【作者】 陈琦；

【导师】 胡亚才；

【作者基本信息】 浙江大学 ， 工程热物理， 2017， 博士

【摘要】 经过百年的理论发展和众多的工程实践,经典热力学已经证明其可靠性,但是对于热力学中的的一些基本概念及其意义仍存在着一些不同的理解。比如温度和热量的定义缠绕问题和熵在温度趋向于0K时的极限值问题,弄清这些问题对热力学发展有积极的意义。长距离运输天然气存在着压力损耗的现象。LNG是一种高质量的冷能,补气压缩机是一种非常可靠的节能技术。本文提出利用LNG补气提高天然气压气机效率,这对节能减排有重大意义。依据本文提出的温热缠绕现象,本文认为热力学温度不唯一。在经典热力学的基础上,通过严格的数学推导,定义了新的、更为普适的温度和热量概念,将它们命名为广义热力学温度和广义热量。以此为基础,定义了广义熵、广义热力学能等物理量。证明了经典热力学中的相应概念仅仅是广义热力学的一个特例,广义热力学遵守经典热力学的基本规律和定理。并在新概念下重新阐述了热力学三大定律,将其推广以适应到广义热力学体系下语境。通过广义热力学体系,证明了当热力学温度趋向于0K时,任何物质的热力学熵趋向于0,即熵具有积分起点。解决了困扰已久的熵的最小极限问题以及热力学,甚至化学和物理上的诸多计算的基础问题。在此基础上,定义了广义热力学体系下绝对熵的概念,定义并命名了新的物理量——火羁(TS),推导了火羁的变换公式,初步探讨了火羁的意义,证明了广义熵产定律。证明了广义热力学各参数的二维全微分关系。给出了广义热力学特性函数的关系以及相同和不同广义热力学系下的麦克斯韦关系式。给出了比热容、焦耳汤普逊系数等物性参数的变换关系和计算方法。给出了广义熵、广义热力学能和广义焓的微分表达式,研究了不同广义热力学系下的矩阵变换关系式。给出了广义热力学系下的熵、火羁、热力学能、焓、自由能、自由焓和火积的积分表达式。本文提出利用液氮补气涡旋压缩机过程来模拟LNG补气天然气压缩机。介绍了涡旋压缩机的基本结构、工作原理和几何结构。给出了涡旋压缩机性能参数的计算方法,广义热力学体系下涡旋压缩机的过程控制方程,以及补气涡旋压缩机内部三段压缩的热力学过程分析。采用广义热力学原理分析了涡旋压缩机补气压缩过程中的绝热指示效率和补气压力以及相对流量比之间的关系,得出了绝热指示效率最大的工况。分析计算了涡旋压缩机压缩过程的广义热量和广义焓的变化;定义了广义焓指示效率、广义吸热指示效率、广义自由焓指示效率和广义火羁指示效率。证明了广义热力学也可以用于实际的过程分析。更多还原

【Abstract】 After hundreds years of theoretical development and numerous engineering practices,the classical thermodynamics theory has been proved correct.But,there are still some different understandings about some basic conceptions and meanings.For example,the twine definition of the temperature and heat,the limit of entropy when the thermodynamic temperature is near OK,figuring these problems out is positive to the development of thermodynamics.For long distance transport of natural gas,the loss of pressure is ineluctable.LNG has high quality of cold energy and the vapor injection technology of compressor is a reliable energy-saving technology.This paper raised that using LNG in vapor-injection to improve the efficiency of the natural gas compressors.It is significant to the energy-saving and emission-reduction.According to the phenomenon "the twine of temperature and heat",this paper put forward that the thermodynamic temperature is not unique.Based on the classical thermodynamics,according to the strict mathematical derivation,this paper defined new and widely applicable generalized conceptions of temperature and heat,and called them generalized thermodynamic temperature and generalized heat.Depending on these,generalized entropy,generalized thermodynamic energy and more parameters were defined and classical thermodynamics was proved merely a special example of the generalized thermodynamics.The generalized thermodynamics obeys the basic laws of the classical thermodynamics.In this paper,three laws of generalized thermodynamics were newly explained to fit the generalized thermodynamics system context.According to the generalized thermodynamics,this paper proved that when the classical thermodynamic temperature tends to 0K,the thermodynamic entropy’s limit of anything is 0,which solves the problem of entropy’s minimum limit and even many basic problems of entropy calculation in thermodynamics,chemistry and physics.And the conception of absolute entropy was raised.A new thermodynamic quantity was also proposed,which is called Jk(kTS).The transformation formulae of Jk is gived,the meaning of it is discussed.The generalized law of entropy production was proved.This paper also proved the two dimensional total differential expressions of generalized thermodynamic parameters,gave the characteristic functions of some generalized thermodynamic parameters,provided the Maxwell relation expressions in same and different generalized thermodynamic systems,rasied the transformation expressions and computational methods of specific heat,Joule Thompson coefficient and some other physical property parameters.The differential expressions of generalized entropy,generalized thermodynamic energy,generalized enthalpy were given.The matrix transformation expressions of different parameters in different generalized thermodynamic systems were studied.This paper also gave the integral expressions of entropy,thermodynamic energy,enthalpy and some other parameters in generalized thermodynamic systems.This paper raised that using liquid nitrogen for vapor-injection of scroll compressor to simulate LNG vapor-injection in natural gas compression,introduced the basic structure,working principle and geometry of scroll compressor,gave the method to calculate the performance parameters of the scroll compressor and the governing equations in generalized thermodynamics,analysed the three-section of the compression process.Using generalized thermodynamic theory,this paper also analysed the relation of the adiabatic efficiency,vapor-injection pressure and relative injection flow ratio in the vapor-injection of scroll compressor,obtained the best optimum condition.The change of generalized heat and generalized enthalpy inthe compression process of the scroll compressor were analyzed and calculated.The generalized enthalpy adiabatic efficiency,generalized absorbing heat adiabatic efficiency,Jk adiabatic efficiency and generalized free energy adiabatic efficiency were defined.These prove that it can be used generalized thermodynamic theory to analyse the actual thermodynamic processes.更多还原