Mechanistic Modeling of Liquid Carry-Over for 3-Phase Flow in GLCC© Compact Separators

2018 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Mechanistic Model ◽  
Pressure Control ◽  
Mechanistic Modeling ◽  
Phase Flow ◽  
Fluid Properties ◽  
Control Configuration ◽  
Carry Over ◽  
Water Cut ◽  
Operational Envelope ◽  
Proper Operation

Gas-Liquid Cylindrical Cyclone (GLCC©) Separators have been in use in petroleum and other related industries for over two decades. Prediction of Liquid Carry-Over Operational Envelope (LCO-OE) is essential for designing and proper operation of GLCC©. Earlier mechanistic models for predicting LCO-OE were based on gas-liquid phase flow. A new mechanistic model has been developed for the prediction of the LCO-OE incorporating the effect of watercut and fluid properties for a GLCC© under liquid level and pressure control configuration. The new model captures the effect of viscosity and surface tension on the LCO-OE and the effect of water cut on the onset of annular mist velocity. Comparison between the developed mechanistic model predictions for LCO-OE with the experimental data show a good agreement.

Wet Gas Separation in Gas-Liquid Cylindrical Cyclone (GLCC) Separator

2007 ◽  
Author(s):  
Robiro Molina ◽  
Shoubo Wang ◽  
Luis E. Gomez ◽  
Ram S. Mohan ◽  
Ovadia Shoham ◽  
...  
Keyword(s):  
High Pressure ◽  
Separation Efficiency ◽  
Mechanistic Model ◽  
Velocity Ratio ◽  
Wet Gas ◽  
Cylindrical Cyclone ◽  
Improved Performance ◽  
Carry Over ◽  
Operational Envelope ◽  
Annular Film

A novel Gas Liquid Cylindrical Cyclone (GLCC©), equipped with an Annular Film Extractor (AFE), for wet gas applications has been developed and studied experimentally and theoretically. Detailed experimental investigation of the modified GLCC has been carried out for low and high pressure conditions. The results show expansion of the operational envelope for liquid carry-over, and improved performance of the modified GLCC. For low pressures, the modified GLCC can remove all the liquid from the gas stream, resulting in zero liquid carry-over. For high pressure conditions, the GLCC with a single AFE has separation efficiency > 80% for gas velocity ratio of < 3. A mechanistic model and an aspect ratio design model for the modified GLCC has been developed, including the analysis of the AFE. The model predictions agree with the experimental data within ± 15% for low pressure and ± 25% for high pressure conditions.

Wet Gas Separation in Gas-Liquid Cylindrical Cyclone Separator

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Robiro Molina ◽  
Shoubo Wang ◽  
Luis E. Gomez ◽  
Ram S. Mohan ◽  
Ovadia Shoham ◽  
...  
Keyword(s):  
High Pressure ◽  
Separation Efficiency ◽  
Mechanistic Model ◽  
Velocity Ratio ◽  
Wet Gas ◽  
Cylindrical Cyclone ◽  
Improved Performance ◽  
Carry Over ◽  
Operational Envelope ◽  
Annular Film

A novel gas-liquid cylindrical cyclone (GLCC©, ©The University of Tulsa, 1994), equipped with an annular film extractor (AFE), for wet gas applications has been developed and studied experimentally and theoretically. Detailed experimental investigation of the modified GLCC has been carried out for low and high pressure conditions. The results show expansion of the operational envelope for liquid carry-over and improved performance of the modified GLCC. For low pressures, the modified GLCC can remove all the liquid from the gas stream, resulting in zero liquid carry-over (separation efficiency=100%). For high pressure conditions, the GLCC with a single AFE has separation efficiency >80% for gas velocity ratio, vsg/vann≤3. A mechanistic model and an aspect ratio design model for the modified GLCC have been developed, including the analysis of the AFE. The model predictions agree with the experimental data within ±15% for low pressure and ±25% for high pressure conditions.

Experimental Investigation of Liquid Carry-Over in GLCC© Separators for 3-Phase Flow

2016 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Heavy Oil ◽  
Phase Flow ◽  
Level Control ◽  
Three Phase ◽  
Three Phase Flow ◽  
Light Oil ◽  
Series Of Experiments ◽  
Oil Water ◽  
Carry Over ◽  
Operational Envelope

Prediction of the Operational Envelope (OPEN) for liquid carry-over is essential for optimized performance of Gas-Liquid Cylindrical Cyclone (GLCC©1) compact separators. This study extends the previous GLCC liquid carry-over studies from 2-phase flow to 3-phase gas-oil-water flow incorporating pressure and level control configurations. A series of experiments were conducted to evaluate the performance of a 3″ diameter GLCC in terms of OPEN for liquid carry-over. Both light oil and heavy oil were utilized, with watercuts ranging from 0 to 100%. The liquid level was controlled at 6″ below the GLCC inlet. A significant effect of watercut on the OPEN for liquid carry-over for three-phase flow was observed. As the watercut reduces, the OPEN for liquid carry-over reduces too. Also, the OPEN for heavy oil reduces as compared to light oil, which could be primary due to the effect of viscosity. Finally, the annular mist velocity increases with the increment of watercut and viscosity.

Performance Improvement of Gas Liquid Cylindrical Cyclone Separators Using Integrated Level and Pressure Control Systems

2000 ◽  
Vol 122 (4) ◽  
pp. 185-192 ◽  
Author(s):  
Shoubo Wang ◽  
Ram S. Mohan ◽  
Ovadia Shoham ◽  
Jack D. Marrelli ◽  
Gene E. Kouba
Keyword(s):  
Control System ◽  
Integrated Control ◽  
Control Valve ◽  
Pressure Control ◽  
Rate Region ◽  
Cylindrical Cyclone ◽  
Pressure Control System ◽  
Carry Over ◽  
Operational Envelope ◽  
Integrated Control System

The performance of gas-liquid cylindrical cyclone (GLCC©) separators for two-phase flow metering loop can be improved by eliminating liquid overflow into the gas leg or gas blow-out through the liquid leg, utilizing suitable integrated control systems. In this study, a new integrated control system has been developed for the GLCC, in which the control is achieved by a liquid control valve in the liquid discharge line and a gas control valve in the gas discharge line. Simulation studies demonstrate that the integrated level and pressure control system is highly desirable for slugging conditions. This strategy will enable the GLCC to operate at constant pressure so as not to restrict well flow and simultaneously prevent liquid carry-over and gas carry-under. Detailed experimental studies have been conducted to evaluate the improvement in the GLCC operational envelope for liquid carry-over with the integrated level and pressure control system. The results demonstrate that the GLCC equipped with integrated control system is capable of controlling the liquid level and GLCC pressure for a wide range of flow conditions. The experimental results also show that the operational envelope for liquid carry-over is improved twofold at higher liquid flow rate region and higher gas flow rate region. GLCC performance is also evaluated by measuring the operational envelope for onset of gas carry-under. [S0195-0738(00)00804-9]

Tangential Wall Jet Flow and Gas Entrainment in Gas-Liquid Cylindrical Cyclone Compact Separator

2019 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Liquid Film ◽  
Mechanistic Model ◽  
Experimental Investigations ◽  
Wall Jet ◽  
Velocity Change ◽  
Gas Entrainment ◽  
Cylindrical Cyclone ◽  
Wall Jet Flow ◽  
Carry Over ◽  
Operational Envelope

Abstract Gas Carry-Under (GCU) is one of the undesirable phenomena that exist in the Gas-Liquid Cylindrical Cyclone (GLCC) separators even within the liquid carry-over Operational Envelope (OE). In order to quantify the GCU, it is important to understand the cause of gas entrainment that occurs in the GLCC other than the incoming entrained gas within the liquid medium. The tangential inclined inlet of 27° with reduced area allows the stratified liquid flow to exit the inlet nozzle tangentially along the wall into the vertical lower part of the GLCC, whereby the liquid film spreads along the wall in an asymmetrical shape. The gas moves to the center of the GLCC and escapes through the gas leg. The liquid film flow is complex and turbulent exhibiting unevenness of the film thickness and asymmetrical velocity distribution. Experimental investigations show that the magnitude of liquid wall jet film tangential and axial velocity change as a function of length along the GLCC below the inlet of the GLCC. This wall jet film flowing down along the wall is the cause for gas entrainment and GCU. The experimental results show that the gas entrainment mechanism is not like the conventional jet entrainment as expected to be occurring in GLCC. The change in velocities of the wall jet film at various liquid heights maintained below the inlet results in varying gas entrainment at various inlet liquid levels and for fluid properties. The wall jet phenomena that takes places at the inlet has been discussed in detail and a mechanistic model capable of predicting the wall jet parameters has been presented in this paper. Further, a novel mechanistic model that is developed for the first time is also presented which can predict the gas entrainment at various liquid levels and flow conditions using the wall jet parameters as an input condition.

Mechanistic Modeling of Dynamic Zero-Net Liquid Holdup (ZNLH) in Gas-Liquid Cylindrical Cyclone (GLCC©) Separator

2018 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Megharaj Praneeth Karpurapu ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Gas Flow ◽  
Mechanistic Model ◽  
Operating Conditions ◽  
Mechanistic Modeling ◽  
Experimental Investigations ◽  
Liquid Holdup ◽  
Technical Performance ◽  
The Past ◽  
Carry Over ◽  
Static Conditions

Over the past 2 decades, GLCC© compact separators have been replacing the conventional vessel type separators in the Oil & Gas Industry, because of its numerous advantages. Despite these advantages, GLCC separators face two critical problems affecting the performance under extreme operating conditions, namely, Liquid Carry Over (LCO) into the gas leg and Gas Carry Under (GCU) into the liquid leg. This study focuses on the LCO phenomenon. Having a deeper insight into the LCO flow phenomenon helps us to enhance the technical performance of GLCC at these extreme conditions. Several studies were presented in the past on experimental investigations and mechanistic modeling of LCO. In the above cases, mechanistic modeling of LCO was based on Zero Net liquid Holdup (ZNLH) parameter. The liquid holdup in the upper part of the GLCC before it is blown out by gas flow is referred to as ZNLH. ZNLH is an important phenomenon affecting the GLCC pressure behavior and performance characteristics. Above mentioned experimental investigations performed to calculate ZNLH were carried out under static conditions where the effects of superficial liquid velocities were neglected. Investigations have been carried out in this study under dynamic conditions to evaluate the effect of superficial liquid velocities on ZNLH. We found that Dynamic ZNLH results are different from static ZNLH data as they show lower liquid holdup for the same gas velocities. A mechanistic model is proposed in this study to predict dynamic ZNLH and this model is validated against the dynamic ZNLH experimental data. It may be noted that a suitable ZNLH model will help in improving the predictions of the LCO mechanistic model considerably.

Gas Carry-Under in Gas-Liquid Cylindrical Cyclone Separator: A Mechanistic Model

2019 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Mechanistic Model ◽  
Liquid Level ◽  
Wall Jet ◽  
Gas Entrainment ◽  
Cylindrical Cyclone ◽  
Tangential Wall ◽  
Control Configuration ◽  
Extensive Experimental Data ◽  
Operational Envelope ◽  
Physical Phenomena

Abstract Gas Carry-Under (GCU) is one of the two undesirable phenomena that occur in the GLCC©,1 (Gas-Liquid Cylindrical Cyclone) separators when it operates even within the Operational Envelope (OPEN). Earlier studies have shown that maintaining a liquid level below the inlet of the GLCC under control configuration affects the GCU in GLCC. It has been identified that the tangential wall jet is the cause of gas entrainment within the GLCC and has been understood to change with liquid level maintained at the inlet. Also, it has been theorized that effective formation of the vortex formed in the lower part of the GLCC, or a stable gas core enhances the separation of gas entrained in the liquid. At present, there is no mechanistic model which captures these complex physical phenomena in the GLCC. This paper presents a newly developed mechanistic model which can predict the GCU for different flow conditions, fluid properties, and various liquid levels. The proposed model captures the various physical phenomena namely: saturated flow at the inlet, tangential wall jet phenomena, gas entrainment and vortex flow that results in separation of gas. The developed model has been compared with the extensive experimental data and is said to be in good agreement.

scholarly journals Inverse mechanistic modeling of transdermal drug delivery for fast identification of optimal model parameters

2020 ◽  
Author(s):  
Thijs Defraeye ◽  
Flora Bahrami ◽  
Rene M Rossi
Keyword(s):  
Drug Delivery ◽  
Inverse Modeling ◽  
Transdermal Drug Delivery ◽  
Drug Transport ◽  
Mechanistic Model ◽  
Mechanistic Modeling ◽  
Drug Uptake ◽  
Added Value ◽  
Model Parameters ◽  
Transdermal Drug Delivery Systems

Transdermal drug delivery systems are a key technology to administer drugs with a high first-pass effect in a non-invasive and controlled way. Physics-based modeling and simulation are on their way to become a cornerstone in the engineering of these healthcare devices since it provides a unique complementarity to experimental data and insights. Simulations enable to virtually probe the drug transport inside the skin at each point in time and space. However, the tedious experimental or numerical determination of material properties currently forms a bottleneck in the modeling workflow. We show that multiparameter inverse modeling to determine the drug diffusion and partition coefficients is a fast and reliable alternative. We demonstrate this strategy for transdermal delivery of fentanyl. We found that inverse modeling reduced the normalized root mean square deviation of the measured drug uptake flux from 26 to 9%, when compared to the experimental measurement of all skin properties. We found that this improved agreement with experiments was only possible if the diffusion in the reservoir holding the drug was smaller than the experimentally-measured diffusion coefficients suggested. For indirect inverse modeling, which systematically explores the entire parametric space, 30 000 simulations were required. By relying on direct inverse modeling, we reduced the number of simulations to be performed to only 300, so a factor 100 difference. The modeling approach's added value is that it can be calibrated once in-silico for all model parameters simultaneously by solely relying on a single measurement of the drug uptake flux evolution over time. We showed that this calibrated model could accurately be used to simulate transdermal patches with other drug doses. We showed that inverse modeling is a fast way to build up an accurate mechanistic model for drug delivery. This strategy opens the door to clinically-ready therapy that is tailored to patients.

Mechanistic Modeling of Five-Axis Machining With a Flat End Mill Considering Bottom Edge Cutting Effect

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Zhou-Long Li ◽  
Li-Min Zhu
Keyword(s):  
Cutting Forces ◽  
Mechanistic Model ◽  
Mechanistic Modeling ◽  
End Mill ◽  
Bottom Edge ◽  
Radial Line ◽  
Bottom Part ◽  
Lead Angle ◽  
Cutting Effect ◽  
Five Axis

In five-axis milling, the bottom edge of a flat end mill is probably involved in cutting when the lead angle of tool axis changes to negative. The mechanistic model will lose accuracy if the bottom edge cutting effect is neglected. In this paper, an improved mechanistic model of five-axis machining with a flat end mill is presented to accurately predict cutting forces by combining the cutting effects of both side and bottom edges. Based on the kinematic analysis of the radial line located at the tool bottom part, the feasible contact radial line (FCRL) is analytically extracted. Then, boundaries of the bottom cutter-workpiece engagements (CWEs) are obtained by intersecting the FCRL with workpiece surfaces and identifying the inclusion relation of its endpoints with the workpiece volume. Next, an analytical method is proposed to calculate the cutting width and the chip area by considering five-axis motions of the tool. Finally, the method of calibrating bottom-cutting force coefficients by conducting a series of plunge milling tests at various feedrates is proposed, and the improved mechanistic model is then applied to predict cutting forces. The five-axis milling with a negative lead angle and the rough machining of an aircraft engine blisk are carried out to test the effectiveness and practicability of the proposed model. The results indicate that it is essential to take into account the bottom edge cutting effect for accurate prediction of cutting forces at tool path zones where the tool bottom part engages with the workpiece.

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