摄动硬球三参数状态方程的应用——Ⅱ、高压液液相平衡的计算

将摄动硬球三参数状态方程应用于二元高压液液相平衡计算。温度差在10—80℃,仅用一个二元相互作用参数,取得良好的关联结果。对包括极性、非对称性物系在内的二十七种物系高压液液相平衡计算结果与其他状态方程比较,有较高的精度,并且与实验值符合较好。对甲烷-正己烷系统的汽液、液液、汽液液三种类型的相平衡数据用同一个二元相互怍用参数得到满意的关联结果。     

BOILING HEAT TRANSFER ON SURFACES WITH ARTIFICIAL NUCLEATION SITES (Ⅰ) EFFECT OF CAVITY SIZE, CAVITY DENSITY ON BUBBLE DEPARTURE DIAMETER AND FREQUENCY

By means of high-speed photography and optical-fiber probe, the effect of nucleation cavity size and cavity density on the bubble departure diameter and frequency has been investigated. The enhanced heating surface employed has artificial nucleation sites arranged regularly.Based on the analysis of the various forces exerted on the vapor bubble, a mathmatical model has been developed for correlating bubble departure diameter and frequency with the surface geometry and the degree of superheat.Experimental data has confirmed the availability of the model presented.     

液体沸腾的给热系数

关於液体沸腾给热系数的准数方程式,前人虽提出不少,但都不够完善,特别是各种盐溶液或多组份的液体混合物,其沸腾给热机理尚待研究。前人实验结果往往相差很大,甚至结论有互相矛盾的地方。 本文采用的研究设备是大容积内水平元管及水平元钣的加热装置。传热表面的材料有黄铜,紫铜,不锈钢,镀镍,镀铬表面等种,以比较不同传热面的影响。对同一材料的传热,又比较了清净表面,老化表面,和有污垢表面的影响。水平元管及水平元钣均用电热,元管的热负荷为1300～40000千卡/米~2·小时,元钣的热负荷范围为20000～900000千卡/米~2·小时。所用物料是清水,5～20%的食盐溶液。研究的结果是: （1）在低热负荷下,加热表面材料不同对沸腾给热是有影响的,主要是由於不同材料对液体的湿润能力不同,接触角大小不同的缘故。但这种影响只是数量上的,对沸腾机理并无影响,也即在下列关系中: a=c·q~n, （1）c值对各种表面来讲是不同的,但n仍然是一样的。 其中以黄铜的a为最高,镀铬的表面为最低。在高热负荷下,加热表面对a无显著的影响。 （2）对同一材料来讲,清净新鲜的表面a最大,老化的次之,有污垢的a最小,而且斜率也不同於前二者。 （3）加热面几何形状相同时,尺寸大小对a的影响在普通生产情     

摄动硬球三参数状态方程的应用——Ⅰ.高压汽液相平衡的计算

应用摄动硬球三参数状态方程(CSPT方程)进行混合物高压汽液相平衡计算。结果表明,硬球三参数状态方程广泛适用于极性、非极性、对称、非对称等各类混合物系。对31种二元混合物系在不同温度、不同压力下汽液相平衡的计算结果与PT三参数状态方程比较,有较高的精度,能很好地与实验数据吻合。     

A NEW METHOD FOR ACHIEVING DROPWISE CONDENSATION (Ⅱ) NEW SURFACE MATERIALS FOR DROPWISE CONDENSATION

Technology of ion-plating and ion-beam mixing was employed to prepare surface alloys on copper tubes. Elements chosen for the purpose are Cr, Fe, Al, N, Bi, Sb, Sn, Se and In. Excellant dropwise condensation of steam was then obtained on some external surfaces of these copper tubes and the mechanism for the dropwise condensation was analysed.The surface characteristics of the Cu-Cr and Cu-Fe alloy layers were analysed by using XPS, AES and AES-PRO of PHI-550 multiple function electron spectroscopy.     

多效多级闪蒸(MEMS)设备的设计计算

一、概况蒸发法(或蒸馏法)海水淡化主要有两大类,卽多效蒸发法和多级闪蒸法。关于两者的原理已作过介绍,不再重述。多效蒸发在化工及其它部门早已应用,在海水淡化领域中应用也较早(如较老的浸管式海水蒸发器),但因加热管管壁结垢,使其应用受到了限制。为了避免结垢,多级闪蒸就逐步发展起来,它的最大特点就是:在传热管管壁上没有沸腾和汽化现象,而汽化是在空的闪蒸室内进     

Filmwise Condensation Heat Transfer Enhancement with Dropwise and Filmwise Coexisting Condensation Surfaces

Six surfaces were prepared with defferent surface division patterns for the experimental investigationof steam condensation heat transfer characteristics for dropwise and filmwise coexisting(DFC)condensationsurfaces under atmospheric pressure Dropwise condensation(DWC)was promoted with an ultrathin polytetrafluoroethylene(PTFE)film,which was prepared by the dynamic ion-beam mixed implantation(DIMI)method.The results showed that the condensation phenomena at the intersection between the dropwise andfilmwise condensation regios were quite different for different relative positions of the dropwise and filmwisecondensation regions.The experimental results revealed that the condensation heat transfer characteristics werehighly influenced by the surface division number and the relative area ratio of the dropwise and filmwise conden-sation regions.The impact of thesc findings on heat transfer enhancement mechanism for condensation heattransfer is discussed in detail.     

聚合物涂层竖板上水蒸气滴状冷凝传热特性的研究

The plasma polymerization method and dynamic ion-beam mixed implantation method were employed to coat ultra-thin polymer films on copper plates. Experiments indicated that steady dropwise condensation of steam at atmospheric pressure occurred. The condensation heat transfer coefficients increased by approximately 3 and 5---7 times for the polytrimethylvinylsilane film and polytetrafiuoroethylene film respectively, compaxed with the value for film condensation under the same experimental conditions. The temperatures on the condensing surface and inside the test block were found to be rapidly and randomly fluctuated. The properties of the coated films and advantages of the methods used in this investigation were discussed briefly.     

聚合物表面性能对强化冷凝传热的影响

对离子束动态混合注入(DIMI)技术制备的黄铜、紫铜、不锈钢和碳钢管基聚四氟乙烯(PTFE)表面的冷凝传热实验发现,用不同加工条件制备的表面具有不同的化学组成、不均匀的表面状态以及不同的物理化学性质,从而导致不同的冷凝成滴面积和传热性能,而且表面加工条件对滴状冷凝传热的寿命有至关重要的作用,不同基体材料应有不同的最佳制备工艺条件.不同工艺条件下制备黄铜基PTFE表面水蒸气竖直管外冷凝传热通量比相应的膜状冷凝提高0.3-4.6倍,冷凝传热系数提高1.6-28.6倍.实验结果也表明冷凝表面基体材料对冷凝传热性能有一定的影响.     

CORRELATION OF CRITICAL LOCI FOR FLUID MIXTURES

The hard-sphere three-parameter equation of state proposed in our previous investigation was applied to correlate binary critical loci of alkane-alkane, aromatic-aromatic, hydrocarbon-inorganic gas and systems containing oxygenated hydrocarbons including those exhibiting type Ⅲ behaviors as classified by van Konynenberg and Scott. A new procedure was also presented which simplified mathematical manipulations and permitted the reduction of the computation time.Results were compared with those obtained by Patel-Teja equation with temperature-dependent binary interaction parameters. Significant improvements were achieved by the proposed equation with temperature-dependent parameters.In addition parameters obtained from the critical locus calculations were used to predict vapor-liquid equilibria of hydrogen-carbon monoxide and hydrogen-carbon dioxide systems. Prediction accuracies were found to be very satisfactory.