槽式孔板的湿气分层流差压预测模型

槽式孔板是一种新型的气液两相流测量元件,与标准孔板相比,槽式孔板具有前后直管段要求低、差压信号平稳、上游液相无累积等优点。通过对槽式孔板的局部阻力进行分析,槽式孔板总压降主要由摩阻压降和加速压降两部分组成。基于气液两相流体流经槽式孔板的流动机理,利用动量守恒关系式和能量守恒关系式计算摩阻压降和加速压降,建立了槽式孔板的分层流差压预测模型。以空气/水为介质,进行了一系列实验,实验结果表明,孔径比为0.75、0.6、0.5的槽式孔板的平均相对误差分别为6.45%、11.06%、12.52%,为湿气计量算法的完善提供了参考。

Prediction of differential pressure of slotted orifice for wet gas stratified flow

Slotted orifice is a new type of flow measuring element for gas-liquid two-phase flow measurement, Comparing with standard orifice,slotted orifice has a lot of advantages.It has less strict requirement for straight pipes upstream and downstream, its differential pressure signals are steady and there is no accumulation of liquid phase in the upstream.By analyzing local resistance of the slotted orifice, total pressure drop mainly consisted of frictional pressure drop and acceleration pressure drop.Based on flow mechanism of gas-liquid two-phase flow passing slotted orifice, frictional pressure drop and acceleration pressure drop could be calculated by momentum conservation equations and mass conservation equations, then the differential pressure drop prediction model could be developed.A series of experiments were carried out on air-water two-phase flow.According to the experimental results, mean relative error of slotted orifice with beta ratio of 0.75, 0.6, 0.5 were 6.45%, 11.06%, 12.52%.This work provided a reference for perfecting the algorithm of wet gas metering.