Thermodynamics

Thermodynamics

Thermodynamics is a basic science that deals with energy and has long been an essential part of engineering curricula all over the word. Thermodynamics can be defined as the science of energy .The name thermodynamics stems from the Greek words therme (heat) and dynamis (power), which is most descriptive of the early efforts to convert heat into power.

The object of Engineering Thermodynamics mainly study on is energy conversion, especially the laws and methods of thermal energy into mechanical energy, and the ways of improving transformation efficiency, so as to increase energy economy.

Its main contents include: the basic concept and the basic law, the analysis and calculation ways of energy conversion process and cycle, the nature of working medium and chemical thermodynamics. Thermodynamic study has two different methods : one is the Macro-Research Method ; the other is Micro-Research Method. Thermodynamic engineering main apply the latter.

Thermodynamics is broadly interpreted to include all aspects of energy and energy transformations, including power generation, refrigeration, and relationships among the properties of matter. All activities in nature involve some interaction between energy and matter; thus, it is hard to imagine an area that does not relate to Thermodynamics in some matter. Applications of Thermodynamics are right where one lives. An ordinary house is, in some respects, an exhibition hall filled with wonders of Thermodynamics. Many ordinary household utensils and applications are designed, in whole or in part, by using the principles of Thermodynamics. Some examples include the electric or gas range, the heating and air-conditioning systems, the humidifier, the pressure cooker, the water heater, the shaver, the iron, and even the computer, and the TV. On a large scale, Thermodynamics plays a major part in the design and analysis of auto motive engines, rockets, jet engines, and conventional or the nuclear power plants.

Heat Transfer

In the wider world we live in a variety of processes occur, in which heat transfer is the closest one of the physical process related to the survival of the human. From the modern building HVAC to the formation of natural wind, frost, rain and snow; from the shell of thermal protection of the space shuttle re-entry to the effective cooling of electronic devices; from the changes throughout the year people dressed to frozen storage of human organs and the heat transfer process are all closely related. Heat transfer is to study the heat transfer law of science caused by the temperature difference.

Heat or thermal energy is transferred from one region to another by three modes: conduction, convection and radiation. Each is important in the design or application of heating, air-conditioning or refrigeration equipment. Heat transfer is among the transport phenomena that include mass transfer, momentum transfer or fluid friction and electrical conduction. Transport phenomena have similar rate equations and flux is proportional to a potential difference. In heat transfer by conduction and convection, the potential difference is temperature difference.

Thermal conduction is the mechanism of heat transfer whereby energy is transported between parts of a continuum from the transfer of kinetic energy between particles or groups of particles at the atomic level. Heat transfer involving motion in a fluid caused by the difference in density and the action of gravity is called natural or free convection. In conduction and convection, heat transfer takes through matter. For radiant heat transfer, there is a change in energy form; from internal energy at the source to electromagnetic energy for transmission, then back to internal energy at the receiver. Whereas conduction and convection are affected primarily by temperature difference and somewhat by temperature level, the heat transferred by radiation increases rapidly as the temperature increases.

Although some generalized heat transfer equations have been mathematically derived from fundamentals, usually they are obtained from correlations of experimental data. Normally, the correlations employ certain dimensionless numbers from analyses such as dimensional analysis or analogy.

Fluid mechanics

A fluid is a substance that deforms continuously when subjected to a shear stress, no matter how small that shear stress may be. A shear force is the force component tangent to a surface.

Fluid mechanics is sciences to study the fluid balance and macro-movement laws. It studies the conditions of fluid balance and pressure distribution; the basic laws of fluid motion; velocity distribution，pressure distribution，energy loss of fluid flow around an object or flow through a channel, , and the interaction between fluid and solid. Study on the method of fluid mechanics, summed up theoretical analysis method and Experimental Study on the methods and Numerical Calculation Method of three Fluid Mechanics as an important branch of classical mechanics and its development and Mathematics and Mechanics development are inseparable.

The science of fluid mechanics began with the need to control water for irrigation and navigation purposes in ancient China, Egypt, Mesopotamia, and India. It is the human struggle against natural disasters in the long-term process of gradually understanding and mastering the laws of nature, of evolution, is the collective wisdom of mankind. Fluid mechanics have broad applications in many industrial technologies. Construction of water conservancy projects, the development of shipbuilding industry are closely related to the development of the establishment of hydrostatics and the development of hydraulics. In Aviation industry, the designs of a variety of aircraft are based on the basic principles of aerodynamics and gas dynamics. In the power industry, hydropower, thermal power plants, or nuclear power, geothermal power plants, their work medium is fluid, so the design of power equipment must comply with the laws of fluid flow. In Machinery industry, the problem solving on lubrication, cooling, hydraulic, pneumatic and hydraulic and pneumatic control , must be apply fluid mechanics. The metallurgical industry will be faced with the flow of gas or the liquid metal in the furnace; flow and cooling, ventilation and other fluid mechanics problems. In addition, the chemical industry, oil industry, civil construction, and even the human body are related to fluid mechanics. So, fluid mechanics are indeed an important subject that many industrial technology departments must application and research on.

At present, the hydrodynamics include : Fluid mechanics, viscous fluid dynamics and rheology, gas dynamics, rarefied gas dynamics, water dynamics, and mechanical, non - newtonian fluid mechanics, chemical fluid mechanics, biological fluid mechanics, Geophysical Fluid dynamics and so on.

Essential Statistical Thermodynamics

Appendix B Essential Statistical Thermodynamics Karl K. Irikura Physical and Chemical Properties Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 Some computational methods, particularly ab initio techniques, produce detailed molecular information but no thermodynamic information directly. Further calculations are needed to generate familiar, ideal-gas quantities such as the standard molar entropy (S E ), heat capacity (C p E ),and enthalpy change [H E (T )-H E (0)]. This Appendix details the necessary procedures, including worked examples. Thermochemical calculations can be extended to transition states of chemical reactions. Procedures are provided for converting such information into rate constants. Tables are also provided for unit conversions and physical constants. Statistical thermodynamics calculations are necessary to compute properties as functions of temperature. In some computations, such as ab initio electronic calculations of molecular energy, the raw results do not even correspond to properties at absolute zero temperature and must always be corrected. All the corrections are based upon molecular spectroscopy, with temperature-dependence implicit in the molecular partition function,Q . The partition function is used not only for theoretical predictions, but also to generate most published thermochemical tables. Many data compilations include descriptions of calculational procedures (1-3). Corrections Unique to Ab Initio Predictions By convention, energies from ab initio calculations are reported in hartrees, the atomic unit of energy (1 hartree = 2625.5 kJ/mol = 627.51 kcal/mol = 219474.6 cm -1) (4). These energies are negative, with the defined zero of energy being the fully-dissociated limit (free electrons and bare nuclei). Ab initio models also invoke the approximation that the atomic nuclei are stationary, with the electrons swarming about them. This is a good approximation because nuclei are much heavier than electrons. Consequently, the Irikura, K. K. In "Computational Thermochemistry: Prediction and Estimation of Molecular Thermodynamics" (ACS Symposium Series 677); Irikura, K. K. and Frurip, D. J., Eds.; American Chemical Society: Washington, DC, 1998. Errata corrected through January 19, 2001

热力学模型

Author(s):Vrachnos, Athanassios ; Kontogeorgis, Georgios ; Voutsas, Epaminondas Address: Thermodynamics and Transport Phenomena Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens 157 80, Greece Title:Thermodynamic Modeling of Acidic Gas Solubility in Aqueous Solutions of MEA, MDEA and MEA-MDEA Blends Source:Industrial & Engineering Chemistry Research 45, no. 14 (2006): 5148-5154 Additional Info: American Chemical Society Standard No:ISSN: 0888-5885 CODEN: IECRED Language:English Abstract:The thermodn. framework that was developed in a previous work [Vrachnos et al. Ind. Eng. Chem. Res. 2004, 43, 2798] for the description of chem. and vapor-liq. equil. of carbon dioxide, hydrogen sulfide, and their mixts. in aq. methyldiethanolamine (MDEA) solns. is revised and extended in this study to the absorption of carbon dioxide into aq. monoethanolamine (MEA) solns. and aq. MDEA-MEA blends. The results of the model are compared with exptl. data taken from the literature. Very satisfactory predictions of acidic gas vapor-liq. equil. over MDEA, MEA, and their blends at various concns., acidic gas loadings, and temps. are obtained.

The first law of thermodynamics 热力学第一定律

The first law of thermodynamics 热力学第一定律 （20）Thermodynamics is a macroscopic science, and at its most fundamental level, is the study of two physical quantities, energy and entropy. Energy may be regarded as the capacity to do work, whilst entropy maybe regarded as a measure of the disorder of a system. Thermodynamics is particularly concerned with the interconversion of energy as heat and work. 热力学是一门宏观的科学，它在最基本的水平上对能量和熵两个物理量进行了研究。能量可以认为是做功的能力，而熵是一个体系混乱度的测量。能量以热和功的形式所进行的相互转变是热力学特别关心的。 In the chemical context, the relationships between these properties may be regarded as the driving forces behind chemical reactions. Since energy is either released or taken in by all chemical and biochemical processes, thermodynamics enables the prediction of whether a reaction may occur or not without need to consider the nature of matter itself. 在化学范围中，这些性质之间相互关系可以认为是化学反应的驱动力。因为在所有化学和生物化学过程中，能量要么被释放，要么被吸入。热力学可以预言一个反应能否发生而不需考虑物质本身的性质。 Consideration of the energetics of a reaction is only one part of the story. Thermodynamics determines the potential for chemical change, not the rate of chemical change---that is the domain of chemical kinetics. 考虑反应的动能学仅仅是研究化学反应的一部分。热力学决定了一个化学变化的潜能，而不是化学变化的速度，即化学变化是动力学研究的范围

热力学四大定律第零定律热平衡Thezerolawofthermodynamics

第零定律：熱平衡 The zero law of thermodynamics T1=T2=T3=T4 第一定律：The first Law of thermodynamics 能量守恆定律(The Law of conservation of energy) △E=Q-W Q=-W= Pdv = -nRTln v2/v1 Q=+nRT ln V2/V1代入 S= dnRT ln V2/V1 T 第二定律: 每一自發性的變化均伴隨著熵的增加 宇宙趨向最大亂度S＞0 熵entropy S ：熱力學函數(thermodynamic function)，熵可解釋為一種物系「亂度」或不規律的一種量度。熵可視為一機率函數 S宇宙= S系統+ S週邊＞0 判斷自發的方法：S＞0(不可逆) S= 0(可逆)，S＜0(不發生)S 表示熵的改變。 宇宙上能量傳遞有方向性的，總是由高能量傳到低能量。 第三定律： 在OK時，一完全結晶物體之熵會等於零， Ｓ＝０ 所有物體都呈現靜止狀態。 海水轉變成淡水化工程 要生產出1噸淡水，需要抽取2.5噸海水作為“原水”。海水被抽出後，首先通過加藥-混凝沉澱環節除去海水大顆粒懸浮物，然後進入氣浮池進行預處理，後經過超濾、反滲透兩個主要環節，充分去除海水中的鹽分、懸浮物、有機物和藻類物質等，最後進入後礦化環節調節水的硬度和pH值，苦澀的海水就變成能夠直飲的淡水了 自然科學: 1543年─哥白尼：(天體運行論)以太陽為中心(日心論) 1.伽利略：望遠鏡→h=1/2gt2 2.刻卜勒：行星三大運動定律 第一定律：「軌道定律」─所有的行星繞著太陽運行 第二定律：等面積定律─T=T2-T1=T4-T3 第三定律：週期定律R13= R23=K T12T22

国外课件热力学Basic thermodynamics

Basic thermodynamics Part of the School of Physics This class provides a basic overview requiring very little prior mathematical knowledge besides basic algebra. For a more involved discussion of thermodynamics which includes detailed derivations of these laws from first principles, please see the class page Statistical mechanics. Thermodynamics is the study of temperature, chemical energy, and the properties of matter as a consequence of its atomic structure. In the discipline of thermodynamics, two areas of interest are most significant: macroscopic thermodynamics, which deals with the properties of bulk matter; that is, large quantities of matter on a 'human' scale of understanding, and statistical mechanics, which relates the macroscopic behavior of matter to microscopic behavior. Heat and Temperature First of all, we must make clear some important definitions which may be different to the kind of language you are used to. In normal conversation, the words heat and temperature are used interchangably. To 'warm' or 'heat' something up is to increase its temperature. One might say 'that fire has a lot of heat in it'. In physics however, the word heat has a very distinct meaning. Heat is a form of energy which is held in matter by the constant jostling of its particles. In macroscopic thermodynamics, heat can be thought of as a massless, invisible substance that can flow from one region to another, but it is very important to remember that this is NOT a real or accurate description of heat, merely a tool to help you visualise how matter and the energy contained within it behaves in the 'real world' as we see it. In reality, heat is an effect of the movement of particles - whether they be atoms, ions, molecules, electrons, photons or any kind of fictional 'magic' particle you could care to imagine. Particles transfer heat between one another by colliding with one another, and over time this will cause heat to flow around in large bodies of matter where it allowed to. Heat is represented in a formula by the symbol Q, and its units, like other forms of energy, are Joules, which have the symbol J Example: The amount of heat in an object is measured in an experiment to be ten Joules; so we would write this result as Q = 10J Temperature, on the other hand, is one of a number of measurements we can make, called thermodynamic variables, of real systems that we study using the laws of thermodynamics. Thermodynamic variables Thermodynamic variables are those properties of a real system which can be observed by simple apparatus on a scale that can be readily understood by human beings. These contrast with statistical variables which by and large are estimations and inferred quantities relevant to the atoms within a material, whose existence is not relevant to macroscopic thermodynamics. At this point we make no hypothesis whatsoever on the nature of the material itself, as the laws of macroscopic thermodynamics are concerned only with large quantities of (usually) homogenous matter.

Thermodynamics

Thermodynamics Thermodynamics is a basic science that deals with energy and has long been an essential part of engineering curricula all over the word. Thermodynamics can be defined as the science of energy .The name thermodynamics stems from the Greek words therme (heat) and dynamis (power), which is most descriptive of the early efforts to convert heat into power. The object of Engineering Thermodynamics mainly study on is energy conversion, especially the laws and methods of thermal energy into mechanical energy, and the ways of improving transformation efficiency, so as to increase energy economy. Its main contents include: the basic concept and the basic law, the analysis and calculation ways of energy conversion process and cycle, the nature of working medium and chemical thermodynamics. Thermodynamic study has two different methods : one is the Macro-Research Method ; the other is Micro-Research Method. Thermodynamic engineering main apply the latter. Thermodynamics is broadly interpreted to include all aspects of energy and energy transformations, including power generation, refrigeration, and relationships among the properties of matter. All activities in nature involve some interaction between energy and matter; thus, it is hard to imagine an area that does not relate to Thermodynamics in some matter. Applications of Thermodynamics are right where one lives. An ordinary house is, in some respects, an exhibition hall filled with wonders of Thermodynamics. Many ordinary household utensils and applications are designed, in whole or in part, by using the principles of Thermodynamics. Some examples include the electric or gas range, the heating and air-conditioning systems, the humidifier, the pressure cooker, the water heater, the shaver, the iron, and even the computer, and the TV. On a large scale, Thermodynamics plays a major part in the design and analysis of auto motive engines, rockets, jet engines, and conventional or the nuclear power plants.

国外高等热力学教学

ChE 760Spring 2002 Advanced Chemical Engineering Thermodynamics Syllabus Instructor:Dr.Victor R.Vasquez email:vvasquez@https://www.wendangku.net/doc/da3713329.html, O?ce phone:(775)784–6060(email preferred)Web Page:https://www.wendangku.net/doc/da3713329.html,/homepage/vvasquez/ O?ce:LME 305O?ce Hours:M 6:00PM –7:00PM F 5:00PM –6:00PM or by appointment Lectures:Tuesday and Thursday,4:30–6:00P.M.,LME 316 Prerequisites:Physical chemistry,chemical engineering thermodynamics,multivariate cal-culus,di?erential equations,computer programming. Educational Objectives:After successfully completing this course,students should be able: ?To understand the fundamental concepts of chemical engineering thermodynamics and to explain these concepts to other chemical engineers.We will re-derive the essential conclusions of classical thermodynamics so that students will comprehend the breadth as well as the limitations of thermodynamics. ?To solve complex chemical engineering problems using thermodynamic concepts,data,and models. ?To use modern chemical engineering thermodynamic models and to understand their limitations.The connections between physical chemistry,chemical engineering ther-modynamics,and chemical process design will be demonstrated. Textbook:Thermodynamics and Its Applications by J.W.Tester and M.Modell,Prentice–Hall,3rd edition,New Jersey,1997. Classroom Format:The class will meet every Tuesday and Thursday for 1.5hours.Class attendance is expected at every class meeting .If,for any reason,you cannot come to class,please call or send an e-mail message to the instructor before class begins.Alternative assignments will be made for missed classes.There will be no make-up exams.Students will be required to lead class discussions based on assigned homework problems.Some of the material is covered in handout material or in library readings.Many of the homework problems will require the use of or the development of computer programs.The typical class will begin with questions asked by the students about the readings and answered by the instructor.For material not covered well in the text,lectures will be given,but these will be rare.Every student is expected to come to class prepared to enter into these discussions.Students unprepared for active discussion of the topic forfeit their “participation ”grade.More importantly,it will be very di?cult to catch up.During most class sessions,the majority of the time will be spent going over problems.Students will be chosen to lead the discussions of individual problems,with constant encouragement,coaching,and assistance from the instructor.The purpose of this classroom format is to enhance life-long learning,critical thinking,and communication skills.These are the three skills that correlate best

热力学

1．给物质同等的热量，一定使它提高同等的温度吗？给物质以热量，一定会使它的温度提高吗？ 答：热量和温度是不同的概念。给物质以热量使其温度升高多少还与其热容量有关，同等的热量给其热容量小的物体，其温度将有较大的升高。给物质以热量，不一定会升高它的温度，例如在冰的熔解或水的蒸发等相变过程中便是如此 2．日常温度计多用水银或酒精作测温物质，用水岂不更便宜？设想一下，如果有人用水来作温度计的测温物质，会产生什么问题？用水温度计测两盆凉水的温度时，若显示出水柱的高度一样，是否两盆水的温度一定相等？这违反热力学第零定律吗？ 答：一定质量的水在4。c时体积最小，大于或小于此温度体积都有所膨胀。用水来作温度计的测温物质，则会出现不同温度下温度计读数一样的问题。用水温度计测两盆温度在4。c上下的凉水时，即使显示出水柱的高度一样，两盆水的温度却是不相等的。这并不违反热力学第零定律，该定律说：“在与外界影响隔绝的条件下，如果物体A、B分别与处于确定状态下的物体C达到热平衡，则物体A和B也是相互热平衡的。”在这里两盆凉水分别是物体A、B，水温度计是物体C.水温度计分别与两盆凉水达到热平衡时只是体积相等，但并不处于同一确定的热力学状态。 3．节日向天空释放许多彩色氢气球，这些气球最后的结局如何？ 随着氢气球升高，外界压强减小，气球膨胀，最后气球爆破。 4．载人橡皮艇在白天还是夜晚吃水深？ 夜晚温度低，橡皮艇内气体密度大，吃水深。 5．尽管分子的微观动力学是可逆的。但是，大量的事实告诉我们，宏观过程是不可逆的。热量总是从高温物体传到低温物体，而不会自发地倒过来；俗话说，覆水难收。如果你把一杯水倒进一桶水里，你再也无法取回同样的一杯水来。什么道理？这是什么在起作用。 温度或物质不均匀分布是非平衡态，而均匀分布是平衡态，前者的概率比起后者是微乎其微的。所以，前者向后者自发地过渡很自然，而后者向前者过渡的概率之小，堪称旷世奇迹。宏观热力学理论把这一切归结到一条定律中，即热力学第二定律，并引进了“熵”这样一个物理量来刻画它。 按热力学第二定律，没有外部的干预，一个孤立系统的熵只能自发地增加，而不会减少。处于热平衡态时熵达到极大，这就是所谓“熵增加原理”。然而，在宏观理论框架里熵的本质是看不清楚的，玻耳兹曼在引进H函数之后给了熵(记作S)一个微观的定义，即 S=klnΩ 上式中的k是玻耳兹曼常量，Ω就是微观量子态的数目，即宏观态出现的概率。不难看出，熵与H的关系是 S=—kH 即H相当于负熵。 从上面的分析可见，熵增加原理的本质。 6．已知，在25℃时反应 H2(气)+Cl2（气）→2HCl(气) 的反应焓为?H反应=—184.62 kJ/mol，定压摩尔热容分别为Cpmol(H2)= 28.6 J/(mol.K)；Cpmol （C12) = 32.2 J/(mol K)和Cpmol (HCl) = 28.5 J/(mol . K)。求75℃时的反应焓。