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 Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings Under Dynamic Loading

1998 ◽  
Vol 120 (2) ◽  
pp. 405-409 ◽  
Author(s):  
P. Monmousseau ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Steady State ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Tilting Pad ◽  
Transient Period ◽  
Final Steady State ◽  
Tilting Pad Journal Bearings

Nowadays, tilting-pad journal bearings are submitted to more and more severe operating conditions. The aim of this work is to study the thermal and mechanical behavior of the bearing during the transient period from an initial steady state to a final steady state (periodic). In order to study the behavior of this kind of bearing under dynamic loading (Fdyn) due to a blade loss, a nonlinear analysis, including local thermal effects, realistic boundary conditions, and bearing solid deformations (TEHD analysis) is realized. After a comparison between theoretical results obtained with four models (ISO, ADI, THD, and TEHD) and experimental data under steady-state operating conditions (static load Ws), the evolution of the main characteristics for three different cases of the dynamic load (Fdyn/Ws < 1, Fdyn/Ws = 1 and Fdyn//Ws > 1) is discussed. The influence of the transient period on the minimum film thickness, the maximum pressure, the maximum temperature, and the shaft orbit is presented. The final steady state is obtained a long time after the appearance of a dynamic load.

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.

Considerations about Maximum Temperature of Toroidal Transformers in Steady-State Conditions

2020 ◽  
Vol 7 (1) ◽  
pp. 22-29
Author(s):  
Adrian Pleșca ◽  
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Ambient Temperature ◽  
Electric Current ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Maximum Difference ◽  
Novel Method ◽  
Theoretical Results

In this paper, a novel method based on a thermal mathematical model which includes the main geometrical, physical and thermal parameters of the toroidal transformer has been developed in order to obtain the maximum temperature inside the transformer during steady-state operating conditions. The influence of electric current and ambient temperature on the maximum temperature has been investigated. To validate the proposed method, some experimental tests have been done. The analyzed transformer had a rated power of 2kVA and the rated primary voltage of 230V. There is a good correlation between experimental and theoretical results with a maximum difference of 3°C.

CFD Simulation of the CANDU-6 Moderator Circulation Under Normal Operating Conditions

2002 ◽  
Author(s):  
Bo Wook Rhee ◽  
Churl Yoon ◽  
Byung-Joo Min
Keyword(s):  
Steady State ◽  
Cfd Simulation ◽  
Volumetric Flow Rate ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Outlet Temperature ◽  
Frictional Pressure Drop ◽  
The Core ◽  
Hydraulic Impedance ◽  
Center Region

A steady-state 3D simulation for predicting the local subcooling of the moderator in the vicinity of the calandria tubes in a CANDU-6 reactor is performed. For the current simulation, a set of grid structures with the same geometry as the CANDU-6 moderator tank, called ‘calandria vessel’, is generated and the momentum, heat and continuity equations are solved by CFX-4.3, a CFD code developed by AEA technology. The standard k-ε turbulence model associated with logarithmic wall treatment is used to model turbulence generation and dissipation within the vessel. The moderator fluid is heavy water. Buoyancy forces are modeled using the Boussinesq approximation in which density is assumed to be a linear function of temperature. The matrix of the calandria tubes in the center region of the calandria vessel is simplified by the porous media approach. The anisotropic hydraulic impedance of the calandria tubes is modeled using the frictional pressure drop correlations suggested by Idelchik and Szymanski. The heat load in this steady-state simulation is conservatively set as 103 MW of 103% full power, consisting of 96.7 MW to the core region and 6.3 MW to the reflector region. The total volumetric flow rate through eight inlet nozzles is 940 L/s and the outlet temperature is constantly 71.0 °C. The thermal boundary condition of the circumferential vessel wall is assumed a little heat flux out. As a result, the velocity field and temperature distribution of a CANDU-6 moderator in the operating condition are presented. The flow pattern identified in this simulation is the weak jet momentum-dominated flow, which is generated by the interaction between the buoyancy force by heating and the dominant momentum forces by inlet jets. The calculated maximum temperature of the moderator is 83.0 °C at the lower center region of the core, which corresponds to the minimum subcooling of 33.0 °C considering the boiling point increase due to the hydrostatic pressure change.

scholarly journals Transient Thermal Response of Turbulent Compressible Boundary Layers

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Hongwei Li ◽  
M. Razi Nalim ◽  
Charles L. Merkle
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Laminar Flow ◽  
Thermal Boundary Layer ◽  
Thermal Response ◽  
Thermal Conditions ◽  
Steady State Solution ◽  
Similarity Transformations ◽  
Keller Box Method ◽  
Transient Thermal

A numerical method is developed with the capability to predict transient thermal boundary layer response under various flow and thermal conditions. The transient thermal boundary layer variation due to a moving compressible turbulent fluid of varying temperature was numerically studied on a two-dimensional semi-infinite flat plate. The compressible Reynolds-averaged boundary layer equations are transformed into incompressible form through the Dorodnitsyn–Howarth transformation and then solved with similarity transformations. Turbulence is modeled using a two-layer eddy viscosity model developed by Cebeci and Smith, and the turbulent Prandtl number formulation originally developed by Kays and Crawford. The governing differential equations are discretized with the Keller-box method. The numerical accuracy is validated through grid-independence studies and comparison with the steady state solution. In turbulent flow as in laminar, the transient heat transfer rates are very different from that obtained from quasi-steady analysis. It is found that the time scale for response of the turbulent boundary layer to far-field temperature changes is 40% less than for laminar flow, and the turbulent local Nusselt number is approximately 4 times that of laminar flow at the final steady state.

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 Response of Servers Through Air Temperature Measurements

2013 ◽  
Author(s):  
Hamza Salih Erden ◽  
H. Ezzat Khalifa ◽  
Roger R. Schmidt
Keyword(s):  
Thermal Conductance ◽  
Thermal Characteristics ◽  
Thermal Response ◽  
Operating Conditions ◽  
Cfd Analysis ◽  
Capacitance Measurements ◽  
Thermal Capacitance ◽  
Transient Thermal ◽  
Transient Thermal Response ◽  
Unsteady Conditions

Transient CFD analysis of data centers requires appropriate representations of the transient thermal characteristics of servers. Thermal conductance and thermal capacitance are two determining characteristics for the response of servers under unsteady conditions. Previous studies proposed tests that require detailed temperature and thermal capacitance measurements for each of the server component, requiring access to individual components inside the server. In this paper, we propose a method for obtaining the transient thermal characteristics of a server from server inlet and outlet temperatures under transient operating conditions.

Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings Under Dynamic Loading

1997 ◽  
Author(s):  
Pascal Monmousseau ◽  
Michel Fillon ◽  
Jean Frêne
Keyword(s):  
Steady State ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Tilting Pad ◽  
Transient Period ◽  
Final Steady State ◽  
Tilting Pad Journal Bearings

Nowadays, the tilting-pad journal bearings are submitted to more and more severe operating conditions. The aim of this work is to study the thermal and mechanical behavior of the bearing during the transient period from an initial steady-state to a final steady-state (periodic). In order to study the behavior of this kind of bearing under dynamic loading (Fdyn) due to a blade loss, a nonlinear analysis, including local thermal effects, realistic boundary conditions and bearing solid deformations (TEHD analysis) is realized. After a comparison between theoretical results obtained with four models (ISO, ADI, THD and TEHD) and experimental data under steady-state operating conditions (static load Ws), the evolution of the main characteristics for three different cases of the dynamic load (Fdyn/Ws<1, Fdyn/Ws=1 and Fdyn/Ws>1) is discussed. The influence of the transient period on the minimum film thickness, the maximum pressure, the maximum temperature and the shaft orbit is presented. The final steady-state is obtained a long time after the appearance of a dynamic load.

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.

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