Author(s): Abdorreza Kabiri-Samani
Linked Author(s):
Keywords: Two-phase flow; Water tunnel; Pressure fluctuation; Experimental model
Abstract: An experimental investigation has been carried out to verify characteristics of pressure fluctuations inside a circular, horizontal and inclined pipeline (90mm inside diameter and 10 m long) carrying two-phase air-water flow in a controlled manner (operating at room temperature and normal pressure). The pressure fluctuation was considered to be due to interaction between the fluid and air bubble compressibility in the pipe. The fluctuating pressure was studied in detail while the flow pattern was mainly slug, wavy or stratified flow. The tests were carried out varying with time, space, water flow rate/air flow rate ratio and pipe inclination. The pressure fluctuations were measured simultaneously at different sectional and longitudinal locations using Differential Pressure Transducer (DPT). Also, the behavior of the air bubbles inside the pipeline was studied using digital camera. The results show that the more intensive phase interaction commences stronger fluctuations. It is shown, that the air-water mixture entering the pipe during rapid filling or surcharging can cause tremendous pressure surge in the system and eventually may cause failure in system (e. g. the maximum pressure inside the pipe would reach up to 10 times of upstream hydrostatic pressure). Finally, relations for forecasting pressure in these situations are presented as a function of flow characteristics, pipe geometry and head water variables.
Year: 2005