Numerical Simulation Of Flow Distribution In Header And Gas-liquid Two-phase Flow Separation

The problem of flow distribution in header is common in all kinds of industries, and the main function of header is to make fluid to be uniform distribution. Uneven distribution of flow will lead to an adverse incident, so it is of great importance to study the problem of flow distribution in header. For the phenomenon of the tubes rupturation, a geometry model was established the same as the actual power station. It is a radial introduced header structure with by-pass pipe. Numerical simulation was performed on the internal flow of header using the method of computational fluid dynamics(CFD) with geometry model builded the same as practical field for the frequent rupture of roof superheater in a power station in this paper. The pressure distribution, velocity distribution and flow distribution was studied. With detailed research, the results indicate that due to the abnormal static pressure distribution in the area of Tee-junction of by-pass tube in header, the static pressure of the branch pipes around inlet tube is so low, and the mass flow rate decreases relatively, then the heat transferation of tubes deteriorates, finally the tubes rupture. This paper proposes an improved geometric construction of branching pipe. By changing the leading direction of inlet branch pipes, the uniformity of mass flow distribution in branch pipes promotes signally. Besides, this common conclusion was extend, and some analogy was considered.As a result, the optimized plan for the structure was designed as a fundamental criterion, and it will be a great reference for further design and optimization of distribution header in power station boilers.The two phase flow separation is a very important problem of two phase flow, and the two phase flow separation will be more complex, and the mechanism is to be advised. In this paper, taking Moisture Separator in nuclear station as an example, the problem of separation for gas and liquid two-phase flow in auxiliary Moisture Separator and Reheater(MSR) was studied, and a new kind of T type tee of high dryness gas-liquid two phase flow separation system device was put forward. By means of reducing the divergent nozzle to accelerate in the system, the centrifugal force at divergent section of the stator blade was generated. Then the saturated vapor and saturated water of wet vapor in high pressure cylinder are split, and then the most of the droplets within the extended period is flung to the wall, then into the cavity between the inner sleeve and mural face is separated. Finally the inner sleeve internal fluid dryness is high and the fluid can flow to MSR directly. For the separation system. It was found that the dryness can upgrade to be95%after leaving stator blade. The feasibility of the construction for high dryness gas-liquid separation is explored, and it is a foundation for further experimental study.