The Experimental Study And Analysis Of Directly Buried Inner Resistance Heat-preservation Pipeline

The object studied in this paper "directly buried innerresistance heat-preservation pipeline" is a new kind of directlyburied heat pipeline.The heat-preservation structure of directlyburied inner resistance heat pipeline is different from not onlythe traditional one, but also the presently used " Steel SheathedSteel" heat pipeline ,It breaks away from the conventional thinking and has innovative value, it's main characteristics are:1. It's core pipe and outer pipe are all steel.2. It composes with air or vacuum layer, reflecting layer and shielding layer, maybe one or two or three layers will be combinated according to the temperature scope of transporting fluid. Though theroratical analysis the inner resistance heat-preservation structure has been proved effectively decrease the surface temperature of outer working pipe.3. With a relatively low surface temperature of working pipe,transporting high temperature fluid non-offset directly buried heat pipeline could be easily implemented.this situation will not appear in traditional heat pipeline.4. . It solved the deviation problem between core pipe, andpolyurethane heat-preservation layer, makes the circulating of directly buried heat pipeline is safer, the service life is longer.5. The core pipes are mounted-separately, after the effection of high temperature fluid, the core pipes can freely contract and protract, and they minimized the thermal stress, enhanced thesafety factor of heat pipeline's functioning. The theroratical significance and academic value of directly buried inner resistance heat-preservation pipeline are:1. . With the technology of directly buried inner resistanceheat-preservation pipeline, the temperature difference between supply water and return water can be increased. Result in the smaller capacity and the lower investment of pressurizing instrument.2. Due to the bigger difference in temperature, the circulating quantity of flow is correspondingly decreased and the electric power is reduced.3. With the decreasing of quantity of flow ,the diameter of supply water pipe and return water pipe are also reduced ,the investment is sharply cut down.4. With the special heat-preservation structure, the surface temperature of working pipe can' be kept within a very low range, makes the non-offset directly buried heat pipeline into reality. Saves the investment of compensator, supporting pierand there examine, repair and maintaining cost.This paper studied the directly buried inner resistance heat-preservation pipeline though experiments, with the help of system identification method verified the experimental data, obtained a quite accurate mathematical model.Another feature of this paper is the use of scientific computational software-MATLAB, and emulated the experimental system.With the powerful modeling ability and accurate computational ability, MATLAB is gradually become a indispensable tool in the field of science and engineering. It is now gradually becoming a required course of universities, it's range of application is more and more wide.With good graphical interface, interactive mode language also known as "what you see ,what you get" , the complicated programme and matrix operation become very easy. The SIMULINK used in this paper is the essential part of MATLAB, it supplies a graphical interface in which model is formed with a lotof block diagrams, compare with traditional software , SIMULINK is more visual, more convenient and flexible. It's abundant module libaray makes the range of users more wide. In the last paragraph, the paper emphasizes the economic analysis of directly buried inner resistance heat-preservation pipeline, though the comparison with traditional directly buried heat pipeline, we proved it is energy saving ,low investment and widely applicable, it's emulation model has theoretical value and instructive in big diameter directly buried heat pipeline.