Abstract
The prediction of stratified flow is important for several industrial applications. Stratified flow experiments were carefully performed in order to investigate the performance of a typical model which uses wall friction factors based on single phase pipe flow as described above. The test facility has a 18.5 m long and 60 mm i.d. (L/D=300) acrylic test section which can be inclined between -10 {sup o} and +10 {sup o}. The liquid holdup was measured by using fast closing valves and the pressure gradients by using three differential pressure transducers. Interfacial waves were measured by thin wire conductance probes mounted in a plane perpendicular to the main flow. The experiments were performed using water and air at atmospheric pressure. The selected test section inclinations were between -3 {sup o} and +0.5 {sup o} to the horizontal plane. A large number of experiments were performed for different combinations of air and water flow rates and the rates were limited to avoid slug flow and stratified flow with liquid droplets. The pressure gradient and the liquid holdup were measured. In addition the wave probes were used to find the wave heights and the wave power spectra. The results show that the predicted pressure
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Citation Formats
Espedal, Mikal.
An experimental investigation of stratified two-phase pipe flow at small inclinations.
Norway: N. p.,
1998.
Web.
Espedal, Mikal.
An experimental investigation of stratified two-phase pipe flow at small inclinations.
Norway.
Espedal, Mikal.
1998.
"An experimental investigation of stratified two-phase pipe flow at small inclinations."
Norway.
@misc{etde_10147748,
title = {An experimental investigation of stratified two-phase pipe flow at small inclinations}
author = {Espedal, Mikal}
abstractNote = {The prediction of stratified flow is important for several industrial applications. Stratified flow experiments were carefully performed in order to investigate the performance of a typical model which uses wall friction factors based on single phase pipe flow as described above. The test facility has a 18.5 m long and 60 mm i.d. (L/D=300) acrylic test section which can be inclined between -10 {sup o} and +10 {sup o}. The liquid holdup was measured by using fast closing valves and the pressure gradients by using three differential pressure transducers. Interfacial waves were measured by thin wire conductance probes mounted in a plane perpendicular to the main flow. The experiments were performed using water and air at atmospheric pressure. The selected test section inclinations were between -3 {sup o} and +0.5 {sup o} to the horizontal plane. A large number of experiments were performed for different combinations of air and water flow rates and the rates were limited to avoid slug flow and stratified flow with liquid droplets. The pressure gradient and the liquid holdup were measured. In addition the wave probes were used to find the wave heights and the wave power spectra. The results show that the predicted pressure gradient using the standard models is approximately 30% lower than the measured value when large amplitude waves are present. When the flow is driven by the interfacial force the test section inclination has minor influence on the deviation between predicted and measured pressure gradients. Similar trends are apparent in data from the literature, although they seem to have gone unnoticed. For several data sets large spread in the predictions are observed when the model described above was used. Gas wall shear stress experiments indicate that the main cause of the deviation between measured and predicted pressure gradient and holdup resides in the modelling of the liquid wall friction term. Measurements of the liquid wall shear stress distribution, also performed in the present study, show that the liquid wall friction factor is unevenly distributed around the liquid wetted perimeter of the pipe. Available models in the literature for calculation of the gas and liquid wall shear stress have been compared to the experimental data from the present study. The interfacial friction factor has been calculated The resulting interfacial friction factor has been compared to available models from the literature. Large deviations are found for most models tested. A model of stratified flow for pipes at small inclinations have been suggested based on the findings. The final model shows pressure gradient and liquid holdup predictions to be within {+-}10% for most of the data. However, the deviation is larger for some of the data points within the transition from small to large amplitude waves. 218 figs., 37 tabs., 101 refs.}
place = {Norway}
year = {1998}
month = {Dec}
}
title = {An experimental investigation of stratified two-phase pipe flow at small inclinations}
author = {Espedal, Mikal}
abstractNote = {The prediction of stratified flow is important for several industrial applications. Stratified flow experiments were carefully performed in order to investigate the performance of a typical model which uses wall friction factors based on single phase pipe flow as described above. The test facility has a 18.5 m long and 60 mm i.d. (L/D=300) acrylic test section which can be inclined between -10 {sup o} and +10 {sup o}. The liquid holdup was measured by using fast closing valves and the pressure gradients by using three differential pressure transducers. Interfacial waves were measured by thin wire conductance probes mounted in a plane perpendicular to the main flow. The experiments were performed using water and air at atmospheric pressure. The selected test section inclinations were between -3 {sup o} and +0.5 {sup o} to the horizontal plane. A large number of experiments were performed for different combinations of air and water flow rates and the rates were limited to avoid slug flow and stratified flow with liquid droplets. The pressure gradient and the liquid holdup were measured. In addition the wave probes were used to find the wave heights and the wave power spectra. The results show that the predicted pressure gradient using the standard models is approximately 30% lower than the measured value when large amplitude waves are present. When the flow is driven by the interfacial force the test section inclination has minor influence on the deviation between predicted and measured pressure gradients. Similar trends are apparent in data from the literature, although they seem to have gone unnoticed. For several data sets large spread in the predictions are observed when the model described above was used. Gas wall shear stress experiments indicate that the main cause of the deviation between measured and predicted pressure gradient and holdup resides in the modelling of the liquid wall friction term. Measurements of the liquid wall shear stress distribution, also performed in the present study, show that the liquid wall friction factor is unevenly distributed around the liquid wetted perimeter of the pipe. Available models in the literature for calculation of the gas and liquid wall shear stress have been compared to the experimental data from the present study. The interfacial friction factor has been calculated The resulting interfacial friction factor has been compared to available models from the literature. Large deviations are found for most models tested. A model of stratified flow for pipes at small inclinations have been suggested based on the findings. The final model shows pressure gradient and liquid holdup predictions to be within {+-}10% for most of the data. However, the deviation is larger for some of the data points within the transition from small to large amplitude waves. 218 figs., 37 tabs., 101 refs.}
place = {Norway}
year = {1998}
month = {Dec}
}