Victor Hidalgo - Academia.edu (original) (raw)

Papers by Victor Hidalgo

Aerospace, 2021

Despite the increasing demand of Unmanned Aerial Vehicles (UAVs) for a wide range of civil applic... more Despite the increasing demand of Unmanned Aerial Vehicles (UAVs) for a wide range of civil applications, there are few methodologies for their initial sizing. Nowadays, classical methods, mainly developed for transport aircraft, have been adapted to UAVs. However, these tools are not always suitable because they do not fully adapt to the plethora of geometrical and propulsive configurations that the UAV sector represents. Therefore, this work provides series of correlations based on off-the-shelf components for the preliminary sizing of propulsion systems for UAVs. This study encompassed electric and fuel-powered propulsion systems, considering that they are the most used in the UAV industry and are the basis of novel architectures such as hybrid propulsion. For these systems, weight correlations were derived, and, depending on data availability, correlations regarding their geometry and energy consumption are also provided. Furthermore, a flowchart for the implementation of the cor...

2017 IEEE 13th International Colloquium on Signal Processing & its Applications (CSPA), 2017

In bearing fault diagnosis, impulse periodic signals are associated with the presence of faults. ... more In bearing fault diagnosis, impulse periodic signals are associated with the presence of faults. This paper uses ensemble empirical mode decomposition (EEMD) and Teager energy operator (TEO) to emphasize periodic faults, thus improving the identification of frequency characteristic faults. In the paper two validation process are carried out, they involve the analysis of a simulated outer race fault signal, and real bearing vibration signals which includes: inner race, rolling element and outer race faults. The results verify that the proposed model enhances the identification of bearing frequency characteristic faults and its harmonics.

AIAA Propulsion and Energy 2020 Forum, 2020

—Large eddy simulation model (LES) and the open source OpenFOAM are used in the present numerical... more —Large eddy simulation model (LES) and the open source OpenFOAM are used in the present numerical study of unsteady cavitating flow around a NACA0015. The results showed a great accuracy with experiments. The validations of the present simulations are strong advantage to solve cavitation problems of turbines for hydroelectric plants which represents more than 46% of electricity in Ecuador. Keywords —Cavitation; LES; Open-source; OpenFOAM; python; turbine.

Advances in Intelligent Systems and Computing, 2019

53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017

Proceedings of the 6th World Congress on Mechanical, Chemical, and Material Engineering, 2020

Resumen: Los beneficios potenciales que representa la aviacion en los campos: economico, de segur... more Resumen: Los beneficios potenciales que representa la aviacion en los campos: economico, de seguridad y de desarrollotecnologico de un pais, han motivado a paises como Ecuador a fomentar el crecimento de la aeronautica en los ultimosanos. Lamanufactura de vehiculos no tripulados y satelites, por ejemplo, han significado importantes pasos en la evolucionde esta rama. En este ambito, la presente investigacion contribuye al estudio de sistemas de propulsion innovadoresde alta eficiencia, que permitan la disminucion del consumo de combustible, emisiones y ruido. El efecto de estas variablesen el medio ambiente ha sido estudiado de una manera extensa. Por tal razon, es conocido que el crecimiento de laaviacion llevara consigo a una alteracion a nivel global del ecosistema. Debido a esto, grandes esfuerzos en investigacionhan sido enfocados a los sistemas de propulsion y fuselaje alternativos, que permitan el desarrollo sustentable dela aviacion. El presente trabajo compila la investigaci...

The present work focuses on the numerical study of the cavitating flow through a Venturi section ... more The present work focuses on the numerical study of the cavitating flow through a Venturi section by applying a scale adaptive simulation model. This study aims to understand the topology and unstable behavior of the cavitation cloud, which includes cavities formation as well as its collapse. Based on computational fluid dynamics, a methodology was developed to analyze the different stages of cavitating flow under the open-source guidelines. In this context, the numerical study was performed using OpenFOAM's environment with the help of the Gmsh meshing tool. For the resolution of Navier-Stokes equations, the PIMPLE algorithm was used considering a RANS equations approximation. Besides, the k-omega SST SAS turbulence model and the Zwart-Gerber-Belamri (ZGB) cavitation model were applied to study phase changes that occurs in the phenomenon. The obtained results of the present research show that the proposed methodology can reproduce the cavitation problem through a Venturi section with enough accuracy compared with experimental data and previous numerical simulations.

Mathematics, 2021

The improvement in energy saving aspects in water systems is currently a topic of major interest.... more The improvement in energy saving aspects in water systems is currently a topic of major interest. The utilization of pumps working as turbines is a relevant strategy in water distribution networks consisting of pressurized pipes, using these machines to recover energy, generate green energy and reduce leakages in water systems. The need to develop energy studies, prior to the installation of these facilities, requires the use of simulation tools. These tools should be able to define the operation curves of the machine as a function of the flow rate. This research proposes a new strategy to develop a mathematics model for pumps working as turbines (PATs), considering the modified affinity laws. This proposed model, which can be input into hydraulic simulation tools (e.g., Epanet, WaterGems), allows estimation of the head, efficiency, and power curves of the PATs when operating at different rotational speeds. The research used 87 different curves for 15 different machines to develop t...

Water, 2021

The present research depicts an analysis of the implementation of computational fluid dynamics (C... more The present research depicts an analysis of the implementation of computational fluid dynamics (CFD) in the study of pumps such as turbines and PATs. To highlight the benefits of CFDs for PAT studies, results from both experimental tests have been compared to better understand the reproduction error phenomena. For this, data analysis used in successful models has been applied to determine variables and parameters, and to report a low relative error. The results show that most of the studies focused on fixed speed rotation with some cases of variable speed rotation. Furthermore, there is not enough information in the academic literature for PAT of axial and mixed flows with fixed and variable speed. Finally, turbulence models based on Reynolds average Navier–Stokes (RANS) have been used to simulate PATs with fixed speed rotation in most cases.

Bulletin of Earthquake Engineering, 2020

The reinforced concrete (RC) diaphragm damage observed during the Northridge earthquake (1994) ha... more The reinforced concrete (RC) diaphragm damage observed during the Northridge earthquake (1994) has motivated numerous analytical and experimental studies focused on evaluating the seismic performance of this important building component. The ASCE/SEI 7-16 recently introduced an alternative methodology to determine diaphragm design forces that considered various diaphragm systems. However, this formulation was developed for typical North American structures (on frames or dual systems combined with gravity framing), which substantially differ from other worldwide common typologies that may not include gravity framing. Throughout this study, the accuracy of the existing code provisions and other alternative methods is evaluated by using three-dimensional computer models of eight symmetric-plan reinforced concrete buildings that are between five and 15 stories high and have non-gravity frames (i.e. all frames are part of the seismic force resisting system) for RC-floor systems. These models are subjected to non-linear response history analysis that considers sets of far-field records. Benchmark values, defined as the mean value of the time responses and their dispersion, are compared with the forces of design codes and procedures. General conclusions indicate that existing provisions underestimate diaphragm design forces for all the systems considered, but the results can substantially improve if a low diaphragm reduction factor is used. Alternative procedures capture the magnitude but not the height distribution. Finally, the level of non-linear behavior of the structural elements was verified; beams exhibit high inelastic response, but the overall structure and the vertical elements mostly kept elastic.

IOP Conference Series: Earth and Environmental Science, 2019

More than a half of the overall power capacity in Ecuador uniquely depends on hydroelectric power... more More than a half of the overall power capacity in Ecuador uniquely depends on hydroelectric power, thanks to its geographical position and large water resources. Most of them use Francis turbines, which present detriment in their lifetime due to the presence of high hardness sediments in the water reservoirs located close to the Andean mountains. In order to mitigate such effect, a structured methodology, which identifies design space variables and defines parameters that governs the phenomenon is developed. The optimization is carried out through genetic algorithms formulated to determine optimal geometrical features and hydraulic parameters based on Euler meanline turbomachinery equation. The objective function for the optimization study at this preliminary stage was erosion factor, whilst the decision variables used were: outlet diameter, acceleration flow, degree of reaction and percentage of curvature deviation from a linear of the blade angle distribution. The results obtained showed that the erosion factor can be reduced by 49 % and that the relative flow velocity at the exit was a key optimization parameter to decrease the runner erosion. This great improvement at preliminary design has been compared with other similar studies, showing a good enough prediction of erosion and the capturing of the phenomena. Furthermore, the important contribution of the present methodology is the development of a simple and versatile tool to define the design space for erosion phenomena and in this way improve the lifetime of the blade turbine runner and hence decreasing maintenance costs.

Experimental parasitology, 2018

The extraction of DNA in taeniid eggs shows complications attached to the composition of stool sa... more The extraction of DNA in taeniid eggs shows complications attached to the composition of stool samples and the high resistance of eggs to degradation. The objective of this study was to test a method of DNA extraction in taeniid eggs by applying a thermal shock to facilitate the chemical-enzymatic degradation of these elements. A group of six tubes containing 1 ml of dog stool sample was spiked with eggs of Echinococcus granulosus and another group of six with Taenia pisiformis. Samples were floated with supersaturated sugar solution and centrifuged. The upper portion of each tube (500 μl) was aspirated and deposited in 1.5 ml tubes. Three tubes from each group were incubated at -20 °C and then at 90 °C, the remaining three from each group, incubated at room temperature. Proteinase K and lysis buffer were added to each tube and incubated for 12 h at 58 °C. The lysis effect was evaluated by microscopy at 3, 6 and 12 h and integrity by electrophoresis in 1% agarose gels. With the same...

Journal of Mechanical Science and Technology, 2017

The present study adopts the filter-based RANS (k-ε) method to analyze unsteady liquid-solid two-... more The present study adopts the filter-based RANS (k-ε) method to analyze unsteady liquid-solid two-phase flow around a step in a rectangle channel. Numerical simulation was carried out in three dimensions using Eulerian-Lagrangian approach, in which the continuous phase is treated by Eulerian method and the motions of the dispersed phases are solved by Lagrangian method. The filter-based unsteady RANS (k-ε) model was implemented via user-defined functions in ANSYS Fluent 14.0. The flow field measurement by PIV experiment and the pressure fluctuation downstream the step were carried out for validation. Based on the comparison between the numerical and experimental data, results show that the pressure and velocity distributions were successfully reproduced. Compared with the standard k-ε model, the filter-based model can improve the prediction accuracy for wake flow and particle motion downstream the step. Furthermore, the numerical simulation reveals that the vorticity described by Q-criterion, promotes the particle motion at the wake area. However, the significant discrepancy of the particle distribution in the wake indicates the importance of turbulence modeling method for liquid-solid two-phase flow simulation.

Chinese Journal of Aeronautics, 2017

52nd AIAA/SAE/ASEE Joint Propulsion Conference, 2016