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1、 For the most part we shall consider systems sufficiently idealized that analysis of their performance is within the range of our studies thus far. 迄今為止,在研究范圍,分析特征對(duì)大部分來(lái)說(shuō),我們要對(duì)系統(tǒng)進(jìn)行充分理想化考慮。 Sufficiently:充分的,充足的。1 A refrigeration cycle is rated in terms of its cop (coefficient of performance): 制冷循環(huán)應(yīng)該依照C
2、OP來(lái)評(píng)價(jià)。 Is rated評(píng)價(jià) COP:工作系數(shù)2 An interesting use of the refrigerator is a heat pump. Here the objective is not to keep a region cool but instead to keep a region (such as a house) warm. 制冷循環(huán)有趣的應(yīng)用是熱泵。這里它的目標(biāo)不是保持一個(gè)區(qū)域涼爽而是保持一個(gè)地區(qū)(例如一個(gè)房子)溫暖。 Objective:目標(biāo),客觀的 Object:目標(biāo)、物體,提出。反對(duì)意見(jiàn)。3 The Carnot cycle is very us
3、eful in estimating limits of efficiency for given operating temperatures; 對(duì)于給定的運(yùn)行溫度而言,卡諾循環(huán)在評(píng)價(jià)效率極限時(shí)非常有用。4 Since the element is very small, we can assume that the density of the fluid within the element is constant。 既然微元非常的小,那么我們可以假設(shè)在微元內(nèi)的流體密度是一個(gè)常數(shù)。5 A pitot tube, a small open tube with its open end po
4、inting upstream, will intercept the kinetic energy of the flow and hence indicate the total energy head. 畢托管,一個(gè)很小,開(kāi)口的管子,開(kāi)口端指向來(lái)流的方向,會(huì)收集流體的動(dòng)能然后表示出總的能量頭。6 The basic modes of heat transfer are conduction and radiation. 傳熱的基本方式是導(dǎo)熱和輻射。7 Here is the density and is the specific heat. 這里 是密度,c 是比熱8c All heat
5、ed solids and liquids as well as some gases emit thermal radiation. 所有被加熱的固體、液體和某些氣體都會(huì)發(fā)出熱射線(熱輻射)。 Emit:發(fā)出,放射9 If the fluid motion is induced by a pump, blower, fan or some similar device, the process is called forced convection. If the fluid motion occurs as a result of the density differences produ
6、ced by the heat transfer itself, the process is called free or natural convection. 如果運(yùn)動(dòng)流體是靠熱泵,風(fēng)機(jī),風(fēng)扇或者其他的類似裝置,這個(gè)過(guò)程被稱為受迫流動(dòng)。如果運(yùn)動(dòng)流體是由于流體本身的密度差所造成的,那么這個(gè)過(guò)程被稱為自然對(duì)流。10 Means of producing refrigeration with machinery, called mechanical refrigeration. 用機(jī)械方式產(chǎn)生制冷,稱為機(jī)械制冷11 Refrigeration is also widely used in bo
7、th comfort air conditioning for people and in industrial air conditioning. 制冷廣泛應(yīng)用于民用舒適型空調(diào)和工藝性空調(diào)。12 The most widespread method of producing mechanical refrigeration is called the vapor compression system. 最為廣泛的機(jī)械制冷方式被稱為蒸汽壓縮式制冷。 13 Another widely used method is called the absorption refrigeration syst
8、em. 另外一個(gè)廣泛應(yīng)用的方式被稱為吸收式制冷系統(tǒng)。 14 The main equipment components of the vapor compression refrigeration system are the familiar evaporator, compressor, and condenser. 蒸汽壓縮式制冷系統(tǒng)主要的組成部件是蒸發(fā)器,壓縮機(jī)和冷凝器。 Components:組成的,構(gòu)成的。15 Air conditioning includes the heating, cooling, humidifying, dehumidifying, and cleani
9、ng (filtering) of air in internal environment. 室內(nèi)空氣品質(zhì)的空氣調(diào)節(jié)包括加熱、冷卻、加濕、除濕和凈化。 humidifying:加濕。16 Cooling tower冷卻塔 Cooling water冷卻水 Water Chiller水冷機(jī)組 Chilled water冷凍水 Outdoor Air新風(fēng) Supply air供風(fēng) Return air回風(fēng) Exhaust air排風(fēng) Air conditioner空調(diào)器 Fan Coil Unit風(fēng)機(jī)盤(pán)管 Air handling unit空氣處理單元 Cooling coil冷卻盤(pán)管 Heati
10、ng coil加熱盤(pán)管 Duct管道,風(fēng)管。 Humidifier加濕 Filter凈化 Diffuser分流 Heat recovery system熱回收系統(tǒng) VAV systems can also reduce first costs by using smaller equipment such as fans, pumps, boilers, chillers and less costly ductwork and piping distribution systems. 變風(fēng)量系統(tǒng)可以通過(guò)用更小的設(shè)備來(lái)減少初投資,例如風(fēng)機(jī)、熱泵、鍋爐、冷機(jī)、費(fèi)用少的低價(jià)風(fēng)管和水網(wǎng)分配系統(tǒng)。18
11、 either dynamic pressure differences due to the flow of the wind around a building, or static pressure differences due to the build-up of warm air within a building (the stack pressure). 這種壓差既可以是由建筑物周圍風(fēng)的流動(dòng)所引起的動(dòng)壓差,還可以是由熱空氣在建筑內(nèi)部積聚所產(chǎn)生的靜壓差。19 Thermodynamics is invaluable in the analysis of any system in
12、volving energy transfers; the most common and practical uses of thermodynamics in engineering are in analysis of systems containing some sort of working substance, usually in a liquid or gaseous phase, which is flowing or circulating through the device. 在分析任何涉及能量轉(zhuǎn)換的系統(tǒng)中,熱力學(xué)是非常有用的;熱力學(xué)在工程中最為廣泛和實(shí)際的應(yīng)用是分析
13、包含某種工質(zhì)的系統(tǒng),通常是在這些裝置中流動(dòng)或者循環(huán)的液體或者氣體相態(tài)。1 The two central concepts of thermodynamics are energy and entropy. Most other concepts we use in thermodynamics, for example temperature and pressure, may actually be defined in terms of energy and entropy. 熱力學(xué)兩個(gè)最主要的概念是能量和熵。另外其他用于熱力學(xué)的概念例如溫度和壓力,或者實(shí)際上也是依照能量和熵被定義。 D
14、efine:定義。2 Entropy has a different character: it cant be destroyed, but its easy to produce more entropy (and almost every thing that happens does). Like energy, entropy too can appear in different forms and be moved around. 熵有不同的特征:它不能被消失,但是它會(huì)很容易產(chǎn)生更多的熵(幾乎所有的事情都會(huì)發(fā)生)。能量和熵可以以不同的形式出現(xiàn)和被轉(zhuǎn)移到其他地方。3 If the
15、substance undergoes a cyclic process, there will be no net change in its internal energy over a cycle, and consequently the net energy transferred to a unit mass of the substance as heat during the cycle must equal the net energy transfer as work from the substance (work done). 如果物質(zhì)經(jīng)歷了一個(gè)循環(huán)過(guò)程,那么,對(duì)于整個(gè)
16、循環(huán)來(lái)說(shuō)內(nèi)能是沒(méi)有變化的。因此再循環(huán)中,以熱的形式傳給單位質(zhì)量物質(zhì)的凈能量必然等于以功的形式向外界傳出的凈能量。4 The highest efficiencies will be obtained when the ratio Tc/Th is as small as possible. One would like to add the energy as heat at as high a temperature as possible and reject energy as heat at the lowest possible temperature. 當(dāng)Tc/Th的比值盡可能小的
17、時(shí)候會(huì)獲得最高的效率。人們總想要在盡可能高的溫度下加熱,在盡可能低的情況下放熱。5 This is the general expression that relates variation of pressure in a static fluid to vertical position. The minus sign indicates that as z gets larger (increasing elevation), the pressure gets smaller. 這是一般的表達(dá)式,它表明了在鉛垂面方向靜壓的變化。負(fù)號(hào)表示當(dāng)Z不斷變大的時(shí)候,壓強(qiáng)越來(lái)越小。6 This i
18、ndicates that a surface of equal pressure for a liquid at rest is a horizontal plane. 這表明一個(gè)等壓面對(duì)其他流體來(lái)說(shuō)是一個(gè)水平線。7 Strictly speaking, it is a surface everywhere normal to the direction of gravity and is approximately a spherical surface concentric with the earth. 嚴(yán)格來(lái)說(shuō),這是一個(gè)表面到處正常的方向重力,大約是一個(gè)球表面同心與地球。8 It i
19、s often more convenient to express pressure in terms of a height of a column of fluid rather than in pressure per unit area. 通常依照一系列的高度來(lái)表示流體壓力會(huì)比每單位面積壓力更方便。9 Heat is defined as energy transferred by virtue of a temperature difference or gradient and is vectorial in the sense that it flows from region
20、s of higher temperature to regions of lower temperature. 由于溫差或者溫度梯度而傳遞的能量被定義為熱。它由高溫區(qū)流向低溫區(qū)。10 At the macroscopic level we state that the heat flux is proportional to the temperature gradient with the proportionality factor being identified as the thermal conductivity k。 在宏觀范圍內(nèi),我們指出,流量正比于溫度梯度,比例因子被定義為
21、導(dǎo)熱系數(shù)K。11 In treating conduction problems, it is often convenient to introduce another property which is related to the thermal conductivity, namely the thermal diffusivity 在處理導(dǎo)熱問(wèn)題時(shí),常常會(huì)引進(jìn)另外一個(gè)與導(dǎo)熱系數(shù)有關(guān)的參數(shù),這個(gè)參數(shù)被命名為為倒溫系數(shù)(熱擴(kuò)散率)a。12 On the macroscopic level, the calculation of thermal radiation is based on the Stefan-Boltzmann law which relates the energy flux emitted by an ide
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