高性能过冷水连续制冰系统

过冷水连续制冰是最近发展起来的一种新的制冰技术，与传统的静态制冰相比，具有较高的制冰率和能量效率，制出的泥状冰分散性好，可以直接随水在管道中输送，在前文研究的基础上，建立了具有较高性能的过冷水连续制冰系统，过冷却器换热段长度3m，过冷却器进口水温为0．5℃，出口水温达到－3．3℃，系统性能可望进一步提高，达到实际开发利用的水平。     

各种因素对过冷水发生结冰的影响

研究外界因素对过冷水发生结冰的影响，是研究防止结冰以及制冰方法的基础。本文研究了结冰基体表面粗糙度，表面材料，表面面积，对结冰基体表面的摩擦、按压等作用，水的流动状态以及对水的磁化等对过冷水发生结冰的影响，对实验结果进行了初步的理论解释，并对文献的实验结果进行了分析。     

冰盘管蓄冰过程的动态特性

建立了直接蒸发过程冰盘管的动态模型，并对模型进行求解，得到冰盘管的结冰半径、热流密度以及蓄冷量随时间变化的关系。该模型能较好的反映冰盘管的动态特性。     

冰蓄冷系统研究新进展

介绍了不同冰蓄冷系统研究的新进展 ,并着重介绍一种新的冰蓄冷技术—过冷水动态制冰技术及与冰蓄冷空调系统有关的低温送风技术 ,以及蓄冷技术应用与峰谷分时电价之间的内在联系。最后 ,对于未来冰蓄冷研究提出几点建议     

过冷水中超音速蒸汽射流形状特征及冷凝传热

研究了浸没在过冷水中的超音速蒸汽射流的形状及其直接接触冷凝传热特性.给出了基于射流出口压力、质量流密度和池水温度的三维识别图与查表识别法2种判断蒸汽射流形状的方法.通过理论分析得到了基于马赫数Ma和雅克比数Ja的蒸汽射流无量纲穿透长度、最大膨胀比以及新的传热关系式,并对相关文献的实验数据进行了拟合与对比验证.结果表明:传热关系式计算值与实验数据拟合结果吻合较好,蒸汽射流无量纲穿透长度计算值与实验数据的误差约为±25%,最大膨胀比误差在±12%;通过蒸汽射流形状判断,选择与其对应的形状与传热关系式,可完成超音速蒸汽射流在过冷水中直接接触冷凝的传热计算.     

涡旋分离技术与冷轧直冷水的闭路净化

介绍内循环涡旋分离技术，结合实例，解决企业污水净化问题。     

综采工作面过断层采煤技术应用探讨

以A煤矿为对象,在概述工作面及断层情况的基础上,对直接过断层、预裂爆破过断层及预掘巷与割底结合过断层等综采工作面过断层采煤技术的具体应用进行了分析探讨,还阐述了裂隙水、断层走向及与工作面交角、断裂带宽度等影响综采工作面过断层的因素。分析结果为综采工作面安全高效开采提供了技术保证,也为其他工作面相似条件下开采实践提供了科学依据。     

综采工作面过断层安全技术措施的应用

断层是综采工作面经常遇到的一种地貌,如果处理不到位,会引发支架移动困难、煤柱煤壁片帮、顶板破碎等问题。分析了过断层常用的施工方法,深入研究了综采工作面过断层安全技术措施,结合实际工作,探讨了综采工作面过断层安全技术措施的实际应用。     

冰蓄冷空调蓄冰罐特性的研究

本文通过对某大厦冰蓄冷空调系统的运行情况的测试,详细研究和分析了蓄冰罐在不同流量下的蓄冷和释冷特性,在融冰工况时,蓄冰罐进口温度出口温度和释冷量的影响。     

Dynamic crystallization characteristics of the working process of small type ice slurry maker

动态冰蓄冷是储能领域中广受制冷界重视的潜热储冷技术,基于平板刮削方式设计并搭建了小型动态制备冰浆实验装置,通过测试制冰溶液的动态结晶降温曲线、不同结晶时刻的含冰率和冰晶当量直径,分析了结晶时间、载冷剂温度、添加剂种类与浓度、刮削速度等因素对冰浆制备过程动态结晶特性的影响。结果表明：刮削速度低于200 r/min,溶液结晶过冷度随刮削速度的增大而增大,冰浆的含冰率以及冰晶粒径均随结晶时间的增加而增大,在冰晶粒径较大时刮削作用引起冰晶颗粒聚并、破碎,导致冰晶粒径增大减缓甚至减小;随添加剂浓度的增大,冰浆含冰率增大速率与冰晶粒径增大量均有所减小,且强极性无机化合物对冰晶生长的抑制效果好于乙二醇等醇类化合物。     

Dynamic modelling and experimental study of an ice generator heat exchanger using supercooled water

Since confirmation of the contribution of the refrigerants to ozone depletion and global warning, many solutions have been carried out to reduce their direct and indirect impact on the environment. One of them consists in using secondary refrigerant fluid (SRF) to reduce the amount of refrigerant flowing in the refrigerant loop. The new two-phase SRF present some advantages, and this paper presents a process using supercooled water to produce such fluid.     

A thermal nonlinear dynamic model for water tube drum boilers

A thermal model for the prediction of possible tube overheating was developed. The model incorporates a nonlinear state space dynamic model that captures the important physical interactions of the main variables of steam generation in naturally circulated water tube drum boilers. This paper provides an investigation of the dynamic effects of rapid rise in fuel flow rate (heat input) on the thermal and flow characteristics of the riser tubes in natural circulation water tube boilers. The system under consideration includes the drum, riser and downcomer as its major components. The dynamic response of the system's state variables due to rapid rises in fuel flow rates was investigated. The results show that the sudden rise in the firing rate is followed by an increase in the steam quality, which is accompanied by a decrease in the circulation rate as a result of increase in the pressure. The riser temperature increases slightly above the saturation temperature due to the increase in the steam temperature and due to the dynamic influence resulting from sudden increase in the heat flux. The present calculations of the water level in the drum provide good comparison with those in the literature. Copyright © 2009 John Wiley & Sons, Ltd.     

Development and rheological characterisation of an industrial liquid fuel consisting of charcoal dispersed in water

Developing an industrial liquid fuel based on charcoal and water was the target of the present work. The relevance of this study is justified by the high energy potential of charcoal, its renewable nature, the easiness of storage and transportation in the liquid form, and by all the associated economic and environmental advantages derived thereof.The ability of a commercially available charcoal to be dispersed in water was evaluated by analysing the rheological behaviour of the resulting charcoal water slurries (ChWS). The charcoal was ground in a conventional ball mill and dispersed in water with the aid of different surfactants. The effects of the most relevant factors influencing the rheological properties of the suspensions were evaluated, including: (i) type of surfactant and its added amount on the fuel viscosity (η) at a given solids fraction; (ii) the charcoal content, which should be as high as possible. The results enabled selecting the most efficient surfactant and its optimal amount required for minimising the fuel viscosity (η) and enhancing the stability of the suspensions. Stable ChWS containing 60 wt.% solids and 1 wt.% surfactant and exhibiting adequate flow properties were successfully obtained.     

Molecular dynamic investigation on sulfur migration during hydrogen production by benzothiophene gasification in supercritical water

Benzothiophene (BT) is a key sulfur-containing intermediate product in the thermal conversion process of coal and heavy oil. The migration process of the sulfur element may affect the thermal utilization design of BT. In this paper, BT was used as a model compound to simulate the supercritical water gasification (SCWG) process by molecular dynamics with a reactive force field (ReaxFF) method, and the laws of hydrogen production and sulfur migration mechanisms were obtained. Increasing the molecule number of supercritical water (SCW) and increasing the reaction temperature can enhance the generation of hydrogen and promote the conversion of organic sulfur to inorganic sulfur. Water was the main source of H₂, and H₂S was the main gaseous sulfur-containing product. SCW had a certain degree of oxidation due to a large number of hydroxyl radicals, which could increase the valence of sulfur. The conversion process of BT in SCW was mainly divided into four stages, including thiophene ring-opening; sulfur separation or carbon chain broke with sulfur retention; carbon chain cleaved, and gas generation. The lumped kinetic parameters of the conversion of sulfur in BT to inorganic sulfur were calculated, and the activation energy was 369.98 kJ/mol, which was much lower than those under pyrolysis conditions. This article aims to clarify the synergistic characteristics of hydrogen production and sulfur migration in the SCWG process of BT from the molecular perspective, which is expected to provide a theoretical basis for pollutant directional removal during hydrogen production by sulfur-containing organic matters in SCW.     

一种新的过程节水分析方法──水夹点技术及应用研究

介绍利用水夹点技术进行过程节水的分析方法,阐述了水夹点系统设计的Ｃ－Ｍ图,浓度组合曲线的构造原理,及水夹点系统设计的原则和具体步骤．应用研究表明,与常规技术相比水夹点技术节水提高１６．３％．     

Modeling of liquid water transport in a proton exchange membrane fuel cell gas flow channel with dynamic wettability

Liquid water transport in the gas flow channel is significantly important for the water removal and management in proton exchange membrane fuel cells. Previous numerical studies consider a single and constant static contact angle for the liquid water transport on the channel surface, which is insufficient to account for the dynamic wettability behavior of the flow. In this study, a dynamic wettability model is developed that incorporates the sliding angle and dynamic contact angles for the simulation of water transport in the flow channel. It is found that both the sliding and dynamic contact angles have significant impact on the characteristics of the water transport and dynamics in the flow channel. Water spreading on the channel surface is elliptic, and its minor and major axes oscillate out of phase with the droplet height. The pressure loss for the 2‐phase flow in the channel is directly related to this oscillation and deformation of the droplet shape. Flow channel surface with a small sliding angle facilitates the water transport and removal and reduces the associated pressure loss in the channel. The conventional static wettability model would overpredict droplet deformation and breakup as well as the pressure loss in the channel.     

Aggregating structure in coal water slurry studied by eDLVO theory and fractal dimension

Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy. Moreover, biomass and waste can be added, making gasification process greener. To expand the application of coal water slurry and gasification process, it is necessary to understand the micro-structure in this large particle suspension system. In this paper, the micro-structure in coal water slurry was studied by extended DLVO (eDLVO) theory and fractal dimension, which is used to explain the mechanism of stability in large particle suspension systems. The interaction between two coal particles was characterized from the interparticle potential and energy barrier based on the eDLVO theory. The rheology and stability between different types of coals are measured and explained by the aggregating structure and fractal dimension in coal water slurry. The results indicated that there would be an aggregating structure in high rank coals, due to the interparticle potential caused by the surface properties, but probably not in low rank coals. This aggregating structure can be described and characterized by fractal dimension. The aggregation of particles is the source of the stability for high rank coals, as the close-packed 3D network structure in large particle suspension can support coal particles from settling down. The results have demonstrated that the combination of the eDLVO theory and rheological measurement is an effective way to investigate the stability of large particle suspension systems.     

Freezing characteristics of supercooled water in gas diffusion layer of proton exchange membrane fuel cells

The freezing characteristics of supercooled water in a gas diffusion layer (GDL), which are the bases for the cold start-up of proton exchange membrane fuel cells (PEMFCs), were investigated. An experimental apparatus for noncontact temperature measurement and observation systems was developed. GDL and GDL with a microporous layer (MPL) were prepared, and freezing experiments using a water-containing GDL under various cooling rates were performed with variations in polytetrafluoroethylene (PTFE) content and water saturation. Furthermore, based on the experimental results, the freezing initiation probability was theoretically investigated to elucidate the freezing characteristics. Results showed that, with increasing supercooling of water in GDL, the freezing probability of water increased abruptly. The effect of saturation showed a different trend depending on PTFE addition. For the GDL without PTFE, the freezing initiations occurred at approximately 6 °C of supercooling degree, and the probability approached 1.0 at approximately 9.5–11.5 °C, with saturation dependency. In contrast, for both GDL and GDL + MPL containing PTFE, the initiation temperature characteristics were relatively similar, which were approximately 8–12 °C, regardless of the saturation and PTFE content. In these cases, the ice-nucleating activity of water in the GDL was possibly stronger than that in the MPL.