Simulation Analysis Of Flow Measurement Characteristics Of Both Elbows In Heating Pipeline

With the rise of global carbon emissions trading market, as well as the deepening of China’s energy conservation and emissions reduction work, The heat source side the contract energy management, heating network side of the transmission and distribution systems, and other distributed heating technology is increasingly used, however, in order to give full play to the energy saving effect of these new technologies, it must be accompanied by a fair, effective and easy to implement heat metering system. In view of the heating pipes can be seen everywhere in both elbows, to study its components in different resistance downstream of the internal flow field characteristics, in order to obtain measurement characteristics as the flow sensor when measures the flow.In this paper, the Fleunt software was used to construct the numerical simulation model of planar double elbows. In order to achieve of heating pipeline with elbow flow meter setting conditions of a few words bend pipe flow is simulated and analyzed. Three factors such as the change of the flow velocity, the absolute roughness of the pipe wall and the bend diameter ratio of the elbow, bending road a few words on the pipeline model is characterized by straight pipe upstream 7D + 90° elbow + intermediate straight section 10 D + 90° elbow + 5D downstream straight pipe were simulated and analyzed, the pipeline flow characteristics of 2D, 5D and 8D positions in the middle straight pipe section of the plane double elbow were obtained.From the point of view of the influence of the change of flow direction on the measurement characteristics of the elbow, within an elbow and rear outer elbow 22.5°, 45° and 67.5°, respectively, at the position set point to take pressure, pressure variation on the above factors to take pressure obtained, and the influence of taking pressure point position deviation both elbow take pressure differential pressure in the pipeline are analyzed, by analyzing the obtained: when both elbows in the pipeline to take pressure near 22.5°, measurement error is large, but with good reproducibility; When the pipe elbow 45° and 67.5° nearby to take pressure, measurement error values for different sections of the press were taken divergent phenomena, 67.5° elbow pressure measuring section near the margin of error of less than 45 ° divergence nearby.From in terms of changes in the flow line density measurement characteristics of elbow, through the establishment of divergent(reducer) tube + elbow, two numerical models to achieve, namely, using pipeline characteristics of straight pipe upstream 5Din + divergent(reducer) tube + middle straigh section 10 D + 90° elbow + 5D downstream straight pipe of the case, when divergence angle(converging angle) changes, the intermediate straight sections at different positions measured velocity field were analyzed, and the downstream elbow in different pressure sections of velocity field and pressure field were analyzed, the influence of the divergent(reducer) tube on the flow characteristics of the downstream elbow was presented. While taking advantage provided in the downstream of the elbow in three different pressure measuring points, changing the fluid flow rate, absolute wall roughness and other influenceing factors, analyzed divergent tube(reducer tube) downstream of the bend to take pressure during pressure variation.