共查询到19条相似文献,搜索用时 171 毫秒
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文章分析了国内化工热力学、工程热力学教材在熵平衡方程推导过程中存在的错误,指出了热力学教材中有关熵流、熵产及损失功计算式表述形式方面存在的问题,并结合笔者多年的教学经验,提出了改进熵平衡方程推导的具体方法和规范熵流、熵产及损失功计算式的建议。 相似文献
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热力学定律一直以来都是学生学习的难点问题。本文通过分析系统变化过程中功和热转化关系,讨论了热力学第二定律的文字表述及克劳修斯不等式;分析了热力学第二定律与亥姆霍兹自由能判据和吉布期自由能判据的直接联系,从微观层次说明了热力学第二定律的本质:即热功转化的不可逆性,决定了隔离系统熵不能减小的宏观事实;对绝对零度不能到达原理及其原因进行了剖析。 相似文献
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本文阐述了化工热力学与化工原理两门课程在能量有效利用方面的内在联系,分析了热力学第一定律在化工原理动量传递中的有关应用;探讨了热力学第二定律在流体流动等单元过程中的应用;并采用热力学方法对化工单元操作过程的经济性进行了分析与讨论。在化工热力学教学中,结合这些知识点的讲授可帮助学生更深层次地理解与掌握化工单元过程的内涵,提高对本课程的学习兴趣,培养学会应用热力学基本原理和方法处理工程实际问题的能力。 相似文献
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本文针对物理化学中的教学难点热力学三大定律进行讨论,指出学习热力学三大定律时应注意的问题,重点论述了热力学第二定律的来源及其应用,指出不同热力学函数判据的来源及其应用条件,以便于学生从宏观上掌握热力学知识体系。 相似文献
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大多数研读热力学的学生都对熵抽象的观念感到痛苦。尤其甚者,他们对热力学第二定律的陈述及如何应用都觉得困惑。这篇短文借着Smith等人著名热力学教科书上的范例阐述有效能量(Exergy)的观念,并进而彰显热力学第二定律的意涵。 相似文献
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以逆向Stirling循环为原理的理想气体的可逆制冷机中功转化为热的比率为η比率=-Q/W1=T1-T2/T1.在可逆制冷机中,实际气体和理想气体的功温比守恒.可逆过程的功温比是状态函数.文章提出了热力学第二定律的新表述,即不可能通过做功使之完全变为热量而不产生其它影响.可证明实际过程的功温比大于可逆过程的功温比,∫(δW/T)实际过程≥∫(δW/T)可逆过程. 相似文献
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熵函数是热力学第二定律的基本概念,教学中导出熵函数的方法繁多。本文对熵函数的经典引入法、直接定义法、类比引入法和统计引入法等进行详细讨论,对每种方法的优缺点以及适用的教学对象进行了评述。 相似文献
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热力学过程的性质、方向和限度判据的研究 总被引:1,自引:1,他引:0
在热力学第二定律的基础上,结合热力学第一定律及相关限制条件,给出了热力学过程性质、方向和限度的判据.对熵判据与其他各种判据的一致性问题进行了探讨,熵判据是热力学过程的基本判据,在相应适用条件下,其他各种热力学判据都可归结为孤立体系的熵增加原理.探讨了热力学过程性质判据与方向和限度判据的特点及适用性. 相似文献
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Computer-aided exergy optimization of chemical engineering processes. Methods of exergy evaluation as the basis of energy and material analysis of chemical processes have been used for some years to evaluate these processes from the view point of the First and Second Law of Thermodynamics and with regard to their influence on the environment. This paper introduces a tool for computer-aided exergy analysis and optimization of complex process plants. This tool is based on a flowsheeting program that is extended to calculate the exergy of material, heat, and work flows. The optimization problem of process plants is solved in a two level approach by parameter optimization and structural optimization. The parameter optimization is realized automatically by the extended flowsheeting program. The structural optimization is based on heuristic rules and experiences of the process engineer. 相似文献
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化工设计课程教学改革建议 总被引:1,自引:1,他引:0
基于化工设计课程在培养优秀化工人才中的重要作用,结合我院目前该课程的开设情况,本文对化工设计课程的教学提出五点建议:重视化工设计课程在培养化工人才中的作用;理论课程的讲授应重视工程观念的培养;加强计算机在教学中的辅助作用;增强实践教学环节的作用;改变单一的考核方式。 相似文献
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The advances made in the field of chemical engineering as applied to the processing of metals and other inorganic materials
are reviewed. The reactions involved in this field are heterogeneous in nature, the fluid-solid noncatalytic reactions being
the most important group of examples. In these heterogeneous reactions, interfacial chemical reactions are always accompanied
by the transfer of mass and heat between the reaction interface and the bulk fluid. The interplay of these steps determines
the overall characteristics and analysis of the reaction rate. The review examines the developments in the quantitative rate
analysis of various fluid-solid reaction systems. Examples are largely drawn from the work of the author and coworkers, which
has led to the formulation of the Law of Additive Reaction Times and its application to a wide range of fluid-solid reactions.
The serious effects of thermodynamics on fluid-solid reaction with small equilibrium constants, in terms of the overall rate
and the falsification of activation energy, have been examined based on a careful quantitative analysis. 相似文献
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ROBERT T. BALMER 《Chemical Engineering Communications》2013,200(1-6):145-154
The similarity between the entropy balance equation of the Second Law of Thermodynamics and the classical balance equations of chemical reaction kinetics or allometric biological growth models is used to construct an entropy model for biological systems. In this model the entropy transport rate is assumed to be proportional to surface area and the entropy production rate is assumed to be proportional to system volume. It is also hypothesize that, at any time (age), the entropy transport and production rates depend directly upon the instantaneous value of the system total entropy. The resulting entropy rate balance can then be solved uniquely for the total system entropy as a function of time (age)
Also, it is postulated that all living systems are characterized by a continuously, decreasing total entropy level, and that biological death occurs at some minimum total entropy value. The time required to reach this minimum is the lifespan of the biological system. 相似文献