建筑环境与设备工程专业英语翻译(共12页).doc

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1、精选优质文档-倾情为你奉上A thermodynamic system is a region in space or a quantity of matter bounded by a closed surface. The surroundings include everything external to the system, and the system is separated from the surroundings by the system boundaries. These boundaries can be movable or fixed, real or imag

2、inary. 一个热力学系统是一个在空间或有事项的数量由一个封闭的表面范围内的区域。周围环境包括一切外部系统，系统是从周围环境隔开的系统边界。这些边界可以是动产或固定的，真实的或想象。The concepts that operate in any thermodynamic system are entropy and energy. Entropy measures the molecular disorder of a system. The more mixed a system, the greater its entropy; conversely, an orderly or u

3、nmixed configuration is one of low entropy. Energy has the capacity for producing an effect and can be categorized into either stored or transient forms as described in the following sections. 熵和能量的概念，在任何热力学系统操作。熵措施分子系统紊乱。更为复杂的系统，其熵值越大，反之，有序或纯配置是低熵之一。能源已经产生效果的能力，并在下面的章节中所述，可以存储或短暂形式分类。Heat Q is the

4、mechanism that transfers energy across the boundaries of systems with differing temperatures, always toward the lower temperature. Heat is positive when energy is added to the system. Work is the mechanism that transfers energy across the boundaries of systems with differing pressures (or force of a

5、ny kind), always toward the lower pressure. If the total effect produced in the system can be reduced to the raising of a weight, then nothing but work has crossed the boundary. Work is positive when energy is removed from the system. 热量Q与不同的温度，跨系统的边界传输能量总是向温度较低的机制。热是积极的，当能量被添加到系统中。 功是指通过存在压差（任一种力）的

6、系统边界传递能量的作用过程，总是指向低压，如果系统中产生的总效果能被简化为一个重物的提升，那么只有功通过了边界，当能量从系统中一出时，功是正的。A property of a system is any observable characteristic of the system. The state of a system is defined by listing its properties. The most common thermodynamic properties are temperature T, pressure p, and specific volume v or

7、density . Additional thermodynamic properties include entropy, stored forms of energy, and enthalpy. Frequently, thermodynamic properties combine to form other properties. Enthalpy h, a result of combining properties, is defined as:h=u+pv where u is the internal energy per unit mass系统属性是系统的任何观察到的特征。

8、系统状态的定义是通过列出其属性。最常见的热力学性质的温度T，压力P，和特定的体积V或密度。其他热力学性质包括熵，能量储存形式，和焓。通常情况下，热力学性质相结合，形成其他属性。焓H，一个属性相结合的结果，被定义为：H = U + PV其中u是每单位质量的内部能量Each property in a given state has only one definite value, and any property always has the same value for a given state, regardless of how the substance arrived at that

9、 state. A process is a change in state that can be defined as any change in the properties of a system. A process is described by specifying the initial and final equilibrium states, the path (if identifiable), and the interactions that take place across system boundaries during the process. 中的每一个给定

10、的状态的属性只有一个定值，和任何财产总是有相同的值给定的状态，不管如何抵达该国的物质。一个进程是一个状态的改变，在系统属性的任何改变，可作为定义。一个过程是指定的初始和最终的平衡状态，路径（如果识别），并采取跨系统的边界，在这个过程中发生的相互作用。A cycle is a process or a series of processes wherein the initial and final states of the system are identical. Therefore, at the conclusion of a cycle, all the properties hav

11、e the same value they had at the beginning. A pure substance has a homogeneous and invariable chemical composition. It can exist in more than one phase, but the chemical composition is the same in all phases一个周期进程的一个过程或一个系列，其中系统的初始和最终状态是相同的的。因此，在一个周期结束时，所有属性具有相同的价值，他们开始。纯物质均匀的和不变的化学成分。它可以存在于超过一个阶段，但

12、在各个阶段的化学成分是一样的If a substance is liquid at the saturation temperature and pressure, it is called a 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 (the temperature is lower than the saturatio

13、n temperature for the given pressure) or a compressed liquid (the pressure is greater than the saturation pressure for the given temperature). 如果一种物质在饱和温度和压力的液体，它被称为饱和液体。如果液体的温度低于现有的压力的饱和温度，它被称为是过冷液体（温度低于给定压力的饱和温度）或压缩液体（压力大于饱和为给定的温度压力）。If a substance exists as a vapor at saturation temperature and p

14、ressure, it is called a saturated vapor. When the vapor is at a temperature greater than the saturation temperature, it is a superheated vapor. Pressure and temperature of a superheated vapor are independent properties, because the temperature can increase while pressure remains constant. Gases such

15、 as air at room temperature and pressure are highly superheated vapors.如果一种物质在饱和温度和压力的蒸气存在，它被称为饱和蒸气。当蒸汽温度大于饱和温度，它是一个热蒸气。过热蒸汽压力和温度是独立的属性，因为温度增加，而压力保持不变。如在常温常压下空气的气体是高度过热蒸汽。The second law of thermodynamics differentiates and quantifies processes that only proceed in a certain direction (irreversible)

16、from those that are reversible. The second law may be described in several ways. One method uses the concept of entropy flow in an open system and the irreversibility associated with the process. The concept of irreversibility provides added insight into the operation of cycles. 热力学第二定律的区别和量化，只有在某一个

17、方向，是可逆的（不可逆）进行的过程。第二定律可能在几个方面。一种方法是使用在一个开放的系统，并与进程关联的不可逆性的熵流的概念。不可逆转的概念到周期的运作提供额外的洞察力。The Carnot cycle, which is completely reversible, is a perfect model for a refrigeration cycle operating between two fixed temperatures, or between two fluids at different temperatures and each with infinite heat c

18、apacity. Reversible cycles have two important properties: (1) no refrigerating cycle may have a coefficient of performance higher than that for a reversible cycle operated between the same temperature limits, and (2) all reversible cycles, when operated between the same temperature limits, have the

19、same coefficient of performance卡诺循环，这是完全可逆的，是一个完美的模型之间的两个固定的温度，或在不同温度和热容量无限每个的两种流体之间的制冷循环的运行。可逆循环有两个重要的属性：（1）无制冷循环的性能系数之间相同的温度限制经营的可逆循环高于，（2）之间相同的温度极限运行时，所有可逆循环，同样的性能系数Flowing fluids in heating, ventilating, air-conditioning, and refrigeration systems can transfer heat, mass, and momentum. This chap

20、ter introduces the basics of fluid mechanics related to HVAC processes, reviews pertinent flow processes, and presents a general discussion of single-phase fluid flow analysis.流动的液体在加热，通风，空调和制冷系统，可以传递热量，质量和动量。本章介绍有关暖通空调过程的流体力学，评论相关的流程，基础知识，并提出了一种单相流体流动分析的一般性讨论。Fluids differ from solids in their reac

21、tion to shearing. When placed under shear stress, a solid deforms only a finite amount, whereas a fluid deforms continuously for as long as the shear is applied. Both liquids and gases are fluids. Although liquids and gases differ strongly in the nature of molecular actions, their primary mechanical

22、 differences are in the degree of compressibility and liquid formation of a free surface. In general, liquids are considered incompressible fluids; gases may range from compressible to nearly incompressible. 流体与固体区别在于他们对剪切力的反应作用。在施加剪切力时，固体只发生有限的变形，而只要有剪切力的作用流体就会连续变形。流体不同于固体剪切他们的反应。当剪切应力下了坚实的变形量只有有限的

23、，而流体的剪切变形。液体和气体都是流体。虽然液体和气体的分子运动特性有着很大的区别，但是他们的主要的力学区别在于可压缩性的程度和液体自由表面（界面）的形成。在一般来说，液体被认为是不可压缩的流体，气体可能范围从可压缩到几乎不可。Viscosity is a measure of a fluids resistance to shear. Viscous effects are taken into account by categorizing a fluid as either Newtonian or non-Newtonian. In Newtonian fluids, the rate

24、 of deformation is directly proportional to the shearing stress; most fluids in the HVAC industry (e.g., water, air, most refrigerants) can be treated as Newtonian. In non-Newtonian fluids, the relationship between the rate of deformation and shear stress is more complicated.粘度是流体的抗剪切的措施。考虑采取分类流体为牛顿

25、或非牛顿粘性的影响。在牛顿流体，变形率是成正比的剪应力;在暖通空调行业（如，水，空气，大部分制冷剂）牛顿流体可以作为治疗。在非牛顿流体，变形和剪切应力率之间的关系更为复杂。Heat is energy in transit due to a temperature difference. The thermal energy is transferred from one region to another by three modes of heat transfer: conduction, convection, and radiation. Heat transfer is among

26、 a group of energy transport phenomena that includes mass transfer, momentum transfer or fluid friction and electrical conduction. 热是由于温差在传输过程中的能量。热能是从一个地区转移到另一个传热的三种模式：传导，对流和辐射。传热之间的能源运输的现象，其中包括传质，动量传递或流体摩擦和导电。Thermal conduction is the mechanism of heat transfer whereby energy is transported betwee

27、n parts of continuum by the transfer of kinetic energy between particles or groups of particles at the atomic level. In gases, conduction is caused by elastic collision of molecules; in liquids and electrically nonconducting solids, it is believed to be caused by longitudinal oscillations of the lat

28、tice structure. Thermal conduction in metals occurs, like electrical conduction, through the motion of free electrons. Thermal energy transfer occurs in the direction of decreasing temperature. In solid opaque bodies, thermal conduction is the significant heat transfer mechanism because no net mater

29、ial flows in the process and radiation is not a factor. 热传导传热，使能量是连续部分之间的运输粒子在原子水平上的颗粒或团体之间的动能转移的机制。气体中，分子的弹性碰撞引起的传导;电导电液体和固体，它被认为是造成晶格结构的纵向振荡。金属的热传导时，如导电，通过自由电子的运动。热能量转移发生在温度降低的方向。在坚实的不透明机构，热传导是显著的传热机制，因为没有净物资流动的过程中，辐射是不是一个因素。When fluid currents are produced by external sources (for example, a blow

30、er or pump), the solid-to-fluid heat transfer is termed forced convection. If the fluid flow is generated internally by nonhomogeneous densities caused by temperature variation, the heat transfer is termed natural convection or free convection.When fluid currents are produced by external sources (fo

31、r example, a blower or pump), the solid-to-fluid heat transfer is termed forced convection. If the fluid flow is generated internally by nonhomogeneous densities caused by temperature variation, the heat transfer is termed natural convection or free convection.当流体的电流是由外部来源（例如，一个鼓风机或泵），固 - 液传热被称为强迫对流

32、。如果是内部所产生的温度变化所造成的非均质密度的流体流动，传热称为自然对流或自然对流。当流体的电流是由外部来源（例如，一个鼓风机或泵），固 - 液传热被称为强迫对流。如果是内部所产生的温度变化所造成的非均质密度的流体流动，传热称为自然对流或自然对流。Equation 1 states that the heat flow rate q in the x direction is directly proportional to the temperature gradient dt/dx and the cross-sectional area A normal to the heat flo

33、w. The proportionality factor is the thermal conductivity k. The minus sign indicates that heat flow is positive the direction of decreasing temperature. Conductivity values are sometimes given in other units，but consistent units must be used in Equation 1 . Equation 1 states that the heat flow rate

34、 q in the x direction is directly proportional to the temperature gradient dt/dx and the cross-sectional area A normal to the heat flow. The proportionality factor is the thermal conductivity k. The minus sign indicates that heat flow is positive the direction of decreasing temperature. Conductivity

35、 values are sometimes given in other units，but consistent units must be used in Equation 1 . 公式（1）在x方向的热流率q是成正比的温度梯度DT/ DX和横截面积一个正常的热流。比例系数，导热系数K。减号表示热流温度降低的方向积极。电导率值有时在其他单位，但一致的单位，必须在使用公式1。公式（1）在x方向的热流率q是成正比的温度梯度DT/ DX和横截面积一个正常的热流。比例系数，导热系数K。减号表示热流温度降低的方向积极。电导率值有时在其他单位，但一致的单位，必须在使用公式1。Basic Paramet

36、ersn Humidity ratio W (alternatively, the moisture content or mixing ratio) of a given moist air sample is defined as the ratio of the mass of water vapor to the mass of dry air in the sample: W = Mw/Mda (7) The humidity ratio W is equal to the mole fraction ratio xw/xda multiplied by the ratio of m

37、olecular masses: W = 0.621 98 xw /xda (8)n Specific humidity is the ratio of the mass of water vapor to total mass of the moist air sample: = Mw/(Mw + Mda) (9a)基本参数湿度比W（另外，水分含量或比例混合），一个给定的潮湿空气样品是干燥的空气质量比样品中的水蒸汽的质量定义为：W = MW/ MDA（7）湿度比W是相等的摩尔分数比XW/ XDA分子群众的比例乘以：W =0.62198 XW/ XDA（8）具体的湿度潮湿的空气样本的总质量之比

38、是水汽质量：= MW /（MW + MDA）（9A）In terms of the humidity ratio, = W/(1 + W) (9b)n Absolute humidity (alternatively, water vapor density) dv is the ratio of the mass of water vapor to total volume of the sample:dv = Mw/V (10)n Density of a moist air mixture is the ratio of total mass to total volume: = (Md

39、a + Mw )/V = (1/v)(1 + W) (11)where v is the moist air specific volume, m3/kgda, as defined by Equation (27).湿度比例方面，= W /（1+ W）（9B）绝对湿度（另外，水蒸气密度）DV的水蒸气的质量样品总量的比例：DV = MW/ V（10）潮湿的空气混合物的密度总量的比例是总质量：=（MDA+ MW）/ V =（1 / V）（1+ W）（11）其中V是潮湿的空气中特定卷，m3/kgda，由方程（27）定义。Thermodynamic wet-bulb temperature t* i

40、s the temperature at which water (liquid or solid), by evaporating into moist air at a given dry-bulb temperature t and humidity ratio W, can bring air to saturation adiabatically at the same temperature t* while the total pressure p is maintained constant. This parameter is considered separately in

41、 the section on Thermodynamic Wet-Bulb and Dew-Point Temperature.热力学湿球温度T *是在水（液体或固体），潮湿的空气中蒸发，在一个给定的干球温度t和湿度比W的温度，可以使空气饱和绝热在同一温度T*而总压力p保持不变。此参数是在热力学湿球和露点温度的部分分开考虑。A principal purpose of heating, ventilating, and air-conditioning systems is to provide conditions for human thermal comfort. A widely a

42、ccepted definition is, “Thermal Comfort is that condition of mind that expresses satisfaction with the thermal environment”. This definition leaves open what is meant by condition of mind or satisfaction, but it correctly emphasizes that the judgment of comfort is a cognitive process involving many

43、inputs influenced by physical, physiological, psychological, and other processes. 供暖，通风和空调系统的一个主要目的是提供人体热舒适的条件。一个被广泛接受的的定义是，“热舒适性，心理状况，与热环境表示满意”。这个定义叶开放的心态或满意的状况是什么意思，但它正确地强调，舒适的判断是一个认知的过程，涉及物理，生理，心理，和其他进程影响了许多投入。The conscious mind appears to reach conclusions about thermal comfort and discomfort fr

44、om direct temperature and moisture sensations from the skin, deep body temperatures, and the efforts necessary to regulate body temperatures. In general, comfort occurs when body temperatures are held within narrow ranges, skin moisture is low, and the physiological effort of regulation is minimized

45、.意识的头脑似乎达到热舒适性和不适的结论，直接从皮肤，深部体温，以及必要的努力来调节体温的温度和水分的感觉。在一般情况下，舒适性发生时体温都在窄幅内举行，皮肤水分低，调节生理努力最小化。Air contaminants are generally either particles or gases. The distinction between particles and gases is important when determining removal strategies and equipment. Although the motion of particles is descr

46、ibed using the same equations used to describe gas movement, even the smallest of particles (approximately 1 nm) are much larger than individual gas molecules, have a much greater mass, and a much lower diffusion rate. 空气污染物一般是颗粒或气体。确定搬迁战略和设备时，粒子和气体之间的区别是重要的的。尽管粒子的运动是用相同的方程用来描述气体运动，甚至最小的粒子（约1纳米），远远高

47、于单个气体分子较大，有更大的质量，扩散速率低得多。The particulate class covers a vast range of particle sizes, from dust large enough to be visible to the eye to submicroscopic particles that elude most filters. Particles may be liquid, solid, or have a solid core surrounded by liquid. They are present in the atmosphere at

48、concentrations ranging from 100 particles/cm3 in the cleanest environments to millions per cubic centimeter in polluted urban environments. 颗粒类，涵盖了从粉尘颗粒大小广阔的范围，足够大的眼睛躲避大多数过滤器的微观粒子，可见。粒子可能是液体，固体或液体包围了坚实的核心。他们中的浓度每立方厘米在受污染的城市环境的范围在清洁的环境中从100 particles/cm3百万的气氛。Also a central cooling and heating plant provides higher diversity and generally operates more efficiently with lower maintenance and labor costs than a decentralized plant. However it does require space at a central location and a p