An interferometric procedure is described for measuring the local surface temperature gradient directly from a wedge (finite) fringe field. For a two-dimensional temperature field, it is shown that the local convective heat transfer coefficient can be obtained by measuring the angle of intersection of a fringe with an isothermal surface. Using an uncertainty analysis it is shown that this method gives the most accurate results for the measurement of relatively low gradients. A correction term for refraction effects and an expression for the optimum wedge fringe spacing are also derived. Measurements of the natural convection from a vertical flat plate are compared to the boundary layer solution.
{"title":"A Technique for Direct Measurement of Local Convective Heat Flux Using Interferometry","authors":"D. Naylor, N. Duarte","doi":"10.1115/imece1999-1110","DOIUrl":"https://doi.org/10.1115/imece1999-1110","url":null,"abstract":"\u0000 An interferometric procedure is described for measuring the local surface temperature gradient directly from a wedge (finite) fringe field. For a two-dimensional temperature field, it is shown that the local convective heat transfer coefficient can be obtained by measuring the angle of intersection of a fringe with an isothermal surface. Using an uncertainty analysis it is shown that this method gives the most accurate results for the measurement of relatively low gradients. A correction term for refraction effects and an expression for the optimum wedge fringe spacing are also derived. Measurements of the natural convection from a vertical flat plate are compared to the boundary layer solution.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129880564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A transient method, based on an inverse heat conduction solution, for experimentally determining the distribution of local heat transfer rates on the surface of a body has been numerically evaluated. The particular interest is in situations in which the heat transfer coefficients are relatively low and in which there are relatively large changes in the heat transfer coefficient over the surface of the body being considered. In the method, a solid body of the shape being investigated, constructed from a low conductivity material, is heated to a uniform temperature and then exposed to a test flow. Using a layer of temperature sensitive crystal placed over the surface of this model or by other means, the time taken for the temperature at a relatively small number of selected points on the surface to reach a selected value is determined. The surface heat flux rate distribution is then found from these measured times using a simple inverse heat conduction method. The feasibility of this method has been evaluated by considering relatively low Reynolds number flow over a square cylinder and natural convective flow over a circular cylinder. Known local heat transfer coefficient distributions for these situation have been applied as boundary conditions in the numerical solution of the transient cooling of a the “experimental” models. These solutions are used to generate “measured” data i.e. to generate simulated experimental data. The inverse heat transfer method has then been used to predict the local heat transfer coefficient distribution over the surface and the predicted and input distributions have been compared. The effect of uncertainties in the experimental measurements on this comparison has then been evaluated using various assumed uncertainty values. The results of the study indicate that the proposed method of measuring local heat transfer coefficients is capable of giving results of good accuracy.
{"title":"A Numerical Evaluation of a Simple Procedure for Using Transient Surface Temperature Measurements to Determine Local Convective Heat Transfer Rates","authors":"P. Oosthuizen, D. Naylor","doi":"10.1115/imece1999-1112","DOIUrl":"https://doi.org/10.1115/imece1999-1112","url":null,"abstract":"\u0000 A transient method, based on an inverse heat conduction solution, for experimentally determining the distribution of local heat transfer rates on the surface of a body has been numerically evaluated. The particular interest is in situations in which the heat transfer coefficients are relatively low and in which there are relatively large changes in the heat transfer coefficient over the surface of the body being considered. In the method, a solid body of the shape being investigated, constructed from a low conductivity material, is heated to a uniform temperature and then exposed to a test flow. Using a layer of temperature sensitive crystal placed over the surface of this model or by other means, the time taken for the temperature at a relatively small number of selected points on the surface to reach a selected value is determined. The surface heat flux rate distribution is then found from these measured times using a simple inverse heat conduction method. The feasibility of this method has been evaluated by considering relatively low Reynolds number flow over a square cylinder and natural convective flow over a circular cylinder. Known local heat transfer coefficient distributions for these situation have been applied as boundary conditions in the numerical solution of the transient cooling of a the “experimental” models. These solutions are used to generate “measured” data i.e. to generate simulated experimental data. The inverse heat transfer method has then been used to predict the local heat transfer coefficient distribution over the surface and the predicted and input distributions have been compared. The effect of uncertainties in the experimental measurements on this comparison has then been evaluated using various assumed uncertainty values. The results of the study indicate that the proposed method of measuring local heat transfer coefficients is capable of giving results of good accuracy.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124148362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The temperature variation along annular fins of uniform thickness and constant thermal conductivity is governed by a differential equation of second order with variable coefficients which is called the modified Bessel equation of zero order. This educational paper addresses a simplistic finite-difference procedure for solving this kind of Bessel equation employing a reduced system of algebraic equations. Approximate temperature distributions and companion heat transfer rates have been computed with the elimination of unknowns by hand and also with the Gauss elimination method using the symbolic algebra software Maple V (Char et al., 1991) on a personal computer. Instructors and students of heat transfer courses may benefit from this alternative computational procedure that seeks to avoid the use and operations with Bessel functions and still produce numerical results of good quality. Rudimentary knowledge of numerical techniques is the only mathematical background that students need to possess in order to implement the computational scheme explained here.
等厚恒导热环形翅片的温度变化由一个二阶变系数微分方程控制，该方程称为修正的零阶贝塞尔方程。这篇教育论文讨论了用简化的代数方程组求解这类贝塞尔方程的简单有限差分程序。近似的温度分布和伴随的传热率已经通过手工消除未知数和高斯消去法在个人计算机上使用符号代数软件Maple V (Char et al.， 1991)计算出来。热传导课程的教师和学生可以从这种替代的计算过程中受益，这种计算过程旨在避免使用贝塞尔函数和操作，并且仍然产生高质量的数值结果。为了实现这里解释的计算方案，学生需要具备的唯一数学背景是基本的数值技术知识。
{"title":"Approximate Temperature Profiles and Companion Heat Transfer Rates of Uniform Annular Fins Using Finite-Differences Instead of Bessel Functions","authors":"A. Campo","doi":"10.1115/imece1999-1144","DOIUrl":"https://doi.org/10.1115/imece1999-1144","url":null,"abstract":"\u0000 The temperature variation along annular fins of uniform thickness and constant thermal conductivity is governed by a differential equation of second order with variable coefficients which is called the modified Bessel equation of zero order. This educational paper addresses a simplistic finite-difference procedure for solving this kind of Bessel equation employing a reduced system of algebraic equations. Approximate temperature distributions and companion heat transfer rates have been computed with the elimination of unknowns by hand and also with the Gauss elimination method using the symbolic algebra software Maple V (Char et al., 1991) on a personal computer. Instructors and students of heat transfer courses may benefit from this alternative computational procedure that seeks to avoid the use and operations with Bessel functions and still produce numerical results of good quality. Rudimentary knowledge of numerical techniques is the only mathematical background that students need to possess in order to implement the computational scheme explained here.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128398035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper discusses an advanced heat pipe mechanism for cooling of high heat flux electronics. The mechanism combines the capillary effect of sintered metal powder wicks with a pulsating motion of the working fluid to maintain sufficient liquid supply to high heat flux regions. The pulsating motion is driven by thermal conditions in the heat pipe evaporator and condenser and can be sustained with proper internal flow channel design. A theoretical model was developed to describe the pulsating motion of the working fluid. Proof-of-concept copper/water heat pipes were tested to verify the heat flux capability of this advanced mechanism. The test results demonstrated over 220W/cm2 heat flux capability, a fourfold improvement over present state of the art heat pipe performance. Comparisons between the test results and the model predictions validated the theoretical model.
{"title":"Combined Pulsating and Capillary Heat Pipe Mechanism for Cooling of High Heat Flux Electronics","authors":"Z. Zuo, M. North, Lee Ray","doi":"10.1115/imece1999-1124","DOIUrl":"https://doi.org/10.1115/imece1999-1124","url":null,"abstract":"\u0000 This paper discusses an advanced heat pipe mechanism for cooling of high heat flux electronics. The mechanism combines the capillary effect of sintered metal powder wicks with a pulsating motion of the working fluid to maintain sufficient liquid supply to high heat flux regions. The pulsating motion is driven by thermal conditions in the heat pipe evaporator and condenser and can be sustained with proper internal flow channel design. A theoretical model was developed to describe the pulsating motion of the working fluid. Proof-of-concept copper/water heat pipes were tested to verify the heat flux capability of this advanced mechanism. The test results demonstrated over 220W/cm2 heat flux capability, a fourfold improvement over present state of the art heat pipe performance. Comparisons between the test results and the model predictions validated the theoretical model.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133854333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past four years we have transformed our undergraduate heat transfer course from a lecture format into what we call a “partial studio model.” Two lecture hours per week are supplemented with a two-hour “hands-on” session in a classroom equipped with a computer for each pair of students. Much of the studio work revolves around a suite of teaching modules that we have developed for use in our undergraduate and graduate heat-and-mass-transfer courses. Most modules include research-based numerical algorithms which solve the governing ordinary and partial-differential equations in real time. Several of the modules may be considered “virtual laboratories,” that is, they allow students to take data from the computer screen for post-processing — much as if they were working in a real, extremely well-equipped, laboratory. Others give the option of performing dozens of “what if” calculations rapidly, thus inviting use in the design process. Each module has been custom tailored for the particular topic; inputs and outputs are limited to only those essential to that problem. Thus, unlike most industry-grade computation fluid dynamics packages, there is virtually no “learning curve” associated with software operations. For a number of these modules we have developed an accompanying desktop experiment to enhance still further the hands-on nature of the studio.
{"title":"Teaching Heat Transfer in a Studio Mode","authors":"R. J. Ribando, Timothy Scott, G. W. O'Leary","doi":"10.1115/imece1999-1143","DOIUrl":"https://doi.org/10.1115/imece1999-1143","url":null,"abstract":"\u0000 Over the past four years we have transformed our undergraduate heat transfer course from a lecture format into what we call a “partial studio model.” Two lecture hours per week are supplemented with a two-hour “hands-on” session in a classroom equipped with a computer for each pair of students. Much of the studio work revolves around a suite of teaching modules that we have developed for use in our undergraduate and graduate heat-and-mass-transfer courses. Most modules include research-based numerical algorithms which solve the governing ordinary and partial-differential equations in real time. Several of the modules may be considered “virtual laboratories,” that is, they allow students to take data from the computer screen for post-processing — much as if they were working in a real, extremely well-equipped, laboratory. Others give the option of performing dozens of “what if” calculations rapidly, thus inviting use in the design process. Each module has been custom tailored for the particular topic; inputs and outputs are limited to only those essential to that problem. Thus, unlike most industry-grade computation fluid dynamics packages, there is virtually no “learning curve” associated with software operations. For a number of these modules we have developed an accompanying desktop experiment to enhance still further the hands-on nature of the studio.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"31 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120926605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. R. Cheruparambil, B. Farouk, J. Yehoda, N. Macken
Results from an experimental study on the rapid measurement of thermal conductivity of chemical-vapor-deposited (CVD) diamond films are presented. The classical thermal comparator method has been used successfully for the measurement of thermal conductivity of bulk materials having high values of thermal resistance. Using samples of known thermal conductivity, a calibration curve is prepared. With this calibration curve, the comparator can be used to determine thermal conductivity of unknown samples. We have significantly modified and extended this technique for the measurement of materials with very low thermal resistance, i.e., CVD films with high thermal conductivity. In addition to the heated probe, the modified comparator employs a thermo-electric cooling element to increase conductive heat transfer through the film. The thermal conductivity measurements are sensitive to many other factors such as the thermal contact resistances, anisotropic material properties, surrounding air currents and temperature, and ambient humidity. A comprehensive numerical model was also developed to simulate the heat transfer process for the modified comparator. The simulations were used to develop a ‘numerical’ calibration curve that agreed well with the calibration curve obtained from our measurements. The modified method has been found to successfully measure the thermal conductivity of CVD diamond films.
{"title":"Thermal Conductivity Measurement of CVD Diamond Films Using a Modified Thermal Comparator Method","authors":"K. R. Cheruparambil, B. Farouk, J. Yehoda, N. Macken","doi":"10.1115/1.1318206","DOIUrl":"https://doi.org/10.1115/1.1318206","url":null,"abstract":"\u0000 Results from an experimental study on the rapid measurement of thermal conductivity of chemical-vapor-deposited (CVD) diamond films are presented. The classical thermal comparator method has been used successfully for the measurement of thermal conductivity of bulk materials having high values of thermal resistance. Using samples of known thermal conductivity, a calibration curve is prepared. With this calibration curve, the comparator can be used to determine thermal conductivity of unknown samples. We have significantly modified and extended this technique for the measurement of materials with very low thermal resistance, i.e., CVD films with high thermal conductivity. In addition to the heated probe, the modified comparator employs a thermo-electric cooling element to increase conductive heat transfer through the film. The thermal conductivity measurements are sensitive to many other factors such as the thermal contact resistances, anisotropic material properties, surrounding air currents and temperature, and ambient humidity. A comprehensive numerical model was also developed to simulate the heat transfer process for the modified comparator. The simulations were used to develop a ‘numerical’ calibration curve that agreed well with the calibration curve obtained from our measurements. The modified method has been found to successfully measure the thermal conductivity of CVD diamond films.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122354699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat flux is a space and time variable reflecting the state of a thermal system. The evaluation of heat flux properties in thermal systems gives the possibility of making an assessment of their efficiency, safety and availability. In this respect, it was proved that heat flux is an important design, diagnostic and control parameter for many thermal systems. This paper describes the evaluation of different aspects of heat flux properties including heat flux as a design parameter, heat flux as a diagnostic parameter and heat flux as a control parameter. The heat flux is proved to reflect the changes in thermal equipment during operation. The malfunction of this equipment is closely related to the change of the heat flux distribution within the system. In this respect, it was demonstrated that the failure of boilers and furnace operation could be diagnosed by the change in the heat flux distribution on the respective heat transfer surfaces. The heat flux, as a diagnostic variable for the assessment of the operation of thermal systems, will open a challenging opportunity for the design of on-line knowledge-based systems. This can be used for the assessment of efficiency and safety of thermal systems. A new method for heat flux measurement is introduced with reference to its use in boiler and glass furnaces. It shows the advantages of the new method when applied in high temperature and hostile environments.
{"title":"Heat Flux: A Design, Diagnostic and Control Parameter for Thermal Equipment","authors":"N. Martins, N. Afgan, M. Carvalho, M. Nogueira","doi":"10.1115/imece1999-1113","DOIUrl":"https://doi.org/10.1115/imece1999-1113","url":null,"abstract":"\u0000 Heat flux is a space and time variable reflecting the state of a thermal system. The evaluation of heat flux properties in thermal systems gives the possibility of making an assessment of their efficiency, safety and availability. In this respect, it was proved that heat flux is an important design, diagnostic and control parameter for many thermal systems.\u0000 This paper describes the evaluation of different aspects of heat flux properties including heat flux as a design parameter, heat flux as a diagnostic parameter and heat flux as a control parameter.\u0000 The heat flux is proved to reflect the changes in thermal equipment during operation. The malfunction of this equipment is closely related to the change of the heat flux distribution within the system. In this respect, it was demonstrated that the failure of boilers and furnace operation could be diagnosed by the change in the heat flux distribution on the respective heat transfer surfaces. The heat flux, as a diagnostic variable for the assessment of the operation of thermal systems, will open a challenging opportunity for the design of on-line knowledge-based systems. This can be used for the assessment of efficiency and safety of thermal systems.\u0000 A new method for heat flux measurement is introduced with reference to its use in boiler and glass furnaces. It shows the advantages of the new method when applied in high temperature and hostile environments.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130741174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is a case study of a senior level project on cogeneration for the Tufts University Medford, MA campus. Eight students were involved — six in the BSME program and two in the BSEnvE program. Through brainstorming and collaborative planning, students developed a “Proposal Document” which defined the study objectives, milestone schedules and deliverables. The student team was then divided into technical and project functional groups. Electronic communication was utilized but “face-to-face” meetings were crucial for maintaining progress. The student team evaluated whole campus and part-campus possibilities taking into account thermal and electrical demand profiles and local infrastructure. The outcome design featured a hybrid conventional combustion/molten carbonate fuel cell system to supply all electrical and partial thermal demands for a complex of buildings housing classrooms, gymnasium facilities and a new field house. Engineering specifications were developed and civil engineering and siting constraints were analyzed. Technology selection was driven not only by engineering constraints but also by student interest in exploring emerging technologies (fuel cells). The team presented written and oral reports to student peers, faculty, university personnel and outside experts. The paper provides an analysis of outcomes, assessments and satisfaction level. High course satisfaction and above average workloads were reported. The paper concludes with an elucidation of lessons learned including project execution, team makeup and background, the proper focus of design project courses, and the synthesis and integration of knowledge. Even in this small, relatively homogeneous mix of students, attention to bridging interdisciplinary gaps was required. Experience from this and similar courses indicate that the goal of capstone “synthesizing” experiences is flawed if the tendency towards “disciplinarity” in undergraduate education continues.
{"title":"Feasibility Study of a Hybrid Combustion-Fuel Cell Cogeneration Plant: A Senior Design Project Case Study","authors":"V. Manno, Katherine K. Friend, E. R. Nelson","doi":"10.1115/imece1999-1136","DOIUrl":"https://doi.org/10.1115/imece1999-1136","url":null,"abstract":"\u0000 This paper is a case study of a senior level project on cogeneration for the Tufts University Medford, MA campus. Eight students were involved — six in the BSME program and two in the BSEnvE program. Through brainstorming and collaborative planning, students developed a “Proposal Document” which defined the study objectives, milestone schedules and deliverables. The student team was then divided into technical and project functional groups. Electronic communication was utilized but “face-to-face” meetings were crucial for maintaining progress. The student team evaluated whole campus and part-campus possibilities taking into account thermal and electrical demand profiles and local infrastructure. The outcome design featured a hybrid conventional combustion/molten carbonate fuel cell system to supply all electrical and partial thermal demands for a complex of buildings housing classrooms, gymnasium facilities and a new field house. Engineering specifications were developed and civil engineering and siting constraints were analyzed. Technology selection was driven not only by engineering constraints but also by student interest in exploring emerging technologies (fuel cells). The team presented written and oral reports to student peers, faculty, university personnel and outside experts.\u0000 The paper provides an analysis of outcomes, assessments and satisfaction level. High course satisfaction and above average workloads were reported. The paper concludes with an elucidation of lessons learned including project execution, team makeup and background, the proper focus of design project courses, and the synthesis and integration of knowledge. Even in this small, relatively homogeneous mix of students, attention to bridging interdisciplinary gaps was required. Experience from this and similar courses indicate that the goal of capstone “synthesizing” experiences is flawed if the tendency towards “disciplinarity” in undergraduate education continues.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123216013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The artificial neural networks technique is applied to control the dynamic behavior of a fin-tube single-row compact heat exchanger. The experimental setup consists of a variable-speed wind-tunnel facility built specifically for heat exchanger analysis. Two different control methodologies were studied. The first one corresponds to adaptive control in which the weights and biases of the artificial neural network that acts as a controller are modified depending on the error obtained between the desired outlet air temperature and its measured value. Experimental results show that the stability of the system varies depending on the different ways of performing the adaptation of the controller. The second control strategy tested corresponds to internal model control. We added a filter and an integral control structure to obtain an offset-free steady state prediction. The control methodology was extensively tested and the results compared to those of conventional PID control. The results were very favorable for the neural controller.
{"title":"Artificial Neural Network Control of an Experimental Heat Exchanger Facility","authors":"Gerardo Díaz, M. Sen, K. T. Yang, R. McClain","doi":"10.1115/imece1999-1134","DOIUrl":"https://doi.org/10.1115/imece1999-1134","url":null,"abstract":"\u0000 The artificial neural networks technique is applied to control the dynamic behavior of a fin-tube single-row compact heat exchanger. The experimental setup consists of a variable-speed wind-tunnel facility built specifically for heat exchanger analysis. Two different control methodologies were studied. The first one corresponds to adaptive control in which the weights and biases of the artificial neural network that acts as a controller are modified depending on the error obtained between the desired outlet air temperature and its measured value. Experimental results show that the stability of the system varies depending on the different ways of performing the adaptation of the controller. The second control strategy tested corresponds to internal model control. We added a filter and an integral control structure to obtain an offset-free steady state prediction. The control methodology was extensively tested and the results compared to those of conventional PID control. The results were very favorable for the neural controller.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117308985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The benefits and advantages of investigative active learning are well documented throughout cognition and educational psychology research literature. But, these techniques are not extensively used in higher education and particularly engineering education. In this paper, a model is presented for applying computer based instruction (CBI) techniques to investigative active learning as practiced in a typical undergraduate heat transfer course. This model is demonstrated with the heat transfer through a composite structural wall problem. An investigative approach is used to coach students as they learn the general solution process. Several different active learning techniques are then applied as a student progresses through each step of the general solution process. These techniques are applicable to any heat transfer problem and when properly implemented, they should improve the learning of the general solution process. The demonstration example is best experienced with a computer. Individuals wishing to explore this model may do so at http://129.118.17.180/mvweb.
{"title":"Investigative Active Learning and the Teaching of Heat Transfer","authors":"Edward E. Anderson","doi":"10.1115/imece1999-1138","DOIUrl":"https://doi.org/10.1115/imece1999-1138","url":null,"abstract":"\u0000 The benefits and advantages of investigative active learning are well documented throughout cognition and educational psychology research literature. But, these techniques are not extensively used in higher education and particularly engineering education. In this paper, a model is presented for applying computer based instruction (CBI) techniques to investigative active learning as practiced in a typical undergraduate heat transfer course. This model is demonstrated with the heat transfer through a composite structural wall problem. An investigative approach is used to coach students as they learn the general solution process. Several different active learning techniques are then applied as a student progresses through each step of the general solution process. These techniques are applicable to any heat transfer problem and when properly implemented, they should improve the learning of the general solution process. The demonstration example is best experienced with a computer. Individuals wishing to explore this model may do so at http://129.118.17.180/mvweb.","PeriodicalId":120929,"journal":{"name":"Heat Transfer: Volume 4","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124511296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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