Santiago Lain

Autonomous University of the West | UAO · Departamento de Energética y Mecánica

This contribution aims at emphasizing the importance of ideal reactors in the field of environmental engineering and in the education of the corresponding engineers. The exposition presents the mass flow governing equations of the ideal reactors (batch, completely mixed flow, and plug flow reactors) as particular cases derived from the integral ver...

Climate change and the energy crisis are two main problems that humanity is currently facing and that require immediate action [...]

This paper presents a numerical study of particle deposition in turbulent flow across bends with large scale roughness. The k-ε RNG model with Enhanced Wall Functions (EWF) for wall treatment and a Lagrangian point particle tracking method with a discrete random walk (DRW) model for turbulence dispersion were chosen in order to study the effect of...

In the present work, a vertical axis turbine with straight blades was analyzed through a numerical simulation in three dimensions, the performance of the turbine was studied while synthetic jets were used as an active flow control method. To carry out the simulations, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations were solved on Sta...

In this contribution, an unsteady numerical simulation of the flow in a microfluidic oscillator has been performed. The transient turbulent flow inside the device is described by the Unsteady Reynolds Averaged Navier–Stokes equations (URANS) coupled with proper turbulence models. The main characteristics of the complex fluid flow inside the device...

In industrial processes such as those related with paper industry, coal or biomass combustion, particles can take irregular non-spherical shapes. However, in related numerical computations the assumption of spherical particle is customary, mainly because the fluid dynamic forces acting on such irregular particles are unknown to a large extent. This...

The objective of this article is to review the methodologies used in the last 15 years to estimate the power loss in wind turbines due to their exposure to adverse meteorological conditions. Among the methods, the use of computational fluid dynamics (CFD) for the three-dimensional numerical simulation of wind turbines is highlighted, as well as the...

This paper presents computational fluid dynamics (CFD) simulations of the flow around a horizontal axis hydrokinetic turbine (HAHT) found in the literature. The volume of fluid (VOF) model implemented in a commercial CFD package (ANSYS-Fluent) is used to track the air-water interface. The URANS SST k-ω and the four-equation Transition SST turbulenc...

The application of Computational Fluid Dynamics (CFD) to energy-related problems has increased in the last decades in both renewable and conventional energy conversion processes. In recent years, the application of CFD in the study of hydraulic, marine, tidal, and hydrokinetic turbines has focused on the understanding of the details of the complex...

The presence of spherical solid particles immersed in an incompressible turbulent flow was numerically investigated from the perspective of the particle mass fraction (PMF or ϕm), a measure of the particle-to-fluid mass ratio. Although a number of different changes have been reported to be obtained by the presence of solid particles in incompressib...

The water level above a hydrokinetic turbine is likely to vary throughout the season and even along the day. In this work, the influence of the free surface on the performance of a three bladed horizontal-axis turbine is explored by means of a three-dimensional, transient, two-phase flow computational model implemented in the commercial CFD softwar...

This paper presents a numerical study of the effects of the inclination angle of the turbine rotation axis with respect to the main flow direction on the performance of a prototype hydrokinetic turbine of the Garman type. In particular, the torque and force coefficients are evaluated as a function of the turbine angular velocity and axis operation...

The prediction of the wear behaviour of components under conditions of cavitation and hard particle erosion requires the implementation of a new model capable of accounting for the accelerated damage due to the synergic effect of both phenomena. In a previous research, several simulations were performed to investigate why the damage on a surface is...

The present contribution aims to determine the dependence of the location of the non-dimensional center of pressure (λ) with orientation (β) for non-spherical particles of regular shape. Prolate and oblate ellipsoids as well as cylinders of various aspect ratios (AR) at several Reynolds numbers (Rep) have been considered. The required flow coeffici...

The increasing interest in renewable energy sources originates from the negative impacts of overexploitation and the use of fossil fuels with their damaging influence on climate change. Besides, the continuous population growth requires higher energy provision or related energy services (e.g., heated living spaces, electricity, information, mobilit...

In this study, the transient numerical simulation of the flow in a fluidic oscillator has been performed. The proposed device includes several geometrical modifications of a previously patented apparatus intended for the synthesis of ozone-rich bubbles in an oxygen plasma. Prior to the experimental construction of the proposed fluidic oscillator, t...

This paper deals with the numerical analysis of the particle inertia and volume fraction effects on colliding particle-pair velocity correlation immersed in an unsteady isotropic homogeneous turbulent flow. Such correlation function is required to build reliable statistical models for inter-particle collisions, in the frame of the Euler–Lagrange ap...

The increasing interest in renewable energy sources originates from the negative impacts of overexploitation and the use of fossil fuels with their damaging influence on climate change. Besides, the continuous population growth requires higher energy provision or related energy services (e.g., heated living spaces, electricity, information, mobilit...

In this work an extended three-dimensional model to describe the process of wall collisions of arbitrary shaped non-spherical particles is developed. This model is derived as the generalized solution of the hard-sphere wall collision model described in Crowe et al. Crowe et al. (2012) [5]. The validation of the new model is performed versus experim...

The numerical computation of spraying systems is favourably conducted by applying the Euler/Lagrange approach. Although sprays downstream of the breakup region are very often rather dilute, droplet collisions may still have a significant influence on the spray evolution and especially the produced droplet size spectrum. Consequently, they have to b...

In this study, three-dimensional transient numerical simulations of the flow around a cross flow water turbine of the type H-Darrieus are performed. The hydrodynamic characteristics and performance of the turbine are investigated by means of a time-accurate unsteady Reynolds-averaged Navier–Stokes (URANS) commercial solver (ANSYS-Fluent v. 19) wher...

Machine components operating in a fluid under conditions of cavitation and hard particle erosion can be severely affected by wear, which may reduce the lifespans of the components. To understand this synergic behaviour, in this work, experimental and numerical approximations of the damage caused by a particle interacting with a spark-generated bubb...

Hydrokinetic energy conversion devices provide the facility to capture energy from water flow without the need of large dams, impoundments, channels or deviation of the water as in conventional hydroelectric centrals. Hydrokinetic systems are intended to be used in streams, either natural (rivers, estuaries, marine currents) or artificially built c...

This paper addresses the effect of inter-particle collisions on the segregation of non-settling inertial particles in homogeneous isotropic turbulence. For this purpose, direct numerical simulations of particles in statistically steady homogeneous isotropic turbulence have been performed by the lattice Boltzmann method considering inter-particle co...

Hard particle erosion and cavitation damage are two main wear problems that can affect the internal components of hydraulic machinery such as hydraulic turbines or pumps. If both problems synergistically act together, the damage can be more severe and result in high maintenance costs. In this work, a study of the interaction of hard particles and c...

The increased use of renewable energy resources for rural electrification has encouraged research and experimental projects decreasing designs uncertainties. This paper presents a deep and critical review of the design of micro hydro-generation technologies for river applications. This article shows three principal aspects: design, analysis and com...

In this contribution, unsteady three-dimensional numerical simulations of the water flow through a horizontal axis hydrokinetic turbine (HAHT) of the Garman type are performed. This study was conducted in order to estimate the influence of turbine inclination with respect to the incoming flow on turbine performance and forces acting on the rotor, w...

In the present study the Euler/Lagrange approach in combination with a proper turbulence model and full two-way coupling is applied for erosion estimation due to particle conveying along a horizontal to vertical pipe bend. Particle tracking considers both particle translational and rotational motion and all relevant forces such as drag, gravity/buo...

Hard particle erosion and cavitation damage are two main wear problems that can affect the internal components of hydraulic machinery such as hydraulic turbines or pumps. If both problems synergistically act together, the damage can be more severe and result in high maintenance costs. In this work, a study of the interaction of hard particles and c...

Nowadays, the global energy crisis has encouraged the use of alternative sources like the energy available in the water currents of seas and rivers. The vertical axis water turbine (VAWT) is an interesting option to harness this energy due to its advantages of facile installation, maintenance and operation. However, it is known that its efficiency...

For calculating dispersed particle-laden flows in confined systems, the well-known Euler/Lagrange approach is most suitable. Lagrangian tracking of non-spherical particles with certain shapes is mostly performed by additionally solving for the orientation of particles in the flow and using resistance coefficients (i.e. drag, lift and torque) which...

Abstract:This study deals with the three-dimensional unsteady numerical simulation of the flowaround a cross-flow vertical-axis water turbine (CFWT) of the Darrieus type. The influence ofturbine design on its hydrodynamic characteristics and performance is investigated by means of atime-accurate Reynolds Averaged Navier Stokes (RANS) commercial sol...

Modelling of collisions between liquid droplets in the frame of a Lagrangian spray simulation has still many openissues, especially when considering higher viscous droplets and if colliding droplets have a large size difference. A generalisation of the collision maps is attempted based on the behaviour of characteristic points, namely the triple po...

In this work, blood flow dynamics was analyzed in a realistic thoracic aorta (TA) model under unsteady-state conditions via velocity contours, secondary flow, pressure and wall shear stress (WSS) distributions. Our results demonstrated that the primary flow velocity is skewed towards the inner wall of the ascending aorta; but this skewness shifts t...

This paper proposes a new methodology to evaluate the technical state of a Francis turbine installed in a hydroelectric plant by coupling computational fluid dynamics (CFD) and rotor-dynamic analysis. CFD simulations predicted the hydraulic performance of the turbine. The obtained field forces, due to the fluid-structure interaction over the blades...

This study presents two-dimensional numerical simulations of the flow around a cross-flow vertical-axis water turbine (straight-bladed Darrieus type) using active flow control by means of synthetic jets. The performance of the turbine is quantitatively analyzed from the hydrodynamic coefficients (torque coefficient, power coefficient, tangential fo...

This study investigated the state of a service reservoir of a drinking water distribution network. Numerical simulation was applied to establish its flow pattern, mixing conditions, and free residual chlorine decay. The influence of the change in the water inlet configuration on these characteristics was evaluated. Four scenarios were established w...

This study presents full transient numerical simulations of a cross-flow vertical-axis marine current turbine (straight-bladed Darrieus type) with particular emphasis on the analysis of hydrodynamic characteristics. Turbine design and performance are studied using a time-accurate Reynolds-averaged Navier–Stokes commercial solver. A physical transie...

The present study discusses two-dimensional numerical simulations of a cross-flow vertical-axis marine (Water) turbine (straight-bladed Darrieus type) with particular emphasis on the turbine unsteady behavior. Numerical investigations of a model turbine were undertaken using commercial computational solvers. The domain and mesh were generated using...

The present contribution summarizes research related to the numerical computation of pneumatic conveying systems applying the Euler/Lagrange approach. For that purpose, a rigorous modelling of the particulate phase was aspired, including the relevant fluid dynamic forces, particle-wall collisions with wall roughness and inter-particle collisions. F...

In this paper the performance of horizontal pneumatic conveying under different gravity environments is evaluated. An Euler–Lagrange approach validated versus ground experiments is employed to predict the relevant particle variables such as particle mass flux, mean conveying and fluctuating velocities in terrestrial, lunar and micro-gravity conditi...

The high parallelism and low cost of the graphic processing units (GPUs) have attracted the interest of scientists and engineers requiring high computational power with a modest investment. This work explores the use of a GPU in the solution of the 2D lid-driven cavity flow problem using the pressure–velocity formulation for Reynolds numbers up to...

The importance of numerical calculations (CFD) for supporting the optimization and lay-out of industrial processes involving multiphase flows is continuously increasing. Numerous processes in powder technology involve wall-bounded gas-solid flows where wall collisions essentially affect the process performance. In modelling the particle wall-collis...

The present contribution describes three-dimensional Euler/Lagrange calculations of confined horizontal gas-particle flows emphasizing the importance of elementary processes, such as particle collisions with rough walls and interparticle collisions, on the predicted two-phase flow variables and pressure drop along the duct. In the chosen configurat...

Three non-Newtonian blood viscosity models plus the Newtonian one are analysed for a patient-specific thoracic aorta anatomical model under steady-state flow conditions via wall shear stress (WSS) distribution, non-Newtonian importance factors, blood viscosity and shear rate. All blood viscosity models yield a consistent WSS distribution pattern. T...

This study presents two-dimensional and three-dimensional numerical simulations of a cross-flow vertical-axis marine current turbine (straight-bladed Darrieus type) with particular emphasis on rotor-performance prediction and hydrodynamic characteristics. Numerical investigations of a model turbine (torque coefficient, power coefficient, tangential...

It has long been recognized that the forces and stresses produced by the blood flow on the walls of the cardiovascular system are central to the development of different cardiovascular diseases (CVDs). However, up to now, the reason why arterial diseases occur at preferential sites is still not fully understood. This paper reviews the progress, mad...

The present study deals with pneumatic conveying of spherical particles in a six meter long horizontal channel with rectangular cross-section from a numerical perspective. Calculations are done for spherical glass beads of different sizes with a mass loading of 1.0 kg particles/kg gas. Additionally, different wall roughnesses are considered. Air vo...

This paper deals with the transport of solid particles in pneumatic conveying systems, namely a 5 m horizontal pipe, a 90° bend and 5 m a vertical pipe. The pipe diameter is 150 mm in all cases and the average conveying velocity is 27 m/s. Three-dimensional stationary numerical computations were performed by the Euler/Lagrange approach in connectio...

Accelerated process of urban growth in Santiago de Cali, have led to settlements in places that could pose a threat to the health of people living in areas close to the Navarro final disposition site. The potential health risk would be present at the time that such people are exposed to contaminants coming from Navarro Dump. A first step in estimat...

This study presents three-dimensional numerical simulations of a cross-flow vertical-axis marine current turbine (straight-bladed Darrieus type) with particular emphasis on rotor-performance prediction and hydrodynamic characteristics. Numerical investigations of a model turbine (power coefficient and flow behaviour) were undertaken using developed...

The actual development of wind energy in several countries around the world become it as the fastest growing power generation technology between green and clean technologies. Almost 50% of the installed wind turbines are induction generators. With the increase of induction instead of synchronous generators, electrical networks are experiencing diff...

Se llevó a cabo una evaluación a escala real de las condiciones de mezcla y su influencia sobre la calidad del agua en un tanque de compensación del sistema de distribución de agua potable de la ciudad de Cali (Colombia). El estudio hidrodinámico con aplicación continua de trazador y mediciones de temperatura y de cloro residual libre para identifi...

We performed a real scale evaluation of mixing conditions and its influence on water quality in a compensation tank of drinking-water distribution system located in the city of Cali, Colombia. The hydrodynamic study with continuous injection of tracer, and temperature and free chlorine measurements for identifying the mixing regime in the tank's in...

We performed a real scale evaluation of mixing conditions and its influence on water quality in a compensation tank of drinking-water distribution system located in the city of Cali, Colombia. The hydrodynamic study with continuous injection of tracer, and temperature and free chlorine measurements for identifying the mixing regime in the tank's in...

Hydrodynamic phenomena take place within water treatment plants associated with physical, operational and environmental factors which can affect the water quality. This study evaluated a hydraulic clarifier’s hydrodynamic pattern using sludge recircula-tion through continuous tracer test leading to determining hydraulic behaviour indicators and sim...