2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application最新文献

{"title":"DJOSER: Analytical Thermal Simulator for Multilayer Electronic Structures. Theory and Numerical Implementation","authors":"P. Bagnoli, C. Casarosa, F. Stefani","doi":"10.1109/THETA.2007.363413","DOIUrl":"https://doi.org/10.1109/THETA.2007.363413","url":null,"abstract":"This paper presents a steady-state thermal simulation strategy called DJOSER, which is dedicated primarily but not exclusively to packaging structures for electronic devices. It is applicable to structures that can be likened to a set of homogeneous layers stacked one on top of the other and possibly separated by thermal contact resistances, where the dissipated powers are due to two-dimensional heat sources distributed on the interfaces between the layers. A broad range of contour conditions and types of dissipated powers is included to make the models as close as possible to the typical structures of modern assembly technologies. Flow and temperature distributions are obtained via a system of integral equations that can be translated directly, with the usual squaring techniques, into a linear algebraic system","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116042044","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}

{"title":"Effect of Frequency on Electrohydrodynamic Enhanced Tube-Side Condensation","authors":"H. Sadek, J. Cotton, C. Ching, M. Shoukri","doi":"10.1109/THETA.2007.363428","DOIUrl":"https://doi.org/10.1109/THETA.2007.363428","url":null,"abstract":"The effect of high voltage AC electric fields on two-phase flow regime redistribution for flowing refrigerant HFC-134a has been investigated. In particular, the effect of the frequency of an applied square wave between 0 and 8 kV was studied. The flow visualization test section at the exit of the heat exchanger was made of quartz tube coated with an electrically grounded transparent conductive film of tin oxide. The flow regime transitions under the applied AC electric fields were recorded using a high speed camera at frames rates of 2000 frames per second for frequencies in the range of 4 Hz to 2 kHz. The experiments were performed at a mass flux of 55 kg/m2s, inlet and outlet qualities of 45% and 30% respectively, which correspond to stratified flow with the liquid level below the electrode (without EHD). At the low frequency range, both the heat transfer and pressure drop increased with an increase of frequency due to the periodic extraction of the liquid stratum. In the intermediate range of frequencies, the time period of the applied signals was less than the time needed to complete the extraction cycle, and therefore the heat transfer decreased while the pressure increased with an increase of frequency. In the high frequency range, the flow regimes approach those for the DC case where the effect of frequency is negligible on both heat transfer and pressure drop. This is mainly because the fluid medium cannot respond to the high frequency of the applied signals","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127055399","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}

{"title":"Heat transfer characteristics of non-Newtonian fluid in a rotating annulus","authors":"Sangmok Han, N. Woo, Y. Hwang","doi":"10.1109/THETA.2007.363442","DOIUrl":"https://doi.org/10.1109/THETA.2007.363442","url":null,"abstract":"Considerable interest has been shown in the problems of viscous flow between concentric annulus with one or both of the cylinders rotating. And the problem of instability of isothermal viscous flow between rotating concentric annulus is also important problem in a rotating electrical machine, especially in the drilling of oil well. This study concerns the phenomena and variables which control the rate of heat transfer in the gap of a rotating annulus. The objective of this study is to study the non-isothermal case, showing the effect of a radial temperature gradient in the annulus on the instability of this type flow. In this study the effect of axial flow rate, rotational speed of inner cylinder and temperature gradient between the cylinders on the heat transfer were investigated","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121925995","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}

{"title":"Design of Heat Conduction Panel: The Case of Multiple Heating Elements Cooled by a Displaced Heat Sink","authors":"W. Nakayama","doi":"10.1109/THETA.2007.363412","DOIUrl":"https://doi.org/10.1109/THETA.2007.363412","url":null,"abstract":"This paper reports the design study performed on a heat conduction panel having several heat sources at separate locations and a heat sink on one of the panel corners. The panel is given a thickness distribution so as to provide spatially varying heat conduction paths from the heat sources to the heat sink The objective of thickness distribution design is to minimize the variation among heat source temperatures, besides to hold the maximum temperature as low as possible. The genetic algorithm is used to search for an optimum thickness distribution. The problem is a generic representation of the situations that are becoming common in compact electronic equipment","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131120900","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}

{"title":"The Thermal Design of a Next Generation Data Center: A Conceptual Exposition","authors":"E. Samadiani, Y. Joshi, F. Mistree","doi":"10.1109/THETA.2007.363416","DOIUrl":"https://doi.org/10.1109/THETA.2007.363416","url":null,"abstract":"In the near future, electronic cabinets of data centers will house high performance chips with heat fluxes approaching 100 W/cm and associated high volumetric heat generation rates. With the power trends in the electronic cabinets indicating 60 kW cabinets in the near future, the current cooling systems of data centers will be insufficient and new solutions will need to be explored. Accordingly, the key issue that merits investigation is identifying and satisfying the needed specifications of the new thermal solutions, considering the design environment of the next generation data centers. Anchoring our work in the open engineering systems paradigm, the authors identify the requirements of the future thermal solutions and explore various design specifications of an ideally open thermal solution for a next generation data center. To approach an open cooling system for the future data centers, the concept of a thermal solution centered on the multi-scale (multilevel) nature of the data centers is discussed. The potential of this solution to be open, along with its theoretical advantages compared with the typical air cooling solutions is demonstrated through some scenarios. The realization problems and the future research needs are highlighted to achieve a practical open multi-scale thermal solution in data centers. Such solution is believed to be the most effective and efficient for the next generation data centers","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133113252","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}

{"title":"Cooling of an Electronic Board in a Vented Cabinet: Heat Transfer Performance and Air Flow Visualization","authors":"M. Misale, G. Tanda","doi":"10.1109/THETA.2007.363419","DOIUrl":"https://doi.org/10.1109/THETA.2007.363419","url":null,"abstract":"In this paper natural convection heat transfer in a vented cabinet is investigated. The cabinet consists of a rectangular, partially open, cavity in which a vertical, isothermal plate, simulating an electronic board, is placed. The experiments were conducted by parametrically varying the spacing between the plate and the cabinet walls, and the location and size of the openings. In particular for each cabinet configuration local and average heat transfer coefficients have been determined by means of a non-intrusive experimental technique (schlieren). Measured data, recast in terms of dimensionless numbers (Nusselt and Rayleigh numbers) are presented and discussed. Moreover, visualizations of thermal field inside the cabinet, by means of colour schlieren technique, are provided for a number of geometric and flow conditions","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116097179","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}

{"title":"An Alternative Method for the Cooling of Power Microelectronics Using Classical Refrigeration","authors":"F. Chiriac, V. Chiriac","doi":"10.1109/THETA.2007.363417","DOIUrl":"https://doi.org/10.1109/THETA.2007.363417","url":null,"abstract":"Classical refrigeration using vapor compression has been widely applied over the last decades to large-scale industrial systems, with few known applications to the microelectronics cooling field, due to the small size limitation. The present study proposes an efficient mechanical refrigeration system to actively cool the electronic components populating a printed circuit board in high-power microelectronics system. The proposed system includes several miniaturized components - compressor, evaporator, condenser - part of a refrigeration system designed to fit the smaller scale power electronics. The system is thermally optimized to reach high COP (coefficients of performance). An array of micro-channels is used for the evaporator/condenser units. A previous study indicated that the R-134s refrigerant provides the best COP/feasibility ratio, while being the most suitable for microelectronics applications (Phelan et al., 2004). The present study develops an analytical model of the proposed small scale vapor compression refrigerator using the R-134a refrigerant. The refrigeration system is thermally optimized for cooling powers ranging from 20 - 100W, with the COP of the system reaching values up to 4.5. In the final section of the study, the efficiency of the proposed system is further compared to existing active cooling techniques using thermoelectric coolers (TEC). The advantages of the proposed system are highlighted, establishing a baseline performance vs. size relationship for vapor-compression refrigerators, to serve as the basis for comparison for future miniaturized refrigeration systems","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"2020 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128117298","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}

{"title":"Thermopower Profiling Across a Silicon P-N Junction Through the 2ω Signal Measurement of AC Current-Heated Tip-Sample Nano-Contact","authors":"Kyeongtae Kim, Jisang Park, Sun Ung Kim, O. Kwon, Joon-Sik Lee, Seung-ho Park, Y. Choi","doi":"10.1109/THETA.2007.363437","DOIUrl":"https://doi.org/10.1109/THETA.2007.363437","url":null,"abstract":"Thermopower profiling with nanometer resolution has important applications in the development of nano-structured high ZT thermoelectric materials and in dopant density profiling of nanoelectronic devices. The authors suggested a new AC type thermopower measurement technique and demonstrated it with a simple experimental setup. Thermopower distribution across a silicon p-n junction was measured point-by-point at every 10 nm free from the noises due to built-in potential and photo-ionization effect and compared with theoretical result. Although this new AC type thermopower measurement technique could not follow the sharp variation of the theoretical thermopower near the p-n junction, it could identify a smooth peak of thermopower distribution in the depletion layer of the p-n junction","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115134542","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}

{"title":"Microscale and Nanoscale Thermal Characterization Techniques","authors":"J. Christofferson, K. Maize, Y. Ezzahri, J. Shabani, X. Wang, A. Shakouri Baskin","doi":"10.1115/1.2993145","DOIUrl":"https://doi.org/10.1115/1.2993145","url":null,"abstract":"In this paper the authors review various microscale and nanoscale thermal characterization techniques that could be applied to active and passive devices. Solid-state micro refrigerators on a chip can provide a uniform and localized temperature profile and they are used as a test vehicle in order to compare the resolution limits of various microscale techniques. After a brief introduction to conventional micro thermocouples and thermistor sensors, various contact and contactless techniques will be reviewed. Infrared microscopy is based on thermal emission and it is a convenient technique that could be used with features tens of microns in size. Resolution limits due to low emissivity and transparency of various materials and issues related to background radiation will be discussed. Liquid crystals that change color due to phase transition have been widely used for hot spot identification in integrated circuit chips. The main problems are related to calibration and aging of the material. Micro Raman is an optical method that can be used to measure absolute temperature. Micron spatial resolution with several degrees temperature resolution has been achieved. Thermoreflectance technique is based on the change of the sample reflection coefficient as a function of temperature. This small change in 10-4-10-5 range per degree is typically detected using lock-in technique when the temperature of the device is cycled. Use of visible and near IR wavelength allows both top surface and through the substrate measurement. Both single point measurements using a scanning laser and imaging with CCD or specialized lock-in cameras have been demonstrated. For ultrafast thermal decay measurement, pump-probe technique using nanosecond or femtosecond lasers have been demonstrated. This is typically used to measure thin film thermal diffusivity and thermal interface resistance. The spatial resolution of various optical techniques can be improved with the use of tapered fibers and near field scanning microscopy. While sub diffraction limit structures have been detected, strong attenuation of the signal reduces the temperature resolution significantly. Scanning thermal microscopy which is based on nanoscale thermocouples at the tip of atomic force microscope has had success in ultra high spatial resolution thermal mapping. Issues related to thermal resistance between the tip and the sample and parasitic heat transfer paths will be discussed","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130199255","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}

{"title":"Three Dimensional Analysis of Displacement Ventilation Systems","authors":"A. Abdel-Rahman, M. Serag-Eldin","doi":"10.1109/THETA.2007.363441","DOIUrl":"https://doi.org/10.1109/THETA.2007.363441","url":null,"abstract":"In this study a three dimensional computational study is conducted in order to investigate the effect of various parameters on the flow in displacement ventilation systems. In addition to demonstrating the importance of three-dimensional effects, it shows the effect of many important geometric and operational parameters on the displacement ventilation in a room. Effects studied include the height of the ceiling, cooling and heating from ceiling, the location and strength of the source heat flux, and the location of the pollutant source. The predictions are made with the aid of a mathematical model comprising governing partial differential equations expressing balance of momentum in three Cartesian-coordinate directions, conservation of mass and energy, and transport equations for the kinetic energy of turbulence and its rate of dissipation. The latter two equations being required by the adopted turbulence model","PeriodicalId":346940,"journal":{"name":"2007 International Conference on Thermal Issues in Emerging Technologies: Theory and Application","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126311892","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}