Luis Obregon - Academia.edu (original) (raw)
Papers by Luis Obregon
Eureka: Physics and Engineering, Nov 29, 2023
Contemporary Engineering Sciences, 2018
The present study shows the effect of the diffusivity of the material of the internal inclined sh... more The present study shows the effect of the diffusivity of the material of the internal inclined sheets on the drying of granular anhydrous lactose with an average particle diameter of 1.68 mm in a continuous powder dryer with adjustable inclined sheets. It was reduced the heat losses in the equipment with an insulator, maintaining the air inlet temperature in 100ºC. To increase the solid-air contact, perforated plates were designed in a square arrangement in line. They were adapted inside the column with an inclination angle of 60º. It was found that the diffusivity of the material, the insulation, and their interaction have significative effects on the drying obtaining a statistical p-values lower than 0.05. The heat losses in the equipment were reduced in 13%.
Contemporary Engineering Sciences, 2018
The general analysis of the research on climate change was built in the tracking information of r... more The general analysis of the research on climate change was built in the tracking information of researchers and the national research groups, which generate scientific knowledge about the climate change in the world. Also, it discusses the scientific production in this field, identifying trends, strengths, and gaps in the generation of new knowledge on climate change. This paper presents a statistical analysis using Histcite software which let to study how relevant a topic is in the world of science giving a line of reference about the issues which have a high significance in the research. The development of a Bibliometric analysis related to climate change using Histcite is based on 862 articles published from 2007 to 2016, obtaining a 73.1% of production articles in this time with an average annual growth of the 8.82% being USA the pioneer country in this research. The quality of the articles was measured by the number of references included, for example, the USA has 26.3% of the citations around the world indicating the high quality of the papers.
Contemporary Engineering Sciences, 2018
In this work, the influence of the emissivity of a solar collector on its thermal performance was... more In this work, the influence of the emissivity of a solar collector on its thermal performance was studied, to evaluate the effect of radiative heat losses on-air preheating appliances. To do so, the equations that define the efficiency of the unglazed solar collector were programmed into a commercial software package (such as MATLAB®, where the emissivity of the collector surface was varied, to study its response when a radiation boundary condition is changed; to validate the obtained results, a comparison with the theoretical results was done to verify the prediction capacity of the programming code. As the results obtained through the code shared the same behavior of the theoretical ones (though a little deviation), it was verified the capabilities of the program to accurately predict the collector efficiency with a higher speed, and at the same time, it allowed to establish that the increase in the emissivity generates a reduction in the thermal efficiency of approximately 20%, which makes it an important factor to control through the design and construction of solar collectors.
Contemporary Engineering Sciences, 2018
In this work, the thermal performance of unglazed transpired solar collector (used in preheating ... more In this work, the thermal performance of unglazed transpired solar collector (used in preheating air), is studied in CFD (Computational Fluid Dynamics), to analyze the influence of flow parameters on their thermal performance. To do so, variations were made in flow parameters (such as flow velocity), to study the response of the system performance by using a CFD model of the fluid volume inside it. The results obtained by the simulation were validated with the theoretical model, and a mesh independence study was carried out, to optimize the simulation process and computational resources; these results allowed to conclude that the developed CFD model can predict accurately the behavior of the flow inside the collector, and that the increment on the flow velocity generates a reduction in the heat loss due to recirculation of the inlet flow, which in turn improves the efficiency of the collector, making these suitable for air heating processes.
International Review on Modelling and Simulations, Feb 28, 2023
Journal of Energy Resources Technology
This paper compares the performance of a group of intelligent algorithms such as the genetic algo... more This paper compares the performance of a group of intelligent algorithms such as the genetic algorithm (GA), particle swarm optimization (PSO), and repulsive particle swarm optimization (RPSO) based on the optimization of thermo-economic indicators such as the payback period (PBP), the levelized energy cost (LEC), the specific investment cost (SIC), and also in the optimization of the thermodynamic process (net power output) of an energy recovery system in a 2 MW natural gas internal combustion engine based on an organic Rankine cycle. Four parameters were considered to analyze and compare the performance of these algorithms: integral of squared error (ISE), integral of absolute error (IAE), integral of time-weighted absolute error (ITAE), and the integral of time-weighted squared error (ITSE). Analyses of variances (ANOVA) were proposed for each of the parameters studied. The PSO and RPSO algorithms presented the best performance in terms of the mean and the standard deviation of t...
Contemporary Engineering Sciences, 2018
This paper shows the application of a software tool to promote the significant learning in refrig... more This paper shows the application of a software tool to promote the significant learning in refrigeration cycles in undergraduate engineering students through case studies. To solve the case studies the tool calculates in MATLAB® the thermodynamic states and energy balances of the simple vapor refrigeration cycle, the cascade, multi-stage, and absorption refrigeration cycle. In the case of a simple refrigeration system, a proportional behavior between the COP and the compressor's work was obtained as a function of the outlet temperature of the evaporator for compressor efficiencies of 100%, 80%, and 60%. In the case of the cascade refrigeration system, the behavior of both the energy consumed by the compressor and the thermal efficiency of the cycle is explained by the pressure at the inlet of the high compressor. In the multi-stage refrigeration cycle, the variation in the pressure of the flash chamber and the compressor efficiency did not affect the vapor fraction. Finally, the case studies obtained through the program facilitate the understanding of thermodynamic phenomena in refrigeration systems, which normally in a traditional classroom would require time and educational resources for their learning.
Contemporary Engineering Sciences, 2018
In this work, the hydraulic and energetic performance of a centrifugal pump is studied in CFD (Co... more In this work, the hydraulic and energetic performance of a centrifugal pump is studied in CFD (Computational Fluid Dynamics), to achieve optimization in its performance through a parametric analysis. Variations were made in pump parameters such as diameter, number of blades and speed of rotation, to study their influence over the general performance of the pump, by using a CFD package; the results obtained were validated in a test bench, to guarantee the prediction capacity of the simulations. In the same way, a theoretical analysis was carried out, comparing the results with the Euler equation and corrections with Stodola equation. An analysis of mesh independence was carried out, to optimize the simulation process and computational resources. The results allowed to conclude that the reduction in the thickness of the pump casing, which has the effect of a larger diameter of the impeller, leads to an increase in the effective head of the pump; similar results are obtained with the increase in the number of blades and the 1350 Jorge Duarte et al. increase in the speed of rotation, although in the latter case, it is less accentuated due to the reduction in volumetric efficiency.
Contemporary Engineering Sciences, 2018
This paper presents a two-dimensional movement analysis and the forces acting on a slider-crank m... more This paper presents a two-dimensional movement analysis and the forces acting on a slider-crank mechanism by applying the Lagrangian approach, to develop a mathematical model for the complete description of the kinetic and kinematics of the mechanism. The aim of the research is restricted to a specific scenario: the determination of the force exerted by the slider, which becomes an important parameter in positive displacement machines (such as for compressors and pumps), and acquires greater value in the study of internal combustion engines (ICE). From the Lagrangian analysis, partial differential equations are obtained, relating the force generated by the slider, with three variables: The crank angular position, its variation concerning time-angular velocity-and the angular acceleration. The results show the Lagrangian analysis as a useful methodology of kinetic analysis, which can be used to design processes to find economical options for the manufacture of machines (mainly ICE) that meet the specifications from the kinetic point of view, with reduced losses.
Chemical engineering transactions, 2018
The undeniable importance of industrial distillation has motivated hundreds, if not thousands of ... more The undeniable importance of industrial distillation has motivated hundreds, if not thousands of theoretical and applied research projects. A considerable amount of those projects has used a bench or pilot scale distillation columns to have experimental confirmation of the proposed innovations. Nevertheless, the automatic control of bench scale distillation columns is not as straightforward as it appears to be, due to the low magnitude of the involved material flows. To precisely manipulate low magnitude flows, special low flow control valves are necessary; this results in high instrumentation costs which are not desirable at bench nor pilot scale. This work treats the simulation and control of a low cost, bench scale column with an electrically heated reboiler and water-cooled condenser. It uses a version of an on-off valve as an actuator to control the distillate composition of the desired product. The use of a solenoid valve results in a discontinuous reflux flow, which changes t...
Chemical engineering transactions, 2018
The use of heat exchangers on extended surfaces has obtained high importance in the last years du... more The use of heat exchangers on extended surfaces has obtained high importance in the last years due to their high implementation in industrial processes, computer systems, refrigerators, electronic equipment, etc. It implies the use of computer technology to have a better comprehension of the phenomena that involve heat transfer in finned surfaces to design new prototypes with high efficiency. There are lots of parameters to consider when designing fins such as their geometry and the type of material making the design highly complex. Also, a selection of adequate fins requires knowledge of temperature distributions through them, which will depend on the properties of the fin material. In this article, it is presented the study of the energy transfer and effectiveness in Extended Surfaces using an educational graphical user interface developed in Matlab as a pedagogical strategy to promote the significant learning in engineering. The program uses the most important experimental correl...
Contenido 1. Introducción 2. Presentación del Software 3. Desarrollo de la guía teórico-práctica ... more Contenido 1. Introducción 2. Presentación del Software 3. Desarrollo de la guía teórico-práctica 4. Resultados y discusiones 5. Conclusiones Referencias Agradecimientos RESUMEN: El artículo presenta una interfaz gráfica de usuario desarrollada en Microsoft Visual Studio para la simulación de procesos de acondicionamiento de aire y el efecto significativo que tiene su implementación en el curso de termodinámica. Se tomó una muestra de los estudiantes de pregrado de ingeniería para implementar una prueba educativa en dos grupos, un grupo experimental y un grupo de control, donde se realizó una prueba previa para determinar el estado actual y una prueba posterior después de haber aplicado el tratamiento al grupo experimental. Para el grupo experimental, el tratamiento fue el desarrollo de unos casos de estudio basados en una guía teórica-practica con la ayuda de la herramienta computacional PSYCROSFAST, mientras que el grupo de control desarrollo la guía teórica-practica sin el programa. El programa permite a los estudiantes interactuar con el comportamiento de la temperatura de bulbo seco, humedad relativa, presión atmosférica, flujo volumétrico y flujo másico del agua implicada en los procesos de acondicionamiento de aire. Para evaluar estadísticamente la diferencia del rendimiento promedio entre los grupos en términos de claridad, precisión y pertinencia, se tomó una población de 60 estudiantes del grupo control y experimental y se realizó una prueba t, que permitió determinar con un nivel de significancia del 5%, la existencia de un efecto significativo al implementar el software como soporte en la enseñanza de los conceptos teóricos involucrados en los procesos de calentamiento y humidificación, enfriamiento y deshumidificación y torre de enfriamiento, promoviendo en los estudiantes el pensamiento crítico y aprendizaje significativo.
Chemical engineering transactions, 2018
In general heat transfer, which is the science that studies the rate of energy transfer, has an e... more In general heat transfer, which is the science that studies the rate of energy transfer, has an extensive working area ranging from biological systems to common household appliances, industrial processes, electronic devices, among others. For engineers, it is necessary to have a complete understanding of this phenomena to design the best equipment that gives the highest efficiency and save the maximum energy possible. Most of the study about heat transfer is addressed to the steady state because systems remain in that state most of the time. However, there are always perturbations that cause variability on the systems producing complications that require immediate attention by the implementation of control of processes. For that reason, it is necessary to know the dynamic behavior of the systems by understanding their transient state. In heat transfer, these systems are designed with different shapes that can be sectioned and studied separately with the use of the common configurati...
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2020
Air conditioning is an essential topic in heat transfer phenomena because it is widely applied in... more Air conditioning is an essential topic in heat transfer phenomena because it is widely applied in homes and industries. It has an incredible amount of applications ranging from health care to food shelf life. With the enhancement of technology, it is necessary to create new devices that increase the efficiency of air conditioning. Hence, it is required to evaluate the trend of study of this topic to help researchers to get the best research direction that promotes the acquisition of better experimental results. For that reason, it was collected a total of 2431 documents about air conditioning from the Science Citation Index Expanded during the period from 2008 to 2019. Next, it was used HistCite to analyze the yearly output, country, institution, citation impact, and citation relationships in this field of study. Results suggest that the research of air conditioning had an increase during the studied 11-year period. The countries with the highest research output were China, The USA, and Japan, and the institutions with the highest research output were the National Natural Science Foundation of China and the Hong Kong Polytech University. The journals with the largest number of articles were Energy and Buildings with 195 publications and Applied Thermal engineering with 164 papers.
Contemporary Engineering Sciences, 2018
In this work, a series of statistical methods were applied in order to characterize the influence... more In this work, a series of statistical methods were applied in order to characterize the influence of operation variables in the energetic performance of industrial-scale milling processes. To do so, a certain set of factors were evaluated, to estimate the correlation degree between these and the energetic consumption rate, which is the most used indicator of energy efficiency. Due to the quantity and level of complexity of the operations involved, statistical package Minitab® was used, being its application an easy way to establish statistical criteria to evaluate the influence of said variables. The results obtained, show that from the set of variables studied, only two (the energy and the production), have a degree of correlation enough to be taken in account into post processing operations; though the behavior of these operation variables differ considerably from each other, the statistical analysis done remarks their influence on the consumption rate using correlation processes, and therefore, this study acts as a basis to future optimization processes that contribute to improve the overall performance of milling operations.
Contemporary Engineering Sciences, 2018
With the aim to enhance the learning process of the unit operation of Leaching, it is presented a... more With the aim to enhance the learning process of the unit operation of Leaching, it is presented a GUI in Matlab® for designing systems with different types of contact where the stages reach the equilibrium between the solid and liquid phase. The program called LeachING is an application of theoretical studies and material balances presented in highly relevant documents and popular academic books, which has a general procedure that initiates by introducing the feed and solvent quantities with their respective compositions, and a raffinate exit condition for multistage equipment. Finally, material balances and multiple iterative routines were used to calculate raffinate and extract exit conditions, and the minimum number of stages necessary to reach them, allowing the user to get the approximate size and cost of the equipment making this software a powerful academic tool. With the program, it was compared the maximum separation for given conditions between countercurrent and crosscurrent equipment, the behavior of the percentage of separation when increasing feeding with constant solvent, and the behavior of the maximum feeding for the different types of contact.
Contemporary Engineering Sciences, 2018
In this work, the kinetic and kinematic variables of serial-driven planar manipulators (also know... more In this work, the kinetic and kinematic variables of serial-driven planar manipulators (also known as RR planar manipulators) were studied to achieve optimization in its performance through a parametric analysis. To do so, the equations that define the behavior of these mechanisms were programmed using the Octave software package, and some variations were made in input parameters, such as torque and forces, to study their influence on the kinetic parameters of the mechanism; to validate the obtained results, these were compared with the analytical solution, to guarantee the prediction capacity of the simulations. The results obtained by using the simulation package shared the same behavior as the results obtained through the application of the theoretical model, with a little deviation from the theoretical results (less than 3%). Besides that, the program code allowed to obtain results to a higher speed than the solution of theoretical equations (harder to solve at hand) with the same accuracy, which is an important parameter when optimization processes are required.
Contemporary Engineering Sciences, 2018
As the years go by, the growing interest of nations in energy generation becomes more evident. Fo... more As the years go by, the growing interest of nations in energy generation becomes more evident. For this reason, this paper presents a study in which an exergetic analysis and the study of the variation of thermal efficiency for a Brayton cycle with regeneration was carried out, varying parameters such as the compression ratio. A spreadsheet was used to study a gas power cycle, an ideal Brayton regeneration cycle with a turbine, a compressor, a regenerator and a combustion chamber which delivers the heat input to the system, finding that if you want to improve the thermal efficiency of a gas power engine using an ideal brayton regeneration cycle you should consider or take into account what has been proposed and demonstrated in this research as a way to achieve this objective, Also thanks to the exergetic analysis that was carried out on the cycle in question, this research can be considered to take action on the components that most destroy useful energy potential. 3566 Guillermo E. Valencia et al.
Eureka: Physics and Engineering, Nov 29, 2023
Contemporary Engineering Sciences, 2018
The present study shows the effect of the diffusivity of the material of the internal inclined sh... more The present study shows the effect of the diffusivity of the material of the internal inclined sheets on the drying of granular anhydrous lactose with an average particle diameter of 1.68 mm in a continuous powder dryer with adjustable inclined sheets. It was reduced the heat losses in the equipment with an insulator, maintaining the air inlet temperature in 100ºC. To increase the solid-air contact, perforated plates were designed in a square arrangement in line. They were adapted inside the column with an inclination angle of 60º. It was found that the diffusivity of the material, the insulation, and their interaction have significative effects on the drying obtaining a statistical p-values lower than 0.05. The heat losses in the equipment were reduced in 13%.
Contemporary Engineering Sciences, 2018
The general analysis of the research on climate change was built in the tracking information of r... more The general analysis of the research on climate change was built in the tracking information of researchers and the national research groups, which generate scientific knowledge about the climate change in the world. Also, it discusses the scientific production in this field, identifying trends, strengths, and gaps in the generation of new knowledge on climate change. This paper presents a statistical analysis using Histcite software which let to study how relevant a topic is in the world of science giving a line of reference about the issues which have a high significance in the research. The development of a Bibliometric analysis related to climate change using Histcite is based on 862 articles published from 2007 to 2016, obtaining a 73.1% of production articles in this time with an average annual growth of the 8.82% being USA the pioneer country in this research. The quality of the articles was measured by the number of references included, for example, the USA has 26.3% of the citations around the world indicating the high quality of the papers.
Contemporary Engineering Sciences, 2018
In this work, the influence of the emissivity of a solar collector on its thermal performance was... more In this work, the influence of the emissivity of a solar collector on its thermal performance was studied, to evaluate the effect of radiative heat losses on-air preheating appliances. To do so, the equations that define the efficiency of the unglazed solar collector were programmed into a commercial software package (such as MATLAB®, where the emissivity of the collector surface was varied, to study its response when a radiation boundary condition is changed; to validate the obtained results, a comparison with the theoretical results was done to verify the prediction capacity of the programming code. As the results obtained through the code shared the same behavior of the theoretical ones (though a little deviation), it was verified the capabilities of the program to accurately predict the collector efficiency with a higher speed, and at the same time, it allowed to establish that the increase in the emissivity generates a reduction in the thermal efficiency of approximately 20%, which makes it an important factor to control through the design and construction of solar collectors.
Contemporary Engineering Sciences, 2018
In this work, the thermal performance of unglazed transpired solar collector (used in preheating ... more In this work, the thermal performance of unglazed transpired solar collector (used in preheating air), is studied in CFD (Computational Fluid Dynamics), to analyze the influence of flow parameters on their thermal performance. To do so, variations were made in flow parameters (such as flow velocity), to study the response of the system performance by using a CFD model of the fluid volume inside it. The results obtained by the simulation were validated with the theoretical model, and a mesh independence study was carried out, to optimize the simulation process and computational resources; these results allowed to conclude that the developed CFD model can predict accurately the behavior of the flow inside the collector, and that the increment on the flow velocity generates a reduction in the heat loss due to recirculation of the inlet flow, which in turn improves the efficiency of the collector, making these suitable for air heating processes.
International Review on Modelling and Simulations, Feb 28, 2023
Journal of Energy Resources Technology
This paper compares the performance of a group of intelligent algorithms such as the genetic algo... more This paper compares the performance of a group of intelligent algorithms such as the genetic algorithm (GA), particle swarm optimization (PSO), and repulsive particle swarm optimization (RPSO) based on the optimization of thermo-economic indicators such as the payback period (PBP), the levelized energy cost (LEC), the specific investment cost (SIC), and also in the optimization of the thermodynamic process (net power output) of an energy recovery system in a 2 MW natural gas internal combustion engine based on an organic Rankine cycle. Four parameters were considered to analyze and compare the performance of these algorithms: integral of squared error (ISE), integral of absolute error (IAE), integral of time-weighted absolute error (ITAE), and the integral of time-weighted squared error (ITSE). Analyses of variances (ANOVA) were proposed for each of the parameters studied. The PSO and RPSO algorithms presented the best performance in terms of the mean and the standard deviation of t...
Contemporary Engineering Sciences, 2018
This paper shows the application of a software tool to promote the significant learning in refrig... more This paper shows the application of a software tool to promote the significant learning in refrigeration cycles in undergraduate engineering students through case studies. To solve the case studies the tool calculates in MATLAB® the thermodynamic states and energy balances of the simple vapor refrigeration cycle, the cascade, multi-stage, and absorption refrigeration cycle. In the case of a simple refrigeration system, a proportional behavior between the COP and the compressor's work was obtained as a function of the outlet temperature of the evaporator for compressor efficiencies of 100%, 80%, and 60%. In the case of the cascade refrigeration system, the behavior of both the energy consumed by the compressor and the thermal efficiency of the cycle is explained by the pressure at the inlet of the high compressor. In the multi-stage refrigeration cycle, the variation in the pressure of the flash chamber and the compressor efficiency did not affect the vapor fraction. Finally, the case studies obtained through the program facilitate the understanding of thermodynamic phenomena in refrigeration systems, which normally in a traditional classroom would require time and educational resources for their learning.
Contemporary Engineering Sciences, 2018
In this work, the hydraulic and energetic performance of a centrifugal pump is studied in CFD (Co... more In this work, the hydraulic and energetic performance of a centrifugal pump is studied in CFD (Computational Fluid Dynamics), to achieve optimization in its performance through a parametric analysis. Variations were made in pump parameters such as diameter, number of blades and speed of rotation, to study their influence over the general performance of the pump, by using a CFD package; the results obtained were validated in a test bench, to guarantee the prediction capacity of the simulations. In the same way, a theoretical analysis was carried out, comparing the results with the Euler equation and corrections with Stodola equation. An analysis of mesh independence was carried out, to optimize the simulation process and computational resources. The results allowed to conclude that the reduction in the thickness of the pump casing, which has the effect of a larger diameter of the impeller, leads to an increase in the effective head of the pump; similar results are obtained with the increase in the number of blades and the 1350 Jorge Duarte et al. increase in the speed of rotation, although in the latter case, it is less accentuated due to the reduction in volumetric efficiency.
Contemporary Engineering Sciences, 2018
This paper presents a two-dimensional movement analysis and the forces acting on a slider-crank m... more This paper presents a two-dimensional movement analysis and the forces acting on a slider-crank mechanism by applying the Lagrangian approach, to develop a mathematical model for the complete description of the kinetic and kinematics of the mechanism. The aim of the research is restricted to a specific scenario: the determination of the force exerted by the slider, which becomes an important parameter in positive displacement machines (such as for compressors and pumps), and acquires greater value in the study of internal combustion engines (ICE). From the Lagrangian analysis, partial differential equations are obtained, relating the force generated by the slider, with three variables: The crank angular position, its variation concerning time-angular velocity-and the angular acceleration. The results show the Lagrangian analysis as a useful methodology of kinetic analysis, which can be used to design processes to find economical options for the manufacture of machines (mainly ICE) that meet the specifications from the kinetic point of view, with reduced losses.
Chemical engineering transactions, 2018
The undeniable importance of industrial distillation has motivated hundreds, if not thousands of ... more The undeniable importance of industrial distillation has motivated hundreds, if not thousands of theoretical and applied research projects. A considerable amount of those projects has used a bench or pilot scale distillation columns to have experimental confirmation of the proposed innovations. Nevertheless, the automatic control of bench scale distillation columns is not as straightforward as it appears to be, due to the low magnitude of the involved material flows. To precisely manipulate low magnitude flows, special low flow control valves are necessary; this results in high instrumentation costs which are not desirable at bench nor pilot scale. This work treats the simulation and control of a low cost, bench scale column with an electrically heated reboiler and water-cooled condenser. It uses a version of an on-off valve as an actuator to control the distillate composition of the desired product. The use of a solenoid valve results in a discontinuous reflux flow, which changes t...
Chemical engineering transactions, 2018
The use of heat exchangers on extended surfaces has obtained high importance in the last years du... more The use of heat exchangers on extended surfaces has obtained high importance in the last years due to their high implementation in industrial processes, computer systems, refrigerators, electronic equipment, etc. It implies the use of computer technology to have a better comprehension of the phenomena that involve heat transfer in finned surfaces to design new prototypes with high efficiency. There are lots of parameters to consider when designing fins such as their geometry and the type of material making the design highly complex. Also, a selection of adequate fins requires knowledge of temperature distributions through them, which will depend on the properties of the fin material. In this article, it is presented the study of the energy transfer and effectiveness in Extended Surfaces using an educational graphical user interface developed in Matlab as a pedagogical strategy to promote the significant learning in engineering. The program uses the most important experimental correl...
Contenido 1. Introducción 2. Presentación del Software 3. Desarrollo de la guía teórico-práctica ... more Contenido 1. Introducción 2. Presentación del Software 3. Desarrollo de la guía teórico-práctica 4. Resultados y discusiones 5. Conclusiones Referencias Agradecimientos RESUMEN: El artículo presenta una interfaz gráfica de usuario desarrollada en Microsoft Visual Studio para la simulación de procesos de acondicionamiento de aire y el efecto significativo que tiene su implementación en el curso de termodinámica. Se tomó una muestra de los estudiantes de pregrado de ingeniería para implementar una prueba educativa en dos grupos, un grupo experimental y un grupo de control, donde se realizó una prueba previa para determinar el estado actual y una prueba posterior después de haber aplicado el tratamiento al grupo experimental. Para el grupo experimental, el tratamiento fue el desarrollo de unos casos de estudio basados en una guía teórica-practica con la ayuda de la herramienta computacional PSYCROSFAST, mientras que el grupo de control desarrollo la guía teórica-practica sin el programa. El programa permite a los estudiantes interactuar con el comportamiento de la temperatura de bulbo seco, humedad relativa, presión atmosférica, flujo volumétrico y flujo másico del agua implicada en los procesos de acondicionamiento de aire. Para evaluar estadísticamente la diferencia del rendimiento promedio entre los grupos en términos de claridad, precisión y pertinencia, se tomó una población de 60 estudiantes del grupo control y experimental y se realizó una prueba t, que permitió determinar con un nivel de significancia del 5%, la existencia de un efecto significativo al implementar el software como soporte en la enseñanza de los conceptos teóricos involucrados en los procesos de calentamiento y humidificación, enfriamiento y deshumidificación y torre de enfriamiento, promoviendo en los estudiantes el pensamiento crítico y aprendizaje significativo.
Chemical engineering transactions, 2018
In general heat transfer, which is the science that studies the rate of energy transfer, has an e... more In general heat transfer, which is the science that studies the rate of energy transfer, has an extensive working area ranging from biological systems to common household appliances, industrial processes, electronic devices, among others. For engineers, it is necessary to have a complete understanding of this phenomena to design the best equipment that gives the highest efficiency and save the maximum energy possible. Most of the study about heat transfer is addressed to the steady state because systems remain in that state most of the time. However, there are always perturbations that cause variability on the systems producing complications that require immediate attention by the implementation of control of processes. For that reason, it is necessary to know the dynamic behavior of the systems by understanding their transient state. In heat transfer, these systems are designed with different shapes that can be sectioned and studied separately with the use of the common configurati...
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2020
Air conditioning is an essential topic in heat transfer phenomena because it is widely applied in... more Air conditioning is an essential topic in heat transfer phenomena because it is widely applied in homes and industries. It has an incredible amount of applications ranging from health care to food shelf life. With the enhancement of technology, it is necessary to create new devices that increase the efficiency of air conditioning. Hence, it is required to evaluate the trend of study of this topic to help researchers to get the best research direction that promotes the acquisition of better experimental results. For that reason, it was collected a total of 2431 documents about air conditioning from the Science Citation Index Expanded during the period from 2008 to 2019. Next, it was used HistCite to analyze the yearly output, country, institution, citation impact, and citation relationships in this field of study. Results suggest that the research of air conditioning had an increase during the studied 11-year period. The countries with the highest research output were China, The USA, and Japan, and the institutions with the highest research output were the National Natural Science Foundation of China and the Hong Kong Polytech University. The journals with the largest number of articles were Energy and Buildings with 195 publications and Applied Thermal engineering with 164 papers.
Contemporary Engineering Sciences, 2018
In this work, a series of statistical methods were applied in order to characterize the influence... more In this work, a series of statistical methods were applied in order to characterize the influence of operation variables in the energetic performance of industrial-scale milling processes. To do so, a certain set of factors were evaluated, to estimate the correlation degree between these and the energetic consumption rate, which is the most used indicator of energy efficiency. Due to the quantity and level of complexity of the operations involved, statistical package Minitab® was used, being its application an easy way to establish statistical criteria to evaluate the influence of said variables. The results obtained, show that from the set of variables studied, only two (the energy and the production), have a degree of correlation enough to be taken in account into post processing operations; though the behavior of these operation variables differ considerably from each other, the statistical analysis done remarks their influence on the consumption rate using correlation processes, and therefore, this study acts as a basis to future optimization processes that contribute to improve the overall performance of milling operations.
Contemporary Engineering Sciences, 2018
With the aim to enhance the learning process of the unit operation of Leaching, it is presented a... more With the aim to enhance the learning process of the unit operation of Leaching, it is presented a GUI in Matlab® for designing systems with different types of contact where the stages reach the equilibrium between the solid and liquid phase. The program called LeachING is an application of theoretical studies and material balances presented in highly relevant documents and popular academic books, which has a general procedure that initiates by introducing the feed and solvent quantities with their respective compositions, and a raffinate exit condition for multistage equipment. Finally, material balances and multiple iterative routines were used to calculate raffinate and extract exit conditions, and the minimum number of stages necessary to reach them, allowing the user to get the approximate size and cost of the equipment making this software a powerful academic tool. With the program, it was compared the maximum separation for given conditions between countercurrent and crosscurrent equipment, the behavior of the percentage of separation when increasing feeding with constant solvent, and the behavior of the maximum feeding for the different types of contact.
Contemporary Engineering Sciences, 2018
In this work, the kinetic and kinematic variables of serial-driven planar manipulators (also know... more In this work, the kinetic and kinematic variables of serial-driven planar manipulators (also known as RR planar manipulators) were studied to achieve optimization in its performance through a parametric analysis. To do so, the equations that define the behavior of these mechanisms were programmed using the Octave software package, and some variations were made in input parameters, such as torque and forces, to study their influence on the kinetic parameters of the mechanism; to validate the obtained results, these were compared with the analytical solution, to guarantee the prediction capacity of the simulations. The results obtained by using the simulation package shared the same behavior as the results obtained through the application of the theoretical model, with a little deviation from the theoretical results (less than 3%). Besides that, the program code allowed to obtain results to a higher speed than the solution of theoretical equations (harder to solve at hand) with the same accuracy, which is an important parameter when optimization processes are required.
Contemporary Engineering Sciences, 2018
As the years go by, the growing interest of nations in energy generation becomes more evident. Fo... more As the years go by, the growing interest of nations in energy generation becomes more evident. For this reason, this paper presents a study in which an exergetic analysis and the study of the variation of thermal efficiency for a Brayton cycle with regeneration was carried out, varying parameters such as the compression ratio. A spreadsheet was used to study a gas power cycle, an ideal Brayton regeneration cycle with a turbine, a compressor, a regenerator and a combustion chamber which delivers the heat input to the system, finding that if you want to improve the thermal efficiency of a gas power engine using an ideal brayton regeneration cycle you should consider or take into account what has been proposed and demonstrated in this research as a way to achieve this objective, Also thanks to the exergetic analysis that was carried out on the cycle in question, this research can be considered to take action on the components that most destroy useful energy potential. 3566 Guillermo E. Valencia et al.