换相器

Mathematic model of the refrigeration system is presented with applying the distributed parameters method. In the models of condenser and evaporator, the flow patterns and its effects on the heat transfer coefficients of refrigerant side are considered.

采用分布参数的方法建立了制冷系统的数学模型，在建立冷凝器和蒸发器两相区模型时采用了分相流模型，并考虑了流型变化对制冷剂流动换热过程的影响。

In Chapter 5 a group of total differential equations for the design of capillarysuction tube with heat recovery exchanger is presented. The calculation results and factors having great influence on the results are given and discussed.

第五章建立了毛细管回热器设计计算的常微分方程组，分析了有关参数取值对计算结果的影响，讨论了当回热段全部或主要处于汽液两相区域时，回热的起始位置、换热温差等因素对于计算结果的影响非常敏感的原因。

Finally, suitable correlation of flow boiling with pure refrigerants in horizontal tubes, condensation heat exchange factor of steam containing non condensable gases and air-side thermal performance of condenser are selected by means of programming calculation.

最后用自编的专用程序计算、拟合了双相变换热器的水平光管内沸腾和汽侧冷凝的换热关联式。

A separated model is developed for the recirculating flow and heat transfer in a kettle reboiler tube bundle.

提出了釜式再沸器管束中循环流动换热的分相预报新模型，考虑了管束下部的过冷沸腾及循环液体的侧面引入。

The writer thinks existing major problems:1、The confusion Produces by the same plant have the different name、the different plant have the same name、think the typeface meaning just the righteousness,even fabricate without basis etc; 2、Because dont understand living creature type and adaptability in the depth of the water for the plants , A great deal of aquatic plants death;3、In planting design, so much express of plants specification ,and many of them are disobey with biology characteristic, so the plants are hard for purchase or the result is very bad after plant; 4、Plant density more than 100 times or less than several decuples of normal.

作者认为存在的主要问题有：1、植物名称同物异名、同名异物、望文成义，甚至凭空捏造等等产生的混乱；2、植物生物型和水深适应性不了解造成的种植水深不符植物习性，从而使大量水生植物死亡；3、种植设计中，苗木规格的表述不妥，许多表述与植物的生物学特性相违背，造成苗木难以采购或种植后效果极差；4、种植密度严重偏大或偏小，偏大的大于正常的100多倍，小的则少几十倍螺旋板换热器。

In this dissertation, at first, the history and present situation of the research related to overheating is reviewed, and then the research works are carried out in following aspects the calculation of radiative properties of coal combustion, the solution of radiative transfer equation in absorbing-scattering media, the analyses of combined heat transfer processes in flue side, the computation method of steam temperature deviation of superheaters and reheaters and the inversion method of their wall metallic temperature in furnace, the numerical simulation of gas-solid two-phase flow, combustion and heat transfer in furnace, the measurement of outlet steam temperature of superheaters and reheaters, engineering reformation of overheating and optimum design of superheaters and reheaters, etc.

本文在综述了与过热器和再热器超温问题有关的研究历史与现状的基础上，在煤粉燃烧产物辐射特性的计算、含散射问题的辐射传递方程的求解、过热器和再热器烟气侧对流与辐射复合换热及汽温偏差的计算和炉内金属壁温的反演、炉内气固两相流动、燃烧、传热过程的数值模拟、过热器再热器炉外出口汽温的测量、过热器再热器超温问题的工程改造及设备的优化设计等方面进行了研究。

The thesis mainly researches on the single phase AC/AC converter in the topologies including AC_Buck and AC_Cuk. Firstly, the operating principles of the two converters are analyzed in detail and the rules of their parameters design are educed; The commutation of their power switches which is the key of these topologies to realize is analyzed in detail and a feasible solution which can be named RCD-Commutation mode is presented and proved effectual by theory analyses and simulation results.

本文首先分析了AC_Buck变换器的变换原理，得出了电路参数设计准则；继而对电路实现的难点即功率管换流问题进行了深入分析，并得出了一种可行的解决方案即RCD换流方案；作为对简单拓扑单相直接AC/AC变换器控制策略的探索，本文以AC_Buck为平台，对电压单闭环瞬时值控制方案进行了研究，在理论分析和仿真研究的基础上设计并制作了一台采用RCD换流、电压单闭环瞬时值控制的AC_Buck变换器原理样机。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐