Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012553
K. Jonnalagadda, M. Patel, A. Skipor
In recent years, proposed legislative action and the product differentiation opportunities presented by environmentally friendly products have combined to significantly increase the development of lead-free solder materials. A few lead-reduced products are already in production and several lead-free products will be released in the next two years. Among the various lead-free solders, the SnAgCu family of solders has emerged as one of the leading candidates for high volume implementation. This paper examines the mechanical fatigue reliability of SnAgCu PBGAs on FR4 boards. While a fairly extensive reliability database is available for BGAs built with tin-lead solders, similar data is not available for BGAs assembled with lead-free solder. Mechanical bend fatigue reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent, during drop. The lead-free reliability data is compared to that from control samples built with tin-lead solders, both in low-cycle and high-cycle fatigue. Failure analysis was conducted to identify failure modes.
{"title":"Mechanical bend fatigue reliability of lead-free PBGA assemblies","authors":"K. Jonnalagadda, M. Patel, A. Skipor","doi":"10.1109/ITHERM.2002.1012553","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012553","url":null,"abstract":"In recent years, proposed legislative action and the product differentiation opportunities presented by environmentally friendly products have combined to significantly increase the development of lead-free solder materials. A few lead-reduced products are already in production and several lead-free products will be released in the next two years. Among the various lead-free solders, the SnAgCu family of solders has emerged as one of the leading candidates for high volume implementation. This paper examines the mechanical fatigue reliability of SnAgCu PBGAs on FR4 boards. While a fairly extensive reliability database is available for BGAs built with tin-lead solders, similar data is not available for BGAs assembled with lead-free solder. Mechanical bend fatigue reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent, during drop. The lead-free reliability data is compared to that from control samples built with tin-lead solders, both in low-cycle and high-cycle fatigue. Failure analysis was conducted to identify failure modes.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"64 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":"124305071","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.2002.1012517
Xi-Shu Wang, Sunxin Zhu, Jiaxin Zhang, G. Shi
Conducting polymer films have been widely used as the small size and lightweight materials for electronic parts, sensors and semiconductors. For reliability of these parts, it is particularly necessary to know the fatigue fracture behavior of the thin film. In this paper, a new fatigue testing method was developed by which fatigue failure on the surface deposited by the electrochemical synthesis on the base of the 304 stainless steel plate under the cyclic tension-tension loading. The fatigue tests were investigated by the stochastic observation method with Scanning Electron Microscopy (SEM). The experimental results show that the fatigue fracture types of the conducting polythiophene thin film on the substrate, through which the nucleation of fatigue microcrack and propagation as well as fatigue embattlement process can be expressed by experimental approach. Additionally, detailed analysis is introduced through observation with SEM and the effects on the results of testing conditions are discussed in this paper.
{"title":"Fatigue failure types of the conducting polythiophene thin film on the stainless substrate","authors":"Xi-Shu Wang, Sunxin Zhu, Jiaxin Zhang, G. Shi","doi":"10.1109/ITHERM.2002.1012517","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012517","url":null,"abstract":"Conducting polymer films have been widely used as the small size and lightweight materials for electronic parts, sensors and semiconductors. For reliability of these parts, it is particularly necessary to know the fatigue fracture behavior of the thin film. In this paper, a new fatigue testing method was developed by which fatigue failure on the surface deposited by the electrochemical synthesis on the base of the 304 stainless steel plate under the cyclic tension-tension loading. The fatigue tests were investigated by the stochastic observation method with Scanning Electron Microscopy (SEM). The experimental results show that the fatigue fracture types of the conducting polythiophene thin film on the substrate, through which the nucleation of fatigue microcrack and propagation as well as fatigue embattlement process can be expressed by experimental approach. Additionally, detailed analysis is introduced through observation with SEM and the effects on the results of testing conditions are discussed in this paper.","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":"122997020","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.2002.1012463
L. Chien, C. Chang
This experimental study investigated the effect of particle size and coating thickness of the porous surface on evaporator thermal resistance of a thermosyphon having a 16 mm diameter circular heating area. Copper particles having two kinds of size distributions were sintered on a copper plate. The two particle distributions were 115 /spl mu/m average diameter in the range 50 to 500 /spl mu/m, and 247 /spl mu/m average diameter in the range 180 to 350 /spl mu/m. The particle coating thickness was either 0.5 or 1.0 mm for each distribution. Water was used as the working fluid, and it was tested at 60 or 70/spl deg/C saturation temperature, which corresponds to sub-atmospheric saturation pressure. The heat flux varied between 30 and 550 kW/m/sup 2/. The boiling surfaces were tested in vertical and horizontal orientations, and the experimental results showed negligible effect on the surface orientation. The best boiling surface in the present study is obtained with a coating 1.0 mm thick and 247 /spl mu/m average particle diameter. At 70/spl deg/C this surface yielded less than 0.025 K/W evaporation thermal resistance at 93 W.
{"title":"Experimental study of evaporation resistance on porous surfaces in flat heat pipes","authors":"L. Chien, C. Chang","doi":"10.1109/ITHERM.2002.1012463","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012463","url":null,"abstract":"This experimental study investigated the effect of particle size and coating thickness of the porous surface on evaporator thermal resistance of a thermosyphon having a 16 mm diameter circular heating area. Copper particles having two kinds of size distributions were sintered on a copper plate. The two particle distributions were 115 /spl mu/m average diameter in the range 50 to 500 /spl mu/m, and 247 /spl mu/m average diameter in the range 180 to 350 /spl mu/m. The particle coating thickness was either 0.5 or 1.0 mm for each distribution. Water was used as the working fluid, and it was tested at 60 or 70/spl deg/C saturation temperature, which corresponds to sub-atmospheric saturation pressure. The heat flux varied between 30 and 550 kW/m/sup 2/. The boiling surfaces were tested in vertical and horizontal orientations, and the experimental results showed negligible effect on the surface orientation. The best boiling surface in the present study is obtained with a coating 1.0 mm thick and 247 /spl mu/m average particle diameter. At 70/spl deg/C this surface yielded less than 0.025 K/W evaporation thermal resistance at 93 W.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"40 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":"115404244","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.2002.1012491
Norbert Müller, Luc G. Fréchette
A numerical optimization tool is used to optimize forced convection micro-channel heat sinks for minimum pump power at high heat fluxes. Results gained with the optimization tool are generalized and optimum configurations are illustrated on design charts. Physical trends are illustrated analytically using the underlying relations. Investigations are done for air and water in single-phase flow with no phase transition; with hydraulic diameters of the micro-channels ranging from about 1 micron to 80 mm. Optimization is shown to have a tremendous effect. It can reduce pump power by several orders of magnitude, especially for high heat flux devices. Using water and air as coolants, designs for heat fluxes of >10 kW/cm/sup 2/ and >100 W/cm/sup 2/ respectively with pump/fan power expenses less than 1% are easily found with the optimization tool. It appears that large aspect ratios for the flow channels are favorable for high heat fluxes in micro heat sinks. For each design, there exists an optimum fin height and ratio of fin thickness to channel width. The design space investigation also suggests that short channels in multiple parallel units are a key feature of compact high heat flux heat sinks. Practical design examples underline the feasibility of the results and general design guidelines are derived.
{"title":"Optimization and design guidelines for high flux micro-channel heat sinks for liquid and gaseous single-phase flow","authors":"Norbert Müller, Luc G. Fréchette","doi":"10.1109/ITHERM.2002.1012491","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012491","url":null,"abstract":"A numerical optimization tool is used to optimize forced convection micro-channel heat sinks for minimum pump power at high heat fluxes. Results gained with the optimization tool are generalized and optimum configurations are illustrated on design charts. Physical trends are illustrated analytically using the underlying relations. Investigations are done for air and water in single-phase flow with no phase transition; with hydraulic diameters of the micro-channels ranging from about 1 micron to 80 mm. Optimization is shown to have a tremendous effect. It can reduce pump power by several orders of magnitude, especially for high heat flux devices. Using water and air as coolants, designs for heat fluxes of >10 kW/cm/sup 2/ and >100 W/cm/sup 2/ respectively with pump/fan power expenses less than 1% are easily found with the optimization tool. It appears that large aspect ratios for the flow channels are favorable for high heat fluxes in micro heat sinks. For each design, there exists an optimum fin height and ratio of fin thickness to channel width. The design space investigation also suggests that short channels in multiple parallel units are a key feature of compact high heat flux heat sinks. Practical design examples underline the feasibility of the results and general design guidelines are derived.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"67 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":"124999184","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.2002.1012449
M. Rencz, V. Székely, G. Farkas, B. Courtois
A method is presented for detecting increased thermal resistance values within a heat conduction path with the help of transient thermal measurements. After summarizing the theoretical background of structure function evaluation it is demonstrated how to determine partial thermal resistances in the cases when one dimensional heat flow may be assumed. The paper presents a typical structure developed to measure small thermal resistance values with the help of the presented method. Simulated results demonstrate the feasibility of the suggested method, and measured examples demonstrate the applicability.
{"title":"Measuring interface thermal resistance values by transient testing","authors":"M. Rencz, V. Székely, G. Farkas, B. Courtois","doi":"10.1109/ITHERM.2002.1012449","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012449","url":null,"abstract":"A method is presented for detecting increased thermal resistance values within a heat conduction path with the help of transient thermal measurements. After summarizing the theoretical background of structure function evaluation it is demonstrated how to determine partial thermal resistances in the cases when one dimensional heat flow may be assumed. The paper presents a typical structure developed to measure small thermal resistance values with the help of the presented method. Simulated results demonstrate the feasibility of the suggested method, and measured examples demonstrate the applicability.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"112 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":"128661551","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.2002.1012571
S. Stern, C. Brooks, M. Strachan, A. Kopf‐Sill, J. W. Parce
Improved thermocycler design can increase the efficiency of genetic analysis based on the polymerase chain reaction. In this report, strategies for chip-based microfluidic thermocyclers are discussed, and the design and performance of devices employing buffer joule heating for thermocycling are presented. Novel joule heating methods involving transfer of electric current directly into the PCR buffer within microchannels are introduced. These methods utilize in-channel platinum electrodes to transfer AC heating current into the buffer under conditions of minimal oxidation-reduction and water electrolysis. Key features of the approach include, (i) very small, nanoliter-level reaction volumes for decreased reagent consumption, (ii) an integrated reagent accession microcapillary for continuous-flow processing and on-chip, run-time reaction assembly options, (iii) rapid thermocycling for better PCR performance, and (iv) simple and fully integrated reaction buffer heating and temperature sensing provided by buffer joule heating technology.
{"title":"Microfluidic thermocyclers for genetic analysis","authors":"S. Stern, C. Brooks, M. Strachan, A. Kopf‐Sill, J. W. Parce","doi":"10.1109/ITHERM.2002.1012571","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012571","url":null,"abstract":"Improved thermocycler design can increase the efficiency of genetic analysis based on the polymerase chain reaction. In this report, strategies for chip-based microfluidic thermocyclers are discussed, and the design and performance of devices employing buffer joule heating for thermocycling are presented. Novel joule heating methods involving transfer of electric current directly into the PCR buffer within microchannels are introduced. These methods utilize in-channel platinum electrodes to transfer AC heating current into the buffer under conditions of minimal oxidation-reduction and water electrolysis. Key features of the approach include, (i) very small, nanoliter-level reaction volumes for decreased reagent consumption, (ii) an integrated reagent accession microcapillary for continuous-flow processing and on-chip, run-time reaction assembly options, (iii) rapid thermocycling for better PCR performance, and (iv) simple and fully integrated reaction buffer heating and temperature sensing provided by buffer joule heating technology.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"39 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":"128719731","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.2002.1012505
S. C. Guttikonda, B. Sammakia
Thermal management is becoming increasingly significant in semiconductor devices because of greater functional densities and smaller devices. A critical factor in obtaining better heat transfer from cavity down devices is the proper choice of heat spreader design. In an earlier study Guttikonda, S.C. and Sammakia, B.G. [2001] presented a comparative basic analysis of two types of heat spreader design and also studied the effect of forced convection cooling for different velocities. It has been noted that the single piece type of heat spreader, with a cavity for the die, is superior to a design incorporating separate heat spreader and stiffeners. The adhesive between the stiffener and the heat spreader was identified as a major resistance in the heat flow path. In the present study a detailed parametric study of the effects of various factors that are responsible for the difference in performance of two designs, is presented. These factors include possible delamination between the die and cover plate/heat spreader and the thermal conductivity of the die attach. The authors also obtained trends to study the effects of heat spreader thickness. All results point towards better performance by the single piece design from a thermal standpoint.
{"title":"Comparative analysis of two heat spreader designs for a wire bond TBGA package","authors":"S. C. Guttikonda, B. Sammakia","doi":"10.1109/ITHERM.2002.1012505","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012505","url":null,"abstract":"Thermal management is becoming increasingly significant in semiconductor devices because of greater functional densities and smaller devices. A critical factor in obtaining better heat transfer from cavity down devices is the proper choice of heat spreader design. In an earlier study Guttikonda, S.C. and Sammakia, B.G. [2001] presented a comparative basic analysis of two types of heat spreader design and also studied the effect of forced convection cooling for different velocities. It has been noted that the single piece type of heat spreader, with a cavity for the die, is superior to a design incorporating separate heat spreader and stiffeners. The adhesive between the stiffener and the heat spreader was identified as a major resistance in the heat flow path. In the present study a detailed parametric study of the effects of various factors that are responsible for the difference in performance of two designs, is presented. These factors include possible delamination between the die and cover plate/heat spreader and the thermal conductivity of the die attach. The authors also obtained trends to study the effects of heat spreader thickness. All results point towards better performance by the single piece design from a thermal standpoint.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"37 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":"129921687","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.2002.1012533
Y. Hwang, R. Radermacher
Due to environmental concerns, a new generation of refrigerants has been introduced. The new fluids perform well, but because of their remaining global warming potential they are still under scrutiny internationally and may be eliminated in the future. Research is underway to develop so-called 'natural fluids' into the final solution to the quest for the ultimate refrigerant. The primary candidates are carbon dioxide and hydrocarbons such as propane and ammonia. Each fluid comes with its own set of challenges. Carbon dioxide requires a transcritical cycle, which reduces its efficiency but, on the other hand, may provide secondary uses due to its high temperature level waste heat. It is under consideration for automotive and military applications. Carbon dioxide hot water beat pumps have been introduced in the market in Japan. Propane performs very well, but it is flammable and thus considered a safety hazard. Ammonia is widely used in large refrigeration plants, although it is toxic and flammable. Its stinging odor warns of any leaks long before any dangerous concentrations are obtained. This presentation will provide an overview of these existing and emerging refrigerants and the opportunities and challenges they provide.
{"title":"Opportunities with alternative refrigerants","authors":"Y. Hwang, R. Radermacher","doi":"10.1109/ITHERM.2002.1012533","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012533","url":null,"abstract":"Due to environmental concerns, a new generation of refrigerants has been introduced. The new fluids perform well, but because of their remaining global warming potential they are still under scrutiny internationally and may be eliminated in the future. Research is underway to develop so-called 'natural fluids' into the final solution to the quest for the ultimate refrigerant. The primary candidates are carbon dioxide and hydrocarbons such as propane and ammonia. Each fluid comes with its own set of challenges. Carbon dioxide requires a transcritical cycle, which reduces its efficiency but, on the other hand, may provide secondary uses due to its high temperature level waste heat. It is under consideration for automotive and military applications. Carbon dioxide hot water beat pumps have been introduced in the market in Japan. Propane performs very well, but it is flammable and thus considered a safety hazard. Ammonia is widely used in large refrigeration plants, although it is toxic and flammable. Its stinging odor warns of any leaks long before any dangerous concentrations are obtained. This presentation will provide an overview of these existing and emerging refrigerants and the opportunities and challenges they provide.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"39 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":"125377642","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.2002.1012531
R. Schmidt, H. Shaukatullah
Due to technology compaction, the Information Technology (IT) industry has seen a large decrease in the floor space required to achieve a constant quantity of computing and storage capability. However, the energy efficiency of the equipment has not dropped at the same rate. This has resulted in a significant increase in power density and heat dissipation within the footprint of computer and telecommunications hardware. The heat dissipated in these systems is exhausted in the room and the room has to be maintained at acceptable temperatures for reliable operation of the equipment. Cooling computer and telecommunications equipment rooms is becoming a major challenge. This paper reviews the literature dealing with various aspects of cooling computer and telecommunications equipment rooms. Included are papers on experimental work analyzing cooling schemes, numerical modeling, energy saving schemes, natural convection room cooling, forced convection room cooling, cooling raised floor versus non-raised floor type installations, and other related areas. This compilation of literature will hopefully spur and help others to take a critical look at the factors that affect the cooling design of computer and telecommunications equipment rooms, improve or develop new schemes for cooling, and hence improve the reliability of the equipment.
{"title":"Computer and telecommunications equipment room cooling: a review of literature","authors":"R. Schmidt, H. Shaukatullah","doi":"10.1109/ITHERM.2002.1012531","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012531","url":null,"abstract":"Due to technology compaction, the Information Technology (IT) industry has seen a large decrease in the floor space required to achieve a constant quantity of computing and storage capability. However, the energy efficiency of the equipment has not dropped at the same rate. This has resulted in a significant increase in power density and heat dissipation within the footprint of computer and telecommunications hardware. The heat dissipated in these systems is exhausted in the room and the room has to be maintained at acceptable temperatures for reliable operation of the equipment. Cooling computer and telecommunications equipment rooms is becoming a major challenge. This paper reviews the literature dealing with various aspects of cooling computer and telecommunications equipment rooms. Included are papers on experimental work analyzing cooling schemes, numerical modeling, energy saving schemes, natural convection room cooling, forced convection room cooling, cooling raised floor versus non-raised floor type installations, and other related areas. This compilation of literature will hopefully spur and help others to take a critical look at the factors that affect the cooling design of computer and telecommunications equipment rooms, improve or develop new schemes for cooling, and hence improve the reliability of the equipment.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"63 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":"121815983","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.2002.1012472
R. Wirtz, J. Xu, Ji-Wook Park, D. Ruch
The present work demonstrates the fabrication methodology of a 3-D, aluminum wire filament, bonded mesh deployed as a heat exchange surface. A model of the effective thermal conductivity of the mesh is developed. Apparatus to measure the coolant pressure-drop and heat transfer coefficient are described. Measurements are reported for fabricated test samples of varying thickness. Mesh Stanton number and friction factor correlations for a coolant with Prandtl number equal to 9.5 (chilled water) are reported. A heat exchanger performance evaluation, comparing the 3D woven mesh technology to another exchanger surface technology, is described. We have found that the weaving/wire bonding process must be carefully controlled to insure that target porosity, specific surface area and effective thermal conductivity are achieved. Effective thermal conductivities are found to be at least two-times larger than achieved in other comparable porous media configurations. Mesh friction factor and Stanton number are comparable to those achieved with other exchanger surface technologies. The exchanger performance comparison shows that exchangers having superior performance can be configured.
{"title":"Thermal/fluid characteristics of 3-D woven mesh structures as heat exchanger surfaces","authors":"R. Wirtz, J. Xu, Ji-Wook Park, D. Ruch","doi":"10.1109/ITHERM.2002.1012472","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012472","url":null,"abstract":"The present work demonstrates the fabrication methodology of a 3-D, aluminum wire filament, bonded mesh deployed as a heat exchange surface. A model of the effective thermal conductivity of the mesh is developed. Apparatus to measure the coolant pressure-drop and heat transfer coefficient are described. Measurements are reported for fabricated test samples of varying thickness. Mesh Stanton number and friction factor correlations for a coolant with Prandtl number equal to 9.5 (chilled water) are reported. A heat exchanger performance evaluation, comparing the 3D woven mesh technology to another exchanger surface technology, is described. We have found that the weaving/wire bonding process must be carefully controlled to insure that target porosity, specific surface area and effective thermal conductivity are achieved. Effective thermal conductivities are found to be at least two-times larger than achieved in other comparable porous media configurations. Mesh friction factor and Stanton number are comparable to those achieved with other exchanger surface technologies. The exchanger performance comparison shows that exchangers having superior performance can be configured.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"11 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":"125669202","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：