Variation of Zero Net Liquid Holdup in a Gas Liquid Cylindrical Cyclone Separator Below Operational Envelope

2020 ◽  
Author(s):  
Malay Jignesh Shah ◽  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Experimental Data ◽  
Water Flow ◽  
Operating Conditions ◽  
Extended Model ◽  
Gas Velocity ◽  
Oil Viscosity ◽  
Liquid Holdup ◽  
Cylindrical Cyclone ◽  
Oil Flow ◽  
Operational Envelope

Abstract Novel experimental and theoretical investigations are carried out on Zero Net Liquid Flow (ZNLF) in the upper part of the Gas-Liquid Cylindrical Cyclone (GLCC©) separator. Experimental data are acquired for the variation of the Zero Net Liquid Holdup (ZNLH) and the associated Churn region height for air-oil and air-water flow. The experiments are carried out at normal operating conditions below the GLCC Operational Envelope (OPEN) for Liquid Carry-Over (LCO). The ZNLH measurements for air-oil flow are higher than those for air-water flow. The Churn region height is higher for air-oil flow, as compared to the air-water flow, for the same operating conditions. The higher oil viscosity, which results in higher frictional and drag forces, leads to greater ZNLH for air-oil flow. The Churn region height is sensitive to the superficial gas velocity, whereby a small increase of gas velocity results in exponential growth of the Churn region height. The model developed by Karpurapu et al. (2018) for predicting the ZNLH at specific operational conditions just below the OPEN for LCO is extended to predict the ZNLH variation along the upper part of the GLCC below the OPEN for LCO, as well as the associated Churn region height. The predictions of the developed extended model for the ZNLH variation compared to the acquired experimental data showing discrepancies of 8% and 3%, respectively, for air-oil and air-water flows.

Modeling Foam Breakup in Batch Separators and Cylindrical Cyclones

SPE Journal ◽  
2018 ◽  
Vol 24 (05) ◽  
pp. 2264-2278
Author(s):  
J. A. Moncayo ◽  
R.. Dabirian ◽  
R.. Mohan ◽  
O.. Shoham ◽  
G.. Kouba
Keyword(s):  
Experimental Data ◽  
Original Model ◽  
Extended Model ◽  
Foam Flow ◽  
Cylindrical Cyclone ◽  
Breakup Data

Summary Models are developed for foam breakup in a batch separator, as well as inlet–cyclone and gas/liquid–cylindrical–cyclone (GLCC) compact separators, by improving the Saint–Jalmes et al. (2000) “1–g” foam–batch–separator model. The modified batch–separator model shows a better performance with respect to experimental data than does the original model. An extension of the modified “1–g” foam–batch–separator model to swirling foam flow in cyclones is developed, which accounts for the effect of higher g–forces in the cyclones. The extended model accurately predicts experimental foam–breakup data for both the inlet–cyclone and the GLCC compact separators.

Analysis and Modeling of Liquid Holdup in Low Liquid Loading Two-Phase Flow Using Computational Fluid Dynamics and Experimental Data

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Miguel Ballesteros ◽  
Nicolás Ratkovich ◽  
Eduardo Pereyra
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Oil And Gas ◽  
Operating Conditions ◽  
Liquid Holdup ◽  
Liquid Loading ◽  
Two Phase ◽  
Acceptable Error ◽  
Pharmaceutical Industries

Abstract Low liquid loading flow occurs very commonly in the transport of any kind of wet gas, such as in the oil and gas, the food, and the pharmaceutical industries. However, most studies that analyze this type of flow do not cover actual industry fluids and operating conditions. This study focused then on modeling this type of flow in medium-sized (6-in [DN 150] and 10-in [DN 250]) pipes, using computational fluid dynamics (CFD) simulations. When comparing with experimental data from the University of Tulsa, the differences observed between experimental and CFD data for the liquid holdup and the pressure drop seemed to fall within acceptable error, around 20%. Additionally, different pipe sections from a Colombian gas pipeline were simulated with a natural gas-condensate mixture to analyze the effect of pipe inclination and operation variables on liquid holdup, in real industry conditions. It was noticed that downward pipe inclinations favored smooth stratified flow and decreased liquid holdup in an almost linear fashion, while upward inclinations generated unsteady wavy flows, or even a possible annular flow, and increased liquid holdup and liquid entrainment into the gas phase.

scholarly journals The Effect of Oil Viscosity on Droplet Generation Rate and Droplet Size in a T-Junction Microfluidic Droplet Generator

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 808 ◽  
Author(s):  
Junyi Yao ◽  
Fan Lin ◽  
Hyun Kim ◽  
Jaewon Park
Keyword(s):  
Water Flow ◽  
Droplet Size ◽  
Droplet Generation ◽  
Generation Rate ◽  
Droplet Generator ◽  
Oil Viscosity ◽  
High Throughput Analysis ◽  
Oil Emulsion ◽  
Oil Flow ◽  
Flow Pressure

There have been growing interests in droplet-based microfluidics due to its capability to outperform conventional biological assays by providing various advantages, such as precise handling of liquid/cell samples, fast reaction time, and extremely high-throughput analysis/screening. The droplet-based microfluidics utilizes the interaction between the interfacial tension and the fluidic shear force to break continuous fluids into uniform-sized segments within a microchannel. In this paper, the effect of different viscosities of carrier oil on water-in-oil emulsion, particularly how droplet size and droplet generation rate are affected, has been investigated using a commonly used T-junction microfluidic droplet generator design connected to a pressure-controlled pump. We have tested mineral oils with four different viscosities (5, 7, 10, and 15 cSt) to compare the droplet generation under five different flow pressure conditions (i.e., water flow pressure of 30–150 mbar and oil flow pressure of 40–200 mbar). The results showed that regardless of the flow pressure levels, the droplet size decreased as the oil viscosity increased. Average size of the droplets decreased by approximately 32% when the viscosity of the oil changed from 5 to 15 cSt at the flow pressure of 30 mbar for water and 40 mbar for oil. Interestingly, a similar trend was observed in the droplet generation rate. Droplet generation rate and the oil viscosity showed high linear correlation (R2 = 0.9979) at the water flow pressure 30 mbar and oil flow pressure 40 mbar.

On the Influence of Lubricant Supply Conditions and Bearing Configuration to the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
Oil Flow ◽  
The Impact ◽  
Bearing System

Engine oil-lubricated (semi) floating ring bearing ((S)FRB) systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermomechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. The paper details a model to predict the pressure and temperature fields and the distribution of thermal energy flows in a bearing system. The impact of lubricant supply conditions, bearing film clearances, and oil supply grooves is quantified. Either a low oil temperature or a high supply pressure increases the generated shear power. Either a high supply pressure or a large clearance allows more flow through the inner film and draws more heat from the hot journal, thought it increases the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat from the shaft. The results identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

Experimental Study and Modeling of Slug Dissipation in a Horizontal Enlarged Impacting Tee-Junction

SPE Journal ◽  
2020 ◽  
Vol 25 (05) ◽  
pp. 2508-2520
Author(s):  
Mobina Mohammadikharkeshi ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Experimental Data ◽  
Liquid Velocity ◽  
Gas Velocity ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Oil Flow ◽  
Flow Mechanisms ◽  
Dissipation Model ◽  
Tee Junction ◽  
Superficial Gas Velocity

Summary A novel experimental and theoretical study on slug dissipation in a horizontal enlarged impacting tee-junction (EIT) is carried out. Both flowing-slug injection and stationary-slug injection into the EIT are studied, and the effects of inlet slug length and liquid-phase fluid properties on the slug dissipation in the EIT are investigated. A total of 161 experimental data are acquired for air-water and air-oil flow. The flowing-slug data (with a horizontal inlet) show that the slug dissipation length increases with increasing mixture velocity, demonstrating a nonlinear trend with a steeper slope at lower mixture velocities. The effect of superficial gas velocity on the slug dissipation length is more pronounced compared with the effect of superficial liquid velocity. For stationary-slug injection into the EIT (with a 5° upward inclined inlet), the injected slug lengths vary between 40d to 100d (d is the inlet diameter). The data reveal that, when increasing the superficial gas velocity or the inlet slug size, the dissipation length in the EIT branches increases. For this case, the ratio of the slug dissipation length to the inlet slug length is higher for air-water compared with air-oil. A slug dissipation model is developed using the slug-tracking approach, which is based on the flow mechanisms of liquid shedding at the back of the slug and liquid drainage and penetration of bubble turning at the front of the slug. These phenomena result in different translational velocities at the back and the front of the slug, which result in the dissipation of the slug body. Evaluation of model predictions against the acquired experimental data shows an average absolute relative error of less than 11%.

Utilization of Churn Flow Coalescer for Improving Foam Breakup in Gas-Liquid Cylinderical Cyclone

2018 ◽  
Author(s):  
Ramin Dabirian ◽  
Ilias Gavrielatos ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Foam Stability ◽  
Operating Conditions ◽  
Stable Foam ◽  
Transition Boundary ◽  
Cylindrical Cyclone ◽  
Inlet Conditions ◽  
Operational Envelope ◽  
Increasing Temperature ◽  
Churn Flow ◽  
Tangential Inlet

Foaming can hinder gas-liquid separation, therefore, it is desirable to break the foam upstream of separation facilities. There are different methods to breakup foam, including chemical (utilizing defoaming agent), mechanical (such as cyclones), and thermal (by increasing temperature). Foam stability and breakup are studied in a standalone Churn Flow Coalescer (CFC) and in a Churn Flow Coalescer/Gas-Liquid Cylindrical Cyclone© (CFC/GLCC©) system. The goal is to investigate the possible improvement of the foam breakup efficiency in the GLCC© by installing a CFC upstream of the GLCC©. Testing the standalone CFC, it was found that the CFC generates more, but less stable, foam that can be broken more easily. Three different CFC’s are tested with diameters of 1″, 2″ and 3″. For the same inlet conditions, the 3″ CFC with tangential inlet was found to be the most efficient for generating less stable foam. The optimal operating conditions for this CFC are at low superficial gas velocities, namely, vsg(CFC) between 0.1 to 0.3 m/s. Higher flow rates generate smaller bubbles and more stable foam. From testing the CFC/GLCC© system, it is found that foam breakup in this system is more efficient than that of the standalone GLCC©, under the same flow conditions. The operational envelope of the CFC is predicted based on the transition boundary to churn flow developed by Taitel et al. (1980), as a function of the CFC aspect ratio (LE/D). The analysis of transition boundary between slug and churn confirm that less stable foam occurs at the left of churn flow transition boundary.

Swirling Flow Regimes and Gas Carry-Under in Gas–Liquid Cylindrical Cyclone Separator in a Separated Outlet Configuration

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Volume Fraction ◽  
Swirling Flow ◽  
Flow Behavior ◽  
Jet Impingement ◽  
Test Facility ◽  
Complex Flow ◽  
Cylindrical Cyclone ◽  
Oil Flow ◽  
Flow Mechanisms ◽  
Operational Envelope

Abstract Gas carry-under (GCU) and the corresponding gas volume fraction (GVF) in the gas–liquid cylindrical cyclone (GLCC©)2 liquid outlet occurs even within its normal operational envelope (OPEN). Few studies are available on GLCC, GCU, and GVF, which have been carried out in a GLCC operated in a metering loop configuration. This study focuses on GLCC GCU and GVF in swirling flow under separated outlet configuration with active control, which increases the GLCC OPEN significantly. A state-of-the-art test facility is used to acquire extensive GCU and GVF data for both air–water and air–oil flow in a 3″ diameter GLCC. The GLCC is equipped with three sequential trap sections to measure the instantaneous GVF and gas evolution in its lower part below the inlet. Also, gas trap sections are installed in the GLCC liquid outlet leg to measure the overall time-averaged GCU and GVF. The extensive acquired data shed light on the complex flow behavior in the lower part of the GLCC and its effect on the GCU and GVF in the GLCC. Tangential wall jet impingement from the GLCC inlet is the cause of gas entrainment and swirling in the lower GLCC body. The swirling flow mechanisms in the lower part of the GLCC are identified, which affect the GCU and GVF. The liquid viscosity and surface tension also affect the results. The GCU and GVF in the GLCC liquid outlet reduce as the superficial liquid velocities are increased for both air–oil and air–water flows, whereby the superficial gas velocities do not have a significant effect. The GCU and GVF for air–water flow are three orders of magnitude lower as compared to the air–oil flow.

Calculations on the Oil Film Between a Propeller Shaft and the Aft Sterntube Bearing

2011 ◽  
Author(s):  
R. Roemen
Keyword(s):  
Operating Conditions ◽  
Practical Significance ◽  
Practical Case ◽  
Oil Viscosity ◽  
Oil Film ◽  
Oil Flow ◽  
Flow Through ◽  
The One ◽  
Main Engine ◽  
General Method

The propulsion plant of a vessel generally consists of a propeller, a main engine and a shaft transferring the power. The shaft is supported by a set of bearings. One bearing in particular, the one directly forward of the propeller, is of special interest in this study. The correct functioning of this bearing is vital for the propulsion plant to remain operating. As a result of the different operating conditions of the propulsion plant particularly this bearing is subjected to varying loads. It also has to accommodate a certain slope mismatch with respect to the shaft. If a bearing functions correctly or not depends on the presence of an oil film between the bearing and the shaft. Also the thickness of the film and the generated pressures within it are deciding whether the loading is acceptable or not. As such a detailed analysis of the oil film between the shaft and the bearing presents a scientifically supported method to evaluate the acceptability of the loading of the bearing. Another advantage is that the method makes it possible to verify the correct functioning of the bearing in varying loads related to off design conditions. This study presents a general method to calculate the minimum oil thickness within a cylindrical bearing given such external parameters as load, slope mismatch, shaft speed and the oil viscosity. First a part of the bearing theory is presented as well as the relations governing the oil flow through the bearing. The method to solve the set of equations used is the finite difference method. Some adaptations of the formulae to enable the use of the method are presented. Also is explained what assumptions and boundary conditions are applied. In succession to the theoretical part the method is validated with a comparison to a set of experimental data. The practical significance of the use of the method is demonstrated by a practical case. Finally some conclusions are presented.

Dual Release Model to Evaluate Dissolution Profiles from Swellable Drug Polyelectrolyte Matrices

2020 ◽  
Vol 17 (6) ◽  
pp. 511-522 ◽  
Author(s):  
Alicia Graciela Cid ◽  
María Verónica Ramírez-Rigo ◽  
María Celeste Palena ◽  
Elio Emilio Gonzo ◽  
Alvaro Federico Jimenez-Kairuz ◽  
...  
Keyword(s):  
Experimental Data ◽  
Drug Release ◽  
Inflection Point ◽  
Release Profile ◽  
Experimental Point ◽  
Extended Model ◽  
Release Process ◽  
Proposed Model ◽  
Dual Release ◽  
Release Model

Background: Mathematical modeling in modified drug release is an important tool that allows predicting the release rate of drugs in their surrounding environment and elucidates the transport mechanisms involved in the process. Objective: The aim of this work was to develop a mathematical model that allows evaluating the release profile of drugs from polymeric carriers in which the swelling phenomenon is present. Methods: Swellable matrices based on ionic complexes of alginic acid or carboxymethylcellulose with ciprofloxacin were prepared and the effect of adding the polymer sodium salt on the swelling process and the drug release was evaluated. Experimental data from the ciprofloxacin release profiles were mathematically adjusted, considering the mechanisms involved in each stage of the release process. Results: A proposed model, named “Dual Release” model, was able to properly fit the experimental data of matrices presenting the swelling phenomenon, characterized by an inflection point in their release profile. This entails applying the extended model of Korsmeyer-Peppas to estimate the percentage of drug released from the first experimental point up to the inflection point and then a model called Lumped until the final time, allowing to adequately represent the complete range of the drug release profile. Different parameters of pharmaceutical relevance were calculated using the proposed model to compare the profiles of the studied matrices. Conclusion: The “Dual Release” model proposed in this article can be used to predict the behavior of complex systems in which different mechanisms are involved in the release process.

scholarly journals Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shaobai Li ◽  
Siyuan Huang ◽  
Jungeng Fan
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Sodium Dodecyl ◽  
Shear Thinning ◽  
Gas Holdup ◽  
Bubble Columns ◽  
Gas Velocity ◽  
Shear Thinning Fluids ◽  
Liquid Surface Tension ◽  
Superficial Gas Velocity

In this study, the gas holdup of bubble swarms in shear-thinning fluids was experimentally studied at superficial gas velocities ranging from 0.001 to 0.02 m·s−1. Carboxylmethyl cellulose (CMC) solutions of 0.2 wt%, 0.6 wt%, and 1.0 wt% with sodium dodecyl sulfate (SDS) as the surfactant were used as the power-law (liquid phase), and nitrogen was used as the gas phase. Effects of SDS concentration, rheological behavior, and physical properties of the liquid phase and superficial gas velocity on gas holdup were investigated. Results indicated that gas holdup increases with increasing superficial gas velocity and decreasing CMC concentration. Moreover, the addition of SDS in CMC solutions increased gas holdup, and the degree increased with the surfactant concentration. An empirical correlation was proposed for evaluating gas holdup as a function of liquid surface tension, density, effective viscosity, rheological property, superficial gas velocity, and geometric characteristics of bubble columns using the experimental data obtained for the different superficial gas velocities and CMC solution concentrations with different surfactant solutions. These proposed correlations reasonably fitted the experimental data obtained for gas holdup in this system.

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