| The gas-liquid two-phase flow and heat transfer problems widely exist in the fields of power,machinery,petrochemical and refrigeration systems.The gas-liquid two-phase flow problems are complex and changeable,and its internal flow mechanism has not yet been fully mastered.In industrial equipment,the uneven distribution of gas-liquid twophase flow affects the safety and economy of the equipment.Therefore,this paper takes the multi-branch distribution header as the object,analyzes and discusses the gas-liquid two-phase flow distribution in the header,and explores the flow characteristics of gasliquid two-phase flow in the header,which has important guiding significance for solving a series of problems caused by the uneven distribution of gas-liquid two-phase flow in the low load water wall distribution header of the boiler.The gas-water two-phase experiments were carried out on the header with ten branch pipes to study the effect of adding flute pipes in the traditional header on the gas-liquid two-phase flow distribution in the header.Comparing the experimental results of the traditional header and the flute-shaped header,it is proved that adding the flute-shaped pipe can obviously improve the gas-liquid flow distribution in the header;The comparison results show that the gas-liquid two-phase distribution characteristics in the three headers are basically the same,but the flow distribution is slightly different.Then the experiments under different gas flow rates are compared.It is concluded that under a low gas flow rate,the header with larger inner diameter of the flute tube has better distribution effect.In contrast,with high gas flow rate,the header with smaller inner diameter of the flute tube can better improve the distribution effect.Finally,the flow state and distribution of the gasliquid two-phase flow in the header are photographed by high-speed photography technology,and the distribution law of the gas-liquid two-phase flow in the header is visually observed.The flute-shaped pipe header is numerically simulated by ANSYS CFX fluid simulation software.The comparison between the flow ratio coefficient and the flow pattern shows that the simulation results are in good agreement with the experimental results.Through the static and dynamic analysis of the L header,the volume fraction nephogram,velocity vector nephogram and streamline diagram are drawn,the flow path of the gas-liquid two-phase flow in the distribution header is obtained,and the distribution law of the gas-liquid two-phase flow in the header is summarized.This article combines experimental and simulation methods to study the flow distribution of gas-liquid two-phase in a multi-branch pipe header.The influence of different inner diameters of flute shaped pipes on flow distribution is obtained,by using ANSYS CFX numerical simulation,the flow interaction mechanism of gas-liquid twophase flow in the header is obtained,and the flow characteristics of working fluids inside the header are mastered.This has practical value for the design and operation of two-phase flow headers. |
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