SDU-Thermodynamics-Chapter01 工程熱力學(xué)課件

1、SHANDONG UNIVERSITYThermodynamics-An Engineering Approach, 5th熱力學(xué)熱力學(xué)原理及工程技術(shù)應(yīng)用原理及工程技術(shù)應(yīng)用 Presented by : 辛公明 Email：Tel: (883) 92428 1SHANDONG UNIVERSITYAuthorsProfessor Yunus A.CengelUniversity of Nevada, Reno Dr. Michael A. Boles North Carolina State University2Turkey土耳其turkey火雞烤火雞，必須具備一定的熱力學(xué)常識(shí)SHANDON

2、G UNIVERSITYReferences 參考教材 工程熱力學(xué)工程熱力學(xué)-第四版第四版 / 沈維道沈維道 童鈞耕童鈞耕 主編主編 精品課程網(wǎng)站浙江大學(xué) 上海交大西安交大 SHANDONG UNIVERSITYThermodynamics is not an easy subject Thermodynamics is a funny subject. The first time you go through it: you dont understand it at all; The second time you go through it, you think you underst

3、and it, except for one or two points; The third time you go through it, you know you dont understand it, but by that time you are so used to the subject, it doesnt bother you anymore. -Arnold SommerfeldSHANDONG UNIVERSITYThermodynamics ？熱熱力力學(xué)學(xué)From Greek words:Thermeheat 熱 thermo(-)dynamicsDynamispow

4、er 動(dòng)力 熱力學(xué)熱情 激情努力科學(xué) 教學(xué) 學(xué)習(xí)SHANDONG UNIVERSITYContent6Chap.1Introduction and basic conceptChap.2Energy, E-transfer, E-analysisChap.3Properties of pure substancesChap.4E analysis of closed systemsChap.5M,E analysis of control systemChap.62nd law of thermodynamicsChap.7EntropyChap.8ExergyChap.9Gas power

5、cyclesChap.10Vapor power cyclesChap.11Refrigeration cyclesChap.12Thermodynamic property relationsChap.13Gas mixturesChap.14Gas-vapor mixtureChap.15Chemical reactionsChap.16Chemical/phase equilibriumChap.17Compressible flowSHANDONG UNIVERSITYContent7Chap.1Introduction and basic conceptChap.2Energy, E

6、-transfer, E-analysisChap.3Properties of pure substancesChap.4E analysis of closed systemsChap.5M,E analysis of control systemChap.62nd law of thermodynamicsChap.7EntropyChap.8ExergyChap.9Gas power cyclesChap.10Vapor power cyclesChap.11Refrigeration cyclesChap.12Thermodynamic property relationsChap.

7、13Gas mixturesChap.14Gas-vapor mixtureChap.15Chemical reactionsChap.16Chemical/phase equilibriumChap.17Compressible flowService packsNozzlesFundamental Thermodynamic Processes SHANDONG UNIVERSITYChapter1 Introduction and Basic Concepts Overview of thermodynamics Unit system Basic/important concepts:

8、 system, surroundings, boundary, closed system, open system, properties, states, equilibrium, process, cycle. etc. Temperature and pressure Problem-solving technique8SHANDONG UNIVERSITYChapter1 Introduction and Basic Concepts Overview of thermodynamics Unit system Basic/important concepts: system, s

9、urroundings, boundary, closed system, open system, properties, states, equilibrium, process, cycle. etc. Temperature and pressure Problem-solving technique9SHANDONG UNIVERSITYOverview of Thermodynamics: what is ?Thermodynamics Science of Energy能量Name from Greek words:Thermeheat 熱 thermodynamicsDynam

10、ispower 動(dòng)力 熱力學(xué)Thermodynamics is a subject that deals with energy, energy transfer，energy transformations, and relationships among the properties of matter. 研究能量、能量傳遞與轉(zhuǎn)換、能量與物質(zhì)性質(zhì)之間關(guān)系10SHANDONG UNIVERSITY Zeroth law of thermodynamics (熱力學(xué)第零定律) By Ralph. H. Flower, 1931) : if Ta=Tc and Tb=Tc; then Ta=Tb

11、;11Overview: Laws of Thermodynamics (熱力學(xué)定律)SHANDONG UNIVERSITY First law of thermodynamics (熱力學(xué)第一定律) ： an expression of conservation of energy principle Ein-Eout=Esystem for closed system： Q=U+W 熱力學(xué)第一定律的解析式，是最根本的能量方程式 Q=dU+W 微分形式 (Conservation of energy principle: energy can neither be created, nor

12、be destroyed; it can change from one form to another, but the total amount of energy remains constant)12Overview: Laws of Thermodynamics (熱力學(xué)定律)熱力學(xué)第一定律的建立宣告了第一類永動(dòng)機(jī)不消耗能量的永動(dòng)機(jī)是不可能實(shí)現(xiàn)的熱力學(xué)第一定律的建立宣告了第一類永動(dòng)機(jī)不消耗能量的永動(dòng)機(jī)是不可能實(shí)現(xiàn)的SHANDONG UNIVERSITY Second law of thermodynamics (熱力學(xué)第二定律) Kelvin-Planck statement: It

13、 is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work. (不可能制造出從單一熱源吸熱、使之全部轉(zhuǎn)化為功而不留下任何其他變化的熱力發(fā)動(dòng)機(jī)) Clausius statement: It is impossible to construct a device that operates in a cycle and produces no effect other than the transfer

14、 of heat from a lower-temperature body to a higher-temperature body. (熱不能自發(fā)地、不付代價(jià)地從低溫物體傳到高溫物體)13Overview: Laws of Thermodynamics (熱力學(xué)定律)熱力學(xué)第二定律那么使制造第二類永動(dòng)機(jī)只從一個(gè)熱源吸熱的永動(dòng)機(jī)的夢(mèng)想破滅熱力學(xué)第二定律那么使制造第二類永動(dòng)機(jī)只從一個(gè)熱源吸熱的永動(dòng)機(jī)的夢(mèng)想破滅SHANDONG UNIVERSITY Third law of thermodynamics (熱力學(xué)第三定律) The entropy of a pure crystalline su

15、bstance at absolute zero temperature is zero在絕對(duì)零度，任何完美晶體的熵為零)絕對(duì)零度不可能到達(dá) . the impossibility of reaching absolute zero of temperature14Overview: Laws of Thermodynamics (熱力學(xué)定律)SHANDONG UNIVERSITYZeroth law of thermodynamics (熱力學(xué)第零定律)First law of thermodynamics (熱力學(xué)第一定律)Second law of thermodynamics (熱力學(xué)

16、第二定律)Third law of thermodynamics (熱力學(xué)第三定律)Carnot Principles (卡諾定理); 孤立系統(tǒng)熵(entropy)增原理Carnot cycle, Rankine cycle15Overview: Laws of Thermodynamics (熱力學(xué)定律)SHANDONG UNIVERSITY First successful steam engine build by ？Watt？ ? 16Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst suc

17、cessful steam engine designed by Thomas Savery (1697 patented a steam-powered pump he called the Miners Friend )Thomas Newcomen created the first practical steam engine in 1712. James Watt improved in 1763 to 1784 (75% less coal) 17Overview: History of Thermodynamics as a scienceAnimation of a schem

18、atic Newcomen steam engine. Steam is shown pink and water is blue. Valves move from open (green) to closed (red)汽缸汽缸/活塞活塞水箱水箱SHANDONG UNIVERSITYFirst and second laws of thermodynamics emerged in 1850s, from works of Lord Kelvin/開爾文開爾文 (1824-1907): developed the Kelvin scale of absolute temperature m

19、easurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (1820-1872) : Rudolph Clausius/克勞修斯克勞修斯 (1822-1888): Sadi Carnot/卡諾卡諾 (1796 1832) James Prescott Joule /焦耳焦耳 (1818-1889) 18Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst and second laws of thermodynamics

20、emerged in 1950s, from works of Lord Kelvin/開爾文開爾文 (1824-1907): developed the Kelvin scale of absolute temperature measurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (1820-1872) : developed a complete theory of the steam engine and indeed of all heat engines. Write first thermody

21、namic textbook in 1859.Rudolph Clausius/克勞修斯克勞修斯 (1822-1888): Sadi Carnot/卡諾卡諾 (1796 1832) James Prescott Joule /焦耳焦耳 (1818-1889)19Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst and second laws of thermodynamics emerged in 1950s, from works of Lord Kelvin/開爾文開爾文 (1824-1907)

22、: developed the Kelvin scale of absolute temperature measurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (1820-1872) : developed a complete theory of the steam engine and indeed of all heat engines. Write first thermodynamic textbook in 1859.Rudolph Clausius/克勞修斯克勞修斯 (1822-1888):

23、in 1850, first stated the basic ideas of the second law of thermodynamics. In 1865 he introduced the concept of entropy. Sadi Carnot/卡諾卡諾 (1796 1832) James Prescott Joule /焦耳焦耳 (1818-1889)20Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst and second laws of thermodynamics eme

24、rged in 1950s, from works of Lord Kelvin/開爾文開爾文 (1824-1907): developed the Kelvin scale of absolute temperature measurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (1820-1872) : developed a complete theory of the steam engine and indeed of all heat engines. Write first thermodynam

25、ic textbook in 1859.Rudolph Clausius/克勞修斯克勞修斯 (1822-1888): in 1850, first stated the basic ideas of the second law of thermodynamics. In 1865 he introduced the concept of entropy. Sadi Carnot/卡諾卡諾 (1796 1832) gave the first successful theoretical account of heat engines, now known as the Carnot cycl

26、e, laying the foundations of the second law of thermodynamics. Others like: Carnot efficiency, Carnot heat engine. James Prescott Joule /焦耳焦耳 (1818-1889) 21Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst and second laws of thermodynamics emerged in 1950s, from works of Lord

27、Kelvin/開爾文開爾文 (1824-1907): developed the Kelvin scale of absolute temperature measurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (1820-1872) : developed a complete theory of the steam engine and indeed of all heat engines. Write first thermodynamic textbook in 1859.Rudolph Clausi

28、us/克勞修斯克勞修斯 (1822-1888): in 1850, first stated the basic ideas of the second law of thermodynamics. In 1865 he introduced the concept of entropy. Sadi Carnot/卡諾卡諾 (1796 1832) gave the first successful theoretical account of heat engines, now known as the Carnot cycle, laying the foundations of the s

29、econd law of thermodynamics. Others like: Carnot efficiency, Carnot heat engine. James Prescott Joule /焦耳焦耳 (1818-1889) discovered relationship of heat to mechanical work ,which led to the theory of conservation of energy(first law of thermodynamics). SI unit of energy, the joule, is named after him

30、.22Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYFirst and second laws of thermodynamics emerged in 1950s, from works of Lord Kelvin/開爾文開爾文 (1824-1907): developed the Kelvin scale of absolute temperature measurement; firstly use thermodynamics in 1849. William Rankine /朗肯朗肯 (182

31、0-1872) : developed a complete theory of the steam engine and indeed of all heat engines. Write first thermodynamic textbook in 1859.Rudolph Clausius/克勞修斯克勞修斯 (1822-1888): in 1850, first stated the basic ideas of the second law of thermodynamics. In 1865 he introduced the concept of entropy. Sadi Ca

32、rnot/卡諾卡諾 (1796 1832) gave the first successful theoretical account of heat engines, now known as the Carnot cycle, laying the foundations of the second law of thermodynamics. Others like: Carnot efficiency, Carnot heat engine. James Prescott Joule /焦耳焦耳 (1818-1889) discovered relationship of heat t

33、o mechanical work ,which led to the theory of conservation of energy(first law of thermodynamics). SI unit of energy, the joule, is named after him.23Overview: History of Thermodynamics as a scienceSHANDONG UNIVERSITYOverview: Application areas of thermodynamics All activities in nature involve some

34、 interaction between energy and matter, from which thermodynamics is involved. Many engineering systems:24SHANDONG UNIVERSITYOverview: Application areas of thermodynamics Other aspects of life: . Thermodynamics is important and very useful for us to understand the real activities around us. ,25SHAND

35、ONG UNIVERSITYOverview: Approach to learn thermodynamicsMacroscopic approach (Classical thermodynamics-經(jīng)典熱力學(xué)) provide a direct and easy way to the solution of engineering problems;Microscopic approach (Statistical thermodynamics-統(tǒng)計(jì)熱力學(xué)) based on the average behavior of large groups of individual part

36、icles. 26SHANDONG UNIVERSITYChapter1 Introduction and Basic Concepts Overview of thermodynamics Unit system Basic/important concepts: system, boundary,surroundings, closed system, open system, properties, states, equilibrium, process, cycle. etc. Temperature and pressure Problem-solving technique27S

37、HANDONG UNIVERSITYUnit System 單位 Primary dimensions 7個(gè)根本量綱: Secondary dimensions: U, E, volume, etc. 28SHANDONG UNIVERSITYUnit System Unit(單位): the magnitudes of dimensions English system英制單位: united states customary system International System國際單位制: SI (Le Systme International d Units) based on a d

38、ecimal relationship between units; Dimensional Homogeneity (量綱一致性)every term in an equation must have the same unit. E= 25kj+7kj/kg is wrong29SHANDONG UNIVERSITYChapter1 Introduction and Basic Concepts Overview of thermodynamics Unit system Basic/important concepts: system, surroundings, boundary, c

39、losed system, open system, properties, states, equilibrium, process, cycle. etc. Temperature and pressure Problem-solving technique30SHANDONG UNIVERSITYBasic/important conceptsTo study a thermodynamical system system/系統(tǒng) surroundings/外界 boundary/邊界 closed system/閉口, open system/開口 property/屬性，參數(shù) stat

40、es/狀態(tài), equilibrium state/平衡態(tài) process/過程 cycle/循環(huán)研究教室的取暖情況 教室/系統(tǒng) 室外/外界 墻/邊界 關(guān)門、窗/閉口系, 開門、窗/開口 50m2，25/屬性，參數(shù) 暖和、不冷/狀態(tài), 無忽冷忽熱/平衡態(tài) 白天-晚上/過程 白天-晚上-白天/循環(huán)31SHANDONG UNIVERSITYBasic concepts: System and boundary Thermodynamic System系統(tǒng): a quantity of matter or a region in space chosen for study (人為分割出來的，作為熱力

41、學(xué)分析對(duì)象的有限物質(zhì)系統(tǒng)). Boundary(邊界): the surface that separates the system from its surroundings. Zero thickness; contain no mass; not occupy any volume 三無. Surroundings(外界):mass and region outside the system3232SHANDONG UNIVERSITY System classification based on the exchange of: Mass-物質(zhì)物質(zhì), M (kg) Heat-熱量熱量,

42、 Q(kJ) Work-功功, W (kJ)Basic concepts: System Classification33SHANDONG UNIVERSITY1234Mass, M heat , QWork, W 1 Open System (Control volume)：Non-Isolated system + related surroundingisolated system1+2 Closed System (Control mass)1+2+3 Adiabatic closed system1+2+3+4 Isolated systemBasic concepts: Syste

43、m Classification34SHANDONG UNIVERSITY1234Mass, M heat , QWork, W 1 Open System (Control volume)：between a system and surrounding, there are exchanges of both energy (heat and work) and mass (開口系統(tǒng)： 熱力系統(tǒng)與外界之間不僅有能量交換而且有物質(zhì)交換)開口系統(tǒng)通常是在某一劃定的空間范圍內(nèi)進(jìn)行的，所以又叫控制容積，或控制體Basic concepts: System Classification35SHAND

44、ONG UNIVERSITY36Basic concepts: Open SystemSHANDONG UNIVERSITY1234Mass, M heat , QWork, W 1+2 Closed System (Control mass): between a system and surrounding, there are exchanges of energy (heat and work), but no mass exchange.(閉口系統(tǒng)： 熱力系統(tǒng)與外界之間只有能量交換，沒有物質(zhì)交換)閉口系統(tǒng)質(zhì)量保持不變，又叫控制質(zhì)量Basic concepts: System Clas

45、sification37SHANDONG UNIVERSITY38Basic concepts: Closed SystemSHANDONG UNIVERSITY1234Mass, M heat , QWork, W 1+2+3 Adiabatic closed systemBasic concepts: System ClassificationAdiabatic system: between a system and surroundings, there are no exchange of heat. (絕熱系統(tǒng)： 熱力系統(tǒng)與外界之間無熱量交換的系統(tǒng))39SHANDONG UNIVE

46、RSITY1234Mass, M heat , QWork, W 1+2+3+4 Isolated system：between a system and surrounding, there are no exchanges of both energy (heat and work) and mass (孤立系統(tǒng)： 熱力系統(tǒng)與外界之間既沒有能量交換，也沒有物質(zhì)交換)Basic concepts: System Classification40SHANDONG UNIVERSITY1234Mass, M heat , QWork, W 1 Open System (Control volum

47、e)：1+2 Closed System (Control mass)1+2+3 Adiabatic closed system1+2+3+4 Isolated systemBasic concepts: System Classification41SHANDONG UNIVERSITYReal or imaginaryFixed or movingBasic concepts: BoundaryBoundary (邊界邊界): the surface that separates the system from its surroundings. Zero thickness; conta

48、in no mass; not occupy any volume. 42Fixed or movingReal or imaginaryProper choice of the system/boundary may greatly simplify the analysisSHANDONG UNIVERSITY43 A、B two tribes “雞、犬之聲相聞，民至老死不相往來 Choose tribe A as a system closed systemBasic concepts: an exampleAB Choose tribe A+B as a system Isolated

49、 systemSHANDONG UNIVERSITYProperties(參數(shù)) of SystemProperty: any characteristic of a system. Intensive/強(qiáng)度量:the value is independent of the mass, T, P, Extensive/廣延量:the value depends on size or extent of a system, e.g: total mass, total volume V, total energy E. The criterion to identifySpecific prop

50、erties: extensive properties per unit mass， v，e, u, s, etc. 廣延量強(qiáng)度量44是否具有可加性是否具有可加性 e.g.: P. T, V, m, SHANDONG UNIVERSITYProperties(參數(shù)) of System Temperature, T : K, , Pressure, P: Pa, kPa, bar, atm Density, : mass per unit volume =m/ V (kg/m3) depends on P and T Most gases : is proportional to press

51、ure and inversely proportional to temperature Liquids and solids depend more on T, less on P. Water density: max4 =1000kg/m3 Specific volume, : volume per unit mass =V/m=1/ Specific weight, weight of a unit volume = g U/內(nèi)能，H/焓， S/熵 45SHANDONG UNIVERSITYState and equilibrium of a system State(狀態(tài)狀態(tài)) :

52、 a set of properties that completely describes a condition of the thermodynamics system. At a given state, all the properties are fixed If one property value is changed, the state changes to a different one Equilibrium(平衡狀態(tài)平衡狀態(tài)): a state of balance. No unbalanced potentials(or driving forces) within

53、 the system系統(tǒng)內(nèi)沒有變系統(tǒng)內(nèi)沒有變化的趨勢(shì)化的趨勢(shì) No changes if a system is isolated from its surroundings(假設(shè)隔離外界，那么系統(tǒng)假設(shè)隔離外界，那么系統(tǒng)狀態(tài)保持不變狀態(tài)保持不變) Thermal equilibrium: no change in temperature Mechanical equilibrium: no change in pressure with time Phase equilibrium: no change of each phase Chemical equilibrium: no chang

54、e in chemical composition46state1Thermal equilibriumSHANDONG UNIVERSITYThe state postulate State postulate(狀態(tài)公理): the state of a simple compressible system is completely specified by two independent, intensive properties. (對(duì)于簡單可壓縮系統(tǒng)，只要有兩個(gè)獨(dú)立狀態(tài)參數(shù)即可確定一個(gè)狀態(tài)) A simple compressible system: no external forc

55、e fields like: electrical, magnetic, gravitational, motion and surface tension effects. Two properties are independent: one can change while other one is constant. T&v, T&P (for single phase system)47SHANDONG UNIVERSITYProcesses and cycles 過程和循環(huán)Process過程: any change that a system undergoes from one

56、equilibrium state to another. The process path indicates a series of equilibrium states through which the system passes during a process and has significance for quasi-equilibrium processes only. Cycle (循環(huán)): a system returns to its initial state at the end of the process. 48SHANDONG UNIVERSITYQuasi-

57、equilibrium process準(zhǔn)平衡過程/準(zhǔn)靜態(tài)過程Quasi-equilibrium(quasi-static) process準(zhǔn)平衡過程準(zhǔn)平衡過程: the process proceeds infinitesimally close to an equilibrium state at all times. (系統(tǒng)在變化所有階段都無限接近于平衡狀態(tài)的過程系統(tǒng)在變化所有階段都無限接近于平衡狀態(tài)的過程)Slow enough to let system adjust itself internally and to keep no properties of certain part

58、 change faster. 系統(tǒng)要足夠慢，系系統(tǒng)要足夠慢，系統(tǒng)工質(zhì)在平衡階段被破壞后的自動(dòng)回復(fù)時(shí)間，即所謂弛豫時(shí)間非常短統(tǒng)工質(zhì)在平衡階段被破壞后的自動(dòng)回復(fù)時(shí)間，即所謂弛豫時(shí)間非常短，系統(tǒng)內(nèi)有足夠時(shí)間來恢復(fù)平衡，系統(tǒng)內(nèi)有足夠時(shí)間來恢復(fù)平衡is idealized process, not actual process是理想過程是理想過程. Useful 熱力學(xué)分析中的作用熱力學(xué)分析中的作用: Easy to analyze Work producing devices deliver most work as standard to compare to actual ones. 49SHA

59、NDONG UNIVERSITYReversible process可逆過程可逆過程: a process that can be reversed without leaving any trace on the surroundings; 當(dāng)完成了某一過程之后，如果有可當(dāng)完成了某一過程之后，如果有可能使工質(zhì)沿相同的路徑逆行而回復(fù)到原來狀態(tài)，并使能使工質(zhì)沿相同的路徑逆行而回復(fù)到原來狀態(tài)，并使相互作用中所涉及的外界亦回復(fù)到原來狀態(tài)，而不留相互作用中所涉及的外界亦回復(fù)到原來狀態(tài)，而不留下任何變化：這一過程就叫可逆過程下任何變化：這一過程就叫可逆過程Irreversible process不可逆過

60、程不可逆過程50 Isothermal process等溫過程: no change in T Isobaric process等壓過程: no change in P Isochoric process等容過程: no change in specific volume Isoentropic process 等熵過程: no change in entropySHANDONG UNIVERSITYThe Steady-Flow Process(穩(wěn)流過程) The steady flow process is a process during which a fluid flows thro