just after the loop seal was cleared.

The bypass between the core side and the downcomer side affects the core liquid depression. Four 5% cold leg break experiments with the different core bypass location, configuration and size were conducted to clarify the bypass effect. When the bypass was relatively small (less than 3% bypass of the initial core flow before the break), the timing of the loop seal clearing delayed with the bypass. When the bypass was relatively large (9.2% of the core flow), the loop seal clearing took place after the break uncovery and the timing was significantly delayed. In general, the smaller minimum core collapsed liquid level was obtained at the earlier timing of loop seal clearing due to the smaller bypass.