Multiphase Flow Measurements by Full Stream Batch Sampling

A new method of multiphase flow measurements that based on the “extracting and separating method” was proposed in this paper. An extraction flow (or sample) is diverted in a manner of time sharing or full stream batch sampling, then the sample is separated into single phase flows and metered with conventional flow meters, the total flow rates of each phase are determined according to the metered values and the extraction ratios. Because the full stream is conducted to the extraction loop during sampling, no matter what the flow regime of multiphase flow is, the extracted stream (or sample) is always the representative of the total stream and the extraction ratio can keep stable. Experiments were conducted in an air‐water‐oil flow test loop, the inside pipe diameter of the test loop was 50 mm, and the superficial gas velocity varied from 4.5 m/s ∼22m/s, the liquid superficial velocity was in the range of 0.02∼0.3m/s, the oil concentration was in the range of 0.0%∼60% by volume. The flow pattern occurring during the experiments included stratified flow, wave flow and annular flow. The experimental results shown that the full stream batch sample method is feasible to measure the multiphase flow rate, and the average error of flow rates measurements for each phase was less than 3.82%.