Liquid Flow In Horizontal Pipe Research Articles

Development of a droplet size model for the separated gas–liquid flow in horizontal pipe and its application

A new model for droplet size prediction in horizontal pipes under stratified and annular flow is presented. The developed model takes into account the effects of the gas velocity, liquid velocity, pipe diameter, and developing length on the droplet size. Four experimental databases of droplet size in air-water horizontal flow under atmospheric pressure were used in the model development. The experimental flow conditions of the database covered a pipe diameter range of 2.45–24 cm, and gas and liquid Reynolds numbers ranges of 50,519–582,524 and 526–14,728, respectively. Droplet size experimental results were predicted by the proposed model with a root-mean-square error of 19.4% under stratified flow conditions, and 7.8% under annular flow conditions. Finally, the applicability of the suggested model was confirmed by benchmark calculations with SPACE code, a best-estimated safety analysis code for nuclear power plants, with experimental droplet parameters under various flow conditions.

Prediction of Turbulent–Turbulent Stratified Gas–Liquid Flow in Horizontal Pipe Using CFD-Generated Specified Shear Wall Method

Prediction of Turbulent–Turbulent Stratified Gas–Liquid Flow in Horizontal Pipe Using CFD-Generated Specified Shear Wall Method

Interfacial shear stress in wavy stratified gas–liquid flow in horizontal pipes

The scope of this study was to improve the Andritsos-Hanratty model for estimating interfacial friction factor and pressure drop in horizontal stratified gas–liquid two-phase flow. New experimental results (focusing on the effects of gas density and surface tension), combined with experimental data available in the literature, permit the development of semi-theoretical correlations for the transition from smooth stratified to 2-D wave region and from the latter to large-amplitude wave region and of different empirical relations for the interfacial friction factor in the two wave regions. The transition correlations agree reasonably well with existing and new data obtained in this work and the modified relations give improved predictions for both liquid holdup and pressure drop during gas–liquid stratified flow in horizontal and slightly downward pipelines as deduced from a statistical analysis of the results.

The effect of liquid viscosity on gas wall and interfacial shear stress in horizontal two-phase pipe flow

An experimental investigation of gas–liquid flow in horizontal pipes is conducted. Consideration of a stationary liquid phase allows the direct calculation of gas wall and interfacial shear stress from measurements of gas velocity, pressure drop, and liquid height without the need for any empirical input. The experiments are conducted to determine the effects of liquid viscosity. The results show that commonly used correlations for interfacial friction factor, which are generally developed in rectangular ducts, are inadequate, especially under conditions of increased liquid viscosity. It is shown that more success can be achieved if the effect of liquid viscosity is considered in the transition to wavy flow. New correlations for shear generated by smooth, rippled and wavy interfaces are proposed.

A flow pattern map for gas—liquid flow in horizontal pipes

Various flow pattern maps for two-phase gas—liquid flow in horizontal pipes are tested against the 5935 flow pattern observations presently contained in the UC Multiphase Pipe Flow Data Bank. A new flow regime correlation representing an extension of the work done by Govier and Aziz [3] is presented and is shown to be in better agreement with the data than the other correlations tested. A computer program for this correlation is included. It is also shown that there is no significant improvement obtained by including the effects of the physical properties of the fluids using any of the physical property parameters which have been proposed so far.

Effect of turbulence-promoters in two-phase gas—liquid flow in horizontal pipes

Studies have been carried out with two-phase air—water flow inside a 21·66 mm i.d. stainless steel tube using stainless steel twisted tape turbulence promoters 20 mm wide and having pitch distances of 75, 100 and 150 mm. The superficial liquid Reynolds numbers were varied over the range 10,050 to 42,150 while those for air were varied from 4,440 to 51,510. Pressure drop and holdup data were collected and photographs of flow patterns obtained. Lockhart—Martinelli parameters Φ and X for two-phase flow, suitably modified in the present paper with the help of the analysis of Smithberg and Landis for single-phase flow with twisted tapes, has been found to be satisfactory for the estimation of two phase pressure drops. The holdup data when analysed in a similar manner showed an agreement between predicted and experimental data within ± 7.5 per cent. Turbulence promoters have tended to accentuate annular flow conditions especially at high gas velocities.