Gas-liquid Two Phase Flow Critical Distribution Characteristics And Application

In two-phase flow system, we always need to distribute the flow into many branches, which include both the quality and phase distribution. Ensuring equal gas and liquid flow rate flow into various branches is to guarantee the normal operation of the two phase flow equipment and the two-phase flow measurement precision. But owning to the phase separation, the gas and liquid flow rate is usually not equal in downstream branches, how to eliminate this phenomenon has been the focus of the two-phase flow field and related research is still not enough.A novel sampler is proposed to distribute gas-liquid two phase flow evenly based on two factors which influence the two-phase flow evenly distribution: the upstream non-uniform distribution environment and the downstream uneven pressure. The distributor mainly consists of a swirl vane, nozzles and fluid splitting room. The swirl van is used to change upstream flow patterns into annular flow with uniform film thickness to make sure all the nozzles have same inlet condition and the nozzles were used to accelerate the gas-liquid mixture to achieve critical flow. In order to investigate the distributor behavior under different extraction ratio, a 2-nozzle and a 4-nozzle distributor were designed.This article mainly uses the method of FLUNT numerical simulation and experimental study. A numerical model was developed to optimize the nozzle structure, simulate the gas and liquid velocity distribution in the distributor. The simulation result shows that all the nozzles have same flow behavior if their outlet pressure is equal. Experiments were carried out in an air-water two-phase flow loop, the distributor were horizontally installed. The experiment mainly includes the following items: Firstly, gas-liquid two phase flow critical condition tests in a single nozzle, The superficial gas velocity varied from 1.00 to 25.00 m/s, the liquid superficial velocity was in the range of 0.01 to 0.50 m/s. Secondly, investigate the distributor’s characteristics with two or four vertical installed nozzles, The superficial gas velocity varied from 5.00 to 20.00 m/s, the liquid superficial velocity was in the range of 0.01 to 0.22 m/s, researching how some influence factors on distribution procession such as the upstream gas liquid ratio, direction of the nozzle, number of the nozzle, etc.The results show that the two-phase flow can reach critical condition when the upstream flow pattern belong to slug or annual flow, the gas and liquid extraction ratio is determined by the number of the nozzles and is independent of flow patterns, gas and liquid superficial velocity, resistance characteristic of the downstream pipeline and the installation direction of the nozzle. In case of the critical conditions, the gas or liquid extraction ratio of the 2-nozzle and 4-nozzle distributor is 0.50 and 0.25 respectively.