scholarly journals Fast simulation of transient temperature distributions in power modules using multi-parameter model reduction

2019 ◽  
Vol 2019 (17) ◽  
pp. 3603-3608 ◽  
Author(s):  
Xiaojun Dong ◽  
Antonio Griffo ◽  
Jiabin Wang
Keyword(s):  
Model Reduction ◽  
Transient Temperature ◽  
Fast Simulation ◽  
Temperature Distributions ◽  
Power Modules

The Transient Temperature Distribution in a Slab Subject to Thermal Radiation

1965 ◽  
Vol 87 (1) ◽  
pp. 117-130 ◽  
Author(s):  
R. D. Zerkle ◽  
J. Edward Sunderland
Keyword(s):  
Temperature Distribution ◽  
Thermal Radiation ◽  
Radiant Heat ◽  
Analog Computer ◽  
Graphical Form ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Temperature Distributions ◽  
Approximate Analytical Solutions ◽  
Wide Range

The transient, one-dimensional temperature distribution is determined for a slab, insulated on one face, and subjected to thermal radiation at the other face. The slab is initially at a uniform temperature and is assumed to be homogeneous, isotropic, and opaque; the physical properties are assumed to be independent of temperature. Transient temperature distributions for both heating and cooling situations are obtained by means of a thermal-electrical analog computer. A diode limiter circuit is used to simulate the nonlinear radiant heat flux. The transient temperature distributions are presented in a dimensionless, graphical form for a wide range of variables. Approximate analytical solutions are also given which complement and extend the solution charts over ranges of parameters not covered in the charts.

Minimizing Burrs and Defects on Microstructures with Laser Assisted Micromachining Technology

2016 ◽  
Vol 10 (6) ◽  
pp. 891-898 ◽  
Author(s):  
Shaolin Xu ◽  
◽  
Shinsaku Osawa ◽  
Ryuichi Kobayashi ◽  
Keita Shimada ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
High Efficiency ◽  
Maximum Shear Stress ◽  
Electroless Nickel ◽  
Transient Temperature ◽  
Experimental Conditions ◽  
Optical Components ◽  
Temperature Distributions ◽  
Periodic Microstructures ◽  
Cutting Processes

Molding technology is widely used to manufacture optical components because of its high efficiency. Along with the quick development of miniaturization in industry, the detrimental effects of previously negligible burrs and defects on mold surfaces have become significant to the performance of components, so these problems should be minimized. In this study, a laser assisted micromachining method was developed to solve this problem during the fabrication of periodic microstructures on a molding material of electroless nickel-phosphorus (NiP) plating. The transient temperature distributions of the workpiece under laser irradiation and the change in the maximum shear stress during the laser assisted micromachining process were simulated to set appropriate experimental conditions. Then, periodic micropyramid structures were fabricated by both conventional cutting and the laser assisted cutting processes. Results show that defects largely decreased on machined structures with the assistance of laser irradiation. The decrease in specific cutting force and the change of chips’ morphology were also utilized to analyze the reasons for this improvement.

Transient temperature distribution in insulated pavements—predictions vs. observations

1970 ◽  
Vol 7 (3) ◽  
pp. 275-284 ◽  
Author(s):  
D. M. Ho ◽  
M. E. Harr ◽  
G. A. Leonards
Keyword(s):  
Transient Temperature ◽  
Site Conditions ◽  
Two Dimensional ◽  
Ambient Conditions ◽  
Layered Systems ◽  
Temperature Variations ◽  
Finite Difference Technique ◽  
Transient Temperature Distribution ◽  
Temperature Distributions ◽  
Number Of Layers

Based on a finite difference technique, computer programs have been developed whereby temperature variations in layered systems as a function of position and time may be computed under conditions of both one- and two-dimensional heat flow by conduction. No limitations are imposed on the number of layers, or on the form of the initial and boundary temperature conditions. Variations in thermal properties of the materials with temperature and location, and the non-linear relation between amount of water frozen as a function of temperature, are directly taken into account. Comparison of predictions with actual measurements demonstrate that accurate forecasts of temperature distributions as a function of time can be made when prevailing ambient conditions are known. Even if the site conditions can be evaluated only approximately sufficiently reliable predictions can be made for design purposes.

Transient Temperature Distributions in a Cylinder Heated by Microwaves

1996 ◽  
Vol 430 ◽  
Author(s):  
H. W. Jackson ◽  
M. Barmatz ◽  
P. Wagner
Keyword(s):  
Numerical Solutions ◽  
Single Mode ◽  
Dielectric Constants ◽  
Microwave Cavity ◽  
Transient Temperature ◽  
Hybrid Heating ◽  
Fine Mesh ◽  
Temperature Distributions ◽  
Analytic Expressions ◽  
Lossy Dielectric

AbstractTransient temperature distributions were calculated for a lossy dielectric cylinder coaxially aligned in a cylindrical microwave cavity excited in a single mode. Results were obtained for sample sizes that range from fibers to large cylinders. Realistic values for temperature dependent complex dielectric constants and thermophysical properties of the samples were used. Losses in cavity walls were taken into account as were realistic thermal emissivities at all surfaces. For a fine mesh of points in time, normal mode properties and microwave power absorption profiles were evaluated using analytic expressions. Those expressions correspond to exact solutions of Maxwell's equations within the framework of a cylindrical shell model. Heating produced by the microwave absorption was included in self-consistent numerical solutions of thermal equations. In this model, both direct microwave heating and radiant heating of the sample (hybrid heating) were studied by including a lossy dielectric tube surrounding the sample. Calculated results are discussed within the context of two parametric studies. One is concerned with relative merits of microwave and hybrid heating of fibers, rods, and larger cylinders. The other is concerned with thermal runaway.

Microscale Radiation Effects in Multilayer Thin-Film Structures During Rapid Thermal Processing

1993 ◽  
Vol 303 ◽  
Author(s):  
Peter Y. Wong ◽  
Christopher K. Hess ◽  
Ioannis N. Miaoulis
Keyword(s):  
Thin Film ◽  
Numerical Model ◽  
Thermal Processing ◽  
Radiation Effects ◽  
Rapid Thermal Processing ◽  
Chemical Vapor ◽  
Film Structure ◽  
Transient Temperature ◽  
Multilayered Structures ◽  
Temperature Distributions

ABSTRACTThe individual film thicknesses of multilayered structures processed by rapid thermal processing are of the same order as the wavelengths of the incident radiation. This induces optical interference effects which are responsible for the strong dependency of surface reflectivity, emissivity, and temperature distributions on the geometry of the layering structures, presence of patterns, and thickness of the films. A two-dimensional, finitedifference numerical model has been developed to investigate this microscale radiation phenomena and identify the critical processing parameters which affect rapid thermal processing of multilayer thin films. The uniformity of temperature distributions throughout the wafer during rapid thermal processing is directly affected by incident heater configurations, ramping conditions, wafer-edge effects, and thin-film layering structure. Results from the numerical model for various film structures are presented for chemical vapor deposition of polycrystalline silicon over oxide films on substrate. A novel technique using an edge-enhanced wafer which has a different film structure near its edge is presented as a control over the transient temperature distribution.

Aerodynamic Heating Numerical Simulation of Terminal-Sensitive Projectile at Deceleration and Despinning Trajectory

2013 ◽  
Vol 376 ◽  
pp. 317-322
Author(s):  
Jun Zhang ◽  
Rong Zhong Liu ◽  
Rui Guo ◽  
Xiao Dong Ma
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Thermal Protection ◽  
Thermal Characteristics ◽  
Simulation Method ◽  
Aerodynamic Heating ◽  
Transient Temperature ◽  
Physical Parameters ◽  
Temperature Distributions ◽  
Infrared Signature

Aero-heating problem severely affects the performance of terminal-sensitive projectile (TSP) when projected out of the carrier capsule by the gunpowder gas at a high speed. In this paper, based on the typical ballistic data and airflow physical parameters at deceleration and despinning trajectory, the aerodynamic thermal characteristics of a TSP was simulated by Fluent, and the transient temperature distributions were obtained under the different flying conditions. Finally, we got stagnation temperatures by the numerical simulations which were similar to those by the engineering evaluation, and demonstrate the effectiveness of the simulation method. The results are valuable to the research of thermal protection and infrared signature of TSP.

scholarly journals Research on parameter estimation in ultrasonic measurement of internal transient temperature distributions

2016 ◽  
Vol 46 (5) ◽  
pp. 509-517
Author(s):  
Bo QIU ◽  
YeWei GUI ◽  
Lei ZENG ◽  
YouAn SHI ◽  
WeiQi QIAN ◽  
...  
Keyword(s):  
Parameter Estimation ◽  
Ultrasonic Measurement ◽  
Transient Temperature ◽  
Temperature Distributions
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