Energy Efficiency Analysis Model And Application Research Of Thermodynamic System Under Multivariate Disturbances

It's always a question of great concern about improving energy-efficiency of thermodynamic systems and reducing energy-consumption of thermal power plant. In order to solve this question, a large number of thermal economy calculation and analysis methods for thermodynamic systems have been invented by many of scientific and technical workers, but these methods had no general form but a complex calculation which would make mistakes easily, or only applied to a specific disturbance, and a hardly controlled situation of multi-model appeared when confronted with random, multivariate disturbances. In a word, these models could not give us a easier and more general calculation model to those random and multivariate disturbances, and made it difficult to analyze the characteristics of thermodynamic system energy-efficiency under random and multivariate disturbances and find the law of thermal economy changes with some commonnesses. So, this paper chose the research on the subject of thermodynamic system energy-efficiency analysis model and its application under multivariate disturbances, and then to find the generally quantitative calculations and analysis method of thermodynamic system energy-efficiency analysis under multivariate disturbance and obtain the randeability of unit energy efficiency index and the distribution law of unit energy efficiency under random multivariate disturbances, finally it could be used to guide excogitation, operation, repair and technical transformation of the thermal power generating unit and improve its energy-efficiency level, reduce its consumption to primary energy source. Therefore, the research on this subject has a great practical and theoretical significance for energy-saving and consumption-reducing of thermal power plant. The main research contents and achievements are as follows:(1) A general physical model for thermal economy analysis of thermodynamic system was established. By the establishment of the mapping rules of standardized topological structure and steam-water parameters, a unified physical model suitable for arbitrary thermal economy analysis of thermodynamic system was founded. The canonical and concise form of this model was one of the innovative points of this paper and it also laid the foundation for the establishment of the unified elementary mathematic model.(2) An elementary mathematical model for thermal economy analysis of thermodynamic system was established. On the basis of the unified physical model, steam turbine internal work equation, cycle heat absorption capacity equation and steam-water distribution equation were respectively established by utilizing energy balance equation and mass balance equation. The three equations, as the elementary mathematic model for thermal economy analysis of thermodynamic system, were the foundation of the final establishment of the energy-efficiency analytical mode of the thermodynamic system under multivariate disturbances. The three elementary equations had generality for arbitrary thermodynamic system and were characterized by a simple, unified form and explicit physical meaning. By the amendent of steam-water distribution equation, the structure self-adaptive steam-water distribution equation for the thermodynamic system was established, which was not only appropriate for the thermodynamic system having a certain fixed structure and arbitrary types, but other thermodynamic systems whose structures usually have some random and dynamic changes. Therefore, it provided a new theoretical tool for the analysis and calculation of thermal economy of thermodynamic system which had a dynamic structures.(3) The energy-efficiency analysis model was established for the thermodynamic system under multivariate disturbances. Based on the basic mathematical model of thermal economy analysis and after strict mathematical derivation, a simple, unified form and explicit physical meaning energy-efficiency analysis model for the thermodynamic system under multivariate disturbances was established with the help of matrix differential theory. In this model, the influence of disturbance changes on energy-efficiency was expressed as the simple product form of intensity coefficients and quantity of disturbance changes. In the derivation, by introducing matrix operator and a new matrix operation method called block multiplication, the mathematics bottleneck of using matrix differential theory to analyze thermal economy of the thermodynamic system was solved, and it also provided a theoretical support for the mathematical analysis of all kinds of matrix-types energy equations. At the same time, by the use of the structure self-adaptive steam-water distribution equation, the energy-efficiency analysis equation could adapt better to the structure changes in operation of the thermodynamic system, especially when the heaters had some arbitrarily and random cuts. The energy-efficiency analysis model under multivariate disturbances provided a general and universal mathematical model for thermal economy calculation and analysis under random, multivariate disturbances, and it also provided a new theoretical support for the optimization design, the operation supervision and repair, and technical reformation of thermodynamic system of thermal power generating units.(4) Discussed the application of energy-efficiency analytical model for the thermodynamic system under multivariate disturbances. It proved the correctness and availability of the energy-efficiency analysis model and analyzed the changing characteristics of intensity coefficients and energy-efficiency under local or euroky multivariate disturbances, so provided the basis for the operation supervision, repair and technical reformation and operation economy enhancment of units.