Numerical Simulation of Droplet Size Distribution in Vertical Upward Annular Flow

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Y. Liu ◽  
W. Z. Li
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Annular Flow ◽  
Liquid Droplet ◽  
Large Diameter ◽  
Droplet Size Distribution ◽  
Population Balance ◽  
Balance Model ◽  
Diameter Distribution ◽  
Two Fluid

The liquid droplet size distribution in gas-liquid vertical upward annular flow is investigated through a CFD (computational fluid dynamics)-PBM (population balance model) coupled model in this paper. Two-fluid Eulerian scheme is employed as the framework of this model and a population balance equation is used to obtain the dispersed liquid droplet diameter distribution, where three different coalescence and breakup kernels are investigated. The Sauter mean diameter d32 is used as a bridge between a two-fluid model and a PBM. The simulation results suggest that the original Luo–Luo kernel and the mixed kernel A (Luo’s coalescence kernel incorporated with Prince and Blanch’s breakup kernel) can only give reasonable predictions for large diameter droplets. Mixed kernel B (Saffman and Turner’s coalescence kernel incorporated with Lehr’s breakup kernel) can accurately capture the particle size distribution (PSD) of liquid droplets covering all droplet sizes, and is appropriate for the description of liquid droplet size distribution in gas-liquid annular flow.

A Probability Model for Fully Developed Annular Flow in Vertical Pipes: Film Thickness, Interfacial Shear Stress, and Droplet Size Distribution

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Ri Zhang ◽  
Haixiao Liu ◽  
Sheng Dong ◽  
Mingyang Liu
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Size Distribution ◽  
Droplet Size ◽  
Annular Flow ◽  
Probability Model ◽  
Interfacial Shear Stress ◽  
Droplet Size Distribution ◽  
Interfacial Shear ◽  
Characteristic Parameters

The movement and distribution of each phase in annular flow can be considered as random events at a microscopic level. Hence, a probability analysis is appropriate to estimate the morphological features and mechanical characteristics of annular flow from a macroscopic scale. In the present work, three characteristic parameters including the film thickness, interfacial shear stress, and characteristic droplet size are predicted by a probability model as the statistical results of abundant samples. The film thickness can be directly calculated as one of the solutions to the basic equations of annular flow. The interfacial shear stress is estimated as a combination of the frictional and dragging components. The droplet size distribution is obtained using a method of undetermined coefficients. These characteristic parameters are well verified by comparing with the experimental data available in the literature. It is demonstrated that the probability model can accurately calculate the film thickness and maximum droplet size, but the predictions of the interfacial shear stress and mean droplet size are relatively coarse. Furthermore, the effects on the film thickness and Sauter mean diameter of other parameters are discussed in detail. Finally, some important phenomena observed in experiments are interpreted by the probability model.

scholarly journals Droplets size evolution of dispersion in a stirred tank

2018 ◽  
Vol 180 ◽  
pp. 02053
Author(s):  
Bohus Kysela ◽  
Jiri Konfrst ◽  
Zdenek Chara ◽  
Radek Sulc ◽  
Darina Jasikova
Keyword(s):  
Droplet Size ◽  
Evaluation Method ◽  
Flow Simulation ◽  
Droplet Size Distribution ◽  
Population Balance ◽  
Metallurgical Industry ◽  
Extraction Process ◽  
Stirred Tank ◽  
Balance Model ◽  
Droplet Sizes

Dispersion of two immiscible liquids is commonly used in chemical industry as wall as in metallurgical industry e. g. extraction process. The governing property is droplet size distribution. The droplet sizes are given by the physical properties of both liquids and flow properties inside a stirred tank. The first investigation stage is focused on in-situ droplet size measurement using image analysis and optimizing of the evaluation method to achieve maximal result reproducibility. The obtained experimental results are compared with multiphase flow simulation based on Euler-Euler approach combined with PBM (Population Balance Modelling). The population balance model was, in that specific case, simplified with assumption of pure breakage of droplets.

Two-fluid model with droplet size distribution for condensing steam flows

Energy ◽  
2016 ◽  
Vol 106 ◽  
pp. 112-120 ◽  
Author(s):  
Włodzimierz Wróblewski ◽  
Sławomir Dykas
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Fluid Model ◽  
Droplet Size Distribution ◽  
Two Fluid Model ◽  
Two Fluid

MODELING DROPLET SIZE DISTRIBUTION NEAR A NOZZLE OUTLET IN AN ICING WIND TUNNEL

2006 ◽  
Vol 16 (6) ◽  
pp. 673-686 ◽  
Author(s):  
Laszlo E. Kollar ◽  
Masoud Farzaneh ◽  
Anatolij R. Karev
Keyword(s):  
Wind Tunnel ◽  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Nozzle Outlet
Sign in / Sign up

Export Citation Format

Share Document