2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)最新文献

{"title":"The Effect of Fin Array Height and Spacing on Heat Transfer Performance during Pool Boiling from Extended Surfaces","authors":"Maureen Winter, J. Weibel","doi":"10.1109/iTherm54085.2022.9899575","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899575","url":null,"abstract":"The use of heat sinks is a promising approach to extend the range of immersion cooling in dielectric fluids to higher heat fluxes for thermal management of next-generation electronics. However, the effects of extended surface area enhancement on the heat transfer performance under pool boiling conditions are not well understood, even in the simple case of straight fins. Further investigation of the heat-flux-dependent variation of boiling modes that can manifest along the fin height is required. Although approaches exist to predict the extended surface pool boiling heat transfer coefficient, they have been developed from single fins. As a result, when applied to fin arrays, they are rarely accurate across the full operating range up to the critical heat flux, particularly if height or spacing varies drastically. To better understand the effects of fin arrays on heat transfer, pool boiling experiments are performed using copper fins in water, varying fin height and spacing. These variations span a range from much larger to less than half of the scale of the capillary length scale, Lb. The pool boiling data, complemented with high-speed visualization of the boiling regimes and bubble dynamics, strongly support a hypothesis that Lb is the key length scale. Heat transfer from fin array heat sinks with heights and spacings above Lb are shown to be accurately predicted using existing fin analysis approaches from the literature. However, spacings smaller than Lb affect the nucleate boiling superheat while heights shorter than Lb are unable to support multiple boiling regimes along the fin sidewall, both leading to disagreement between the experiments and predictions. These aspects, coupled with observation of vapor entrapment between closely spaced fins, indicate that new predictive methods must be developed. The valuable insights offered into the effects of fin array height and spacing on pool boiling provide a pathway toward heat sink design optimization for immersion cooling applications.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114803701","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":"High Strain Rate Materials Characterization at Low Test Temperatures for Thermally Aged SAC-Q Solder Alloys","authors":"P. Lall, Vikas Yadav, J. Suhling, David Locker","doi":"10.1109/iTherm54085.2022.9899535","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899535","url":null,"abstract":"A number of doped SnAgCu alloys have emerged to mitigate the effects of thermal aging on the property deterioration of the interconnects. Much less is known about the performance of alloys at low temperatures simultaneously with high strain rates which may be encountered in harsh environment applications including automotive, aerospace and defense. Electronics in harsh environments is often used for function critical use. High strain-rate and low temperatures may occur during storage, transport and operation. In this paper, data on the evolution of material properties including the elastic modulus, ultimate tensile strength is presented for SAC-Q solder which includes Bi in addition to SnAgCu. The high strain rate low temperature data has been fit to the Anand Viscoplasticity Model to represent the non-linear constitutive behavior. The evolution of the Anand Constants has been presented with the increase in storage duration for period of upto 1-year at a storage temperature of 50°C. The accuracy of Anand model has been quantified by comparing the experimentally measured data with the predicted data with the computed model constants. The Anand parameters have been implemented in an FE-framework to simulate the drop events for a ball-grid array package on printed circuit board assembly to determine hysteresis loop and plastic work density. Effect of the evolution of the properties on the change in the hysteresis loops has been assessed.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114646797","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":"Analysis of process dependent mechanical properties of sintered copper nanoparticle pillars for the plating-free bumping by finite element method","authors":"S. Kohara, T. Aoki, Chinami Marushima, C. Taylor, K. Sueoka, T. Hisada","doi":"10.1109/iTherm54085.2022.9899672","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899672","url":null,"abstract":"Previous studies of sintered copper nanoparticles used in the plating-free bumping by injection molded solder (IMS) have shown that their microstructural features depend on the sintering conditions such as temperature and gas atmosphere. The other study has shown that the elastic modulus and yield of sintered Cu nanoparticles (NPs) also depend on the sintering temperature. In this report, the relationships between the morphological features and elastic modulus of sintered Cu nanoparticles is studied by nanoindentation and by finite element method (FEM). Mechanical testing by nanoindentation revealed that the elastic modulus of sintered Cu nanoparticles depends not only on the sintering temperature, but also on the sintering gas atmosphere. The results together with the previous study on the microstructures indicate that the Cu NPs processed in nitrogen and those processed in formic acid are at the different stages of coalescence and void growth dynamics. Young’s modulus values of sintered Cu nanoparticles processed in formic acid were higher than those processed in nitrogen for the same sintering temperatures. The values of Young’s modulus for the sintering temperatures of 150, 200 and 250°C were 66, 71 and 86 GPa for the nitrogen case and 82, 100 and 99 GPa for the formic acid case, respectively. The reference value for the plated copper was 138 GPa. To elucidate the relationship between the morphological features and the mechanical properties, Young’s modulus and yield were calculated by numerical testing of representative volume elements constructed with morphological features using FEM. Morphological features used for the analyses were neck width and the void ratio which are associated with the particle coalescence and the void growth respectively. The calculation showed that an increase in the neck width results in an increase of Young’s modulus and yield whereas an increase in void ratio results in a decrease of Young’s modulus and yield. Evolution of Young’s modulus with sintering temperature was compared with that obtained by nanoindentation. For the formic acid case, the variation of Young’s modulus was best described by a hierarchical model incorporating both the neck width and the void ratio suggesting that both the particle coalescence and the void growth are important dynamics determining the mechanical properties for this system. Statistical analysis was also performed on the Young’s modulus data randomly generated by FEM to determine the relative influence of the morphological features on elastic modulus.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"67 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127565418","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":"Enhancing Efficiency and Lifetime of Photovoltaic Systems Through Passive Convective Cooling","authors":"Erik P. Soderholm, Eoin Cotter, D. McCloskey","doi":"10.1109/iTherm54085.2022.9899647","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899647","url":null,"abstract":"Solar Photovoltaic (PV) technology is being installed at a rapid pace. Panel efficiencies and lifetimes are negatively affected by high operating temperatures. This study examines the cooling of PV panels with enhanced rearward convection. This is achieved through simple Aluminium fin structures which reduce operating temperatures by increasing the convective heat transfer coefficient and the area for heat exchange to occur. A temperature drop of ~10°C was measured throughout the day with a corresponding rise in peak output power of 19%. This was done with simple straight fins. An overall heat transfer coefficient of 26.0 W/m2 °C was increased to 36.4 W/m2 °C for the modified panel. For commercial adoption the main improvements to be made are using less material and designing a form factor which could be retrofitted to currently deployed systems or integrated into current manufacturing processes.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127591975","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":"Channel design to effectively increase oscillation amplitude in micro-pulsating heat pipes","authors":"C. Jung, S. Kim","doi":"10.1109/iTherm54085.2022.9899519","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899519","url":null,"abstract":"A channel design of micro-pulsating heat pipes (MPHPs) to increase the oscillation amplitude in the horizontal orientation is proposed. For this, the topology optimization is performed in the direction of maximizing the ratio of pressure drop in the backward direction to that in the forward direction, defined as diodiciy (Di). It is numerically confirmed that the topology-optimized Tesla-valve (TV) has a high Di value of 1.9. MPHPs with conventional and topology-optimized channel design are fabricated to investigate the effects of the TV on flow characteristics and thermal performance of MPHPs. The width, length, and thickness of MPHPs are 53.5 mm, 80 mm, and 2 mm, respectively. A closed-loop square channel with ten-turn and an average hydraulic diameter of 0.9 mm is engraved on 1 mm thick silicon. Then, 1 mm thick glass is anodically-bonded on the top of the etched silicon for flow visualization. Inside the channel, HFE-7000 is filled by 54% as a working fluid. Experiments are conducted at various input powers in a horizontal orientation. The movements of menisci are tracked through a high-speed photography. It is experimentally confirmed that the TV effectively increases oscillation amplitude at input powers of more than 24 W. Consequently, the thermal resistance of the MPHP with the TV is 35% lower on average than that of the conventional MPHP. In this study, a channel design of MPHPs capable of increasing oscillation amplitude in the horizontal orientation is proposed for the first time, which allows MPHPs to overcome the limitation of performance attributed to the inclination angle.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127490000","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":"Zener Diode Reverse Breakdown Voltage as a Simultaneous Heating and Temperature Sensing Element","authors":"R. McAfee, M. Fish, J. Gess","doi":"10.1109/iTherm54085.2022.9899600","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899600","url":null,"abstract":"Near-junction, low-cost, and high accuracy temperature-sensing methods are needed for electronics cooling. Electrical components, either thermal test die or active integrated circuit devices, can be used as temperature sensors provided that a temperature sensitive parameter is available and calibrated. Zener diodes lend themselves to use as static or dynamic temperature sensors when integrated into an existing package. However, the use of Zener diodes to simultaneously heat and sense has not been explored in literature. When a Zener diode with a high reverse breakdown voltage is selected the power dissipation can be fine-tuned to desired heating conditions and be concurrently used to sense temperature. A methodology for using Zener reverse breakdown to generate accurate junction heating curves is established.The reverse breakdown voltage of the diodes is used to define I-V-T surfaces for calibration. Calibration temperatures are established using a single-phase liquid cooled cold plate. Thermal calibration methods are developed based on existing JEDEC standards for electrical test methods for simple integrated circuit devices.The methodology was applied to develop phase change material heating curves and compare them to other thermal solutions. The developed methodology can be used for future applications requiring simultaneous heating and sensing.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124299606","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":"Performance Analysis of the Analog Path of Read-Out Integrated Circuit for MEMS structures under Temperature Variation","authors":"M. Jankowski, J. Nazdrowicz, A. Napieralski","doi":"10.1109/iTherm54085.2022.9899610","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899610","url":null,"abstract":"The paper presents a time-analysis of capacitive analog readout circuit properties for a range of operating temperatures. Comparison of schematic-based and post-layout extraction-based behavior is conducted, and the analysis includes and compares simulation and measurement results. The presented analysis identifies the temperature-relation of the circuit readout values as well as shows the influence of environment temperature on noise levels.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121528985","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":"Hotspot Cooling Performance of Two-Phase Confined Jet Impingement Cooling at the Stagnation Zone","authors":"T. Chowdhury, S. Putnam","doi":"10.1109/iTherm54085.2022.9899618","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899618","url":null,"abstract":"Jet impingement can be particularly effective for removing high heat fluxes from local hotspots. Two-phase jet impingement cooling combines the advantages of both the nucleate boiling heat transfer with the single-phase sensible cooling. This study investigates two-phase confined jet impingement cooling of local, laser-generated hotspots in a 100 nm thick Hafnium (Hf) thin film on glass. The jet/nozzle diameter is ∼1.2 mm and the normal distance between the nozzle outlet and the heated surface is ∼3.2 mm. The jet coolants studied are FC 72, Novec 7200, and Ethanol with jet nozzle outlet Reynolds numbers ranging from 250 to 5000. The hotspot area is ∼0.06 mm2 and the applied hotspot-to-jet heat fluxes range from 20 W/cm2 to 350 W/cm2. This heat flux range facilitates studies of both the single-phase and two-phase heat transport mechanisms for heat fluxes up to critical heat flux (CHF). The temporal evolution of the temperature distribution of the laser-heated surface is measured using infrared (IR) thermometry. This study focuses on the stagnation point heat transfer - i.e., the jet potential core is co-aligned with the hotspot center. For ethanol, the CHF is ∼315 W/cm2 at Re ∼1338 with a corresponding heat transfer coefficient of h ∼102 kW/m2 K. For FC 72, the CHF is ∼94 W/cm2 at Re∼ 5000 with• a corresponding h∼ 56 kW/m2.K. And for Novec 7200, the CHF is ∼108 W/cm2 at Re∼ 4600 with a corresponding h ∼ 50 kW/m2•K.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"81 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124710814","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":"Optimization of Hydrogen Generator for UAVs","authors":"Christopher T. Barrow, Geo Jong Kim, Cutler Phillippe, J. Maddox, Hyun Tae Hwang","doi":"10.1109/iTherm54085.2022.9899635","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899635","url":null,"abstract":"An optimization study was conducted for an Unmanned Aerial Vehicle (UAV) hydrogen generator containment vessel utilizing ammonia borane pellets. The optimization considered pellet size, number of pellets, pellet spacing, chamber volume, and wall thickness. Candidate configurations were selected using an energy balance analysis. A transient Computational Fluid Dynamics (CFD) analysis was performed on the candidate configurations to monitor heat transfer through the vessel before and after the reaction to ensure no other pellets reached the activation temperature. Chamber volume and pellet spacing were found to be the dominant parameters and a minimal mass design is presented.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129793494","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":"Welcome to ITHERM 2022","authors":"","doi":"10.1109/itherm54085.2022.9899611","DOIUrl":"https://doi.org/10.1109/itherm54085.2022.9899611","url":null,"abstract":"","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"1025 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134213763","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}