Chapter 1 Introduction to Thermal
Science
第一章热科学基础
Acoustic flow meter 声波流量计Corrugated fin 波状散热片Adiabatic []绝热的Cross product 矢量积Aerodynamics 空气动力学Denominator 分母
Affiliation 联系Developed flow 充分发展流
Airfoil 机翼,螺旋桨Diffusion 扩散
Alternative 替代燃料Doppler effect 多普勒效应Anemometer 风速计Double-pipe heat exchanger 套管式
换热器
Angular speed 角速度Dry saturated vapor 干饱与蒸汽Area density 表面密度Electrode 电极
Baffle 挡板Electrolyte 电解,电解液
Bifurcation 分形Electrostatic 静电的
Blackbody 黑体Emissivity 发射率
Blade 浆叶,叶片Equilibrium 平衡
Boiler 锅炉Fluid mechanics 流体力学
Boundary layer 边界层Forced convection 强制对流Carnot Cycle 卡诺循环Free convection 自然对流
Cartesian coordinates 笛卡尔坐标系Friction loss 摩擦损失
Celsius Degree 摄氏度Glass ceramic 微晶玻璃,玻璃陶瓷
Heat engine 热机
Compact heat exchanger 紧凑式换热
器
Composition 成分,合成物Heat pump 热泵
Compressed liquid 压缩液体Hydrofoil 水翼
Compressibility 可压缩性,压缩率Hypersonic speed 高超音速Condensation 凝结Infinitesimal 无穷小的
Condenser 冷凝器Inflating/deflating 充气/压缩Conduction 导热Internal combustion engine 内燃机Control volume 控制体Isentropic 等熵的
Convection 对流Isobaric 等压的
Isolated system 孤立体系的
Coriolis-accelaration flowmeter 科
氏加速流量计
Isometric 等容的Rough-wall tube 粗糙管
Isothermal 等温的Saturation 饱与
Kinematic viscosity 运动黏度Shear stress 剪切力、切应力Laminar 层流Shell-and-tube heat exchanger管壳
式换热器
Manuscript 手稿,原稿Specific volume 比容
Moisture 湿度,水分Steady 稳态的,定常的
Molecule (化学)分子Stifling engine 斯特林机
Molten polymer 熔融聚合物Strain rate 变形速度,应变率
Muti-disciplinary 多学科的Streamline 流线
Newtonian Fluid 牛顿流体Strut 支撑,支柱
Subcooled liquid过冷液体
Nominal temperature gradient 法向
温度梯度
Numerator (数学)分子Superheated vapor 过热蒸汽
Parallel flow 平行流动,并流Surrounding 环境,外界
Pathline迹线Thermal conductivity 热传导率Phase change 相变Thermal efficiency 热效率
Plane flow 平面流,二元流Thermodynamics 热力学
Plate and flame heat exchanger
Torsional 扭力的,扭转的
板式换热器
Polymer solution 胶浆Trailing edge 机翼后缘、尾缘
Proof 校样Transmitter 传送装置、发送器Propeller 螺旋桨,推进器Turbine meter 涡轮流量计
Pump泵Turbulent 湍流的
Qulity 干度Ultrosonic 超声波的
Qusi-equilibrium 准平衡、准静态Uniform flow 均匀刘
Radiation 辐射Vacuum 真空
Rankin Cycle 朗肯循环View factor 角系数
Viscous 黏性的
Regenerative heat exchanger
蓄热/再生式换热器
Reservoir 水库,蓄水池Cortex shedding 漩涡脱落
Reversible 可逆的Water faucet 水龙头,水嘴
Rotameter 转子流量计
Bi Biot number 比澳数NPSH 汽蚀余量
CFD 计算流体力学NTU 传热单元数
CHF 临界热流量Nu 努谢尔特数
COP 制冷系数PE 势能
Eu 欧拉数Pr 普朗特数
Fo 富立叶数Ra 瑞利数
Fr 弗劳德数Re 雷诺数
Gr 格拉晓夫数Sc 施密特数
KE 动能St 斯坦顿数 , 斯特劳哈数
LMTD对数平均温差We 韦伯数
1.1Fundamental of Engineering Thermodynamics
1.1工程热力学基础
Thermodynamics is a science in which the storage, transformation and transfer of energy are studied、 Energy is stored as internal energy (associated with temperature), kinetic energy (du to motion), potential energy (due to elevation) and chemical energy (due to chemical composition); it is transformed from one of these forms to another; and it is transferred across a boundary as either heat or work、热力学就是一门研究能量储存、转换及传递的科学。能量以内能(与温度有关)、动能(由物体运动引起)、势能(由高度引起)与化学能(与化学组成相关)的形式储存。不同形式的能量可以相互转化,而且能量在边界上可以以热与功的形式进行传递。
In thermodynamics, we will derive equations that relate the transformations and transfers of energy to properties such as temperature, pressure and density、 Substances and their properties, thus, become very important in thermodynamics、 Many of our equations will be based on experimental observations that have been organized into mathematical statements or laws, the first and second laws of
thermodynamics are most widely used、
在热力学中,我们将推导有关能量转化与传递与物性参数,如温度、压强及密度等关系间的方程。因此,在热力学中,物质及其性质变得非常重要。许多热力学方程都就是建立在实验观察的基础之上,而且这些实验观察的结果已被整理成数学表达式或定律的形式。其中,热力学第一定律与第二定律应用最为广泛。
1.1.1Thermodynamic system and control volume
1.1.1热力系统与控制体
A thermodynamic system is a fixed quantity of matter contained within some enclosure、The surface is usually an obvious one (like that surrounding the gas in the cylinder)、 However, it may be an imagined boundary (like the deforming boundary of a certain amount of mass as it flows through a pump)、
热力系统就是一包围在某一封闭边界内的具有固定质量的物质。系统边界通常就是比较明显的(如气缸内气体的固定边界)。然而,系统边界也可以就是假想的(如一定质量的流体流经泵时不断变形的边界)。
All matter and space external to a system is collectively called its surroundings、 Thermodynamics is concerned with the interaction of a system and its surroundings, or one system interacting with another、 A system interacts with its surroundings by transferring energy across its boundary、 No material crosses the boundary of a system、 If the system does not exchange energy with the surroundings, it is an isolated system、系统之外的所有物质与空间统称外界或环境。热力学主要研究系统与外界或系统与系统之间的相互作用。系统通过在边界上进行能量传递,从而与外界进行相互作用,但在边界上没有质量交换。当系统与外界间没有能量交换时,这样的系统称为孤立系统。
In many cases, an analysis is simplified if attention is focused on a particular volume in space into which, or from which, a substance flows、Such a volume is a control volume、 A pump, a turbine, and an inflating or deflating balloon are examples of control volume、 The surface that completely surrounds the control volume is called a control surface、在许多情况下,当我们只关心空间中有物质流进或流出的某个特定体积时,分析可以得到简化。这样的特定体积称为控制体。例如泵、透平、充气或放气的气球都就是控制体的例
子。包含控制体的表面称为控制表面。
Thus, we must choose, in a particular problem, whether a system is to be considered or whether a control volume is more useful、 If there is mass flux across a boundary, then a control volume is required; otherwise, a system is identified、
因此,对于具体的问题,我们必须确定就是选取系统作为研究对象有利还就是选取控制体作为研究对象有利。如果边界上有质量交换,则选取控制体有利;反之,则应选取系统作为研究对象。
1.1.2Equilibrium, process and cycle
平衡、过程与循环
When the temperature of a system is referred to, it is assumed that all points of the system have the same, or essentially the same temperature、 When the properties are constant from point to point and when there is no tendency for change with time, a condition of thermodynamic equilibrium exists、 If the temperature, say, is suddenly increased at some part of the system boundary, spontaneous redistribution is assumed to occur until all parts of the
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system are at the same temperature、
对于某一参考系统,假设系统内各点温度完全相同。当物质内部各点的特性参数均相同且不随时间变化时,则称系统处于热力学平衡状态。当系统边界某部分的温度突然上升时,则系统内的温度将自发地重新分布,直至处处相同。
When a system changes from one equilibrium state to another, the path of successive sates through which the system passes is called process、If, in the passing one state to the next, the deviation from equilibrium is infinitesimal, a quasi-equilibrium process occurs, and each state in the process may be idealized as an equilibrium state、 Quasi-equilibrium processes can approximate many processes, such as the compression and expansion of gases in an internal combustion engine, with no significant loss of accuracy、 If the system goes from one equilibrium state to another
through a series of non-equilibrium states (as in combustion), a non-equilibrium process occurs、
当系统从一个平衡状态转变为另一个平衡状态时,系统所经历的一系列由中间状态组成的变化历程称为过程。若从一个状态到达另一个状态的过程中,始终无限小地偏离平衡态,则称该过程为准静态过程,可以把其中任一个中间状态瞧作为平衡状态。准静态过程可近似视为许多过程的叠加结果,而不会显著减小其精确性,例如气体在内燃机内的压缩与膨胀过程。如果系统经历一系列不平衡状态(如燃烧),从一个平衡状态转变为另一个平衡状态,则其过程为非平衡过程。
When a system in a given initial state experiences a series of process and returns to the initial state, the system goes a cycle、 At the end of the cycle, the properties of the system have the same values they had at the beginning、
当系统从一个给定的初始状态出发,经历一系列中间过程又回到其初始状态,则称系统经历了一个循环。循环结束时,系统中的各参数又与初始参数相同。
The prefix iso- is attached to the names of any property that remain unchanged in a process、An isothermal process is one in which the temperature is held constant; in an iso-baric process, the pressure remains constant; an isometric process is a constant-volume process、在任一特性参数名称前加上前缀iso-,表示该参数在整个过程保持不变。等温(isothermal)过程中温度保持不变;等压(isobaric)过程中压强恒定;等容(isometric)过程中体积保持不变。
1.1.3Vapor-liquid phase equilibrium in pure substance
纯物质的气-液相平衡
Consider as a system 1 kg of water contained in the piston or cylinder arrangement shown in Fig、1-1(a)、 Suppose the piston and weight maintain a pressure of 0、1MPa in the cylinder and that the initial temperature is 20℃、 As heat is transferred to the water, the temperature increase appreciably, the specific volume increase slightly, and the pressure remains constant、When the temperature reaches 99、6℃, additional heat transfer results in a change of phase, as indicated in Fig、1-1 (b)、 That is, some of the liquid becomes vapor, and during this
process both the temperature and pressure remain constant, but the specific volume increases considerably、 When the last drop of liquid has vaporized, further transfer of heat results in an increase in both temperature and specific volume of the vapor, as shown in Fig、1-1(c)、如图1-1(a)所示,由活塞与气缸组成的装置中装有1kg水。假定活塞与其上的重物使气缸内压强维持在0、1Mpa,初始温度20℃。当有热量开始传递给水时,缸内水温迅速上升,而比容略有增加,气缸内压强保持恒定不变。当水温达到99、6℃时,如若再增加传热量,水将发生相变,如图1-1(b)所示。也就就是说,一部分水开始气化变为蒸汽,在此相变过程中,温度与压强始终保持不变,但比容却有大幅度的增加。当最后一滴液体被气化时,进一步的加热将使蒸汽温度与比容均有所增加,如同1-1(c)所示。
图1-1 液体在常压下的蒸发过程
The term saturation temperature designates the temperature at which vaporization takes place at a given pressure、 This pressure is called the saturation pressure for the given temperature、 Thus, for water at 99、6℃, the saturation pressure is 0、1MPa, and for water at 0、1MPa the saturation temperature is 99、6℃、
在给定压强下发生气化的温度称为饱与温度,压强称为给定温度下的饱与压强。因此,99、6℃水的饱与压强就是0、1MPa,0、1MPa水的饱与温度为99、6℃。
If a substance exists as liquid at the saturation temperature, it is called saturated liquid、 If the temperature of the liquid is lower than the saturation temperature for the existing pressure, it is called either a subcooled liquid (implying that the temperature is lower
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than the saturation temperature for the given pressure) or a compressed liquid (implying that the pressure is greater than the saturation pressure for the given temperature)、
如果某一工质为液态并处于其饱与温度与饱与压强下,则称该液体为饱与液体。如果液体温度低于当前压强下的饱与温度,则称该液体为过冷液体(表明液体的当前温度低于给定压强下的饱与温度)或压缩液体(表明液体的当前压强大于给定温度下的饱与压强)。
When a substance exists as part liquid and part vapor at the saturation temperature, its quality is defined as the ratio of the mass of vapor to
the total mass、 Thus, in Fig、1-1(b), if the mass of vapor is 0、2 kg and the mass of liquid is 0、8 kg, the quality is 0、2 or 20%、 Quality has meaning only when the substance is in a saturated state、若某一工质在饱与温度下以液、气共存的形式存在,则称蒸汽质量与总质量之比为干度。因此,如图1-1(b)所示,若蒸汽质量为0、2kg,液体质量为0、8kg,则其干度为0、2或20%。干度只有在饱与状态下才有意义。
If a substance exists as vapor at the saturation temperature, it is called saturation vapor (Some times the term dry saturation vapor is used to emphasize that the quality is 100%)、 When the vapor is at a temperature greater than the saturation temperature, it is said to exist as superheated vapor、 The pressure and temperature of superheated vapor are independent properties, since the temperature may increase while the pressure remains constant、
若某一工质处于饱与温度下并以蒸汽形态存在,则称该蒸汽为饱与蒸汽(有时称为干饱与蒸汽,意在强调其干度为100%)。当蒸汽温度高于其饱与温度时,则称之为过热蒸汽。过热蒸汽的压强与温度就是彼此独立的,因为温度上升时,压强可能保持不变。
Let us plot on the temperature-value diagram of Fig、1-2 the constant-pressure line that represents the states through which the water passes as it is heated from the initial state of 0、1 MPa and 20℃、 Let state A represent the initial state, B the saturated-liquid state(99、6℃), and line AB the process in which the liquid is heated from the initial temperature to the saturation temperature、 Point C is the saturated-vapor state, and line BC is the constant-temperature process in which the change of phase from liquid to vapor occurs、 Line CD represents [
] the process in which the steam is superheated at constant pressure、Temperature and volume both increase during this process、在图1-2所示的温度-比容图上作等压线,表示水由初压0、1MPa、初温20℃被加热的过程。点A代表初始状态,点B为饱与液态(99、6℃),线AB表示液体由初始温度被加热至饱与温度所经历的过程。点C表示饱与蒸汽状态,线BC表示等温过程,即液体气化转变为蒸汽的过程。线CD表示在等压条件下蒸汽被加热至过热的过程,在此过程中,温度与比容均增大。
图1-2 温度-比容曲线
表1-1 一些物质的临界参数
In a similar name, a constant pressure of 10 MPa is represented by line IJKL, for which the saturation temperature is 311、1℃、 At a pressure of 22、09MPa, represented by line MNO, we find, however, that there is no constant-temperature vaporization process、 Instead, point N is a point of inflection with a zero slope、 This point is called the critical point、At the critical point the saturated-liquid and saturated-vapor states are identical、 The temperature, pressure and specific volume at critical point are called the critical temperature, critical pressure and critical volume、 The critical-point data for some substances are given in Table 1-1、
类似地,线IJKL表示压强为10MPa下的等压线,相应的饱与温度为311、1℃。但就是,在压强为22、09MPa条件下(线MNO),不存在等温蒸发过程。相反,点N就是个转折点,在该点上,切线斜率为零,通常把N点称为临界点。在临界点处,饱与液体与饱与气体的状态都就是相同的。临界点下的温度、压强与比容分别称为临界温度、临界压强与临界比容。一些工质的临界点数据如表1-1所示。
1、1、4 The first law of thermodynamics
The first law of the thermodynamics is commonly called the law of conservation of energy、
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In elementary physics courses, the study of conservation of energy emphasizes changes in kinetic and potential energy and their relationship to work、 A more general form of conservation of energy includes the effects of heat transfer and internal energy changes、 Other forms of energy could also be included, such as electrostatic, magnetic, strain and surface energy、
1、1、4 热力学第一定律
通常把热力学第一定律称为能量守恒定律。在基础物理课程中,能量守恒定律侧重动能、势能的变化以及与功之间的相互关系。更为常见的能量守恒形式还包括传热效应与内能的变化。当然,也包括其它形式的能,如静电能、磁场能、应变能与表面能。
Historically,[]the first law of thermodynamics was
stated for a cycle: the net heat transfer is equal to the net work done for a system undergoing a cycle、
历史上,用热力学第一定律来描述循环过程:净传热量等于循环过程中对系统所做的净功。
1、1、5 The second law of thermodynamics
The second law of thermodynamics can be stated in a variety of ways、Here we present two: the Clausius statement and the Kelvin-Planck statement、
1、1、5 热力学第二定律
热力学第二定律有多种表述形式。在此列举两种:克劳修斯表述与凯尔文-普朗克表述。
Clausius statement
It is impossible to construct a device that operates in a cycle and whose sole effect is transfer of heat from a cooler body to a hotter body、克劳修斯表述:制造一台唯一功能就是把热量从低温物体传给高温物体的循环设备就是不可能的。
图1-3 第二定律的违背
This statement relates to a refrigerator (or a heat pump)、 It states that it is impossible to construct a refrigerator that transfers energy from a cooler body to a hotter body without the input of work; this violation is shown in Fig、1-3(a)、
以冰箱(或热泵)为例,不可能制造一台不用输入功就能把热量从低温物体传给高温物体的冰箱,如图1-3(a)所示。
It is impossible to construct a device that operates in a cycle and produces no other effect than the production of work and the transfer of heat from a single body、
凯尔文-普朗克表述:制造一台从单一热源吸热与做功的循环设备就是不可能的。
In other words, it is impossible to construct a heat engine that extracts energy from reservoir, does work, and does not transfer heat to a low-temperature reservoir、 This rules out any heat engine that is 100 percent efficient, like the one shown in Fig、1-3(b)、
换句话说,制造这样一台从某一热源吸热并对外做功,而没有与低温热源进行换热的热机就是不可能的。因此,该表述说明了不存在工作效率为100%的热机,如图1-3(b)所示。 1、1、6 The Carnot Cycle
The heat engine that operates most efficiently between a high-temperature reservoir and a low-temperature reservoir is the Carnot engine 、 This is an ideal engine that uses reversible process to form its cycle of operation; such a cycle is Carnot cycle 、 The Carnot engine is very useful, since its efficiency establishes the maximum possible efficiency of any real engine 、 If the efficiency of a real is significantly lower than the efficiency of Carnot engine between the same temperature limits, then additional improvements may be possible 、 1、1、6 卡诺循环
卡诺机就是低温热源与高温热源间运行效率最高的热机。卡诺机就是一个理想热机,利用多个可逆过程组成一循环过程,该循环称为卡诺循环。卡诺机非常有用,因为它的运行效率为任何实际热机最大可能的效率。因此,如果一台实际热机的效率要远低于同样条件下的卡诺机效率,则有可能对该热机进行一些改进以提高其效率。
图1-4 卡诺循环
The ideal Carnot cycle in Fig 、1-4 is composed of four reversible processes: 1→2: Isothermal expansion: 2→3;Adiabatic reversible expansion:3→4;Isothermal compression:4→1;Adiabatic
reversible compression 、 The efficiency of a Carnot cycle is
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T T η=- Note that the efficiency is increased by raising the temperature T H at which heat is added or by decreasing the temperature T L at which heat
is rejected 、
理想的卡诺循环包括四个可逆过程,如图1-4所示:1→2等温膨胀;2→3绝热可逆膨胀;3→4等温压缩;4→1可逆绝热压缩。卡诺循环的效率为
1L H
T T η=- (1-1) 注意,提高T H (提高吸热温度)或降低T L (降低放热温度)均可使循环效率提高。
ACCOUNTING ENGLISH Middle-of-term Test Papers PartⅠ.Translating the following terms 1、Notes to financial statements 2、Accounting elements 3、Variable costs 4、Economic entity 5、Depreciation expense 6、Deferred income taxes 7、Nominal accounts 8、ROA 9、LIFO 10、Work in process 11、现金收支 12、原材料 13、制造费用 14、相关性 15、持续经营 16、复式记账 17、优先股 18、预付费用 19、购货退回与折让 20、永续盘存制
PartⅡ.True or False 1、 The accounting process generates financial reports for both “internal ”and “external”users. 2、The balance sheet reflects the basic accounting equation and the means of financing the organization's assets. 3、The existence of Accounts Receivable on the Balance Sheet indicates that the company has one or more creditors. 4、Liabilities are classified and presented in increasing order of liquidity. 5、Working capital equals current assets less current liabilities. 6、Declaration of dividends reduces the retained earnings portion of the owners' equity of the corporation and creates a liabilities called Dividends Payable. 7、A chart of accounts is a listing of the titles of all accounts. 8、The cash basis of accounting often violates the matching rule. 9、Closing entries convert real and nominal accounts to zero balance. 10、The work sheet is published with the balance sheet and income statement, as a supplementary statement. 11、A company's sustainable growth rate is the highest growth rate in sales it can attain without issuing new stock. 12、Only rapidly growing firms have growth management problems.
Chest plain film/plain chest radiography 胸部平片Posteroanterior 后前位 Left-lateral 左侧位 Contour 轮廓 Symmetric 对称 Lung field 肺野 Lung marking 肺纹理 Lesion 病变 Lung hilar 肺门 Mediastinum 胸廓 Diaphragm 膈肌 Rib 肋骨 Round-shaped 类圆形的 Mass 团块 Post-basic segment 后基底段 Lobulated-edge 边缘分叶 Well-defined margin 边界清楚 ill-define margin 边缘不清vague margin Homogeneous attenuation 密度均匀 Thoracic vertebraes 胸椎 Obstructive atelectasis 阻塞性肺不张 Sign of “recersal S”反S征 Bilateral 双侧的 Cloud-shaped areas 大片密度增高区域 Piece-like high attunuation 片状高密度Pulmonary edema 肺水肿 Node 结节 Acute miliary tuberculosis 急性粟粒性肺结核Anteroposterior abdomen plain film 腹部平片Supine overhead projection 仰卧前后位投照Radiopaque foreign body 不透光异物 Stone 结石 Liver 肝gallbladder 胆kidney 肾 Bowel 肠 Distension 扩张 Free gas 游离气体 Vertebrate and pelvis bone 腰椎和骨盆 Plain film of pelvis 骨盆平片 Acetabulun 髋臼 Hip joint 髋关节 Bone destruction 骨质破坏 Femoral head 股骨头 The left hip joint space 左髋关节间隙Osteoporosis 骨质疏松
Enhancement of Forced Convection Heat Transfer Rongzhen You Class 1202 of Power Engineering In my College Students Innovative Project, we are supposed to adopt some methods to enhance the forced convection heat transfer on the plain surface. Although we have taken several technical methods into consideration, most of them are too difficult for us to apply in our project. Therefore, I would like to make an introduction to these methods here. Firstly, machining some grooves or dimples on the plain plates is one of important methods to enhance the convection heat transfer. The grooves or dimples can change the flow field of the fluid near the surface, for which the fluid would be turbulent than before. In this way, the Nusselt number of the near surface fluid would be raised, and than the convection heat-transfer coefficient would increase. This method can enhance the convection heat transfer on the plain plate to some extent, but it’s still ineffective for the reason that the improvement of heat-transfer coefficient of the fluid in the near wall region can not enhance the heat-transfer of the mainstream. Secondly, some researchers come up with an idea that using spiral fine ribs (SFRs) in plate channel to enhance the convection heat transfer. They equally placed the SFRs in the channel, which can form a packing layer resembling a kind of quasi-porous media with large porosity and can produce efficient disturbance both to the boundary layer and the mainstream. The operation principle of SFRs is that the multi-longitudinal vortices induced by SFRs can significantly increase the tangential velocity components in the cross section, which is helpful to promote the micro-fluctuation in the fluid. What’s more, the transport action caused by the longitudinal vortices can improve the mass exchange between the boundary layer and the mainstream. These two factors can not only speed up the heat migration from the channel walls, but also enhance the heat diffusion in the mainstream. This improves the temperature distribution uniformity in channel. Thirdly, the most efficient way to enhance the convection heat transfer is installing fins on the plain plate. Base on this thought, some researchers have fabricated many different types of fins, such as columned pin fins, conical pin fins, elliptical pin fins, cross-cut pin fins and longitudinal vortex generator arrays (LVG). Nowadays, fins with geometric shape pins have been commonly used to in the engineering. As for the vortex generator, it can disturb the flow field by the vortex and generate vortex after the generator, which can break the boundary lay on the surface and transfer the heat into mainstream quickly. Nowadays, many researchers have proved that the LVG effect is much better than the straight fins within a certain limit of Reynolds number, as well as that the multi rows LVG can improve the whole heat transfer effect. The methods mentioned above sounds pretty advanced, but it’s quiet difficult for us, regular college students, to apply these methods in our project. Because we couldn’t analysis the complex flow field in these special structure, unless we use the FLUENT software to build up their mathematic model. As the advanced usage of FLUENT is out of our ability, we have no choices but to install the straight fins on the heat transfer surface. Some researchers have found that the overall thermal resistance of straight fins is lower than other geometric pin fins, due to the combination effect of enhanced later conduction along the fins and the lower flow bypass characteristics. At last, our experiment also proved that the straight fin can meet the requirement of the enhancement of forced convection heat transfer.
经济管理学院专业英语结课论文
一学习总结 1理论课程学习总结 人说，“走进大学就一只脚踏进了社会”，这句话没说错。上大学之前，我们有三分之二的时间在学校认真学习科学知识，缺乏自理能力，不懂人情世故。而上了大学之后，不仅要学习，还要管理好自己的生活、处理好与同学、老师的关系。所有这些都不是老师和爸妈能教会的，要靠自己在日常生活中不断的学习和总结经验教训。 在大学里，有些人刻苦专研专业知识，希望将来在专业方面有所突破或能继续深造；有些人则在学好功课的基础上，发现了自己某方面的潜力，比如：较强的社交能力、体育比较好等。而大学这样一个宽松的环境正为他们提供了一个实现自我的舞台。因此，在大学里，我们不仅可以更深入的学习科学知识，还可以在业余时间挖掘自身的潜力和增强自身的特长。但不管将来你从事什么工作，首先要学好英语和用好计算机，这是形势所迫，也是现实。随着现代化步伐的加快，计算机已经成为我们进行各项工作的主要工具，而学好英语是用好计算机的基础，以后走上工作岗位，不会英语和计算机，我们将寸步难行。 但有很多同学说，英语很难学，就是学不好。其实并不是不能学好，我认为没有学不会的东西，除非你不去努力或方法不对。说句实在话，学语言确实是一件比较困难的事，尤其是在一个没有相关语言环境的情况下去学。因为学语言包括听，说，读，写四个方面，要想做到这四个方面都强确实不容易。但我们可以先掌握好基础知识，再根据自己以后的发展方向决定在哪个方面进行提高。比如，你决定以后从事软件开发的工作，那你可以多看看这方面的英文版的书籍。 可是，尽管英语是如此的难学，很多同学还是不以为然。许多同学进入大学后就想着如何去玩，觉得初中、高中这六年憋得实在不行了。可是放松也要有限度，不能荒废了学业，难道辛辛苦苦考上大学就是来玩的吗？因此，当我们在享受大学生活给我们带来新鲜和刺激时，不要忘了花点时间去读读单词，看看英语文章。把英语学习当成一种乐趣，而不仅仅是应付学校的考试和通过四六级。 其次，就要说到计算机知识的学习了，对于我们信息管理专业来说，计算机就是我们谋生的工具。首先，我们应学会最基本的使用电脑的操作，如开机、关机、软件的安装、office的使用、电脑的日常维护等。此外，随着科学技术的日新月异的发展，网络在人们的生活中起着越来越重要的作用，不管是日常生活、交友、娱乐还是工作，人们越来越依赖于网络。因此我们还要学会上网，学会利
第二章锅炉 2.1 简介SSC 锅炉利用热量使水转变成蒸汽以进行各种利用。其中主要是发电和工业供热。由于蒸汽具有有利的参数和无毒特性，因此蒸汽作为一种关键的工质（资源）被广泛地应用。蒸汽流量和运行参数的变化很大：从某一过程里1000磅/小时（0.126kg/s）到大型电厂超过10×106磅/小时（1260kg/s），压力从一些加热应用的14.7磅/ in2（1.0135bar）212F（100℃）到先进循环电厂的4500磅/ in2（310bar）1100F（593℃）。 现代锅炉可根据不同的标准分类。这些包括最终用途、燃烧方式、运行压力、燃料和循环方式。 大型中心电站的电站锅炉主要用来发电。它们经过优化设计，可达到最高的热效率。新机组的关键特性是利用再热器提高整个循环效率。 各种附加的系统也产生蒸汽用于发电及其他过程应用。这些系统常常利用廉价或免费燃料，联合动力循环和过程，以及余热回收，以减少总费用。这些例子包括：燃气轮机联合循环（CC）：先进的燃气轮机，将余热锅炉作为基本循环的一部分，以利用余热并提高热效率。 整体煤气化联合循环（IGCC）：在CC基础上增加煤气化炉，以降低燃料费用并将污染排放降到最低。 增压循环流化床燃烧（PFBC）：在更高压力下燃烧，包括燃气净化，以及燃烧产物膨胀并通过燃气轮机做功。高炉排烟热量回收：利用高炉余热产生蒸汽。 太阳能蒸汽发生器：利用集热器收集太阳辐射热产生蒸汽。 2. 2 Development of Utility Boiler 现代660MW燃煤锅炉有大约6000吨的压力部件，包括500千米的受热面管材，3.5千米连接管与联箱和30000个管接头焊口。 这是经过大约50年发展的结果，并形成了煤粉在具有蒸发管束的炉膛燃烧，烟气然后流经对流过热器和热回收表面的基本概念并保留至今。蒸汽参数的提高，机组容量的增大及燃料燃烧特性的改进都要求在材料、制造技术和运行程序上相应发展。 二战后的一些年里，在电厂安装锅炉的数量多于汽轮机是很常见的，锅炉提供蒸汽到母管然后到汽机。这种布置反应了锅炉的可用性低于汽轮机。四十年代后期，随着锅炉可用性的提高，锅炉和汽机开始可以相互配套使用。 锅炉和汽机成套的变化使得再热成为可行，而且伴随着高温钢材的应用，经过蒸汽参数的不断提高，达到了当前的标准循环2400lbf/in2(165.5bar)，568℃和再热568℃。为充分利用更高的蒸汽参数和获得经济容量，在接下来的15年，机组容量又增加了20倍。 2.3 燃料与燃烧 大部分锅炉以煤、天然气和石油作为燃料。然而，在过去的几十年里，至少在发电领域核能开始扮演一个主要角色。 同样，不断增加的各种生物质和过程副产品也成为蒸汽生产的热源。这些包括泥煤、木材及木材废弃物、稻草、咖啡渣、稻谷壳、煤矿废弃物（煤屑）、炼钢炉废热甚至太阳能。 现代美国中心电站用燃料主要是煤，或是烟煤、次烟煤或是褐煤。 虽然天然气和燃油也许是未来化石燃料电厂的燃料选择，但煤仍然是今后新的，基本负荷电站锅炉的主要燃料。 2.3.1 煤的分类
Chinese by Jerry Norman 龚群虎 Page number, Chinese, English 1 0 2 共时synchronic 3 历时diachronic 4 linguist 语言学家 5 汉语研究Chinese studies 6 调号tone mark 7 1-1 8 甲骨文oracle bone inscription/script 9 古汉语Classical Chinese 10 中古汉语Middle Chinese 11 早期白话Early Vernacular Chinese 12 上海方言Shanghai dialect 13 书面语言written language 14 口头语言spoken language 15 文化连续性cultural continuity 16 汉语方言Chinese dialects 17 北京话Peking dialect 18 广州话Cantonese 19 文言文Literary Chinese 20 方言学家dialectologist 21 金文bronze inscription/script 22 孔子Confucius 23 孟子Mencius 24 方言描写dialect description 25 高本汉（人名）Bernhard Karlgren 26 中古汉语（高本汉）Ancient Chinese 27 赵元任（人名）Yuen Ren Chao 28 吴语Wu dialects 29 方言调查dialect survey/fieldwork 30 共通语koine 31 现代汉语Modern Chinese 32 方言dialect 33 1-2 34 （汉语）周边语言neighboring languages 35 阿尔泰语系Altaic language family 36 突厥语言Turkic languages 37 蒙古语言Mongolian languages 38 通古斯语言Tungusic languages 39 日语Japanese
1.开口系统：与外界既有物质交换又有能量交换，把研究对象控制在某个空间。---定容积系统 An Open system (or a control volume 控制体积）is a properly selected region in space. Both mass and energy can cross the boundary of a control volume. such as, A Water heater, a turbine and a compressor, etc 2.闭口系统：系统与外界只有能量（功量、热量）的交换而无质量交换。——定质量系统A Closed system (a control mass 控制质量) consists of a fixed amount of mass, and no mass can cross its boundary. That is, no mass enters or leave a closed system. such as, Piston-cylinder device (汽缸-活塞装置） 3.绝热系统：系统与外界只有功量和质量的交换，而无热量的交换。Adiabatic system is that no heat cross the boundary or heat is negligible compared with work cross the boundary 4.孤立系统：系统与外界既无能量交换又无质量交换，即系统与环境不发生任何作用。Isolated system is a special case that no mass and energy cross the boundary. 5.热力学第一定律：自然界一切物体都具有能量，能量有各种不同形式，它能从一种形式转化为另一种形式，从一个物体传递给另一个物体，在转化和传递过程中能量的总和不变。 The first explicit statement of the first law of thermodynamics："In all cases in which work is produced by the agency of heat, a quantity of heat is consumed which is proportional to the work done; and conversely, by the expenditure of an equal quantity of work an equal quantity of heat is produced." 6.热力学第二定律：不可能把热从低温物体传到高温物体而不产生其他影响；不可能从单一热源取热使之完全转换为有用的功而不产生其他影响；不可逆热力过程中熵的微增量总是大于零。 Second law of thermodynamics： Impossible to heat from low temperature to high temperature object object does not produce other effects; not possible from a single heat source heat so completely converted into useful work and does not produce other effects; irreversible thermodynamic entropy in the process of the incremental volume is always greater than zero. 7.锅炉：锅炉利用热量使水转变成蒸汽以进行各种利用。 Boilers use heat to convert water into steam for a variety of applications. 8.汽轮机：将蒸汽的热能转换为机械能的叶轮式旋转原动机。 Steam Turbine is the impeller rotating prime mover that the thermal energy of the steam is converted to mechanical energy 。 9.省煤器：省煤器（英文名称Economizer）就是锅炉尾部烟道中将锅炉给水加热成汽包压力下的饱和水的受热面。The economizer (Name Economizer) is the rear of the boiler flue of the boiler feed water is heated into steam drum pressure saturated water heating surface。 10.空预器：空气预热器就是锅炉尾部烟道中的烟气通过内部的散热片将进入锅炉前的空气预热到一定温度的受热面。 The air preheater through the fins of the internal heating surface will enter the air is preheated to a certain
热能工程专业英语 ability 能力 ABNORMAL ABN 不规则的abnormal operating condition 异常工况 abort 中断,停止 ABOVE ABV 在……上面 abrader 研磨,磨石,研磨工具abrasion resistance 耐磨性abrupt change 突变 absence 失去 Absence of brush 无(碳)刷Absolute ABS 绝对的 absolute expansion 绝对膨胀ABSOLUTE EXPANSION ABS X 绝对膨胀 ABSOLUTE PRESSURE ABS P 绝对压力 Absolute atmosphere ATA 绝对大气压 absorb 吸收 ABSORBER ASB 阻尼器吸收器absorptance 吸收比,吸收率 AC Lub oil pump 交流润滑油泵acceleration 加速acceleration limiter 加速度限制器 accelerator 加速器 accept 接受 acceptance test 验收试验access 通道 accident ACCD 事故accommodate 容纳 accomplish 完成,达到accumulate 累积 accumulator 蓄能器accumulator 蓄电池,累加器ACCUMULATOR ACM 收集(累加)器本资料为网络资料整理，只供学习交流使用，不做商业用途。Accumulator battery 蓄电池组accuracy 精确度，准确度 acid 酸性,酸的 acid cleaning 酸洗 ACID CLEANING ACD CLG 酸清洗 Acid washing 酸洗 ACIDIC ACID ACD 酸化学物质 acknowledge ACK 确认 acquisition 发现,取得 act ACT 动作 action 动作，行为 active ACTIVE 激励 active current 有功电流 active power 有效功率 active zone 有效区 active power A_PW 有功功率 actual value 实际值 actuator 驱动器 additional safeguard oil 附 加保安油 address 地址 adequate 适当的，充分的 ADJACENT ADJ. 相邻的 ADJACENT BOILER ADJ. BLR 邻 炉 adjust 调整，校正 adjustable fan blade 可调扇 页 adjustable key 可调整销 adjusting ADJ 调整 adjustment 调整，调节 admission steam 进汽 Admission mode 进汽方式 adopt 采用 Aerial line 天线 aerodynamic loss 空气动力损 失 本资料为网络资料整理，只供学 习交流使用，不做商业用途。 affect 影响 after 以后 AFTERCONDENSER ACDS 凝结器后 AFTERCOOLER ACLR 冷却器后 agent 代理 agreement 协议 AI (analog input) 模拟量输入 Ail leak AL 漏风 Air AIR 空气 air & gas system 空气及气体 系统 AIR BLAST CIRCUIT BREAKER A BLS CCT BKR 空气(风机)断路器 ABCS AIR BLAST CIRCUIT BREAKER A BLS CCT BKR 鼓风机回路断路器 ABCD air chamber 空气室 air compressor 空气压缩机 AIR COMPRESSOR A CPRS 空压机 AIR COMPRESSOR AND DRIER A CPRS &DRR 空压机及其驱动装置 AC&D AIR CONDITIONING (SYSTEM) A COND (SYS) 空气调节系统 AIR COOLED A COL 空气冷却的 AIR COOLED CONDENSING PLANT A COL CDSG PT 空气冷却设备ACCP AIR COOLED CONDENSING UNIT A COL CDSG U 空气冷却设备ACCU air cooler 空气冷却器 AIR COOLER A CLR 空气冷却器 air cushion 气垫 air gap 空气隙 AIR HANDLING UNIT A HDLG U 空 气输送设备AHU AIR HEATER A HTR 空气加热器 air inlet valve 进气阀 air nozzles 空气喷嘴 air preheater 空气预热器 AIR PRESSURE REDUCER A P RDCR 空气减压器APRD AIR RECEIVER A RCVR 储气罐 Air compressor 空压机 Air duct pressure 风管压力 本资料为网络资料整理，只供学 习交流使用，不做商业用途。 Air ejector 抽气器 Air exhaust fan 排气扇
第一章热科学基础 1.1工程热力学基础 热力学是一门研究能量储存、转换及传递的科学。能量以内能（与温度有关）、动能（由物体运动引起）、势能（由高度引起）和化学能（与化学组成相关）的形式储存。不同形式的能量可以相互转化，而且能量在边界上可以以热和功的形式进行传递。 在热力学中，我们将推导有关能量转化和传递与物性参数，如温度、压强及密度等关系间的方程。因此，在热力学中，物质及其性质变得非常重要。许多热力学方程都是建立在实验观察的基础之上，而且这些实验观察的结果已被整理成数学表达式或定律的形式。其中，热力学第一定律和第二定律应用最为广泛。 1.1.1热力系统和控制体 热力系统是一包围在某一封闭边界内的具有固定质量的物质。系统边界通常是比较明显的（如气缸内气体的固定边界）。然而，系统边界也可以是假想的（如一定质量的流体流经泵时不断变形的边界）。 系统之外的所有物质和空间统称外界或环境。热力学主要研究系统与外界或系统与系统之间的相互作用。系统通过在边界上进行能量传递，从而与外界进行相互作用，但在边界上没有质量交换。当系统与外界间没有能量交换时，这样的系统称为孤立系统。 在许多情况下，当我们只关心空间中有物质流进或流出的某个特定体积时，分析可以得到简化。这样的特定体积称为控制体。例如泵、透平、充气或放气的气球都是控制体的例子。包含控制体的表面称为控制表面。 因此，对于具体的问题，我们必须确定是选取系统作为研究对象有利还是选取控制体作为研究对象有利。如果边界上有质量交换，则选取控制体有利；反之，则应选取系统作为研究对象。 1.1.2平衡、过程和循环 对于某一参考系统，假设系统内各点温度完全相同。当物质内部各点的特性参数均相同且不随时间变化时，则称系统处于热力学平衡状态。当系统边界某部分的温度突然上升时，则系统内的温度将自发地重新分布，直至处处相同。 当系统从一个平衡状态转变为另一个平衡状态时，系统所经历的一系列由中间状态组成的变化历程称为过程。若从一个状态到达另一个状态的过程中，始终无限小地偏离平衡
心理学专业英语总结——HXY 随意传阅·顺颂试安 注释：1.“*”在书上是黑体字，但感觉不重要背了也没什么卵用 2.“”背景色项表示答案恰好有三项，可能出选择 3. 人名已加黑，可能连线或选择 4. 每章节的末尾有方便记忆的单词表（只包括这篇总结中出现的关键单词） 5. 方便理解记忆，已在各项下方注明中文释义 6.“,”大部分都是作为点之间的分割，类似于逗号，前后不连成句子Chapter 1——Perspectives in psychology 心理学纵览 Section 1: Approaches to psychology 心理学入门 What is psychology? 心理学是什么 Definitions: The scientific study of behaviour and mental processes. 定义：对行为和心理过程的科学研究 Psychology come from: ① philosophy, ② biology ③ physics. 心理学来源于：哲学、生物学和医学 When: 1879 as a separate scientific discipline. 形成于：1879年，作为独立学科
History (develop): structuralism, functionalism, psychoanalysis, behaviourism, cognitive psychology, humanistic approach, biological approach. 历史发展：结构主义，机能主义，精神分析，行为主义，认知，人本主义，生理。 The psychoanalytic approach to psychology 精神分析理论 Origins & history: Sigmund Freud, unconscious mental causes, treat as the causes of mental disorders, built up an theory. 历史来源：弗洛伊德提出潜意识心理动机，把它视为心理疾病的原因，并建立理论。 Assumptions: unconscious processes, psychic determinism, hydraulic drives, psychodynamic conflict, stages of development. 假设：潜意识过程，精神决定论，驱力（攻击、性），心理动力冲突，发展阶段 Methods of investigation: case study (method), free association (tech), dream analysis (tech). 研究方法：个案研究方法，自由联想技术，梦的解析技术 *Areas of explanation: personality development, moral/gender development, aggression, abnormality, memory. 可解释领域：人格发展，道德/性别发展，攻击性，异常，记忆 *Weaknesses: unrefutable, theoretically unscientific. 缺点：不可被其他事件驳斥，因此理论不具科学性
6.1 ?s most efficient speed is usually much higher than that of the machine it is driving ,so a speed reduction gear usually has to be used . 600 000马力的汽轮机。 转子——叶轮上装有动叶，转子两端装有轴颈。 轴承箱——安装在气缸上，用来支承转子的轴。 调速器和阀门系统——通过控制蒸汽流量来调节涡轮的速度和出力，同时还有轴承润滑系统以及一套安全装置。 某种类型的联轴器——用来连接从动机械 …catch ?the steam from the nozzle smoothly ,and they are curved so that they change the direction of the jet and in so doing receive an impulse which pushes 6.1（见原文）所示为一种简单的冲动式汽轮机。 …reaction ? turbine . moving blades are also nozzles ,similar to the stationary nozzles but facing the other way ,and in addition to catching and deflecting the steam issuing from the stationary （见原文中图6.2）它综合了冲力和反作用力的原理。 6.2中的涡轮壳带有一整圈喷嘴，这些喷嘴和反冲式涡轮机里的一样，也是弯曲的，并以最有效的角度引导蒸汽喷向转动的叶片。 ,under these conditions the exhaust volume flow becomes large ,and it is necessary to have more than one exhaust stage ;for example ,a large turbine may have three are
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