Carlos F Torres

Carlos F Torres
University of the Andes (Venezuela) | ULA · School of Mechanical Engineering

PhD, MSc, BSc

About

87
Publications
29,392
Reads
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1,001
Citations
Citations since 2017
24 Research Items
777 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Additional affiliations
July 2012 - December 2014
University of Tulsa
Position
  • Research Associate
September 2008 - January 2009
University College London
Position
  • Research Associate
September 1995 - present
University of the Andes (Venezuela)
Position
  • Professor (Full)
Education
August 2001 - December 2005
University of Tulsa
Field of study
  • Mechanical Engineering
September 1998 - July 2001
University of the Andes (Venezuela)
Field of study
  • Applied Mathematics
September 1989 - February 1995
University of the Andes (Venezuela)
Field of study
  • Mechanical engineering

Publications

Publications (87)
Article
Full-text available
Continuous flow gas lift is one of the most common artificial lift methods widely used in the oil industry. A continuous volume of high-pressure gas is injected as deep as possible into the tubing, to gasify the oil column and thus facilitate the production. If there is no restriction in the amount of injection gas available, sufficient gas can be...
Article
A method for exploration of erosion in multiphase flow can be Computational Fluid Dynamics (CFD). A key advantage of utilizing CFD is that it can deliver a great deal of information such as the effects of different parameters on erosion, maximum erosion rate, and areas susceptible to erosion damage. The current work used a computational fluid dynam...
Article
Full-text available
Flow pattern transition prediction models are presented for oil–water flow in horizontal pipes. The transition between stratified and non-stratified flow is predicted using Kelvin–Helmholtz (KH) stability analysis for long waves. New, simplified, and more practical physical mechanisms/mechanistic models are proposed for the prediction of the transi...
Article
Full-text available
Gas–liquid multiphase flow can be observed within different industrial processes, and Computational Fluid Dynamics (CFD) can be utilized as a tool for scrutiny of this kind of flows. Although the CFD simulations of multiphase are computationally-demanding, they can deliver a great deal of information. But, the larger point is whether the available...
Article
Full-text available
Stratified and annular gas–liquid flow patterns are commonly encountered in many industrial applications, such as oil and gas transportation pipelines, heat exchangers, and process equipment. The measurement and visualization of two-phase flow characteristics are of great importance as two-phase flows persist in many fluids engineering applications...
Article
Full-text available
The Gorlov helical turbines can be used to generate electric energy by making use of the flow of fluids. Because of its operation in some cases, this turbines show phenomenon of cavitation that erodes their structure. This article exposes a strategy to determine the cavitation in operational conditions of Gorlov helical turbines. Based on the cavit...
Article
Full-text available
A Generalized Additive Model (GAM) is proposed to predict the pressure drop in a gas–liquid two-phase flow at horizontal, vertical, and inclined pipes based on 21 different dimensionless numbers. It is fitted from 4605 points, considering a fluid pattern classification as Annular, Bubbly, Intermittent, and Segregated. The GAM non-parametric method...
Conference Paper
Full-text available
Hydrokinetics turbines are used to take advantege of energies associated with te flow currents of tides river. Estimates of the energy that can be obtained from them are necessary in their design. Through modeling and simulation with the support of Computational Fluid Dynamics it is possible to determine the torque and consequently the performance...
Conference Paper
Full-text available
Gorlov hydrokinetic turbines are models of helical turbines for the generation of electrical energy by harnessing the hydraulic potential of rivers and tides. In the use of computational tools as a support for Fluid Mechanics, an investigation is carried ut to determine the influence on the performance of these turbines of the solidity ratio as a c...
Article
Full-text available
This paper presents an easy-to-use MATLAB© program to characterize slug flow, one of the most observed gas-liquid flow patterns in pipes. “BSignalProcessing2020.m” based on the study reported in [1] is a flexible, expandable, and adaptable statistical algorithm used to calculate the film and slug cut threshold values, the disregard cut value to gro...
Article
Slug flow is one of the most observed gas-liquid flow patterns in pipes. Owing to its high occurrence, the estimation of slug characteristics is essential for many engineering processes. The slug flow characterization is usually carried out by models and correlations previously calibrated with experimental data generated by the interpretation of vo...
Article
Full-text available
A new methodology has been developed for analyzing heat and mass transfer to predict wax deposition in crude oil pipelines using the law of the wall dimensionless parameters. A set of physically meaningful dimensionless groups and parameters has laid a strong foundation behind the proposed methodology. The paper presents a discussion regarding the...
Article
In Part 1 of this work,[1] new experimental data on high viscosity oil‐gas flow in inclined downward flow were presented. Flow patterns transitions were identified and analyzed, and the performance of some flow pattern prediction models was validated. This study uses the same experimental data set generated for a mixture of air‐oil (with a viscosit...
Article
This work provides new experimental data on high viscosity oil‐gas flow. A set of 170 downward flow experiments were carried out using a mixture of air and mineral oil (213 mPa.s, 50.8 mm internal diameter, 21.5 m long) for five different elevations: ‐45°, ‐60°, ‐70°, ‐80°, and ‐85°. Superficial liquid and gas velocities varied from 0.05 m/s to 0.7...
Article
Full-text available
The determination of multiphase flow parameters such as flow pattern, pressure drop and liquid holdup, is a very challenging and valuable problem in chemical, oil and gas industries, especially during transportation. There are two main approaches to solve this problem in literature: data based algorithms and mechanistic models. Although data based...
Article
Two-phase flow models play a fundamental role in the design, improvement, and operation of oil and gas production systems. Considering very large high-viscosity oil reserves around the world, the understanding of two-phase flow systems, which involves high-viscosity-liquids (>100 mPa s), becomes a relevant topic. The behavior of this kind of flows...
Article
Full-text available
En este artículo, se presenta un proceso h-adaptativo que define una malla óptima para calcular la solución de pro-blemas de contorno parabólicos usando el método de Diferencias Miméticas. La estimación del error, en la variable espacial, se hace a partir de la versión discreta del operador gradiente. La experimentación numérica evidencia el buen c...
Article
Full-text available
In this paper, we present an h-adaptive process that defines an optimal mesh to compute the solution transient of convection-diffusion-reaction boundary value problems by using mimetic numerical methods. The estimation of the error, in the spatial variable, is made from the discrete version of the gradient operator. The numerical experiment shows t...
Conference Paper
Full-text available
In this paper a data analytical approach featuring support vector machines (SVM) is employed to train a predictive model over an experimental dataset, which consists of the most relevant studies for two-phase flow pattern prediction. The database for this study consists of flow patterns or flow regimes in gas-liquid two-phase flow. The term flow pa...
Preprint
In this paper a data analytical approach featuring support vector machines (SVM) is employed to train a predictive model over an experimentaldataset, which consists of the most relevant studies for two-phase flow pattern prediction. The database for this study consists of flow patterns or flow regimes in gas-liquid two-phase flow. The term flow pat...
Article
Understanding two-phase flow behavior in upward vertical wells is critical for proper well design and operation. Current two-phase slug flow models and their closure relationships are based on experimental data with low viscosity liquids (μL < 20 mPa s). However, recent studies show that two-phase flow behavior of high viscosity liquids is signific...
Article
Full-text available
Huge waves are periodic interfacial structures which are observed in vertical co-current gas-liquid two-phase flow under churn and the transition between churn and annular flows. Published data examining vertical gas-liquid flow indicate that a huge wave has either a continuous gas core surrounded by a large-scale interfacial wave or a core with a...
Article
Slug-liquid holdup is a critical slug-flow parameter, which affects average liquid holdup and pressure gradient in pipes. Most experimental slug-liquid-holdup studies in the literature were conducted either by use of low-viscosity liquid for all inclination angles or high-viscosity liquid for horizontal and slightly inclined pipes, indicating a lac...
Article
An experimental study is conducted using a 0.152-m ID facility to investigate the wave characteristics of two-phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low liquid loading condition, which is very commonly observed in wet gas pipelines. The experiments are conducted with water as the liquid phase, and re...
Article
Understanding the behavior of two-phase flow is a key parameter for a proper oil/gas-production-system design. Mechanistic models have been developed and tuned to model the entire production system. Most existing two-phase-flow models are derived from experimental data with low-viscosity liquids (μL<20 mPa s). However, behavior of two-phase flow is...
Conference Paper
Full-text available
In order to better model complex real-world data such as multiphase flow, one approach is to develop pattern recognition techniques and robust features that capture the relevant information. In this paper, we use deep learning methods, and in particular employ the multilayer perceptron, to build an algorithm that can predict flow pattern in two-pha...
Preprint
In order to better model complex real-world data such as multiphase flow, one approach is to develop pattern recognition techniques and robust features that capture the relevant information. In this paper, we use deep learning methods, and in particular employ the multilayer perceptron, to build an algorithm that can predict flow pattern in twophas...
Article
Modeling of three-phase flow can be described as a combination of two-phase gas-liquid flow modeling, and a liquid phase oil-water mixing modeling. A mechanistic model is proposed to predict flow characteristics of three-phase stratified wavy flow in pipeline. For the gas-liquid interactions, Watson's (1989)³⁰ combined momentum balance equation der...
Article
Most of the commonly used multiphase flow models neglect the amount of droplets entrained in stratified wavy flow. However, the experimental data presented in this study show high entrainment values, exceeding 50% in some cases. This shows that neglecting entrainment phenomenon can introduce a major source of discrepancy into multiphase flow modeli...
Conference Paper
Full-text available
El patrón de flujo tipo tapón (slug flow), se presenta comúnmente en flujo multifásico gas-líquido. Se caracteriza por tener burbujas alargadas y paquetes de líquido entre ellas. Este patrón se manifiesta en numerosas aplicaciones de ingeniería, por lo cual, ha sido extensamente estudiado experimental, analítica y numéricamente, y continúa siendo t...
Article
An experimental study is conducted by use of a 6-in.-inner- diameter (ID) facility to investigate characteristics of three-phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low-liquid-loading condition, which is very commonly observed in wet-gas pipelines. The analyzed flow characteristics include wave pattern,...
Article
Full-text available
El presente trabajo es un estudio experimental que forma parte del proceso de caracterización de la cámara de combustión del motor del cohete sonda ULA-1A, desarrollado por el Programa de Ciencias Espaciales de la Universidad de Los Andes, Mérida, Venezuela. El motor del ULA-1A utiliza granos de combustible sólido compuesto por nitrato de potasio (...
Article
Wire-mesh sensors (WMS), developed at HZDR [4] and [13], are widely used to visualize two-phase flows and measure flow parameters, such as phase fraction distributions or gas phase velocities quantitatively and with a very high temporal resolution. They have been extensively applied to a wide range of two-phase gas–liquid flow problems with conduct...
Conference Paper
Liquid loading, a common problem in matured gas fields, is investigated experimentally in highly deviated gas wells. The experiments were carried out using air and water in a 3-in ID pipe at well deviation from 60° to 88° from vertical. Pressure gradient and liquid holdup were measured, and flow pattern characteristics as well as onset of liquid lo...
Article
Annular two-phase flow has been vastly investigated because of its large and deep involvement in industrial processes, particularly in nuclear engineering and petroleum production facilities. Much effort has been devoted to investigating upward flows involving the flow patterns, void fraction, as well as local interfacial characteristics. However,...
Conference Paper
An experimental study is conducted using a 6-in ID facility to investigate characteristics of three-phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low liquid loading condition, which is very commonly observed in wet gas pipelines. The analyzed flow characteristics include wave pattern, liquid holdup, water h...
Article
A challenging area in the field of multiphase flow is the study of churn flow. According to the multiphase flow community, churn flow has not been widely investigated in intermediate and large diameter pipes at high gas and liquid flow rates. The present work deals with an experimental study of upward vertical air–water flow in a 76.2 mm I.D. pipe....
Article
Effect of liquid viscosity on mean void fraction under different flow conditions was studied. The changes in the flow structure due to increasing liquid viscosity were shown. It was shown how liquid viscosity can influence the appearance frequencies of interfacial structures within churn flow. a b s t r a c t In the churn flow regime, periodical in...
Conference Paper
Accumulation of liquid, as oil and/or water, at the bottom of an upward inclined pipe is known to be the source of many industrial problems, such as corrosion and terrain slugging. Accurate prediction of the critical gas velocity that can unload the liquid accumulation is of great importance. An experimental study has been conducted in an upwards i...
Article
In gas well production, liquid is produced in two forms, droplets entrained in the gas core and liquid film flowing on the tubing wall. For most of the gas well life cycle, the predominant flow pattern is annular flow. As gas wells mature, the produced gas flow rate reduces decreasing the liquid carrying capability initiating the condition where th...
Conference Paper
Full-text available
Mature gas wells tend to suffer from flow rate fluctuations due to an inability to remove liquids. Flow-rate stabilization is essential for profitable operation of these wells. Moreover, the use of nozzles can help make in-situ foam treatments more efficient. The combined use of venturi nozzles and foamers is proposed as a novel artificial lift met...
Article
Resumen: El presente trabajo es un estudio experimental de la eficiencia de la combustión en un motor cohete de combustible sólido, perteneciente al programa de ciencias espaciales de la Universidad de Los Andes. El objetivo principal fue la evaluación de la combustión en este motor, el cual utiliza granos de combustible sólido compuesto, del tipo...
Conference Paper
Liquid loading is the inability of a riser or gas well to produce liquids, resulting in reduction of gas production in mature gas fields. Mechanisms describing liquid loading initiation are not well understood for inclined pipes or deviated wells. Knowing the effect of pipe inclination over the liquid-loading initiation will help for the developmen...
Article
This study investigates the effects of oil viscosity, pipe diameter, and pipe inclination angle on drift velocity. Experiments were conducted for medium viscosity oils using a 0.0508-m ID pipe for inclination angles between 0° and 90°. In these experiments, it was observed that as the liquid viscosity increased, the drift velocity decreased. Drift...
Article
Full-text available
Fluid flowing through pipelines often encounters fittings such as elbows. Although it is true that two-phase flow patterns observed in elbows are qualitatively the same as those seen in straight pipes, the presence of a pipe elbow can modify relative positions and local velocities of the two phases as they are subjected to forces in addition to tho...
Conference Paper
Wire-Mesh sensors (WMS), developed at HZDR (Da Silva 2007), are potential tools to measure phase fraction distributions quantitatively and visualize two-phase pipe flow phenomena with a very high temporal resolution. They have been extensively applied to a wide range of two-phase gas-liquid flow situations with conducting and non-conducting liquids...
Conference Paper
Full-text available
In gas well production, liquid is produced in two forms, droplets entrained in the gas core and liquid film flowing on the tubing wall. For most of the gas well life cycle, the predominant flow pattern is annular flow. As gas wells mature, the produced gas flow rate reduces decreasing the liquid carrying capability initiating the condition where th...
Conference Paper
Full-text available
Low Liquid Loading is a very common occurrence in wet gas pipelines where very small amounts of liquid flow along with the gas, mainly due to condensation of hydrocarbon gases and water vapor. The effects of low liquid loading on different flow characteristics, and flow assurance issues such as pipe corrosion prove the necessity of analyzing the fl...
Conference Paper
Full-text available
A wire mesh sensor (WMS) is a device used to investigate multi-phase flows. The WMS measures the instantaneous local electrical conductivity of multiphase flows at different measuring points. There is a significant difference in the electrical conductivity of the employed fluids (in this work air and water, conductivity of water is much higher than...
Conference Paper
Full-text available
Interfacial wave characteristics have been studied experimentally in stratified-wavy configuration for air-oil two-phase flow at Tulsa University Fluid Flow Projects (TUFFP) 6-inch low pressure flow loop. Flow rates of each test fluid are adjusted such that the superficial gas and liquid velocities vary between 9.2 m/s ≤ vsg ≤ 15 m/s and 0.01 m/s ≤...
Conference Paper
Typically pressure drop prediction of gas-liquid flow in pipes is carried out by mechanistic models. A proper prediction of the pressure drop requires prior identification of the flow pattern. Previous studies indicate (Gokcal, 2003 and 2008) that the most likely flow pattern for highly viscous oil is slug flow, which consists of a liquid slug regi...
Conference Paper
Full-text available
Stratified and annular gas-liquid flow patterns are commonly encountered in oil and gas transportation pipelines. The measurement and visualization of two-phase flow characteristics are of great importance as two-phase flows persist in many fluids engineering applications. A Wire Mesh Sensor technique based on conductance measurements was applied t...
Article
Full-text available
In this work, the study, modeling and simulation of custom designed geothermal power plant production processes are presented. A model based on the thermodynamical steam power cycles theory is developed using directed graphs, in order to consider different types of geothermal power plant structural models to be studied. The model includes steady st...
Conference Paper
Different methods for solving the system of nonlinear partial differential equations that describes isothermal gas flow in pipelines are presented. Three of these schemes include a multiplier of inertia, using the method of characteristics. The main difference between two of these models is determined by the approach of the terms of the momentum eq...
Article
Full-text available
Este trabajo presenta un método de solución para el problema inverso de difusión unidimensional, capaz de predecir los flujos y distribución en un dominio gobernado por una ecuación diferencial parcial del tipo parabólico con condiciones de frontera. Para hacer esto, se determinan los coeficientes de sensibilidad a través de la resolución de un sis...
Article
A novel methodology is presented to quantify the confidence level in the prediction of gas–liquid two-phase flow patterns in pipes. An experimental flow pattern data base has been collected, consisting of 12 studies (a total of 9029 data points). The experimental data are compared with the predictions of the unified Barnea (1987) model (any other m...
Conference Paper
Full-text available
La necesidad de suministrar energías limpias aprovechando las potencialidades hidraulicas ha motivado desarrollo de turbinas hidrocinéticas. El estudio de un modelo particular de turbina hidrocinética, la Gorlov, ha planteado la necesidad de determinar su comportamiento fluido dinámico. Con herramientas de modelado numérico se pretende valorar pote...
Conference Paper
Full-text available
Predecir patrones de flujo en tuberías de flujo bifásico es un problema actual de investigación y desarrollo. El enfoque usual consiste en coleccionar datos de flujo (gas y líquido), las propiedades del fluido (densidad del gas, densidad del líquido, viscosidad del gas, viscosidad del líquido, velocidad superficial del gas, velocidad superficial de...
Conference Paper
Full-text available
En este trabajo se presenta un esquema de paralelización de un modelo de simulación para regímenes estacionario y transitorio de una red de gasoductos. La red del gasoducto está constituida por un conjunto de tramos y nodos. El modelo está caracterizado por la estimación y corrección de presiones en los nodos de la red hasta que se satisfaga un cri...
Conference Paper
Full-text available
Este artículo presenta un modelo matemático para un tramo de gasoducto considerando distintos escenarios de funcionamiento; desde los regímenes estacionarios isotérmicos, hasta los transitorios no isotérmicos. La definición de la presión y la temperatura al principio del tramo, y el flujo másico al final del tramo, serán utilizadas como condiciones...
Conference Paper
Full-text available
Se ha desarrollado un modelo numérico para simular flujo laminar no newtoniano en tuberías anulares excéntricas. El modelo utiliza el método de los volúmenes finitos y coordenadas bipolares para la generación de la malla. El uso de una viscosidad efectiva en la ecuación de momentum permite el estudio del comportamiento de cualquier fluido para el c...