Jaime Gros - Academia.edu (original) (raw)
Papers by Jaime Gros
The University of Zaragoza through CIRCE, the New Enterprise foundation, an Opel foundation and t... more The University of Zaragoza through CIRCE, the New Enterprise foundation, an Opel foundation and the local Government of Aragon have been developed a program to introduce the Stirling Engine as a low cost tool to educate students in mechanical engineering. The promotion of a prize like GNAT Power organized by the magazine Model Engineer in London, has improved the practical education of students in the field of mechanical devices and thermal engines. Two editions of the contest, 1993 and 1994, awarded the greatest power Stirling engine made by only using a little candle of paraffin as a heat source. Four engines were presented in the first edition, with an average power of about 100 mW, and seven engines in the second one, achieving a power of about 230 mW. Presentations in Technical Schools and the University have been carried out. Also low cost tools have been made for measuring an electronic device to draw the real internal pressure volume diagram using a PC. A very didactic softw...
Energies, 2019
Stirling-like thermoacoustic generators are external combustion engines that provide useful acous... more Stirling-like thermoacoustic generators are external combustion engines that provide useful acoustic power in the absence of moving parts with high reliability and respect for the environment. The study of these systems involves a great complexity since the parameters that describe them, besides being numerous, present a high degree of coupling between them. This implies a great difficulty in characterizing the effects of any parametric variation on the performance of these devices. Due to the huge amount of data to analyze, the experiments and simulations required to address the problem involve high investments in time and resources, sometimes unaffordable. This article presents, how a sensitivity analysis applying the response surface methodology can be applied to optimize the feedback branch of a thermoacoustic Stirling-like engine. The proposed study is made by evaluating the comparative relevance of seven design variables. The dimensional reduction process identifies three sign...
Machines
The equations governing energy conversion in traveling wave thermoacoustic machines are affected ... more The equations governing energy conversion in traveling wave thermoacoustic machines are affected by their multiphysics nature. Their theoretical study is complicated and, in order to obtain real results, it is necessary to resort to prototypes and experimental tests. This work presents the theoretical–experimental study of a thermoacoustic Stirling engine in which, by altering some of its critical parts and analysing the experimental result, it is possible to improve its performance. The methodology used is based on the study and modelling of the active and reactive acoustic power flow for the improvement of the output power of the thermoacoustic engine. The work and analysis are illustrated through the instrumentation of a thermoacoustic Stirling engine with three different feedbacks. The present work presents the experimental results obtained in all cases, including their parameters, experimental data and analysis. The results are compared with the virtual computational models, al...
Alexandria Engineering Journal, 2020
The analysis of thermoacoustic engines and the equations that describe the internal physical phen... more The analysis of thermoacoustic engines and the equations that describe the internal physical phenomena are far from simple. Previous studies on energetic characterisation of thermoacoustic engines are based only on the determination of the active acoustic power flow distribution. In this paper, another variable, known as the reactive acoustic power, is additionally estimated and studied. This article proposes a simple method which is based on the combination of both active and reactive acoustic power flow for the evaluation and optimisation of thermoacoustic Stirling engines. In addition the paper illustrates the method using a thermoacoustic Stirling engine demonstrator design which is able to fit three different feedback branches. The results show that the amount of reactive acoustic power supplied towards the core branch differs depending on the specifications of the selected feedback branch. Besides, the amount of reactive acoustic power distributed towards the core branch is a good indicator of the grade of traveling-wave phasing. An improvement of 16.4% in the active acoustic power towards the extraction branch is achieved and besides, the amplification of the active acoustic power through the core branch has increased by 12%. The method can serve as an effective tool to study and optimise thermoacoustic devices.
E3S Web of Conferences
The work focuses on the theoretical study and design of Thermoacoustic Stirling-Like Cycle Engine... more The work focuses on the theoretical study and design of Thermoacoustic Stirling-Like Cycle Engines. One of the main goals of this study is to describe the application of a methodology for energy analysis and optimization of thermoacoustic devices. This new approach avoids complicated mathematical treatments, facilitates access to this fascinating technology for all audiences. The presented methodology is based on the distribution of the active and reactive acoustic power flow according to the passive acoustic circuit. In addition, this methodology allows optimizing the device by comparing different acoustic circuits. This method is evaluated at a theoretical level with the models and simulations developed, for each of the case studies described. Besides, this publication shows the praxis from the first steps, so the reader is guided in the design and manufacture of a compact Stirling thermoacoustic energy recovery engine, operating in laboratory conditions. The resulting demonstrato...
The University of Zaragoza through CIRCE, the New Enterprise foundation, an Opel foundation and t... more The University of Zaragoza through CIRCE, the New Enterprise foundation, an Opel foundation and the local Government of Aragon have been developed a program to introduce the Stirling Engine as a low cost tool to educate students in mechanical engineering. The promotion of a prize like GNAT Power organized by the magazine Model Engineer in London, has improved the practical education of students in the field of mechanical devices and thermal engines. Two editions of the contest, 1993 and 1994, awarded the greatest power Stirling engine made by only using a little candle of paraffin as a heat source. Four engines were presented in the first edition, with an average power of about 100 mW, and seven engines in the second one, achieving a power of about 230 mW. Presentations in Technical Schools and the University have been carried out. Also low cost tools have been made for measuring an electronic device to draw the real internal pressure volume diagram using a PC. A very didactic softw...
Energies, 2019
Stirling-like thermoacoustic generators are external combustion engines that provide useful acous... more Stirling-like thermoacoustic generators are external combustion engines that provide useful acoustic power in the absence of moving parts with high reliability and respect for the environment. The study of these systems involves a great complexity since the parameters that describe them, besides being numerous, present a high degree of coupling between them. This implies a great difficulty in characterizing the effects of any parametric variation on the performance of these devices. Due to the huge amount of data to analyze, the experiments and simulations required to address the problem involve high investments in time and resources, sometimes unaffordable. This article presents, how a sensitivity analysis applying the response surface methodology can be applied to optimize the feedback branch of a thermoacoustic Stirling-like engine. The proposed study is made by evaluating the comparative relevance of seven design variables. The dimensional reduction process identifies three sign...
Machines
The equations governing energy conversion in traveling wave thermoacoustic machines are affected ... more The equations governing energy conversion in traveling wave thermoacoustic machines are affected by their multiphysics nature. Their theoretical study is complicated and, in order to obtain real results, it is necessary to resort to prototypes and experimental tests. This work presents the theoretical–experimental study of a thermoacoustic Stirling engine in which, by altering some of its critical parts and analysing the experimental result, it is possible to improve its performance. The methodology used is based on the study and modelling of the active and reactive acoustic power flow for the improvement of the output power of the thermoacoustic engine. The work and analysis are illustrated through the instrumentation of a thermoacoustic Stirling engine with three different feedbacks. The present work presents the experimental results obtained in all cases, including their parameters, experimental data and analysis. The results are compared with the virtual computational models, al...
Alexandria Engineering Journal, 2020
The analysis of thermoacoustic engines and the equations that describe the internal physical phen... more The analysis of thermoacoustic engines and the equations that describe the internal physical phenomena are far from simple. Previous studies on energetic characterisation of thermoacoustic engines are based only on the determination of the active acoustic power flow distribution. In this paper, another variable, known as the reactive acoustic power, is additionally estimated and studied. This article proposes a simple method which is based on the combination of both active and reactive acoustic power flow for the evaluation and optimisation of thermoacoustic Stirling engines. In addition the paper illustrates the method using a thermoacoustic Stirling engine demonstrator design which is able to fit three different feedback branches. The results show that the amount of reactive acoustic power supplied towards the core branch differs depending on the specifications of the selected feedback branch. Besides, the amount of reactive acoustic power distributed towards the core branch is a good indicator of the grade of traveling-wave phasing. An improvement of 16.4% in the active acoustic power towards the extraction branch is achieved and besides, the amplification of the active acoustic power through the core branch has increased by 12%. The method can serve as an effective tool to study and optimise thermoacoustic devices.
E3S Web of Conferences
The work focuses on the theoretical study and design of Thermoacoustic Stirling-Like Cycle Engine... more The work focuses on the theoretical study and design of Thermoacoustic Stirling-Like Cycle Engines. One of the main goals of this study is to describe the application of a methodology for energy analysis and optimization of thermoacoustic devices. This new approach avoids complicated mathematical treatments, facilitates access to this fascinating technology for all audiences. The presented methodology is based on the distribution of the active and reactive acoustic power flow according to the passive acoustic circuit. In addition, this methodology allows optimizing the device by comparing different acoustic circuits. This method is evaluated at a theoretical level with the models and simulations developed, for each of the case studies described. Besides, this publication shows the praxis from the first steps, so the reader is guided in the design and manufacture of a compact Stirling thermoacoustic energy recovery engine, operating in laboratory conditions. The resulting demonstrato...