Research On Relation Between Economic Heating Radius And Economic Specific Frictional Resistance

With the gradually improvement of the people’s living standards in our country, the demand for heat supply network is continuously growing. Since the super-large scale heat supply network investment and transmission energy consumption have great influences on the energy conservation and economic efficiency of heating, there will be an urgent necessity to launch a study on the influencing factors of the heat supply network investment and transmission energy consumption, among which are two essential factors:economic specific frictional resistance and economic heating radius. Therefore, the study on the relations between them is of big significance for the development of heat supply network in our country.This article firstly made the theoretical modeling and solving on the relations between economic specific frictional resistance and economic heating radius, introduced the related knowledge of techno-economic evaluation before modeling, established appropriate mathematical model based on the optimal theory of minimized life cycle cost of heat supply network, and discussed the relationship between economic specific frictional resistance and economic heating radius. Differential equations have been solved so as to get the formal analytical solution to the relationship between economic specific frictional resistance and economic heating radius by using differentials.Then taking certain districts with heat supply in Beijing as examples, this article adopted the cost information of October 2015, solved the characteristic factors of heat supply network through the 1st order data fitting method, as well as illustrated other parameters on the selection and calculation of supply and return water temperature. With differential equations solved by MATLAB, I gained and drew the numerical solution to the relationship between economic specific frictional resistance and economic heating radius under different heat supply scales and supply and return water temperature differences. The simulation was carried out for different heat supply scales when the supply and return water temperature was 40 ℃、50℃、60℃、70℃、80、℃ respectively through COMSOL software.Besides, this article also made a brief introduction to the concepts and differences between analytical solution and numerical solution, as well as a sensitivity analysis of the influencing factors on the relations between economic specific frictional resistance and economic heating radius, with the heat supply scale and the supply and return water temperature difference being the main key factors. By changing the heat supply scale and the supply and return water temperature, then observing the variation trend of the relations between economic specific frictional resistance and economic heating radius, the sensitivity on the heat supply scale and the supply and return water temperature difference caused by the relations between economic specific frictional resistance and economic heating radius could be studied.Finally, the economic heating radius solving software applicable for engineering was worked out based on the study result of the relations between economic specific frictional resistance and economic heating radius in this article. I also explained the programming process of the software in detail from three aspects:interface design, core program design and usage. The interface design contained the process of software programming, some necessary controls, edit box, drawing area, physical quantity and unit, etc. The core program design was mainly made up of the solving procedure of differential equations, the approximately analytical solution to the relations between economic specific frictional resistance and economic heating radius, and the drawing program design of its numerical solution. While the usage primarily consisted of the significance of each edit box and controls, and the using procedures of the software.