膨胀接触蒸发式制冷的实验与分析

叙述了膨胀接触蒸发式制冷的实验装置、制冷原理、分析方法与实验和计算结果及结论。     

步进式加热炉滑道冷却方式的发展趋势

简要介绍了国外步进式加热炉汽化冷却发展情况。从理论上、实际运用上较详细地阐述了步进炉采用汽化冷却优于水冷却。     

Experimental investigation and cost assessment of the salt production by solar assisted evaporation of saturated brine

The technical feasibility and economy of solar heat collection-forced evaporation process are the keys to its practicality,especially its application in strong brine treatment.The operation cost of applying solar collection in salt manufacturing through depth evaporation of brine has been studied.For Na~+,K~+,Mg~(2+)//Cl~-,SO_4~(2-)-H_2O salt–water system,most of the Na Cl and all of the Carnallite were separated.The operation cost reached the optimum when the heat collection and evaporation were controlled at 75 and 55°C,respectively.When the solar radiation amount was 19557 kJ·m~(-2)·d~(-1),the solar collector area for producing Carnallite was about 34.27 m~2·(t salt)~(-1),and the operation cost was 13 USD?(t salt)~(-1).The energy consumption of salt manufacturing is at least 25%higher than that of natural evaporation.Regarding the economy,the solar assisted salt manufacturing process is recommended to be performed at a production scale of more than 20 tons per day.     

Optical properties of a silicon-nanocrystal-based-microcavity prepared by evaporation

A silicon-based microcavity constituted by a SiO/SiO₂ multilayer and Si/SiO₂ Bragg mirrors was prepared by the evaporation technique. We give details about the microcavity realization process. The optical properties of the Si nanocrystals, obtained by the thermal dissociation of the SiO layers, were analyzed by continuous-wave and angle-resolved photoluminescence (PL) experiments. The results show a strong anisotropy of the light emitted by the silicon nanocrystals for a cavity constituted by mirrors with only two distributed Bragg reflectors (DBR).     

Evaporation and dispersion of respiratory droplets from coughing

Understanding how respiratory droplets become droplet nuclei and their dispersion is essential for understanding the mechanisms and control of disease transmission via droplet‐borne and airborne routes. A theoretical model was developed to estimate the size of droplet nuclei and their dispersion as a function of the ambient humidity and droplet composition. The model‐predicted dried droplet nuclei size was 32% of the original diameter, which agrees with the maximum residue size in the classic study by Duguid, 1946, Edinburg Med. J., 52 , 335 and the validation experiment in this study, but is smaller than the 50% size predicted by Nicas et al., 2005, J. Occup. Environ. Hyg., 2 , 143. The droplet nuclei size at a relative humidity of 90% (25°C) could be 30% larger than the size of the same droplet at a relative humidity of less than 67.3% (25°C). The trajectories of respiratory droplets in a cough jet are significantly affected by turbulence, which promotes the wide dispersion of droplets. We found that medium‐sized droplets (e.g., 60 μm) are more influenced by humidity than are smaller and larger droplets, while large droplets (≥100 μm), whose travel is less influenced by humidity, quickly settle out of the jet.     

Rainfall identification and estimation in Guangzhou area used for building energy simulation

In uncomfortably warm areas and seasons of the year, passive cooling effects resulting from natural rainfall evaporation can greatly cut down on building energy consumption. To simulate the passive evaporation cooling effect and evaluate the relevant energy-saving potentials, hourly rainfall data are needed. However, in currently used building energy simulation software, such as DOE, EnergyPlus and DeST, no rainfall information is provided in the climatic database. This paper uses a limited set of monthly and daily rainfall distribution data in Guangzhou area to identify and model monthly, daily and hourly rainfall patterns. For a current weather database used by building energy simulation software, rainy days and rainy hours are distinguished using distance discriminant analysis, which uses measured data samples for rain identification. According to an autocorrelation analysis of rain sequences, a one-order AR model is suitable for monthly rainfall estimation by AIC criterion judgment. Distribution of daily rainfall month-by-month shows a Gamma distribution model agrees well with daily rainfall distribution. Using a Gamma distribution model and monthly total rainfall, daily rainfall is assigned stochastically. Analysis shows distribution patterns of hourly rainfall percentage, both in the rainy season and non-rainy season, coincide well with the Beta distribution. Using a Beta distribution model and daily total rainfall, hourly rainfall is assigned stochastically. A comparison of statistics features of simulated data to that of measured data validates the method.     

DCS在碱回收黑液蒸发过程中的应用

介绍了一种新的蒸发工段DCS控制方法,采用S7PLC CPU 414—2DP,连接ET200系列的分布式I／O系统及标准服务系统所组成的DP控制网络,对碱回收黑液蒸发过程实施集散控制的优化控制方案。     

超声波防除积垢节能技术

本文选择糖厂蒸发罐积垢为研究对象,研究了超声波防除传热设备积垢的作用。在弄清机理的基础上进行生产性试验,结果表明：超声波不仅具有减缓积垢形成速度又能破坏已有积垢的双重作用,能提高蒸发系统的传热系数０．６～０．８倍,停止使用化学清洗剂煮罐,处长设备使用寿命,减轻劳动强度,无化学污染,是一项新型高效的节能技术。     

异形竖板降膜蒸发器的蒸发浓缩特性

以绿茶汁为物料 ,建立了反映蒸发浓缩性能与品质保持性能的蒸发浓缩过程质量评估准则IQ ,并以此准则为依据 ,以管式降膜蒸发器性能对比的方法 ,研究了热力浓缩新设备异形竖板降膜蒸发器的综合性能。结果表明 ,与管式蒸发器相比 ,异形竖板降膜蒸发器更适宜于液体食品的蒸发。     

分隔式降膜蒸发罐及其传热优势

介绍了一种新型降膜蒸发罐－－分隔式降膜蒸发罐,并通过对降膜蒸发罐的糖液沸点升高和蒸发罐传热系数的分析讨论,阐述了分隔式降膜蒸发罐的传热优势。