管道充水过程气液两相流动力学特性分析

管道充水过程涉及复杂的气液两相瞬变过程,合理分析、评价其两相动力学特性对工程的优化设计、安全运行,以及数值模拟研究具有重要意义。基于量纲分析和相似理论,建立了充水过程的气相模型相似律,认为通气孔排气过程的动力相似律可近似套用重力相似律,据此推导出了管内滞留气囊原、模型的几何比尺关系。将建立的气相模型相似律应用于南水北调北京段西四环暗涵通气孔水工模型试验,分析了充水全过程中两相流各动力学测量参数,得出暗涵合理的充水流量。最后采用定量和定性分析相结合的方法,对管道中滞留气囊对输水能力的影响进行了评价。

Analysis of Dynamic Characteristics of Gas-liquid Flow During Water-filling Process in Pipeline

The water-filling process in pipeline involves gas-liquid two-phase transient flow. A reasonable analysis and assessment of the two-phase dynamic characteristics is very important for the optimization design and safe operation of engineering project and numerical simulation study. Based on the dimensional analysis and similarity theory, the similarity laws of the gas-phase model during the water-filling process were established, and the dynamic similarity laws of the exhaust process in vents were similar to the gravity similarity laws; therefore the geometric proportion relationship of detained air bubbles in the pipeline in the prototype and model was obtained. The similarity laws of the gas-phase model were applied to the hydraulic model test of the culvert air vent on the West 4th Ring Road of Beijing in the South-to-North Water Diversion Project, which provided the dynamic parameters of gas-liquid two-phase flow during the water-filling process and the reasonable water-filling flow rate in the culvert. Furthermore, the effects of the detained air bubbles on the conveyance capacity were analyzed quantitatively and qualitatively.