Jorge Hiroshi Kurita Nagasawa - Academia.edu (original) (raw)
Papers by Jorge Hiroshi Kurita Nagasawa
Este trabajo trata sobre el uso de las plataformas estratosféricas como herramienta integradora d... more Este trabajo trata sobre el uso de las plataformas estratosféricas como herramienta integradora de las ciencias, la educación y la investigación. Tal abordaje es debido al poco interés y desarrollo científico, tecnológico, de investigación y educación ligado al estudio aeroespacial en el Paraguay. Este trabajo busca como fines vincular dos necesidades aparentemente disímiles, pero fuertemente ligadas: la expansión de la investigación científica en el Paraguay y la de despertar en los jóvenes el interés por la ciencia y la tecnología. Con esos fines, se pretende llevar a cabo investigaciones, talleres, capacitaciones y concursos, que establezcan nuevas experiencias científicas y la aplicación de innovadores métodos educativos en estudiantes de diferentes puntos del país. Este propósito fue conseguido mediante la aplicación de las tendencias pedagógicas dinámicas, proactivas en el proceso, como el aprendizaje basado en proyectos, el aprendizaje cooperativo, la educación emocional, el pensamiento visual y de diseño, el pensamiento críticoconstructivo y las tendencias tecno-creativas alentando a los estudiantes a diseñar, construir, probar, operar y procesar datos de las plataformas. Como resultado del éxito de este programa, al apoyar la educación STEAM, el gobierno local inició el proceso para incluir la Educación
Bulletin of the American Physical Society, Nov 23, 2009
Reported experimental and computational results confirm that both the flow features and heat tran... more Reported experimental and computational results confirm that both the flow features and heat transfer rates inside a condenser depend on the specification of inlet, wall, and exit conditions. The results show that the commonly occuring condensing flows' special sensitivity to changes in exit conditions (i.e. changes in exit pressure) arise from the ease with which these changes alter the vapor flow field in the interior. When exit pressure is changed from one steady value to another, the changes required of the interior vapor flow towards achieving a new steady flow are such that they do not demand removal of the new exit pressure imposition back to the original steady value-as is the case for incompressible single phase flows with an original and "required" exit pressure. Instead, new steady flows may be achieved through appropriate changes in the vapor/liquid interfacial configurations and associated changes in interfacial mass, heat transfer rates (both local and overall), and other flow variables. This special feature of these fows is for the commonly occurring large heat sink situations for which the condensing surface temperature (not heat flux) remain approximately the same for any given set of inlet conditions while exit condition changes. In this paper's context of flows of a pure vapor that experience film condensation on the inside walls of a vertical tube, the reported results provide important quantitative and qualitative understanding as well as exit-condition based categorization of the flows. Experimental results and selected relevant computational results that are presented here reinforce the fact that there exist multiple steady solutions (with different heat transfer rates) for multiple steady prescriptions of the exit-conditioneven though the other boundary conditions do not change. However for some situations that do not fix any specific value for the exit condition (say exit pressure) but allow the flow the freedom to choose any exit pressure value within a certain range, experiments confirm the computational results that, given enough time, there typically exists, under normal gravity conditions, a self selected "natural" steady flow with a "natural" exit condition. This happens if the vapor flow is seeking (or attracted to) a specific exit condition and the conditions downstream of the condenser allow the vapor flow a range of exit conditions that includes the specific "natural" exit condition of choice. However, for some unspecified exit condition cases involving partial condensation, even if computations predict that a "natural" exit condition choice exists, the experimental arrangement employed here does not allow the flow to approach its steady "natural" exit condition value and, instead, it only allows oscillatory exit conditions leading to an oscillatory flow. For the reported experiments, these oscillatory pressures are induced and imposed by the instabilities in the system components downstream of the condenser.
Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering
Toxic gasses generated as a result of landfill fire are a big concern to human health, especially... more Toxic gasses generated as a result of landfill fire are a big concern to human health, especially in heavily populated urban areas. Such a situation occurred on September 25, 2020, at the country’s main landfill situated in Asuncion city, the most populated urban area in Paraguay. This is a recurrent situation, two days later; another fire started at the same landfill. It took 12 hours to control the fire. This event generated a plume of toxic smoke that spread through the urban area. This caused severe respiratory problems to the citizens living in the surrounding buildings. This work is a case study on the analysis of the smoke plume spreading from this landfill in an eventual fire in different wind directions. The main goal was to conduct computational fluid dynamics CFD simulation to be able to map the risk zone on this surrounding urban area. In order to validate this simulation, it was important to replicate this toxic cloud flow by conducting a computational fluid dynamics CF...
Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering
Evidence of a Non-Newtonian behavior of automatic transmission fluid at sub-zero conditions was p... more Evidence of a Non-Newtonian behavior of automatic transmission fluid at sub-zero conditions was presented by several authors such as Khalil et. al. Accurate viscosity data of this fluid at cold conditions are critical, especially in the very competitive automotive industry. The proper design of a transmission fluid filter, this is, the calculation of the effective area of filtration media, depends heavily on this information. Technical difficulties of viscosity measurements by different shear rates at subzero conditions are driven by its cost and accuracy. In order to solve this issue, here is presented an alternative indirect viscosity measurement. By assuming Darcy’s law behavior on a fluid flow through a simple single flat sheet media configuration, for a given temperature and shear rate, apparent viscosity was calculated. This paper shows a correlation between Computational Fluid Dynamics (CFD) results and Test data. Effective shear rates in the porous media were obtained from f...
26th AIAA Aerodynamic Decelerator Systems Technology Conference
Volume 10: Fluids Engineering, 2021
The COVID 19 pandemic has struck the global economy and slowed down human activity. Paraguay, a s... more The COVID 19 pandemic has struck the global economy and slowed down human activity. Paraguay, a small South-American country, was not an exception. This work results from the urgent need to reopen universities, schools, and other academic institutions to resume teaching activities in light of restrictive access to online learning in Paraguay. In order to contain the spread of this virus, school activities such as course lectures were placed on hold indefinitely. Inappropriate airflow in an enclosed space is one of the main factors in the spread of this virus. When combined with personal protective equipment, proper air ventilation and air replacement can significantly reduce this airborne virus’s spread. Potential sources of contaminant accumulation are stagnant locations of air in a closed volume. It is, therefore, essential to first identify these hot spots. Utilizing computational tools, such as CFD, an airflow analysis can be conducted to see any potential stagnant point. In the...
Bulletin of the American Physical Society, 2009
2019 ASEE Annual Conference & Exposition Proceedings
Oscar Matías González Chamorro was born in Caaguazu city. He is a sophomore electromechanical eng... more Oscar Matías González Chamorro was born in Caaguazu city. He is a sophomore electromechanical engineering student from the School of Engineering at Universidad Nacional de Asuncion. Oscar currently works as a teaching assistant and a junior researcher. He also collaborates with the Paraguay Space Agency (AEP) and, the Aerospace Research Group (GADI) from the Polytechnic School at Universidad Nacional de Asuncion. In 2017 he has participated in the first round of Paraguay Science Clubs, a Scientific Enterprise Initiative workshop developed by the Benjamin Franklin Science Corner. Oscar mainly stands out for its leadership and talent in the development of community projects. He is the General Coordinator of a project called PROYECTO ARAPY-GLOBO SONDA PARAGUAY. He was awarded the Outstanding Young of the City of Caaguazú award in the year 2017. He was the winner of TOYP JCI CDE, Ten Outstanding Young Persons organized by the Junior International Chamber, in the category of scientific and technological development in 2018. The ARAPY Project intends to carry out aerospace explorations in different parts of the country with the use of the High Altitude Balloons (HAB). The purpose is to support the development of technology and science exploration processes, scientific research and education. Arapy project purpose is to spark awareness to young Paraguayan students in scientific research, to motivate the interest in science and technology. With these objectives, Arapy project carried out workshops, trainings and competitions, in rural community schools, to allow them experience scientific and innovative teaching methods.
2020 ASEE Virtual Annual Conference Content Access Proceedings
in Paraguay, where he got his BS in Electromechanical Engineering. After graduation, he spent som... more in Paraguay, where he got his BS in Electromechanical Engineering. After graduation, he spent some time in academia working as faculty. During this tenure he taught courses on heat transfer, fluid mechanics and physics. In 2004 Dr. Kurita was granted the Fulbright scholarship to attend a graduate program on Mechanical Engineering at Michigan Technological University. He has finished his MS and then continued with a doctorate program. His doctorate research was funded by NASA and the NSF. Dr. Kurita's contribution to his field was well published in several papers from high impact journals. From 2011 Dr. Kurita worked as a development engineer II, in the competitive automotive industry, Filtran LLC, located in Des Plaines Illinois. His experience as an experimental researcher helped Filtran to develop special testing techniques never implemented before on filtration systems. In addition, Dr. Kurita worked in the CAE group, contributing to develop simulation techniques to help develop state of the art filtration systems. From 2016 Dr. Kurita is back to his alma mater as an assistant professor in Universidad Nacional de Asuncion. Later the same year, he is appointed to lead the research department of the School of Engineering. From 2017 he is appointed to be the head of the Mechanical Engineering Department at Universidad Nacional de Asuncion. He is currently working as the director of the Planning Directorate of the Paraguayan Space Agency. For his contributions to the Paraguayan society in the field of science and engineering, he was acknowledged as the "Exceptional Protagonist of 2017" by the Ultimahora news, a major newspaper in Paraguay. Another distinction, the "Outstanding Citizen Award," was granted by the city council of the city of Asuncion in 2017.
Preliminary experimental flow regime types have been observed for partial and full condensation i... more Preliminary experimental flow regime types have been observed for partial and full condensation in a horizontal channel of millimeter scale. Effects of hydrostatic pooling, wall vibrations, vapor flow pulsations, and solid-liquid-vapor contact on the top surface of the condenser are observed. Wave phenomena such as wave reflection, standing waves, and waves on the interface of vapor bubbles are presented in 2 and 3 dimensions. Due to the high density and low kinematic viscosity of the liquid phase of the fluid (perfluorohexane), the effects observed are primarily inertial. It is found that in these flows pressure pulsation and surface tension effects very strongly influence the morphology of the interface where it contacts the top wall. Wall vibrations contribute to standing waves on the interface. This investigation outlines some of the types of flow one might expect to encounter in a millimeter scale horizontal condenser with wall vibration and pressure pulsation where inertial ef...
ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 2, 2009
This paper presents computational simulations for internal condensing flows over a range of tube/... more This paper presents computational simulations for internal condensing flows over a range of tube/channel geometries ranging from one micro-meter to several millimeters in hydraulic diameters. Over the mm-scale, three sets of condensing flow results are presented that ...
Experimental Thermal and Fluid Science, 2011
In the present experimental study, condensation of steam inside helically coiled tubes was invest... more In the present experimental study, condensation of steam inside helically coiled tubes was investigated. Three helical coils of coil diameter 110, 135 and 160 mm were tested. The effect of mass flux, coil curvature ratio and temperature difference between steam and tube inner wall on the condensation heat transfer coefficient were analysed. The condensation heat transfer coefficient increases with the increase in the value of mass flux. Temperature difference has substantial effect on the heat transfer coefficient. For the first time, the effect of coil curvature ratio on condensation heat transfer is studied and discussed in the paper. It is found that helical coil having greater coil curvature ratio has high values of condensation heat transfer coefficient in comparison to a low curvature ratio. Experimental results are compared with the work of earlier investigators. A new empirical correlation is developed to predict the condensation heat transfer coefficient.
Proceeding of 5-6th Thermal and Fluids Engineering Conference (TFEC), 2021
Proceeding of Second Thermal and Fluids Engineering Conference, 2017
Este trabajo trata sobre el uso de las plataformas estratosféricas como herramienta integradora d... more Este trabajo trata sobre el uso de las plataformas estratosféricas como herramienta integradora de las ciencias, la educación y la investigación. Tal abordaje es debido al poco interés y desarrollo científico, tecnológico, de investigación y educación ligado al estudio aeroespacial en el Paraguay. Este trabajo busca como fines vincular dos necesidades aparentemente disímiles, pero fuertemente ligadas: la expansión de la investigación científica en el Paraguay y la de despertar en los jóvenes el interés por la ciencia y la tecnología. Con esos fines, se pretende llevar a cabo investigaciones, talleres, capacitaciones y concursos, que establezcan nuevas experiencias científicas y la aplicación de innovadores métodos educativos en estudiantes de diferentes puntos del país. Este propósito fue conseguido mediante la aplicación de las tendencias pedagógicas dinámicas, proactivas en el proceso, como el aprendizaje basado en proyectos, el aprendizaje cooperativo, la educación emocional, el pensamiento visual y de diseño, el pensamiento críticoconstructivo y las tendencias tecno-creativas alentando a los estudiantes a diseñar, construir, probar, operar y procesar datos de las plataformas. Como resultado del éxito de este programa, al apoyar la educación STEAM, el gobierno local inició el proceso para incluir la Educación
Bulletin of the American Physical Society, Nov 23, 2009
Reported experimental and computational results confirm that both the flow features and heat tran... more Reported experimental and computational results confirm that both the flow features and heat transfer rates inside a condenser depend on the specification of inlet, wall, and exit conditions. The results show that the commonly occuring condensing flows' special sensitivity to changes in exit conditions (i.e. changes in exit pressure) arise from the ease with which these changes alter the vapor flow field in the interior. When exit pressure is changed from one steady value to another, the changes required of the interior vapor flow towards achieving a new steady flow are such that they do not demand removal of the new exit pressure imposition back to the original steady value-as is the case for incompressible single phase flows with an original and "required" exit pressure. Instead, new steady flows may be achieved through appropriate changes in the vapor/liquid interfacial configurations and associated changes in interfacial mass, heat transfer rates (both local and overall), and other flow variables. This special feature of these fows is for the commonly occurring large heat sink situations for which the condensing surface temperature (not heat flux) remain approximately the same for any given set of inlet conditions while exit condition changes. In this paper's context of flows of a pure vapor that experience film condensation on the inside walls of a vertical tube, the reported results provide important quantitative and qualitative understanding as well as exit-condition based categorization of the flows. Experimental results and selected relevant computational results that are presented here reinforce the fact that there exist multiple steady solutions (with different heat transfer rates) for multiple steady prescriptions of the exit-conditioneven though the other boundary conditions do not change. However for some situations that do not fix any specific value for the exit condition (say exit pressure) but allow the flow the freedom to choose any exit pressure value within a certain range, experiments confirm the computational results that, given enough time, there typically exists, under normal gravity conditions, a self selected "natural" steady flow with a "natural" exit condition. This happens if the vapor flow is seeking (or attracted to) a specific exit condition and the conditions downstream of the condenser allow the vapor flow a range of exit conditions that includes the specific "natural" exit condition of choice. However, for some unspecified exit condition cases involving partial condensation, even if computations predict that a "natural" exit condition choice exists, the experimental arrangement employed here does not allow the flow to approach its steady "natural" exit condition value and, instead, it only allows oscillatory exit conditions leading to an oscillatory flow. For the reported experiments, these oscillatory pressures are induced and imposed by the instabilities in the system components downstream of the condenser.
Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering
Toxic gasses generated as a result of landfill fire are a big concern to human health, especially... more Toxic gasses generated as a result of landfill fire are a big concern to human health, especially in heavily populated urban areas. Such a situation occurred on September 25, 2020, at the country’s main landfill situated in Asuncion city, the most populated urban area in Paraguay. This is a recurrent situation, two days later; another fire started at the same landfill. It took 12 hours to control the fire. This event generated a plume of toxic smoke that spread through the urban area. This caused severe respiratory problems to the citizens living in the surrounding buildings. This work is a case study on the analysis of the smoke plume spreading from this landfill in an eventual fire in different wind directions. The main goal was to conduct computational fluid dynamics CFD simulation to be able to map the risk zone on this surrounding urban area. In order to validate this simulation, it was important to replicate this toxic cloud flow by conducting a computational fluid dynamics CF...
Volume 8: Fluids Engineering; Heat Transfer and Thermal Engineering
Evidence of a Non-Newtonian behavior of automatic transmission fluid at sub-zero conditions was p... more Evidence of a Non-Newtonian behavior of automatic transmission fluid at sub-zero conditions was presented by several authors such as Khalil et. al. Accurate viscosity data of this fluid at cold conditions are critical, especially in the very competitive automotive industry. The proper design of a transmission fluid filter, this is, the calculation of the effective area of filtration media, depends heavily on this information. Technical difficulties of viscosity measurements by different shear rates at subzero conditions are driven by its cost and accuracy. In order to solve this issue, here is presented an alternative indirect viscosity measurement. By assuming Darcy’s law behavior on a fluid flow through a simple single flat sheet media configuration, for a given temperature and shear rate, apparent viscosity was calculated. This paper shows a correlation between Computational Fluid Dynamics (CFD) results and Test data. Effective shear rates in the porous media were obtained from f...
26th AIAA Aerodynamic Decelerator Systems Technology Conference
Volume 10: Fluids Engineering, 2021
The COVID 19 pandemic has struck the global economy and slowed down human activity. Paraguay, a s... more The COVID 19 pandemic has struck the global economy and slowed down human activity. Paraguay, a small South-American country, was not an exception. This work results from the urgent need to reopen universities, schools, and other academic institutions to resume teaching activities in light of restrictive access to online learning in Paraguay. In order to contain the spread of this virus, school activities such as course lectures were placed on hold indefinitely. Inappropriate airflow in an enclosed space is one of the main factors in the spread of this virus. When combined with personal protective equipment, proper air ventilation and air replacement can significantly reduce this airborne virus’s spread. Potential sources of contaminant accumulation are stagnant locations of air in a closed volume. It is, therefore, essential to first identify these hot spots. Utilizing computational tools, such as CFD, an airflow analysis can be conducted to see any potential stagnant point. In the...
Bulletin of the American Physical Society, 2009
2019 ASEE Annual Conference & Exposition Proceedings
Oscar Matías González Chamorro was born in Caaguazu city. He is a sophomore electromechanical eng... more Oscar Matías González Chamorro was born in Caaguazu city. He is a sophomore electromechanical engineering student from the School of Engineering at Universidad Nacional de Asuncion. Oscar currently works as a teaching assistant and a junior researcher. He also collaborates with the Paraguay Space Agency (AEP) and, the Aerospace Research Group (GADI) from the Polytechnic School at Universidad Nacional de Asuncion. In 2017 he has participated in the first round of Paraguay Science Clubs, a Scientific Enterprise Initiative workshop developed by the Benjamin Franklin Science Corner. Oscar mainly stands out for its leadership and talent in the development of community projects. He is the General Coordinator of a project called PROYECTO ARAPY-GLOBO SONDA PARAGUAY. He was awarded the Outstanding Young of the City of Caaguazú award in the year 2017. He was the winner of TOYP JCI CDE, Ten Outstanding Young Persons organized by the Junior International Chamber, in the category of scientific and technological development in 2018. The ARAPY Project intends to carry out aerospace explorations in different parts of the country with the use of the High Altitude Balloons (HAB). The purpose is to support the development of technology and science exploration processes, scientific research and education. Arapy project purpose is to spark awareness to young Paraguayan students in scientific research, to motivate the interest in science and technology. With these objectives, Arapy project carried out workshops, trainings and competitions, in rural community schools, to allow them experience scientific and innovative teaching methods.
2020 ASEE Virtual Annual Conference Content Access Proceedings
in Paraguay, where he got his BS in Electromechanical Engineering. After graduation, he spent som... more in Paraguay, where he got his BS in Electromechanical Engineering. After graduation, he spent some time in academia working as faculty. During this tenure he taught courses on heat transfer, fluid mechanics and physics. In 2004 Dr. Kurita was granted the Fulbright scholarship to attend a graduate program on Mechanical Engineering at Michigan Technological University. He has finished his MS and then continued with a doctorate program. His doctorate research was funded by NASA and the NSF. Dr. Kurita's contribution to his field was well published in several papers from high impact journals. From 2011 Dr. Kurita worked as a development engineer II, in the competitive automotive industry, Filtran LLC, located in Des Plaines Illinois. His experience as an experimental researcher helped Filtran to develop special testing techniques never implemented before on filtration systems. In addition, Dr. Kurita worked in the CAE group, contributing to develop simulation techniques to help develop state of the art filtration systems. From 2016 Dr. Kurita is back to his alma mater as an assistant professor in Universidad Nacional de Asuncion. Later the same year, he is appointed to lead the research department of the School of Engineering. From 2017 he is appointed to be the head of the Mechanical Engineering Department at Universidad Nacional de Asuncion. He is currently working as the director of the Planning Directorate of the Paraguayan Space Agency. For his contributions to the Paraguayan society in the field of science and engineering, he was acknowledged as the "Exceptional Protagonist of 2017" by the Ultimahora news, a major newspaper in Paraguay. Another distinction, the "Outstanding Citizen Award," was granted by the city council of the city of Asuncion in 2017.
Preliminary experimental flow regime types have been observed for partial and full condensation i... more Preliminary experimental flow regime types have been observed for partial and full condensation in a horizontal channel of millimeter scale. Effects of hydrostatic pooling, wall vibrations, vapor flow pulsations, and solid-liquid-vapor contact on the top surface of the condenser are observed. Wave phenomena such as wave reflection, standing waves, and waves on the interface of vapor bubbles are presented in 2 and 3 dimensions. Due to the high density and low kinematic viscosity of the liquid phase of the fluid (perfluorohexane), the effects observed are primarily inertial. It is found that in these flows pressure pulsation and surface tension effects very strongly influence the morphology of the interface where it contacts the top wall. Wall vibrations contribute to standing waves on the interface. This investigation outlines some of the types of flow one might expect to encounter in a millimeter scale horizontal condenser with wall vibration and pressure pulsation where inertial ef...
ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 2, 2009
This paper presents computational simulations for internal condensing flows over a range of tube/... more This paper presents computational simulations for internal condensing flows over a range of tube/channel geometries ranging from one micro-meter to several millimeters in hydraulic diameters. Over the mm-scale, three sets of condensing flow results are presented that ...
Experimental Thermal and Fluid Science, 2011
In the present experimental study, condensation of steam inside helically coiled tubes was invest... more In the present experimental study, condensation of steam inside helically coiled tubes was investigated. Three helical coils of coil diameter 110, 135 and 160 mm were tested. The effect of mass flux, coil curvature ratio and temperature difference between steam and tube inner wall on the condensation heat transfer coefficient were analysed. The condensation heat transfer coefficient increases with the increase in the value of mass flux. Temperature difference has substantial effect on the heat transfer coefficient. For the first time, the effect of coil curvature ratio on condensation heat transfer is studied and discussed in the paper. It is found that helical coil having greater coil curvature ratio has high values of condensation heat transfer coefficient in comparison to a low curvature ratio. Experimental results are compared with the work of earlier investigators. A new empirical correlation is developed to predict the condensation heat transfer coefficient.
Proceeding of 5-6th Thermal and Fluids Engineering Conference (TFEC), 2021
Proceeding of Second Thermal and Fluids Engineering Conference, 2017