| This paper introduces the current development status of large-capacity thermal power plants firstly, and then points out that the circulating mode of the power units produces corresponding changes with the growing capacity of the units, results in energy consumption of water-vapor flow resistance for a power plant thermodynamic system increase gradually. Detailed analysis for the throttling effect of water and steam of the units in different pressure classes is given, getting trends of throttling coefficient with temperature and pressure and throttling effect for the influence degree of each thermal equipment, which has certain guiding significance for analyzing the flow resistance irreversible losses in power plant thermal equipments.In power plant thermal equipments, the flow process of water and steam is a complex heat transfer and throttling problem. At present, the research work of water and steam flow resistance in thermal equipments are mainly in experiment and simulation, not much for the theoretical study of the flow process thermodynamic analysis. The difference between the power produce fuel consumption and the net fuel consumption had been cleared about in this article, we pointed out that the pump pressure head and the heat absorbed by the refrigerant overcome the energy consumption of water vapor flow resistance together, brought forward repeated computation of the folw resistance irreversible losses existed in the thermodynamics calculation method of power plant thermal system.Therefore, the thermodynamic properties of water and steam in the flow process is studied on the basis of the thermodynamic, getting the specific algorithm to calculate the folw resistance irreversible losses which has the important meaning to improve the accuracy of the thermodynamic calculations. Take a specific large-scale coal-fired generating unit as an example, this paper systematically calculated the flow resistance irreversible losses in the entire thermal system and each thermal equipment, and made a distinction between flow resistance irreversible losses caused by the pump power consumption and endothermic interaction. |
