HEAT-TRANSFER AND GAS-HOLDUP STUDIES IN A BUBBLE COLUMN: AIR-WATER-GLASS BEAD SYSTEM

Air-holdup and heat-transfer coefficient values are measured in a 0.305 m diameter bubble column equipped with a seven-tube bundle for the air-water and air-water-glass bead system. The dependence of these two properties on air velocity (up to 0.28 m/s), temperature (297-343 K), glass bead powder average size (50-143.3 μm), solids concentration in the slurry (up to 20 weight percent) and bubble column diameter (0.108 and 0.305 m), is experimentally investigated. The effect of internals, as simulated by a single probe and a seven-tube bundle, in the two bubble columns is also examined. The models and correlations commonly employed to estimate these properties are assessed on the basis of generated data.     

再入飞行器再入函数及其导数与积分

从“直线弹道”的基本假设和结论出发,推导并给出了再入飞行器再入大气层过程中,诸多物理量的近似解析计算公式,揭示了各物理量之间内在的本质联系、各物理量随再入高度的基本变化规律以及它们与再入飞行器再入初始速度、初始弹道倾角、再入飞行器质阻比的关系。     

换热型节能技术在基站中的应用研究

换热型节能技术虽在基站中得到了大量应用,但由于应用场景至今还没有科学客观定量评估规定,使工程实施处于一种无章可循的尴尬局面,阻碍了换热型节能技术的进一步推广和应用。深入研究分析了基站内各类设备工作环境温湿度、空气清洁度和换热型节能设备能效比等技术指标,对比了不同标准中相关技术指标,指出了不同标准相关技术指标差别和部分标准存在的问题,并结合大气空气质量和环境温度等因素,提出了换热型节能技术应用场景和新风系统工程设计方法。     

风冷压缩单元式空调器节能探讨

从分析风冷压缩单元式空调器的制冷原理入手,提出了两种空气源热泵热水模块＋空气源压缩制冷模块机,为提高能源综合利用效率、节约建筑能耗提供了一定的实践思路。     

矿用隔爆型变频器散热方式的选择

根据变频器功率和使用环境的不同,为矿用隔爆型变频器提出几种适合的散热方式。     

FR-4基材高导热印制板的研制

介绍一款用FR-4基材,结合导热胶,制作高导热印制电路板的方式。这款印制板既解决了客户要求导热系数高,又成本低廉、可靠性好,还可以代替高成本的金属基印制板。同时在制作方式上,还能利用原来生产设备,生产工艺也可不作大的调整,能够快速导入批量生产。     

进口板式换热器在亚法糖厂的使用

本文着重介绍了进口板式换热器在云南亚法糖厂的使用情况,并从节能角度出发,通过分析,提出了更有效发挥板式换热器节能效果的方法。     

Heat spreading in a thin longitudinal fin

In view of the trend towards higher power densities in ever shrinking geometries, understanding heat spreading fundamentals is gaining importance. In this paper heat spreading in thin longitudinal geometries is considered. This geometry is of practical interest in one-dimensional Cartesian geometries. A characteristic length is derived and it is shown that this has physical significance for the distance that heat spreads, and for the total amount of heat cooled away. Furthermore, it is investigated when “thin” is a viable assumption. The use of the characteristic length is illustrated for the case of a line source cooling to a plate and for the case of the fins of a plate heatsink. The results are compared to numerical simulations. The work is an extension of the authors' earlier work on heat spreading in infinite longitudinal geometries and heat spreading in infinite and finite circular geometries.     

直拉硅单晶热处理及其对太阳电池性能的影响

研究了直拉头尾料P型硅单晶片在360～1 300℃范围热处理前后氧碳含量、电阻率和少子扩散长度的变化规律及其对所制成太阳电池性能的影响。已证实在最佳的热处理条件下样品含氧量减少,少子扩散长度和电池效率达到最大,比未作热处理的单晶电池效率提高0.5～2倍,为利用这类单晶提供了有效方法。对此现象用热施主与深中心相互作用的模型作了初步解释。