Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012466
Hocheol Ryu, Duckjong Kim, S. Kim
In the present work, heat transfer and fluid flow in square pin fin heat sinks are analyzed through an experimental method. Twenty aluminum square pin fin heat sinks having a 101.43 mm /spl times/ 101.43 mm base size are tested with inlet velocity ranging from 1 m/s to 5 m/s. In each test, the heat sink is heated uniformly at the bottom. From the experimental results, effects of the height of the heat sink and the ratio of the spacing between the adjacent fins to the fin pitch on the pressure drop across the heat sink and the thermal resistance of the heat sink are investigated. In addition, design guidelines for shrouded square pin fin heat sinks are suggested considering both pumping power and thermal resistance.
本文采用实验方法对方针翅片散热器的传热和流体流动进行了分析。20铝制方脚翅片散热器具有101.43 mm /spl倍/ 101.43 mm的基础尺寸，测试入口速度范围从1m /s到5m /s。在每次测试中，散热器的底部被均匀加热。根据实验结果，研究了散热器高度和相邻翅片间距与翅片间距的比值对散热器压降和热阻的影响。此外，提出了考虑泵送功率和热阻的带冠方针翅片散热器的设计准则。
{"title":"Experimental analysis of shrouded pin fin heat sinks for electronic equipment cooling","authors":"Hocheol Ryu, Duckjong Kim, S. Kim","doi":"10.1109/ITHERM.2002.1012466","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012466","url":null,"abstract":"In the present work, heat transfer and fluid flow in square pin fin heat sinks are analyzed through an experimental method. Twenty aluminum square pin fin heat sinks having a 101.43 mm /spl times/ 101.43 mm base size are tested with inlet velocity ranging from 1 m/s to 5 m/s. In each test, the heat sink is heated uniformly at the bottom. From the experimental results, effects of the height of the heat sink and the ratio of the spacing between the adjacent fins to the fin pitch on the pressure drop across the heat sink and the thermal resistance of the heat sink are investigated. In addition, design guidelines for shrouded square pin fin heat sinks are suggested considering both pumping power and thermal resistance.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129608712","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012581
Xuejun Fan, S. Haque
Major MOSFET manufacturers have recently introduced innovative packaging options to achieve the next level of breakthroughs in electrical and thermal performance. Some of the innovations involve replacement of wire-bonds with solder-bumps for device interconnections in power devices and reduction in number of interfaces/paths for heat dissipation. The overall goal is to achieve small form factor MOSFET packages with significant improvements in electrical and thermal performance. This paper outlines the recent trends in MOSFET packaging and provides package-level thermal modeling results of wire-bond, strap bond, flipchip, ball-grid-array, and micro-lead-frame based packages. It also highlights the critical issues related to the processing, cost and reliability of such packages, which must be addressed before the conventional lead-frame based discrete solutions can be replaced with the new ones. Fundamental cooling mechanisms associated with different packaging technologies for MOSFETs are investigated. The impact of the internal package design on thermal performance is discussed in detail. The role of underfill materials in flip chip and BGA applications is also addressed.
{"title":"Emerging MOSFET packaging technologies and their thermal evaluation","authors":"Xuejun Fan, S. Haque","doi":"10.1109/ITHERM.2002.1012581","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012581","url":null,"abstract":"Major MOSFET manufacturers have recently introduced innovative packaging options to achieve the next level of breakthroughs in electrical and thermal performance. Some of the innovations involve replacement of wire-bonds with solder-bumps for device interconnections in power devices and reduction in number of interfaces/paths for heat dissipation. The overall goal is to achieve small form factor MOSFET packages with significant improvements in electrical and thermal performance. This paper outlines the recent trends in MOSFET packaging and provides package-level thermal modeling results of wire-bond, strap bond, flipchip, ball-grid-array, and micro-lead-frame based packages. It also highlights the critical issues related to the processing, cost and reliability of such packages, which must be addressed before the conventional lead-frame based discrete solutions can be replaced with the new ones. Fundamental cooling mechanisms associated with different packaging technologies for MOSFETs are investigated. The impact of the internal package design on thermal performance is discussed in detail. The role of underfill materials in flip chip and BGA applications is also addressed.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"1986 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130518289","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012456
F. Milanez, M. Yovanovich, J. Culham
This paper presents studies on thermal contact conductance at light contact loads. Surface profilometry measurements are presented which show that actual surface asperity height distributions are not perfectly Gaussian. The highest asperities are truncated, leading the existing thermal contact conductance models to underpredict experimental data. These observations have been incorporated into modifications of existing contact conductance models. The preliminary model has been compared against thermal contact conductance data presented in the open literature, and good agreement is observed. The truncation leads to an enhancement of thermal contact conductance at light contact pressures. The truncation is a function of the roughness level: the rougher the surface, the more truncated the surface height distribution.
{"title":"Effect of surface asperity truncation on thermal contact conductance","authors":"F. Milanez, M. Yovanovich, J. Culham","doi":"10.1109/ITHERM.2002.1012456","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012456","url":null,"abstract":"This paper presents studies on thermal contact conductance at light contact loads. Surface profilometry measurements are presented which show that actual surface asperity height distributions are not perfectly Gaussian. The highest asperities are truncated, leading the existing thermal contact conductance models to underpredict experimental data. These observations have been incorporated into modifications of existing contact conductance models. The preliminary model has been compared against thermal contact conductance data presented in the open literature, and good agreement is observed. The truncation leads to an enhancement of thermal contact conductance at light contact pressures. The truncation is a function of the roughness level: the rougher the surface, the more truncated the surface height distribution.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130631000","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012475
M. Nagulapally, K. Karimanal
Shell conduction plates (thin conducting plates) are computational fluid dynamics (CFD) objects that may be used to model three-dimensional conduction in thin, plate-like objects used in electronic cooling applications. The use of zero thickness conducting plates for fins of extruded heat sinks can result in significant reduction in mesh elements when compared to an equivalent case using thick fins. Shell conduction plates model three dimensional conduction in a solid as well as viscous stresses at a fin surface accurately. However, they do not account for the flow impedance caused by the thickness of the actual plates. Therefore, volumetric resistances with appropriate flow loss coefficients derived from existing channel flow correlations were used to account for the flow blockage caused by the fins. The validity of using such a hybrid approach to model extruded heat sinks was studied using Icepak, a CFD software for electronics cooling applications. Results suggest that the present approach can be used to reduce the cost of computational analysis while maintaining accuracy. The above approach resulted in savings in CPU requirements by a factor of approximately 4 to 5. For the cases considered, the grid sizes were reduced by approximately 60%.
{"title":"Use of shell conduction plates for compact models of extruded heat sinks in forced convection environments","authors":"M. Nagulapally, K. Karimanal","doi":"10.1109/ITHERM.2002.1012475","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012475","url":null,"abstract":"Shell conduction plates (thin conducting plates) are computational fluid dynamics (CFD) objects that may be used to model three-dimensional conduction in thin, plate-like objects used in electronic cooling applications. The use of zero thickness conducting plates for fins of extruded heat sinks can result in significant reduction in mesh elements when compared to an equivalent case using thick fins. Shell conduction plates model three dimensional conduction in a solid as well as viscous stresses at a fin surface accurately. However, they do not account for the flow impedance caused by the thickness of the actual plates. Therefore, volumetric resistances with appropriate flow loss coefficients derived from existing channel flow correlations were used to account for the flow blockage caused by the fins. The validity of using such a hybrid approach to model extruded heat sinks was studied using Icepak, a CFD software for electronics cooling applications. Results suggest that the present approach can be used to reduce the cost of computational analysis while maintaining accuracy. The above approach resulted in savings in CPU requirements by a factor of approximately 4 to 5. For the cases considered, the grid sizes were reduced by approximately 60%.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131661284","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012551
C. Basaran, Y. Wen
The reliability of solder joints in electronic packaging is becoming more important as Ball Grid Array (BGA) develops rapidly into the most popular packaging technology. Thermal fatigue of solder joints has been a reliability concern in the electronic packaging industry since the introduction of surface mount technology (SMT). Micro-structural coarsening (grain growth) is considered to be closely related to thermomechanical fatigue failure. Many researchers proposed coarsening models for bulk scale metals. But these models have never been verified for micron scale actual BGA solder balls. In the present study, three different grain growth models are investigated experimentally on BGA solder balls in a real life electronic package. Model simulations obtained from three models were compared against test data. The best performing model was chosen for finite element fatigue reliability studies based on continuum damage mechanics.
{"title":"Grain growth in eutectic Pb/Sn ball grid array solder joints","authors":"C. Basaran, Y. Wen","doi":"10.1109/ITHERM.2002.1012551","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012551","url":null,"abstract":"The reliability of solder joints in electronic packaging is becoming more important as Ball Grid Array (BGA) develops rapidly into the most popular packaging technology. Thermal fatigue of solder joints has been a reliability concern in the electronic packaging industry since the introduction of surface mount technology (SMT). Micro-structural coarsening (grain growth) is considered to be closely related to thermomechanical fatigue failure. Many researchers proposed coarsening models for bulk scale metals. But these models have never been verified for micron scale actual BGA solder balls. In the present study, three different grain growth models are investigated experimentally on BGA solder balls in a real life electronic package. Model simulations obtained from three models were compared against test data. The best performing model was chosen for finite element fatigue reliability studies based on continuum damage mechanics.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123465738","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012563
C. Basaran, S. Nie, C. Hutchins
Particle filled solid surface composites are used to fabricate kitchen countertops and sinks which may be subjected to severe temperature variations, giving rise to high thermal stresses. These stresses may lead to failure by cracking in regions subjected to large temperature variation. An aim of this paper is to investigate mechanisms of failure in solid surface materials using in situ observations during tensile, compressive and fatigue loading and to define test configurations that give meaningful measurements of material properties. Experiments show that the failure in tension occurs in several stages. In flexural loading the failure process is more complex. Consequently, flexural testing should not be used as a substitute for the measurement of ultimate tensile strength in a particle filled solid surface composite. The application of conventional damage mechanics to describe the failure of test specimens is also discussed.
{"title":"Experimental study of failure mechanisms in particle filled acrylic composites","authors":"C. Basaran, S. Nie, C. Hutchins","doi":"10.1109/ITHERM.2002.1012563","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012563","url":null,"abstract":"Particle filled solid surface composites are used to fabricate kitchen countertops and sinks which may be subjected to severe temperature variations, giving rise to high thermal stresses. These stresses may lead to failure by cracking in regions subjected to large temperature variation. An aim of this paper is to investigate mechanisms of failure in solid surface materials using in situ observations during tensile, compressive and fatigue loading and to define test configurations that give meaningful measurements of material properties. Experiments show that the failure in tension occurs in several stages. In flexural loading the failure process is more complex. Consequently, flexural testing should not be used as a substitute for the measurement of ultimate tensile strength in a particle filled solid surface composite. The application of conventional damage mechanics to describe the failure of test specimens is also discussed.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121419239","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012493
E. Alawadhi, C. Amon
This paper investigates the effectiveness of a Thermal Control Unit (TCU) for portable electronic devices by performing experimental and numerical analyses. The TCU objective is to improve thermal management of electronic devices where their operating time is limited to few hours. It is composed of an organic Phase Change Material (PCM) and a Thermal Conductivity Enhancer (TCE). The TCU can provide a reliable solution to portable electronic devices, which avoids overheating and thermally-induced fatigue, as well as a solution which satisfies the ergonomic requirement. Since the thermal conductivity of the PCM is very low, a TCE is incorporated into the PCM to boost its conductivity. The TCU structure is complex, and modeling an electronic device with it requires time and effort. Hence, this research develops approximate, yet effective, solutions for the TCU. The TCU component properties are averaged and a single TCU material is considered. This approach is evaluated by comparing the numerical predictions with the experimental results. The numerical model is used to study the effect of some important parameters that are experimentally expensive to examine, such as the heat transfer coefficient, the PCM latent heat, the Stefan number, and the effect of the heat source power.
{"title":"Thermal analyses of a PCM thermal control unit for portable electronic devices: experimental and numerical studies","authors":"E. Alawadhi, C. Amon","doi":"10.1109/ITHERM.2002.1012493","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012493","url":null,"abstract":"This paper investigates the effectiveness of a Thermal Control Unit (TCU) for portable electronic devices by performing experimental and numerical analyses. The TCU objective is to improve thermal management of electronic devices where their operating time is limited to few hours. It is composed of an organic Phase Change Material (PCM) and a Thermal Conductivity Enhancer (TCE). The TCU can provide a reliable solution to portable electronic devices, which avoids overheating and thermally-induced fatigue, as well as a solution which satisfies the ergonomic requirement. Since the thermal conductivity of the PCM is very low, a TCE is incorporated into the PCM to boost its conductivity. The TCU structure is complex, and modeling an electronic device with it requires time and effort. Hence, this research develops approximate, yet effective, solutions for the TCU. The TCU component properties are averaged and a single TCU material is considered. This approach is evaluated by comparing the numerical predictions with the experimental results. The numerical model is used to study the effect of some important parameters that are experimentally expensive to examine, such as the heat transfer coefficient, the PCM latent heat, the Stefan number, and the effect of the heat source power.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127663159","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012450
M. Burzo, P. Komarov, P. Raad
The performance and reliability of electronic devices composed of multiple thin layers of material are highly dependent on effective thermal management. Since the thermal properties of thin films, such as SiO/sub 2/, can vary considerably from bulk values, the determination of those properties is critical for the purposes of design. A new transient thermo-reflectance system has been employed to measure the thermal characteristics of thin-film SiO/sub 2/ layers. Results show that for layers of SiO/sub 2/ in the range of 100-1000 /spl Aring/, the intrinsic thermal conductivity is independent of thickness and smaller than the traditionally reported value of bulk silicon dioxide (1.4 W/m-K). The intrinsic value was measured to be around 90% and 75% of this bulk value for thermally grown (TG) and ion beam sputtered (IBS) oxides, respectively. The thermal interface resistances of TG and IBS SiO/sub 2/ films were measured at 1.68 /spl times/ 10/sup -8/ m/sup 2/-K/W and 2.58 /spl times/ 10/sup -8/ m/sup 2/-K/W, respectively. If a chromium film of around 100 /spl Aring/ is deposited between the gold and SiO/sub 2/ layers, the interface thermal resistance improves to 0.78 /spl times/ 10/sup -8/ m/sup 2/-K/W for TG films and 1.15 /spl times/ 10/sup -8/ m/sup 2/-K/W for IBS films. Thus, the effective thermal resistance of SiO/sub 2/ thin-films (i.e., with interface effects) is up to one order of magnitude smaller than the values reported for bulk SiO/sub 2/.
{"title":"Thermal transport properties of gold-covered thin-film silicon dioxide","authors":"M. Burzo, P. Komarov, P. Raad","doi":"10.1109/ITHERM.2002.1012450","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012450","url":null,"abstract":"The performance and reliability of electronic devices composed of multiple thin layers of material are highly dependent on effective thermal management. Since the thermal properties of thin films, such as SiO/sub 2/, can vary considerably from bulk values, the determination of those properties is critical for the purposes of design. A new transient thermo-reflectance system has been employed to measure the thermal characteristics of thin-film SiO/sub 2/ layers. Results show that for layers of SiO/sub 2/ in the range of 100-1000 /spl Aring/, the intrinsic thermal conductivity is independent of thickness and smaller than the traditionally reported value of bulk silicon dioxide (1.4 W/m-K). The intrinsic value was measured to be around 90% and 75% of this bulk value for thermally grown (TG) and ion beam sputtered (IBS) oxides, respectively. The thermal interface resistances of TG and IBS SiO/sub 2/ films were measured at 1.68 /spl times/ 10/sup -8/ m/sup 2/-K/W and 2.58 /spl times/ 10/sup -8/ m/sup 2/-K/W, respectively. If a chromium film of around 100 /spl Aring/ is deposited between the gold and SiO/sub 2/ layers, the interface thermal resistance improves to 0.78 /spl times/ 10/sup -8/ m/sup 2/-K/W for TG films and 1.15 /spl times/ 10/sup -8/ m/sup 2/-K/W for IBS films. Thus, the effective thermal resistance of SiO/sub 2/ thin-films (i.e., with interface effects) is up to one order of magnitude smaller than the values reported for bulk SiO/sub 2/.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127798741","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012494
S. Krishnan, S. Garimella
The melting and re-solidification of a phase change material in a container of rectangular cross-section with multiple discrete heat sources mounted on one side is investigated for electronics cooling by latent heat energy storage. This numerical study focuses on the thermal management issues that arise when electronic components experience a sudden surge in power dissipation. The transient response of the energy storage system to short pulses in power dissipation is studied. Convective cooling using air-cooled heat sinks on the sides of the containment remote from the heat sources provides for heat rejection to ambient air. The analysis is performed under different pulse frequencies. Different aspect ratios for the containment volume as well as different locations for the heat sources are studied in order to identify an optimal arrangement. Conduction and convection in the phase change material as well as conduction through the containment walls are considered in the computations. The constitutive equations are implicitly solved using a fully transient method on fixed orthogonal co-located finite volumes. The system is characterized based on the rate of heat absorption as well as the maximum temperatures experienced at the heat sources. Improvements that can be made in the application of latent heat energy storage in electronics cooling applications are discussed based on the results from the present study.
{"title":"Performance analysis of a phase change energy storage system for pulsed power dissipation","authors":"S. Krishnan, S. Garimella","doi":"10.1109/ITHERM.2002.1012494","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012494","url":null,"abstract":"The melting and re-solidification of a phase change material in a container of rectangular cross-section with multiple discrete heat sources mounted on one side is investigated for electronics cooling by latent heat energy storage. This numerical study focuses on the thermal management issues that arise when electronic components experience a sudden surge in power dissipation. The transient response of the energy storage system to short pulses in power dissipation is studied. Convective cooling using air-cooled heat sinks on the sides of the containment remote from the heat sources provides for heat rejection to ambient air. The analysis is performed under different pulse frequencies. Different aspect ratios for the containment volume as well as different locations for the heat sources are studied in order to identify an optimal arrangement. Conduction and convection in the phase change material as well as conduction through the containment walls are considered in the computations. The constitutive equations are implicitly solved using a fully transient method on fixed orthogonal co-located finite volumes. The system is characterized based on the rate of heat absorption as well as the maximum temperatures experienced at the heat sources. Improvements that can be made in the application of latent heat energy storage in electronics cooling applications are discussed based on the results from the present study.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127927978","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}
Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012498
J. Lohan, V. Eveloy, P. Rodgers
A detailed characterization of the airflow patterns around Printed Circuit Board (PCB)-mounted electronic components has been undertaken using three different, but complementary flow visualization techniques. Uniform airflows of 2 m/s, 4 m/s and 5.5 m/s were directed over Plastic Quad Flat Pack (PQFP) components mounted on a double Euro-Card PCB. The complexity of PCB topology and resulting flow phenomena, was increased in three stages from just one, centrally placed component, to seven components and finally to the most complex case consisting of a symmetrical in-line array of fifteen components. Traditional smoke- and paint-flow visualization techniques, as well as a novel paint-film evaporation technique, were applied to help identify the sensitivity of the flow phenomena and its impact on convective heat transfer, to both air velocity and PCB topology. Combined, these techniques not only helped characteristic features of these flows such as separation/reattachment points, re-circulation zones and horseshoe vortices to be identified, but also showed in a qualitative way, using the evaporation technique, how these flow phenomena impact on PCB/component surface heat transfer. Linking the flow phenomena with the surface heat transfer in this way also provides, in the early design phase, a means of identifying both an appropriate numerical flow modeling strategy for the flow phenomena present, and the locations of high aerodynamic disturbance on the PCB, where temperature prediction accuracy must be viewed with caution.
{"title":"Visualization of forced air flows over a populated printed circuit board and their impact on convective heat transfer","authors":"J. Lohan, V. Eveloy, P. Rodgers","doi":"10.1109/ITHERM.2002.1012498","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012498","url":null,"abstract":"A detailed characterization of the airflow patterns around Printed Circuit Board (PCB)-mounted electronic components has been undertaken using three different, but complementary flow visualization techniques. Uniform airflows of 2 m/s, 4 m/s and 5.5 m/s were directed over Plastic Quad Flat Pack (PQFP) components mounted on a double Euro-Card PCB. The complexity of PCB topology and resulting flow phenomena, was increased in three stages from just one, centrally placed component, to seven components and finally to the most complex case consisting of a symmetrical in-line array of fifteen components. Traditional smoke- and paint-flow visualization techniques, as well as a novel paint-film evaporation technique, were applied to help identify the sensitivity of the flow phenomena and its impact on convective heat transfer, to both air velocity and PCB topology. Combined, these techniques not only helped characteristic features of these flows such as separation/reattachment points, re-circulation zones and horseshoe vortices to be identified, but also showed in a qualitative way, using the evaporation technique, how these flow phenomena impact on PCB/component surface heat transfer. Linking the flow phenomena with the surface heat transfer in this way also provides, in the early design phase, a means of identifying both an appropriate numerical flow modeling strategy for the flow phenomena present, and the locations of high aerodynamic disturbance on the PCB, where temperature prediction accuracy must be viewed with caution.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128008990","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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