Generation of reduced dynamic thermal models of electronic systems from time constant spectra of transient temperature responses

2011 ◽  
Vol 51 (8) ◽  
pp. 1351-1355 ◽  
Author(s):  
Marcin Janicki ◽  
Jedrzej Banaszczyk ◽  
Bjorn Vermeersch ◽  
Gilbert De Mey ◽  
Andrzej Napieralski
Keyword(s):  
Time Constant ◽  
Transient Temperature ◽  
Electronic Systems ◽  
Thermal Models ◽  
Temperature Responses ◽  
Reduced Dynamic

Thermal Behavior Evaluation During Mechanical Design: Validation of Thermal Numerical Gearbox Models

2000 ◽  
Author(s):  
Lionel Manin ◽  
Daniel Play
Keyword(s):  
Steady State ◽  
Experimental Validation ◽  
Mechanical Design ◽  
Numerical Models ◽  
Side Wall ◽  
Experimental Results ◽  
Transient Temperature ◽  
Transmitted Power ◽  
Thermal Models ◽  
Thermal Network Method

Abstract In todays mechanical design, static and dynamic numerical models are widely used, and thermal models are needed to make robust design. Thermal models, based on the thermal network method, are now available. Several hypotheses are made as physical phenomena are complex and experimental validation is necessary. A thermal model of gearbox has been already presented and compared to few experimental results that had allowed global validation of the model. Now, the experimental validation is concerned with thermal transient and steady state behavior of gearbox versus transmitted power and lubrication conditions in order to finely validate the model. The test gearbox is compound of 3 spur gears supported by 6 spherical roller bearings, a housing and a lubrication circuit cooled by an oil-air exchanger. The maximum transmitted power is 500 kW. Gears, bearings, housing, shafts, and the lubrication circuit have been equipped with thermocouples, flux-meters and flow-meters. Heat flux were measured on the internal and external side walls of the housing. Oil flowing on a side wall has been measured. Experiments were run under several transmitted powers and oil flows at meshing. Thermal map at steady state and transient temperature rises of technological elements are obtained for each test. Finally, transient temperature rises and steady state from numerical and experimental results are compared. The comparison shows a good agreement, and the importance of taking into account oil flowing on the inside walls of the housing is brought to the fore. The difficulty of evaluating the oil flowing on the internal walls of a housing is discussed and illustrated with numerical results.

scholarly journals Transient temperature responses of beam load cell.

1985 ◽  
Vol 51 (461) ◽  
pp. 273-276
Author(s):  
Yukio KOJIMA ◽  
Michito UTSUNOMIYA ◽  
Seiji NISHIDE
Keyword(s):  
Load Cell ◽  
Transient Temperature ◽  
Temperature Responses

Transient Response Characteristics of Vapor Deposited Micro Heat Pipe Arrays

1995 ◽  
Vol 117 (1) ◽  
pp. 82-87 ◽  
Author(s):  
G. P. Peterson ◽  
A. K. Mallik
Keyword(s):  
Heat Pipe ◽  
Time Constant ◽  
Imaging System ◽  
Heat Pipes ◽  
Silicon Wafers ◽  
Thermal Time ◽  
Transient Temperature ◽  
Micro Heat Pipe ◽  
Thermal Time Constant ◽  
Micro Heat Pipes

The transient thermal response of vapor deposited micro heat pipe arrays fabricated as an integral part of silicon wafers was measured to determine if these arrays could be used to reduce the local temperature gradients and improve the reliability of semiconductor devices. Wafers with arrays of 34 and 66 micro heat pipes were evaluated using an IR thermal imaging system in conjunction with a VHS video recorder. These arrays occupied 0.75 and 1.45 percent, of the wafer cross-sectional area, respectively. The wafers with micro heat pipe arrays demonstrated a 30 to 45 percent reduction in the thermal time constant when compared to that obtained for plain silicon wafers. This reduction in response time was shown to lead to a significant reduction in the maximum wafer temperature, due to the increased effective thermal conductivity caused by the vaporization and condensation occurring in the individual micro heat pipes. The experimental results were then used to validate a transient numerical model, capable of accurately predicting the transient temperature profile and thermal time constant of the wafer/heat pipe combinations.

Compact Thermal Models: A Global Approach

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Mohamed-Nabil Sabry ◽  
Hossam Saleh Abdelmeguid
Keyword(s):  
Degrees Of Freedom ◽  
Quantitative Description ◽  
Operating Conditions ◽  
Electronic Systems ◽  
New Approach ◽  
Thermal Models ◽  
Cooling Devices ◽  
Precision Level ◽  
Access To Data ◽  
Level Of Analysis

The construction and usage of compact thermal models (CTMs), for the thermal analysis as well as the design of cooling devices for electronic systems, are reviewed. These models have many advantages over the so called detailed models based on 3D simulations, mainly being a convenient and simple quantitative description of the modeled object, when constructional details are either unavailable or too detailed to be of use at the desired level of analysis. However, CTMs have manifested some deficiencies in many cases, in particular, multiple chip modules (MCM) and stacked dies. The opposite approach, detailed modeling, is more reliable, although extremely heavy. A new approach is proposed that solves this dilemma by bridging the gap between compact and detailed models. While retaining all advantages of CTMs, i.e., having a limited number of degrees of freedom and not requiring detailed constructional features, it can attain any required precision level depending on the degree of complexity adopted. It gives reliable results covering all operating conditions including MCM and stacked dies. Moreover, it gives access to data on surface temperature gradients that were never obtained before by compact models and are highly important for reliability issues.

scholarly journals Variability, timescales, and non-linearity in climate responses to black carbon emissions

2018 ◽  
Author(s):  
Yang Yang ◽  
Steven J. Smith ◽  
Hailong Wang ◽  
Catrin M. Mills ◽  
Philip J. Rasch
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
Climate Models ◽  
The Arctic ◽  
Transient Temperature ◽  
Quasi Equilibrium ◽  
Earth System ◽  
Large Variability ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Black carbon (BC) particles exert a potentially large warming influence on the Earth system. Reductions in BC emissions have attracted attention as a possible means to moderate near-term temperature changes. For the first time, we evaluate regional climate responses, non-linearity, and short-term transient responses to BC emission perturbations in the Arctic, mid-latitudes, and globally based on a comprehensive set of emission-driven experiments using the Community Earth System Model (CESM). Surface temperature responses to BC emissions are complex, with surface warming over land from mid-latitude BC perturbations partially offset by ocean cooling. Climate responses do not scale linearity with emissions. While stronger BC emission perturbations have a higher burden efficiency, their temperature sensitivity is lower. BC impacts temperature much faster than greenhouse gas forcing, with transient temperature responses in the Arctic and mid-latitudes approaching a quasi-equilibrium state with a timescale of 2–3 years. We find large variability in BC-induced climate changes due to background model noise. As a result, perturbing present-day BC emission levels results in no discernible net global-average surface temperature signal. In order to better understand the climatic impacts of BC emissions, both the drivers of non-linear responses and response variability need to be assessed across climate models.

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