【作者】 张来强；

【导师】 陈焕新；

【作者基本信息】 华中科技大学 ， 制冷及低温工程， 2007， 硕士

【摘要】 为了准确计算二氧化碳的热物性参数,本文将赫姆霍兹自由能方程应用于二氧化碳热物性参数的计算,求出了二氧化碳的焓、熵以及压力等热物性参数,并将计算结果与用EES软件计算的结果进行了比较,两者的偏差可满足工程实际的要求,为二氧化碳的热物性参数的计算提供了一种好的方法。某化工企业拟采用煤代油方案,将导致二氧化碳压缩机进口参数发生变化,为保证安全、节能,须对压缩机进行调节。而准确计算二氧化碳物性参数是对离心式二氧化碳压缩机进行性能校核及技术改造的有效保证,本文分别采用查压焓图表法、赫姆霍兹自有能法、临界压缩性系数法、L-K法、R-K法等五种方法,对二氧化碳在压缩机各段进出口工况点的物性参数进行计算,并对计算结果进行了分析、比较,指出五种方法对不同的物性参数计算精度不尽相同,而综合来看,赫姆霍兹自由能方法有着更好的准确度。本文第四章关于二氧化碳压缩机的调节计算就采用了此种方法。为了提出最佳的改造方案,本文采用增大标准流量、调节转速、进口预旋以及进口节流等多种方法对压缩机进行调节,计算了各种调节方式二氧化碳压缩机每段的进口冲角,讨论了压缩机能否正常运行以及其运行效率,综合各种调节方法的使用,给出了使压缩机预防喘振、稳定运行的调节方案。更多还原

【Abstract】 For the sake of precisely calculating the thermophysical properties of the carbon dioxide, this thesis uses Helmholtz free energy to calculate the thermophysical properties of carbon dioxide. Through calculating, we get the pressure, entropy and enthalpy of the carbon dioxide. When compared with the result from the EES, we find the windage is small enough to satisfy the actual request. It provides a good method to calculate the thermophysical properties of carbon dioxide.A chemical engineering enterprise is going to adopt coal substitute oil as energy source, it would result in the change of carbon dioxide compressor inlet parameters. To guarantee the safety and energy-saving, the compressor must be mediated. Precise calculation on thermophysical properties of carbon dioxide is effective on property colibration and technical renovation for carbon dioxide centrifugal compressor. In my thesis , five schemes are adopted respectively, such as Pressure-Enthalpy diagram and saturated tables lookup method, the Helmholtz free energy method, critical compressibility coefficient method, L-K method and R-K method, to compute thermophysical properties on the compressor’s operation points of carbon dioxide. Consequent results are analyzed and compared, which shows that there’re some differences concerning calculating precision of distinct thermophysical properties. But the Helmholtz free energy method is the best choice because of its good nicety. In the fourth chapter of my thesis, we use the Helmholtz free energy method for the adjustment calculate of the carbon dioxide compressor.So as to give the best adjustment choice, this thesis adopts aggrandizement of standard flow, regulate rotation rate, mount inlet whirl, and inlet throttle means to adjust compressor, counts per segmental import angle of attack of carbon dioxide compressor, discuss compressor can be able to failure-free operation or not, as well as its operating efficiency. With considering all methods, It gives the best choice to preventing asthmatic aremble , and make the compressor operate stably.更多还原