热力学(火用)及其普遍化表达式的动力学特征

分析了功、热、能和的物理意义以及与热力学定律的关系,做功和传热是能和传递与转换的两种途径,从热力学第一定律定义的能量只有相对意义。是系统相对于环境所具有的做最大有用功的能力,相对于选定的环境,是系统的状态参量。常规的计算式是从热力学第一和第二定律导出的结果,从动力学的角度讨论了及其普遍化表达式的物理含义。起源于系统与环境的不平衡,如果系统与环境之间存在着某种(或几种)强度量差,在强度量差的推动下系统可能自动地变化到与环境相平衡的状态(寂态),在这样的过程中系统可以对外做功,这种做最大有用功的能力就是系统的。在能量公设的基础上,的微分被普遍地表示为强度量差与其共轭的广延量微分的乘积。的普遍化表达式完整地反映了的物理含义及其动力学特征,利用能量和的普遍化表达式导出了损失的普遍化表达式。

Thermodynamic Exergy and Dynamic Characteristics of its Generalized Expressions

Analyzed were the physical meaning of work,heat,energy and exergy as well as their relations with thermodynamic laws.Doing work and transferring heat are the two ways for transferring and converting energy and exergy.The energy defined from the first law of thermodynamics has only a relative meaning.Exergy represents the ability of a system to do maximal useful work with respect to an environment.Relative to a specified environment,exergy is the status parameter of a system.The conventional calculation formula of exergy is derived from the first and second law of thermodynamics.From the viewpoint of dynamics discussed was the physical meaning of exergy and its generalized expression.The exergy originates from the non-equilibrium of a system with its environment.If any (or several kinds of) intensive property difference exists between a system and its environment,then under the driving force of such an intensive property difference,the system may automatically change to a state featuring a balance with its environment (dead state).During this process,the system can do work to the outside world and such an ability to do maximal useful work is defined as the exergy of the system.On the basis of energy postulation,the differential of exergy is generally expressed as a product of the intensive property difference and the differential of its conjugated extensive variables.The generalized expressions of exergy can fully reflect the physical meaning and dynamic characteristics of exergy.By employing the generalized expressions of energy and exergy,derived was the generalized expression of exergy losses.