插拔式变比例均匀取样器及气液两相流量计量

分流比是取样型多相计量装置的关键参数,传统取样装置取样比固定,难以适应现场工况变化。为实现取样比在线调节,提出一种插拔式新型取样器,分流孔数为20,直径为3 mm,沿主管管周均匀布置,取样截面上游设置螺旋器诱发来流形成均匀螺旋环状流,通过特殊设计的取样管可动态改变分流孔的连接方式从而获得期望的取样比。根据取样孔和主流孔阻力平衡关系,推导气液相分流系数公式,并在气液两相流试验环道上进行试验验证。结果表明气液相分流系数主要取决于取样孔和主流孔的数目,不受气液相折算速度、入口流型的影响,气液相流量测量最大误差小于±5%;与单孔取样相比,三孔取样阻力损失更低,同时由于进行了多点取样,降低了对液膜均匀程度的依赖,能够在更低的气液相流速工况下工作。

Equal sampling at various extraction ratios with plug type sampler and its application in gas-liquid two-phase flow rate metering

The extraction ratio is one of the key parameters of sampling multiphase metering device.The traditional sampling device has a fixed sampling ratio,which makes it difficult to adapt to the change of working conditions.In order to realize the online adjustment of the sampling ratio,a new type of sampler was proposed.The number of split holes is 20 and the diameter is 3 mm.They are evenly distributed along the circumference of the main pipe.A spiral device was made above the upstream of the selected cross section to induce fluids,forming a uniform spiral annular flow.A desired extraction ratio can be obtained by the specially designed sampling tube,to dynamically modulate the connection formats of the spilt holes.Based on the resistance equilibrium relationship between the sampling hole and the mainstream hole,the formulas of the gas-liquid two-phase fraction of taken off were derived.Moreover,the experiments were conducted on a gas-liquid two-phase flow experimental loop.The results show that the fraction of gas and liquid taken off mainly depends on the number of sampling holes and mainstream holes,and it is independent of the gas-liquid superficial velocity and inlet flow pattern.The maximum measurement error of the gas and liquid flow rate is less than±5%.Compared with the single-hole sampling,the three-hole sampling has a lower resistance loss.Sampling with multiple points is also performed,which reduces the dependence of the uniformity of the liquid film,and it can work well in a lower gas-liquid flow rate range.