Numerical Simulation Of Flow Problems Headers With T-type Three-way Pipe And Parallel Tube Platen System Utility Boiler

The steam always pass in and out the distribution headers and collection headers of Large-capacity utility boiler,either Domestic type or imported type, through T-type three-way pipes, currently. The original purpose is to reduce the diameter of Guide Steam tube, to simplify the structure and reduce the pressure drop of system, then to uniform flow distribution. But in fact, from running practice of domestic plant in recent years, we find that the pressure drop wasn't reduced but increased and non-uniformity of flow distribution just moved from all the header system to some section, even worse. Then some pipes will be broken easily because of over-temperature. Therefore, predicting the flow mass deviation correctly is helpful for setting up a more reasonable system to reduce these phenomena.In this paper, starting from the general partial differential equations of flow problems, a 3-D partitioning parallel CFD procedure is developed under MPI environment, based on SIMPLE-C, domain decomposition method and Dirichlet-Neumann algorithm. And then, for a model of a experimental model of headers with T-type three-way pipes and parallel tube platen in a utility boiler, the partitioning structured grids of distribution header, collection header and parallel tubes are generated. Then, the partitioning parallel numerical simulation of this flow problem is realized and the results of the velocities, pressure and flow mass of each of tubes are obtained. The flow characteristics are analyzed and discussed to determine the position which will be broken easily basing on these results. Then, the static pressure distribution along the distribution headers and collection headers with two typical header connecting systems of type T was measured on the cold model test rig. And the flow distribution was acquired according to the flux balance between the total flux in the parallel branch tubes and the flux in the header inlet. Last, the efficiency of partitioning parallel calculation over a PC network is discussed and some strategies of partitioning parallel calculation are summarized. Meanwhile, an effective method is provided to solve other lager scale and complex flow problems. The results of numerical simulation are compared with the experimental results for single phase fluid in the headers. This method is proved reasonable and effective. It could be used as a tool of optimization and accident diagnostics.