Efficient Thermal Analysis of Lab-Grown Diamond Heat Spreaders

2021 ◽  
Author(s):  
Zihao Yuan ◽  
Tao Zhang ◽  
Jeroen Van Duren ◽  
Ayse K. Coskun
Keyword(s):  
Steady State ◽  
Real World ◽  
High Performance ◽  
Silicon Layer ◽  
Maximum Temperature ◽  
Cooling Performance ◽  
Thermal Models ◽  
Heat Spreaders ◽  
Transient Simulations ◽  
Transient Thermal

Abstract Lab-grown diamond heat spreaders are becoming attractive solutions compared to traditional copper heat spreaders due to their high thermal conductivity, the ability to directly bond them on silicon, and allow for an ultra-thin silicon layer. Researchers have developed various thermal models and prototypes of lab-grown diamond heat spreaders to evaluate their cooling performance and heat spreading ability. The majority of existing thermal models are built using finite-element method (FEM) based simulators such as COMSOL and ANSYS. However, such commercial simulators are computationally expensive and lead to long solution times along with large memory requirements. These limitations make commercial simulators unsuitable for evaluating numerous design alternatives or runtime scenarios for real-world high-performance processors. Because of this modeling challenge, none of the existing works have evaluated the thermal behavior of lab-grown diamond heat spreaders on real-world high-performance processors running realistic application benchmarks. Recently, we have developed a parallel compact thermal simulator, PACT, that is able to carry out fast and accurate steady-state and transient thermal simulations and can be extended to support emerging integration and cooling technologies. In this paper, we use PACT to evaluate the steady-state and transient cooling performance of lab-grown diamond heat spreaders against traditional copper heat spreaders on various real-world high-performance processors (e.g., Intel i7 6950X, IBM Power9, and PicoSoC). By using PACT with architectural performance and power simulators such as Sniper and McPAT, we are able to run transient simulations with realistic benchmarks. Simulation results show that lab-grown diamond heat spreaders achieve maximum temperature and thermal gradient reductions of up to 26.73 °C and 13.75 °C when compared to traditional copper heat spreaders, respectively. The maximum steady-state and transient simulation times of PACT for the real-world high-performance chips and realistic applications used in our experiments are 259 s and 22 min, respectively.

Thermal Simulation Benchmark of Graphic Module Under Installed, Operating Conditions

2005 ◽  
Author(s):  
Fariborz Forghan ◽  
Gregory J. Kowalski ◽  
Mansour Zenouzi ◽  
Hameed Metghalchi
Keyword(s):  
Steady State ◽  
Computer Games ◽  
Electronic Device ◽  
Thermal Response ◽  
Thermal Simulation ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Software Environment ◽  
Transient Thermal ◽  
Graphic Module

The thermal performance of a graphic module on graphic card is theoretically and experimentally investigated. Unlike prior benchmark studies, this study involves a practical electronic device operating in a real software environment. The temperatures at five locations on the module and at one point on the board are measured as a function of time during the operation of a series of computer games. The theoretical model is developed using Flotherm to simulate the transient thermal response. There is close agreement from 3% to 10% between the numerical steady state case prediction and test data. The calculated transient trends using Flotherm model closely agree with experimental results and demonstrate the rapid increase in temperature as the number of module operations increases during the games. The results for the maximum temperature are directly linked to the software operation and exhibit a superposition type behavior in which the observed maximum operating temperature can exceed that estimated by steady state conditions. As expected, the results demonstrate that a carefully constructed thermal simulation can accurately predict the thermal response of a module under actual operating conditions.

Transient Thermal Effects and Heat Partition in Sliding Contacts

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
R. Bosman ◽  
M. B. de Rooij
Keyword(s):  
Steady State ◽  
Thermal Effects ◽  
Continuity Condition ◽  
Contact Temperature ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Heat Partition ◽  
Transient Thermal ◽  
State Assumption ◽  
Good Agreement

In tribological applications, calculating the contact temperature between contacting surfaces makes it possible to estimate lubricant failure and effectiveness, material failure, and other phenomena. The contact temperature can be divided into two scales: the macroscopic and the microscopic scales. In this article, a semi-analytical transient temperature model is presented, which can be used at both scales. The general theory is presented here and used to calculate the contact temperatures of single micro- and macrocontacts. For the steady state situation, the results obtained are in good agreement with those found in literature. Further, it is shown that the simplification of modeling a microcontact as an equivalent square uniform heat source to simplify the calculation of the maximum temperature is justified in the fully plastic regime. The partition is calculated by setting a continuity condition on the temperature field over the contact. From the results, it can be concluded that at low sliding velocities the steady state assumption, which is often used for microcontacts, is correct. However, at higher sliding velocities, the microcontact is not in the steady state and transient calculation methods are advised.

Transient Thermal Management of a Handset Using Phase Change Material (PCM)

2002 ◽  
Vol 124 (4) ◽  
pp. 419-426 ◽  
Author(s):  
Marc Hodes ◽  
Randy D. Weinstein ◽  
Stephen J. Pence ◽  
Jason M. Piccini ◽  
Lou Manzione ◽  
...  
Keyword(s):  
Steady State ◽  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
Maximum Temperature ◽  
Ir Camera ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Time Required ◽  
Transient Thermal

The power density of portable electronic devices continues to increase because packaging advances reduce their size even as features are added and enhanced. Designing thermal management systems to accommodate steady-state conditions as opposed to fixed duty cycles can substantially increase cost, size, and weight. The feasibility of transient thermal management of handsets using phase change materials (PCMs) was experimentally investigated using an ABS handset mock-up. At selected intervals of time, the nonuniform case temperature of the handset was measured using an infrared (IR) camera, while thermocouples measured the temperatures of the PCM and simulated power amplifier (heater). Transient and steady-state heat transfer rates by natural convective and radiation from the handset to the environment were numerically computed from the temperature data in the thermal images. The effects of PCM material, power supplied to the handset, and handset orientation on the time required for the handset case to reach a given (maximum) temperature and “recovery” time were examined.

Investigation of High Performance Heat Sink Characteristics in Forced Convection Cooling of Power Electronic Systems

2011 ◽  
Author(s):  
Giti Karimi-Moghaddam ◽  
Craig Rende ◽  
Richard D. Gould ◽  
Subhashish Bhattacharya
Keyword(s):  
Nusselt Number ◽  
Steady State ◽  
Forced Convection ◽  
Heat Sink ◽  
High Performance ◽  
Temperature Limit ◽  
Simulation Software ◽  
Temperature Fields ◽  
Junction Temperature ◽  
Maximum Temperature

This study presents the experimental performance of a high fin density heat sink for semiconductor power modules — such as IGBTs. As a case study a commercially available extruded heat sink has been chosen. By analyzing the steady-state maximum temperatures as well as various geometric orientations, Nusselt number correlations were found experimentally, which can be used to predict the performance of the heat sink. It was found that the experimental Nusselt number correlations can predict the performance of the heat sink to within a 10%. Furthermore, steady-state maximum temperature results showed that for low fan speeds (2 m/s–3 m/s), the device junction temperatures achieved a value no higher than 80°C, which is well below the junction temperature limit for 125°C for silicon power semiconductor devices. Furthermore, it was shown that for two heat sinks in series forced convection tests, gap spacing between the devices has a minimal effect on the overall performance. Also, a numerical simulation study using COMSOL Multiphysics simulation software to study flow and temperature fields has been conducted. These modeling results the thermal behavior of heat sink are validated by experimental measurements.

Transient Thermal Analysis of Cryogenic Liquid Hydrogen Tank With Active Circulation

2007 ◽  
Author(s):  
Son H. Ho ◽  
Muhammad M. Rahman
Keyword(s):  
Heat Pipe ◽  
Liquid Hydrogen ◽  
Cryogenic Liquid ◽  
Forced Flow ◽  
Maximum Temperature ◽  
Condenser Section ◽  
Working Pressure ◽  
Evaporator Section ◽  
Transient Simulations ◽  
Transient Thermal

This paper presents the transient analysis of fluid flow and heat transfer in a zero boil-off (ZBO) cryogenic storage tank of liquid hydrogen. The system includes a tank with cylindrical wall and oblate spheroidal top and bottom, a heat pipe located along the symmetric axis of the tank, and an active circulator. The heat pipe has a rounded evaporator section at its end. The active circulator is an assembly of a pump body, a suction tube for collecting fluid inside the tank, and a spray nozzle from which the fluid is discharged onto the evaporator section of the heat pipe, which is kept at a constant low temperature, where the heat is removed passively to the condenser section of the heat pipe located outside the tank and eventually to the ambient via a cryocooler. Whenever the maximum temperature inside the tank reaches the boiling point under the working pressure in the tank, the pump is activated to create a forced flow from the nozzle to cool off the heated fluid. After a preset period of time, the pump is shut down and standby until the maximum temperature reaches its threshold again and then the pump starts a new cycle. The transient simulations allow the visualization of flow field and temperature distribution, as well as the computation of maximum and mean temperatures of the fluid at various stages of the pump cycle.

scholarly journals Effects of operating and material parameters on the thermal characteristics of a wet clutch

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110341
Author(s):  
Zhigang Zhang ◽  
Ling Zou ◽  
Hang Liu ◽  
Yonglong Chen ◽  
Benzhu Zhang
Keyword(s):  
Heat Flux ◽  
Applied Pressure ◽  
Thermal Characteristics ◽  
Thermal Models ◽  
Material Parameters ◽  
Heat Transfer Theory ◽  
Friction Disk ◽  
Viscous Shear ◽  
Wet Clutch ◽  
Transient Thermal

Based on the frictional mechanism of a wet clutch, frictional models of wet clutch engagement were established using the modified Reynolds equation and the elastic contact model between frictional pairs. Then, the heat flux models for the viscous shear and asperity friction were built, and the two-dimensional transient thermal models for the separator plate, friction disk, and ATF heat convection model were deduced based on the heat transfer theory and conservation law of energy. Finally, the Runge–Kutta numerical method was used to solve the frictional and thermal models. The average temperature of the separator plate, friction disk, and ATF were calculated. The effects of operating and material parameters, such as applied pressure, initial angular velocity, friction lining permeability, surface combined roughness RMS, equivalent elastic modulus, and ATF flow, on the thermal characteristics of friction pairs and ATF during engagement, were studied. The simulation results show that the temperature characteristics of the separator plate, friction disk, and ATF depend mainly on the viscous shear and asperity friction heat flux, and that the operating and material parameters of the wet clutch also have significant impacts on the overall variation trend of the thermal characteristics of the separator plate, friction disk, and ATF.

Decreased Gamma Auditory Steady-State Response Is Associated With Impaired Real-World Functioning in Unmedicated Patients at Clinical High Risk for Psychosis

2020 ◽  
pp. 155005942098270
Author(s):  
Sarah Ahmed ◽  
Jennifer R. Lepock ◽  
Romina Mizrahi ◽  
R. Michael Bagby ◽  
Cory J. Gerritsen ◽  
...  
Keyword(s):  
Steady State ◽  
High Risk ◽  
Functional Impairment ◽  
Real World ◽  
Steady State Response ◽  
Clinical High Risk ◽  
State Response ◽  
Auditory Steady State Response ◽  
Gamma Synchrony ◽  
40 Hz

Aim Deficits in synchronous, gamma-frequency neural oscillations may contribute to schizophrenia patients’ real-world functional impairment and can be measured electroencephalographically using the auditory steady-state response (ASSR). Gamma ASSR deficits have been reported in schizophrenia patients and individuals at clinical high risk (CHR) for developing psychosis. We hypothesized that, in CHR patients, gamma ASSR would correlate with real-world functioning, consistent with a role for gamma synchrony deficits in functional impairment. Methods A total of 35 CHR patients rated on Global Functioning: Social and Role scales had EEG recorded while listening to 1-ms, 93-dB clicks presented at 40 Hz in 500-ms trains, in response to which 40-Hz evoked power and intertrial phase-locking factor (PLF) were measured. Results In CHR patients, lower 40-Hz PLF correlated with lower social functioning. Conclusions Gamma synchrony deficits may be a biomarker of real-world impairment at early stages of the schizophrenia disease trajectory.

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