工程热力学EngineeringThermodynamics工程热力学工程热力学.ppt

工 程 热 力 学 Engineering Thermodynamics,西安建筑科技大学环境与市政工程学院 School of Municipal & Environmental Engineering Xian University of Architecture & Technology,主 讲 人：赵 蕾 Zhao Lei Email:,教师介绍,赵 蕾, 博士，副教授, 硕士生导师 环境与市政工程学院,Address：环境与市政工程学院实验教学楼206室热工流力教研室 Tel：82202185 E-mail: ,助教介绍,Name: Address：高层研究生公寓 Tel：,Introduction (绪论),What does thermodynamics concern? Main Contents of Engineering Thermodynamics Some Requirements for this course,Thermodynamics can be defined as a branch of science of energy.,heat,Therme,dynamis,power,(Greek words),热能,Thermal Energy,工程热力学是重要的技术基础课,0.1 What does thermodynamics concerns? (热力学涉及哪些内容?）,Thermodynamics is the branch of science which studies the rule that governs the transformation of thermal energy to other forms of energy. Also it studies how to use thermal energy efficiently. 工程热力学是一门研究热能有效利用及热能和其它形式能量转换规律的科学 It includes all aspects of energy and energy transformations（能量转换）, including power generation, refrigeration and relationships among the properties of matter.,热电厂(热能机械能) Thermal Power Plant (Thermal Energy Mechanical Energy,飞机(热能机械能) Aeroplane (Thermal Energy Mechanical Energy,汽车 (热能机械能) Vehicle (Thermal Energy Mechanical Energy),冰箱 (机械能热能) Refrigerator (Mechanical Energy Thermal Energy,? Why do we need to learn Engineering Thermodynamics?,自然能源的种类 (Categories of natural energy resources) A.化学能（Chemical energy ）: such as : 煤炭 （coal） 石油 （crude oil） 天然气（ natural gas ） 沼气 （firedamp, etc）.,2.自然界中的能源 （Natural energy resources),B. 机械能（Mechanical energy） such as: 风力资源 （wind resources） 水力资源 （water resources） 潮汐能 （tidal energy）, etc. C. 热 能（ Thermal energy） such as: 太阳能（solar energy） 地热能（geothermal energy）,etc. D. 原子能（Nuclear energy ）,Chemical energy Thermal energy,Fusion or fission reaction,Combustion（燃烧）,directly used,Mechanical energy can be used directly.,（核聚变或和裂变）,(2) 能源的利用（Utilization of Energy Resources ）,Thermal energy,Nuclear energy Thermal energy,indirectly used,能源转换与利用的关系(Relationship between energy transformation and utilization),热 能,电 能,机 械 能,风 能,水 能,化 学 能,核 能,地 热 能,太 阳 能,一次能源 (天然存在),二次能源,光电转换,燃料电池,光热,聚变,裂变,燃烧,水车,水轮机,风车,热机,电动机,发电机,90%,转换,直接利用,利用,生物质,90% of energy resources are transformed into thermal energy before it is used.,(3) 能量转换的共同点(A rule in common),Then, thermal energy is transformed into mechanical energy and used indirectly,How can thermal energy be transformed into mechanical energy more efficiently?,Thermal energy Mechanical energy (1) 广泛性 universally Heart the heating and air-conditioning systems, the refrigerator, humidifier, the pressure cooker, the water heater, the shower, the iron and even the computer. automotive engines,rockets, jet engines,and conventional and nuclear power plans, solar collector and the design of vehicles from ordinary cars to airplanes.,transformed,3.热力学的研究对象 (What does Thermodynamics study?),Disorganized energy organized energy （无序能） （有序能）,transformed,(2)代表性（ Representatively ）,(3)实用性 (Practicality),4.能量转换的一些实例 (Examples of Some energy transformation application ),(1)火力发电装置 (Steam power plant),火力发电装置基本特点,锅 炉,汽轮机,发电机,给水泵,凝汽器,过热器,1、热源 2、工质 （水，蒸汽） 3、工质状态的变化 (加压、加热、 膨胀做功、放热) 4、冷源,Generalized Representation of Heat Engines （热机工作原理的示意）,热 源 (Hot Reservoir),冷 源 (Cold Reservoir),How many W can be produced by absorbing QH? Is there any relationship between QH,QL and W?,Is QL necessarily to be discharged to its surroundings, becoming waste energy?,(2) 内燃机装置 Internal combustion engine,空气、油,废气,吸气,压缩点火,膨胀,排气,内燃机装置基本特点,1、热源 2、工质（燃气） 3、工质经历状态变化 (加压、加热、 膨胀做功、放热) 4、冷源,冰箱 (Refrigerator),(3)制冷空调装置 Refrigeration System,(3)制冷空调装置 Refrigeration System,1、冷源 2、工质（制冷剂） 3、循环 (加压消耗外界的功量、放热、膨胀、吸热) 4、热源,Heat source of high temperature （高温热源 hot reservoir） Working substance or working medium （工作介质） C. The change in state of working medium （工质的 状态变化） D. Heat sink of low temperature （低温冷源 cold reservoir） Thermal energy reservoir: heat source heat sink,(4) Main Factors in energy transformation (能量转换中的主要因素),0.2 研究的主要内容 Main Contents,能量转换的基本定律 Basic Principles of Thermodynamics 热力学第一定律 （能量守恒原理） The first law of thermodynamics (conservation of energy principle) For example: a rock falling off a cliff human body It asserts that energy is a kind of thermodynamic property of substance.,It asserts that energy has quantity as well as quality and actual process occur in the direction of decreasing quality of energy. 阐明能量不仅有量的属性，而且也有质的属性，过程总是朝着能量贬值的方向进行。 For example: a cup of hot water,(2) 热力学第二定律 The second law of thermodynamics （）,2.工质的性质 Properties of Working Medium,(1) 理想气体的性质 Properties of Ideal Gases (2) 水蒸气的性质 Properties of Steam or Water Vapor (3) 湿空气 Moist Air,3. 工程应用 Some applications,喷管中的流动 Flow through Nozzles (2) 动力循环 Power Cycles (3) 制冷循环Refrigeration Cycles,主要内容 Main Contents,第一章 热力学基础知识 第二章 理想气体的热力性质 第三章 热力学第一定律 第四章 理想气体的热力过程 第五章 热力学第二定律 第七章 水蒸气 第八章 湿空气 第九章 蒸气的流动 第十章 蒸气的动力循环 第十一章 制冷循环,(1) 宏观方法 ( Classical Method) 连续体(continuum)，用宏观物理量描述其状态，其基本规律是无数经验的总结 特点：可靠，普遍，不能任意推广 经典 （宏观,平衡）热力学 classical (macroscopic, equilibrium) thermodynamics,4.工程热力学研究方法 (Study Method),从微观粒子的运动及相互作用角度研究热现象及规律。 Microscopic approach is based on the average behavior of large groups of individual particles 特点：揭示本质，模型近似 微观（统计）热力学 microscopic (statistical) thermodynamics,(2) 微观方法(Statistical Method),0.3 教 学 要 求 Some Requirements for this course,1. Clearly understand and firmly grasp of the basic principles 弄清基本概念，注意每章后的思考题 2. Finish the assignment independently and submit it a week after it is assigned. 独立完成作业，布置作业后的下周按时交,3、Explore your activeness, think hard, attend to discussion in class. 发挥主观能动性，勤于思考，积极课堂讨论， 4、Solve problems as soon as it is discovered 有问题及时解决，不要拖至考试,Problem Solving Technique (解题方法）,(1) Problem statement （问题陈述） (2) Schematic （示意图） (3) Assumptions （假设） (4) Physical Laws （物理定律） (5) Properties （物性参数） (6) Calculations （计算） (7) Reasoning, Verification, and Discussion （推理、证明和讨论）,Neatness （整洁） Organization （有条理） Completeness （完整） Visual appearance （工整）,Requirements for writing form （对作业的要求）,请在布置了作业以后的一周内交作业。,作业得分在C及以下的同学可以重新做好之后 请老师另阅。,Remark on Significant Digits （有效数字）,Reporting results should be rounded to three significant digits. （结果保留三位有效数字） It is more appropriate to retain all the digits during intermediate calculations and to do the rounding in the final step.,About the Exam 考试成绩,1、Assignment 10% (平时作业10%) 2、Exercise and discussion in class 10% (课堂练习及讨论参与情况 10） 3、Experiment 10% (实验情况及报告10%) 3、Final Exam 70%（ 期末考试70%）,热力学方面获诺贝尔奖的科学家（1）,J.D.范.德瓦尔斯 Johannes van der Waals (1837-1923) 荷兰 气体和液体状态方程 1910年诺贝尔