Droplet deposition and coalescence in curved pipes

A novel and systematic experimental investigation of droplet deposition and coalescence in curved pipes was conducted. Various curved pipe bends, which are utilized as flow conditioning devices upstream of wet gas separators, were tested. The deposition rate was measured by removing the liquid film, which is generated by the deposited droplets. Data were collected for about 200 experimental runs, varying vratio up to 4.5 for two liquid loadings of 700 and 1400 m3/MMsm3. The results show that the 180° pipe bend and the long elbow bend performances are similar, which are the best among the curved pipes tested. As compared to the straight pipe, the 180° pipe bend and the long elbow bend increase the droplet deposition percentage by about 20%. However, at low gas velocities, the difference between the performances of the straight pipe and the long elbow bend is not significant. The long elbow bend is recommended for field applications for its performance, availability, and easy installation.;A model for the prediction of droplet deposition in a long elbow bend is developed, based on the physical phenomena consisting of a force balance and a conservation of angular momentum on a droplet. The model enables tracking the droplet movement in the elbow, subject to a droplet deposition criterion to identify the depositing droplets. A comparison between the model predictions and experimental data shows a good agreement with average error about 20%. A design code is developed, based on the proposed model, which is validated against experimental data.