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With the decreasing sizes of transistors and the increasing integrated circuit (IC) density, heat dissipation can be a limiting factor in developing emerging semiconductor technologies, such as silicon-on-insulator (SOI) based transistors and 3D-stacked ICs. To overcome this challenge, accurate thermal simulations are needed. The goal of this investigation is to explore the use of proper orthogonal...
Lead free solder materials are widely used in electronic packaging industry due to environmental concerns. However, experimental testing and microstructural characterization have revealed that Pb-free solders exhibit evolving properties that change significantly with environmental exposures such as isothermal aging and thermal cycling. These changes are especially large in harsh environments, where...
Experimental testing and microstructural characterization have revealed that lead-free solders exhibit evolving properties that change significantly with environmental exposures such as isothermal aging and thermal cycling. These changes are especially large in harsh environments, where the effects of aging on solder joint behavior must be accounted for and included in constitutive models when predicting...
We present results of modeling for the design of microgaps for the removal of high heat fluxes, i.e., 1 kW/cm2, at low wall temperature (∼ 85°C) via a strategy of very high mass flux (>1000 kg/m2s), high quality (outlet vapor mass quality >90%), two-phase forced convection. Modeling includes (1) thermodynamic analysis to obtain performance trends across a wide range of candidate coolants, (2)...
An experimental study is performed to characterize the effect of squeezing conditions on the particle distribution and bond line thickness of particle filled polymeric thermal interface materials (TIM). Two different commercial particle-filled polymeric TIMs with different particle volume fractions have been used in this study. Rheological properties such as yield stress and viscosity are measured...
Nanoengineered structures have received significant attention due to the application of porous media convection structures. Metal porous structures provide unique combinations of large surface to volume ratio, high conductivity, and mechanical compliance. The integration of metal porous structures can improve the performance of convective heat exchangers for high heat flux thermal management. Copper...
To meet the high cooling demand in the electronics industry, enhanced microchannel heat sinks were introduced. However, the intricacies and high costs associated with microfabrication technologies prove them unsuitable for application in conventional heat exchangers. Hence, the motivation to implement microscale passages in macro geometries ensues. In this study, the annular microchannel is formed...
In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are...
Improved-efficiency heat spreaders must address ergonomic- and performance-driven thermal management demands of electronic devices of increasingly thin form factor. Heat pipes offer a potential high-conductance solution, but performance limitations unique to sub-millimeter thickness devices must be characterized. Using a reduced-order, one-dimensional resistance network and a two-dimensional numerical...
This paper presents numerical simulations based on the concept of local and global dimensional analysis to reproduce the thermodynamics and aerodynamics of server-fins, i.e., detachable flat/curved fins on the inlet/outlet of a server, for enhancing energy efficiency in data centers. Server-fin designs, combinations of shapes and opening angles, are evaluated by transient analysis, vorticity analysis,...
Insulated gate bipolar transistors are the power semiconductors used for high current applications as a switching device. It is widely used in electrical and hybrid vehicles. It has become increasingly important to understand the reliability of these modules. The lifetime prediction is based on the assumption that the solder interconnections are the weakest part of the module assembly and that the...
Analytical models of stress and deformxation of through-silicon vias (TSV), relative to numerical ones, have the advantage of being inexpensive to evaluate and in providing insight. They have the additional advantage of allowing one to embed them in ECAD tools for real time design decisions. Motivated by this reasoning, in this paper, an analytical model for the three-dimensional state of stress in...
Modern electronics feature high surface heat fluxes, particularly at localized hot spots, which can be detrimental to chip performance. While techniques have been developed to alleviate these local effects, they are typically advanced solutions using embedded cooling devices. Instead, an effective, less aggressive solution involves the adaptation of traditional micro-channel cooling to the particular...
Laminar mixed convection heat transfer in a two dimensional symmetrically and partially heated vertical channel is investigated. The heated portions exist on the both walls of channel and their temperature is constant. The number of the heated portions is changed from 2 to 4 for each wall; however the total length of the heated portions is fixed. The fluid inlet velocity is uniform and air is taken...
Heat exchangers are important facilities used in data center cooling systems. The effectiveness of the heat exchangers strongly influences the thermal performance of the cooling systems. Rear door heat exchangers, in-row, overhead coolers and fully contained cabinets are some examples of executing liquid and hybrid cooling systems used in data centers. A liquid to liquid heat exchanger is an important...
In 2011 IBM announced the Power 775 Supercomputing node/system which, for the time, was a monumental leap forward in computing performance and energy efficiency. The system was designed from the start with water cooling in mind. The result: a system with greater than 95% of its heat load conducted directly to water and a system that, together with a rear door heat exchanger, removes 100% of its heat...
Over the past few years there has been a steep upward trend in power consumption in electronic equipment, which in turn has led to more dissipation of heat. The current air-cooling technology has started to show limitations for high heat flux cooling. On the other hand, there are still barriers to the adoption of liquid-cooling technology such as higher procurement and operational costs, reliability...
We analyzed a new approach on porous metal heat sinks for highly integrated electronic applications aiming to address the exponential increase in the thermal management requirements of higher coefficient of performance (COP). Since the applications will be targeted to electronics cooling, we particularly look into air as the working fluid. The large area-to-volume ratio of porous structures could...
This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures.
The traditional approach of thermo-mechanical (T-M) reliability modeling is based on power cycle events. This approach is not useful for products which are rarely powered down, because power cycles alone do not capture all the reliability stress from temperature variation over these products' use life. This paper describes a methodology to determine the temperature cycle requirements for products...
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