气相流量变化过程瞬态压力特性的试验研究

气液混输管道中常常出现由气相流量变化引起的瞬态过程，在接近现场管道的多相流环道上进行了气量变化的瞬态试验，讨论了瞬态压力特性。当气量突变后，压力波向下游传播，各点依次发生变化，变化趋势相同，而压力最大变化值沿线衰减，压力变化速率也递减。当突然增加气相流量时，管道压力突增，其峰值超过最终稳态压力值，在峰值附近有一段时间压力基本不变，随后压力降低，向终稳态发展，而突然减小气量，变化方向则相反。气量减小的瞬态过程时间长于气量增加的瞬态过程时间。小液量和大液量工况下的瞬态压力变化有所不同，两种情况下的过冲量沿线变化趋势相反。

Experimental Research on the Pressure Characteristics of the Gas Flow Rate Transients

Transient flow induced by the change of fluid flow rate occurs frequently in two-phase pipelines, therefore it is highly significant to study transient two-phase flows. For the purpose of studying the characteristic of the transient flow initiated by the change of gas flow rate ,the experiments of transient flow were conducted on the multiphase flow loop. The transient pressure characteristics are elaborated. After the sudden change of gas flow rate, the pressure waves propagate downstream while the maximum pressure change amplitudes and the change velocity attenuate along the pipeline. Increasing the gas flow rate leads to the sharp increase of pressure and the peak pressure exceeds the steady state value. Near the peak,there exists a short period that the pressure is almost constant. Then the pressure falls and tends to the final steady state. Decreasing the gas flow rate causes the reverse change that takes more time than the process of increasing the flow rate. The transient pressure response in the low liquid flow rate and high flow rate are different. The evolutions of pressure overshoot and undershoot along the pipeline show opposite trend in the two cases.