Ghassan Abdul-Majeed | University of Baghdad (original) (raw)

Papers by Ghassan Abdul-Majeed

Research paper thumbnail of Enhancing Multi-Class DDoS Attack Classification using Machine Learning Techniques

Journal of Advanced Research in AppliedSciencesand Engineering Technology, 2024

Distributed Denial of Service (DDoS) attacks, which adversely impact network availability, confid... more Distributed Denial of Service (DDoS) attacks, which adversely impact network availability, confidentiality, and integrity, represent a persistent threat. These attacks involve affected systems consuming resources through spurious requests instead of serving legitimate clients. Various methodologies exist for detecting and mitigating DDoS attacks, with Machine Learning (ML) emerging as a particularly effective approach due to its predictive capabilities after training on pertinent data. The primary objective of this study is to identify an improved ML algorithm for the detection of multiple DDoS types, considering metrics such as accuracy, precision, recall, and training time. Leveraging WEKA tools and the CICDDoS2019 dataset, several machinelearning algorithms, including Multilayer Perceptron, Reduced Error Pruning (REP) Tree, Partial Decision Tree (PART), RandomForest, and J48, were trained and evaluated. Among these, J48 was determined to be the superior algorithm for classifying four DDoS types (UDP, SYN, Portmap, MSSQL), based on the aforementioned criteria. The algorithms were experimented with using diverse sets of features, and optimal results were obtained using six features, resulting in an overall accuracy of 99.97%. Subsequently, the selected algorithm was integrated into a real-time model, exhibiting exceptional performance, which will be thoroughly elucidated and discussed in a forthcoming paper.

Research paper thumbnail of Review of: "Measuring researchers’ success more fairly: going beyond the H-index

The manuscript opens the door to discuss and suggest new models based on the variables mentioned ... more The manuscript opens the door to discuss and suggest new models based on the variables mentioned by the authors. Although the implementation of the suggested model is not easy, I think the information presented is a good exercise. The MS is well written and deserves publication. Minor revisions are required from my review.

Research paper thumbnail of Detection of Over Normal Pore Pressure Intervals by Using Well Logs

Journal of Petroleum Research and Studies

Pore pressure is very important parameter that impacting on drilling, production planning and ope... more Pore pressure is very important parameter that impacting on drilling, production planning and operations. Drilling and production processes cannot be beginning if pore pressure is not estimated. There is a limit of difference between hydrostatic pressure of mud column and pore pressure during drilling to ensure that the layers are preserved from fracturing, as well as that kicking does not occur inside the well. Difference between pore pressure and bottom hole flowing pressure is a key for production process. Over (Abnormal) pressure intervals are causing many problems during drilling. In present study, pore pressure is estimated firstly as a hydrostatic pressure, and secondly, after determination of shale flag, two methods of Eaton slowness and Bowers original are used for detecting of over (Abnormal) pressure shale intervals. Compressional and density logs of three wells (X3, X4, and XD) located at Y oil field and producing from Asmari formation are used to perform the present stu...

Research paper thumbnail of Review of: "Measuring researchers’ success more fairly: going beyond the H-index

The manuscript opens the door to discuss and suggest new models based on the variables mentioned ... more The manuscript opens the door to discuss and suggest new models based on the variables mentioned by the authors. Although the implementation of the suggested model is not easy, I think the information presented is a good exercise. The MS is well written and deserves publication. Minor revisions are required from my review.

Research paper thumbnail of An empirical approach for predicting slug to pseudo-slug transition of air/water upward two-phase flow

Experimental and Computational Multiphase Flow, 2024

Pseudo-slug (PSL) flow is an intermittent flow that has short, frothy, and chaotic slugs, which a... more Pseudo-slug (PSL) flow is an intermittent flow that has short, frothy, and chaotic slugs, which are not fully formed and have a structure velocity that falls between the conventional slug translational velocity and the wave celerity. It is important to predict the transition from conventional slug (SL) flow to PSL to determine the pressure gradients and liquid holdups. Literatures revealed that PSL can comprise a significant portion of the conventional flow pattern map, especially in highly deviated large-diameter (D) wellbores and pipelines. Several studies investigated the behavior of PSL; however, certain models were developed to predict SL/PSL transition. In the present study, an empirical model is derived employing the modified gas and liquid Froude numbers in measured dataset of Zhu (2019). The dataset consists of 125 data points, covering inclination angle (θ) from 2 o to 89.4 o with D of 0.1016 m. The range of superficial gas velocity is 0.124-3.313 m/s, with a constant liquid superficial velocity of 0.05 m/s. The suggested model accurately predicts all the data points and captures the expected effects of θ, D, and the gas density on the SL/PSL transition. The proposed model predicted well when validated against several independent experimental studies.

Research paper thumbnail of Pressure recovery model for gas–liquid two-phase flow across sudden expansions

Experimental and Computational Multiphase Flow

Research paper thumbnail of Internet of Things Authentication Based on Chaos-Lightweight Bcrypt

Journal of Baghdad College of Economic sciences University, 2019

Research paper thumbnail of Predicting Autism Spectrum Disorder (ASD) for Toddlers and Children Using Data Mining Techniques

Journal of Physics: Conference Series, 2021

Autism Spectrum Disorder (ASD) is a contemporary disease that has recently spread among toddlers ... more Autism Spectrum Disorder (ASD) is a contemporary disease that has recently spread among toddlers and children. Many researchers have been interested to determine the features of the autism. However, this kind of studies is costly in term of the gathering information from several sources. In this paper, we introduced and applied a novel and early prediction techniques based on the using of data mining and machine learning tools. It is difficult to determine the features of any autism ages. In this paper, we used data mining predication techniques which play an integral role to predict the symptoms of autism for any age group. The data of this study is AQ-10 dataset which are involved for toddlers and children. The results present a superior performance for ASD classification. Random forest, Decision Tree, Support Vector Machine, and Naive Bayes the accuracy of 1.0 with the features selected by correlation technique.

Research paper thumbnail of Proposal for providing secure Zoom meeting through Corona pandemic

Journal of Engineering Research , 2023

The Zoom program is widely used to manage meetings around the world, but it is easy to leak the a... more The Zoom program is widely used to manage meetings around the world, but it is easy to leak the associated Personal Meeting ID. The present study aims at improving the security for Zoom meetings during the transmission process. A new encryption algorithm is proposed to achieve this goal. The system includes three steps namely; separating images, scrambling one-half of the image, encrypting, and substituting the other scrambled half. Implementation of these three steps is achieved by using: cutting the image vertically, Arnold Cut Map, and tRNA respectively. The Bioinformatics technique (tRNA) used in encrypting (red and green) colors, and the Arnold cut map used in the scrambling and shifting process in the encryption method. The performance of the proposed system is measured by using a series of tests such as key sensitivity, histogram analysis, information entropy, correlation analysis, NCPR, similarity, and PSNR test. The results reveal a high sensitivity for initial values, resistant to statistical attack, and have the best performance in the NCPR test. It also passes the evaluation criteria for the both encryption method and S-Box. The complexity of the suggested system is represented by the attacker's need to know many chaos parameters, the logistic method (Arnold cut map), the utilized visual cryptographic techniques, and the methods used to generate the S-Box and keys. The consumed time is fewer than AES algorithm because AES takes huge time in the encryption process especially for big data. The proposed key needs to refresh only one time to make big changed and produces high security.

Research paper thumbnail of Modeling of asphaltene precipitation using CPA-EOS for live oil in an iraqi oil well

AIP Publishing, 2023

Asphaltenes are a solubility class that is described as the heaviest and most polar component of ... more Asphaltenes are a solubility class that is described as the heaviest and most polar component of crude oil.
Asphaltene precipitation (AP) and deposition during oil production, processing, and transportation are major issues for the
oil industry. The present research describes the phase behavior and Asphaltene precipitation for live oil from a well in south
of Iraq. The research highlights numerous key methodologies for modeling Asphaltene phase behavior using a combination
of Multiflash software and the cubic-plus association equation of state (CPA-EOS) model for AP. The outputs of this
suggested combination are the Asphaltene precipitation Envelope and AP Curve, from which we can predict the operation
conditions for occurring AP. Prediction of these conditions can enhance reservoir performance and production systems
to reduce AP by controlling the reservoir variables that affect AP (i.e. pressure, temperature and fluid composition).

Research paper thumbnail of A mechanistic model for vertical and inclined two-phase slug flow

Elsevier

This work proposes a mechanistic model for predicting the flow behavior for upward vertical and i... more This work proposes a mechanistic model for predicting the flow behavior for upward vertical and inclined two-phase slug flow. Expressions for bubble rise velocity, liquid film velocity, liquid holdup around the Taylor bubble, and liquid slug void fraction are derived from the relationships between the two-phase velocities. Based on measured void fraction data, the proposed liquid slug void fraction equation exhibits better performance than the existing models. The proposed mechanistic Ž model and twelve commonly used slug models are compared with the Tulsa University Fluid Flow Projects data bank 1052. well cases. This data covers a wide range of the flow conditions, well geometry and fluid properties. The comparison Ž. Ž. indicates that: 1 the new model is straightforward and is therefore easier to apply than other models, 2 the model is in Ž. very good agreement with the measured data and 3 the model performs best and clearly outperforms all other models.

Research paper thumbnail of Liquid holdup in horizontal two-phase gas--liquid flow

Journal of Petroleum Science and Engineering, 1996

The purpose of this study was to simplify and improve the mechanistic model developed by Taitel a... more The purpose of this study was to simplify and improve the mechanistic model developed by Taitel and Dukler (1976) for estimating the liquid holdup in horizontal two-phase flow. An experimental study was first conducted to develop a data bank used for evaluation and ...

Research paper thumbnail of Development of Low Cost Intelligent Tracking System Realized on FPGA Technology for Solar Cell Energy Generation

Research paper thumbnail of New correlation for estimating the viscosity of undersaturated crude oils

Journal of Canadian Petroleum …, 1990

A new general correlation for estimating the viscosity of undersaturated crude oils has been deve... more A new general correlation for estimating the viscosity of undersaturated crude oils has been developed using 253 experimentally obtained oil viscosities on 41 different oil samples collected from two different unpublished sources. The developed correlation is derived from plotting (P-Pb) vs (f.I-Oa - f.I-Ob) on log-log paper. The plot reveals a series of straight lines of a constant slope equal to 1.11. It is found that the intercepts of the resulting lines can be accurately represented as a function of API gravity and solution gas-oil ratio at bubble point pressure. The present correlation shows excellent results and clearly outperforms the existing correlations, when tested against the present data bank (253 points) and against available data from the literature (137 points).

Research paper thumbnail of The Sensitivity of Pressure-Loss Correlation to Water-Cut, Pipe Inclination Angle, API Gravity, and Oil Viscosity Changes

Research paper thumbnail of Correlations Developed to Predict Two Phase Flow through Wellhead Chokes

Annual Technical Meeting, 1988

... ABSTRAcr The correlations included in this study are those of Gilbert • Ros Baxendall. Achong... more ... ABSTRAcr The correlations included in this study are those of Gilbert • Ros Baxendall. Achonge, Poettmann-Beck, Omana, Ashford and Hazim-Ghassan • The average percent error. ... Gilbert • 1 .546 1. 89 Ros .05747 .5 2.00 Baxendall .1046 .546 1. 93 Achange .26178 .65 1.88 ...

Research paper thumbnail of Measuring research performance of Iraqi universities using Scopus data

Research paper thumbnail of Prediction of Slug Frequency for Medium Liquid Viscosity Two-Phase Flow in Vertical, Horizontal, and Inclined Pipes

SPE Production & Operations

Summary Several experimental studies have been conducted to investigate the effect of liquid visc... more Summary Several experimental studies have been conducted to investigate the effect of liquid viscosity on slug frequency in horizontal, vertical, and inclined two-phase flows. Analyses of these studies reveal that the slug frequency is positively related to superficial liquid velocity and liquid viscosity; the superficial gas velocity has a dual minor effect on slug frequency, with an initial increase for low superficial gas velocity and then a decrease for high superficial gas velocity; and the slug frequency increases with increasing flow deviation from horizontal. Also, the analyses reveal that for inclined viscous flow, the slug frequency and slug length follow the same inverse relationship shown in horizontal and vertical slug flows. In the literature, several models have been developed for predicting slug frequency in viscous horizontal flows, whereas only a few models exist for viscous vertical and inclined flows. In this study, we aim to develop models for prediction of slug...

Research paper thumbnail of Prediction of Slug/Churn Transition for Viscous Upward Two-Phase Flows in Vertical Pipes

SPE Production & Operations

Summary In this study, we investigate the effect of liquid viscosity (μL) on the slug/churn trans... more Summary In this study, we investigate the effect of liquid viscosity (μL) on the slug/churn transition in gas/liquid flows in vertical pipes. A total of 80 experimental churn-flow data points from two different sources are compiled as a data set, covering liquid viscosities from 17.23 to 586 mPa·s. Air was used in these studies as a gas phase with two different liquids, aqueous glycerol and a commercial synthetic mineral oil, flowing in vertical pipes of 0.0192- and 0.0508-m inner diameter (ID). The data set is used to examine the existing slug/churn-flow-transition models and provide further insights into the effect of μL on the transition. The existing models are categorized into two groups according to their response of the slug/churn transition to the increase in liquid superficial velocity (Vsl) on the Vsg/Vsl flow map. The first category exhibits a decrease in superficial gas velocity (Vsg) with the increase in Vsl at slug/churn (the transition concave to the left). The other ...

Research paper thumbnail of The suitability of the dimensionless terms used in correlating slug liquid holdup with flow parameters in viscous two-phase flows

International Communications in Heat and Mass Transfer

Research paper thumbnail of Enhancing Multi-Class DDoS Attack Classification using Machine Learning Techniques

Journal of Advanced Research in AppliedSciencesand Engineering Technology, 2024

Distributed Denial of Service (DDoS) attacks, which adversely impact network availability, confid... more Distributed Denial of Service (DDoS) attacks, which adversely impact network availability, confidentiality, and integrity, represent a persistent threat. These attacks involve affected systems consuming resources through spurious requests instead of serving legitimate clients. Various methodologies exist for detecting and mitigating DDoS attacks, with Machine Learning (ML) emerging as a particularly effective approach due to its predictive capabilities after training on pertinent data. The primary objective of this study is to identify an improved ML algorithm for the detection of multiple DDoS types, considering metrics such as accuracy, precision, recall, and training time. Leveraging WEKA tools and the CICDDoS2019 dataset, several machinelearning algorithms, including Multilayer Perceptron, Reduced Error Pruning (REP) Tree, Partial Decision Tree (PART), RandomForest, and J48, were trained and evaluated. Among these, J48 was determined to be the superior algorithm for classifying four DDoS types (UDP, SYN, Portmap, MSSQL), based on the aforementioned criteria. The algorithms were experimented with using diverse sets of features, and optimal results were obtained using six features, resulting in an overall accuracy of 99.97%. Subsequently, the selected algorithm was integrated into a real-time model, exhibiting exceptional performance, which will be thoroughly elucidated and discussed in a forthcoming paper.

Research paper thumbnail of Review of: "Measuring researchers’ success more fairly: going beyond the H-index

The manuscript opens the door to discuss and suggest new models based on the variables mentioned ... more The manuscript opens the door to discuss and suggest new models based on the variables mentioned by the authors. Although the implementation of the suggested model is not easy, I think the information presented is a good exercise. The MS is well written and deserves publication. Minor revisions are required from my review.

Research paper thumbnail of Detection of Over Normal Pore Pressure Intervals by Using Well Logs

Journal of Petroleum Research and Studies

Pore pressure is very important parameter that impacting on drilling, production planning and ope... more Pore pressure is very important parameter that impacting on drilling, production planning and operations. Drilling and production processes cannot be beginning if pore pressure is not estimated. There is a limit of difference between hydrostatic pressure of mud column and pore pressure during drilling to ensure that the layers are preserved from fracturing, as well as that kicking does not occur inside the well. Difference between pore pressure and bottom hole flowing pressure is a key for production process. Over (Abnormal) pressure intervals are causing many problems during drilling. In present study, pore pressure is estimated firstly as a hydrostatic pressure, and secondly, after determination of shale flag, two methods of Eaton slowness and Bowers original are used for detecting of over (Abnormal) pressure shale intervals. Compressional and density logs of three wells (X3, X4, and XD) located at Y oil field and producing from Asmari formation are used to perform the present stu...

Research paper thumbnail of Review of: "Measuring researchers’ success more fairly: going beyond the H-index

The manuscript opens the door to discuss and suggest new models based on the variables mentioned ... more The manuscript opens the door to discuss and suggest new models based on the variables mentioned by the authors. Although the implementation of the suggested model is not easy, I think the information presented is a good exercise. The MS is well written and deserves publication. Minor revisions are required from my review.

Research paper thumbnail of An empirical approach for predicting slug to pseudo-slug transition of air/water upward two-phase flow

Experimental and Computational Multiphase Flow, 2024

Pseudo-slug (PSL) flow is an intermittent flow that has short, frothy, and chaotic slugs, which a... more Pseudo-slug (PSL) flow is an intermittent flow that has short, frothy, and chaotic slugs, which are not fully formed and have a structure velocity that falls between the conventional slug translational velocity and the wave celerity. It is important to predict the transition from conventional slug (SL) flow to PSL to determine the pressure gradients and liquid holdups. Literatures revealed that PSL can comprise a significant portion of the conventional flow pattern map, especially in highly deviated large-diameter (D) wellbores and pipelines. Several studies investigated the behavior of PSL; however, certain models were developed to predict SL/PSL transition. In the present study, an empirical model is derived employing the modified gas and liquid Froude numbers in measured dataset of Zhu (2019). The dataset consists of 125 data points, covering inclination angle (θ) from 2 o to 89.4 o with D of 0.1016 m. The range of superficial gas velocity is 0.124-3.313 m/s, with a constant liquid superficial velocity of 0.05 m/s. The suggested model accurately predicts all the data points and captures the expected effects of θ, D, and the gas density on the SL/PSL transition. The proposed model predicted well when validated against several independent experimental studies.

Research paper thumbnail of Pressure recovery model for gas–liquid two-phase flow across sudden expansions

Experimental and Computational Multiphase Flow

Research paper thumbnail of Internet of Things Authentication Based on Chaos-Lightweight Bcrypt

Journal of Baghdad College of Economic sciences University, 2019

Research paper thumbnail of Predicting Autism Spectrum Disorder (ASD) for Toddlers and Children Using Data Mining Techniques

Journal of Physics: Conference Series, 2021

Autism Spectrum Disorder (ASD) is a contemporary disease that has recently spread among toddlers ... more Autism Spectrum Disorder (ASD) is a contemporary disease that has recently spread among toddlers and children. Many researchers have been interested to determine the features of the autism. However, this kind of studies is costly in term of the gathering information from several sources. In this paper, we introduced and applied a novel and early prediction techniques based on the using of data mining and machine learning tools. It is difficult to determine the features of any autism ages. In this paper, we used data mining predication techniques which play an integral role to predict the symptoms of autism for any age group. The data of this study is AQ-10 dataset which are involved for toddlers and children. The results present a superior performance for ASD classification. Random forest, Decision Tree, Support Vector Machine, and Naive Bayes the accuracy of 1.0 with the features selected by correlation technique.

Research paper thumbnail of Proposal for providing secure Zoom meeting through Corona pandemic

Journal of Engineering Research , 2023

The Zoom program is widely used to manage meetings around the world, but it is easy to leak the a... more The Zoom program is widely used to manage meetings around the world, but it is easy to leak the associated Personal Meeting ID. The present study aims at improving the security for Zoom meetings during the transmission process. A new encryption algorithm is proposed to achieve this goal. The system includes three steps namely; separating images, scrambling one-half of the image, encrypting, and substituting the other scrambled half. Implementation of these three steps is achieved by using: cutting the image vertically, Arnold Cut Map, and tRNA respectively. The Bioinformatics technique (tRNA) used in encrypting (red and green) colors, and the Arnold cut map used in the scrambling and shifting process in the encryption method. The performance of the proposed system is measured by using a series of tests such as key sensitivity, histogram analysis, information entropy, correlation analysis, NCPR, similarity, and PSNR test. The results reveal a high sensitivity for initial values, resistant to statistical attack, and have the best performance in the NCPR test. It also passes the evaluation criteria for the both encryption method and S-Box. The complexity of the suggested system is represented by the attacker's need to know many chaos parameters, the logistic method (Arnold cut map), the utilized visual cryptographic techniques, and the methods used to generate the S-Box and keys. The consumed time is fewer than AES algorithm because AES takes huge time in the encryption process especially for big data. The proposed key needs to refresh only one time to make big changed and produces high security.

Research paper thumbnail of Modeling of asphaltene precipitation using CPA-EOS for live oil in an iraqi oil well

AIP Publishing, 2023

Asphaltenes are a solubility class that is described as the heaviest and most polar component of ... more Asphaltenes are a solubility class that is described as the heaviest and most polar component of crude oil.
Asphaltene precipitation (AP) and deposition during oil production, processing, and transportation are major issues for the
oil industry. The present research describes the phase behavior and Asphaltene precipitation for live oil from a well in south
of Iraq. The research highlights numerous key methodologies for modeling Asphaltene phase behavior using a combination
of Multiflash software and the cubic-plus association equation of state (CPA-EOS) model for AP. The outputs of this
suggested combination are the Asphaltene precipitation Envelope and AP Curve, from which we can predict the operation
conditions for occurring AP. Prediction of these conditions can enhance reservoir performance and production systems
to reduce AP by controlling the reservoir variables that affect AP (i.e. pressure, temperature and fluid composition).

Research paper thumbnail of A mechanistic model for vertical and inclined two-phase slug flow

Elsevier

This work proposes a mechanistic model for predicting the flow behavior for upward vertical and i... more This work proposes a mechanistic model for predicting the flow behavior for upward vertical and inclined two-phase slug flow. Expressions for bubble rise velocity, liquid film velocity, liquid holdup around the Taylor bubble, and liquid slug void fraction are derived from the relationships between the two-phase velocities. Based on measured void fraction data, the proposed liquid slug void fraction equation exhibits better performance than the existing models. The proposed mechanistic Ž model and twelve commonly used slug models are compared with the Tulsa University Fluid Flow Projects data bank 1052. well cases. This data covers a wide range of the flow conditions, well geometry and fluid properties. The comparison Ž. Ž. indicates that: 1 the new model is straightforward and is therefore easier to apply than other models, 2 the model is in Ž. very good agreement with the measured data and 3 the model performs best and clearly outperforms all other models.

Research paper thumbnail of Liquid holdup in horizontal two-phase gas--liquid flow

Journal of Petroleum Science and Engineering, 1996

The purpose of this study was to simplify and improve the mechanistic model developed by Taitel a... more The purpose of this study was to simplify and improve the mechanistic model developed by Taitel and Dukler (1976) for estimating the liquid holdup in horizontal two-phase flow. An experimental study was first conducted to develop a data bank used for evaluation and ...

Research paper thumbnail of Development of Low Cost Intelligent Tracking System Realized on FPGA Technology for Solar Cell Energy Generation

Research paper thumbnail of New correlation for estimating the viscosity of undersaturated crude oils

Journal of Canadian Petroleum …, 1990

A new general correlation for estimating the viscosity of undersaturated crude oils has been deve... more A new general correlation for estimating the viscosity of undersaturated crude oils has been developed using 253 experimentally obtained oil viscosities on 41 different oil samples collected from two different unpublished sources. The developed correlation is derived from plotting (P-Pb) vs (f.I-Oa - f.I-Ob) on log-log paper. The plot reveals a series of straight lines of a constant slope equal to 1.11. It is found that the intercepts of the resulting lines can be accurately represented as a function of API gravity and solution gas-oil ratio at bubble point pressure. The present correlation shows excellent results and clearly outperforms the existing correlations, when tested against the present data bank (253 points) and against available data from the literature (137 points).

Research paper thumbnail of The Sensitivity of Pressure-Loss Correlation to Water-Cut, Pipe Inclination Angle, API Gravity, and Oil Viscosity Changes

Research paper thumbnail of Correlations Developed to Predict Two Phase Flow through Wellhead Chokes

Annual Technical Meeting, 1988

... ABSTRAcr The correlations included in this study are those of Gilbert • Ros Baxendall. Achong... more ... ABSTRAcr The correlations included in this study are those of Gilbert • Ros Baxendall. Achonge, Poettmann-Beck, Omana, Ashford and Hazim-Ghassan • The average percent error. ... Gilbert • 1 .546 1. 89 Ros .05747 .5 2.00 Baxendall .1046 .546 1. 93 Achange .26178 .65 1.88 ...

Research paper thumbnail of Measuring research performance of Iraqi universities using Scopus data

Research paper thumbnail of Prediction of Slug Frequency for Medium Liquid Viscosity Two-Phase Flow in Vertical, Horizontal, and Inclined Pipes

SPE Production & Operations

Summary Several experimental studies have been conducted to investigate the effect of liquid visc... more Summary Several experimental studies have been conducted to investigate the effect of liquid viscosity on slug frequency in horizontal, vertical, and inclined two-phase flows. Analyses of these studies reveal that the slug frequency is positively related to superficial liquid velocity and liquid viscosity; the superficial gas velocity has a dual minor effect on slug frequency, with an initial increase for low superficial gas velocity and then a decrease for high superficial gas velocity; and the slug frequency increases with increasing flow deviation from horizontal. Also, the analyses reveal that for inclined viscous flow, the slug frequency and slug length follow the same inverse relationship shown in horizontal and vertical slug flows. In the literature, several models have been developed for predicting slug frequency in viscous horizontal flows, whereas only a few models exist for viscous vertical and inclined flows. In this study, we aim to develop models for prediction of slug...

Research paper thumbnail of Prediction of Slug/Churn Transition for Viscous Upward Two-Phase Flows in Vertical Pipes

SPE Production & Operations

Summary In this study, we investigate the effect of liquid viscosity (μL) on the slug/churn trans... more Summary In this study, we investigate the effect of liquid viscosity (μL) on the slug/churn transition in gas/liquid flows in vertical pipes. A total of 80 experimental churn-flow data points from two different sources are compiled as a data set, covering liquid viscosities from 17.23 to 586 mPa·s. Air was used in these studies as a gas phase with two different liquids, aqueous glycerol and a commercial synthetic mineral oil, flowing in vertical pipes of 0.0192- and 0.0508-m inner diameter (ID). The data set is used to examine the existing slug/churn-flow-transition models and provide further insights into the effect of μL on the transition. The existing models are categorized into two groups according to their response of the slug/churn transition to the increase in liquid superficial velocity (Vsl) on the Vsg/Vsl flow map. The first category exhibits a decrease in superficial gas velocity (Vsg) with the increase in Vsl at slug/churn (the transition concave to the left). The other ...

Research paper thumbnail of The suitability of the dimensionless terms used in correlating slug liquid holdup with flow parameters in viscous two-phase flows

International Communications in Heat and Mass Transfer