scholarly journals Modelling thermal properties of large LED modules

2019 ◽  
Vol 37 (4) ◽  
pp. 628-638 ◽  
Author(s):  
Przemysław Ptak ◽  
Krzysztof Górecki ◽  
Barbara Dziurdzia
Keyword(s):  
Thermal Properties ◽  
Temperature Distribution ◽  
Power Dissipation ◽  
Thermal Model ◽  
Parameters Estimation ◽  
Internal Temperature ◽  
Practical Usefulness ◽  
Good Agreement

AbstractIn this paper a problem of modelling thermal properties of large LED modules is considered. The compact thermal model of such modules is proposed. The form of this model is presented and a method of parameters estimation is described. The practical usefulness of this model is verified experimentally by comparing the results of calculations and measurements of internal temperature of selected LEDs included in LED modules. The modules were fabricated by Fideltronic, Poland and measurements of temperature distribution on the surface of the modules at selected variants of power dissipation were performed at the Gdynia Maritime University. Good agreement between the results of measurements and modelling was obtained.

scholarly journals Measurements and Computations of Internal Temperatures of the IGBT and the Diode Situated in the Common Case

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 210
Author(s):  
Paweł Górecki ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Properties ◽  
Measurement Error ◽  
Thermal Model ◽  
Bipolar Transistor ◽  
Internal Temperature ◽  
Self Heating ◽  
Factors Influencing ◽  
Proposed Model ◽  
The Common ◽  
Transient Thermal

This article proposes effective methods of measurements and computations of internal temperature of the dies of the Insulted Gate Bipolar Transistor (IGBT) and the diode mounted in the common case. The nonlinear compact thermal model of the considered device is proposed. This model takes into account both self-heating phenomena in both dies and mutual thermal couplings between them. In the proposed model, the influence of the device internal temperature on self and transfer thermal resistances is taken into account. Methods of measurements of each self and transfer transient thermal impedances occurring in this model are described and factors influencing the measurement error of these methods are analysed. Some results illustrating thermal properties of the investigated devices including the IGBT and the antiparallel diode in the common case are shown and discussed. Computations illustrating the usefulness of the proposed compact thermal model are presented and compared to the results of measurements. It is proved that differences between internal temperature of both dies included in the TO-247 case can exceed even 15 K.

Impact of Cargo Stacking Modes on Temperature Distribution Inside Marine Reefer Containers

2017 ◽  
Vol 25 (03) ◽  
pp. 1750020 ◽  
Author(s):  
Ankang Kan ◽  
Jin Hu ◽  
Zhipeng Guo ◽  
Chuang Meng ◽  
Chen Chao
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Internal Temperature ◽  
Temperature Distributions ◽  
Key Factor ◽  
Simulation Results ◽  
Cfd Method ◽  
Sidewall Surface ◽  
Good Agreement

The refrigerated/chilled quality of marine cargo is vitally influenced by the temperature distribution inside reefer container. The stacking mode is a key factor affecting temperature distribution. CFD method is employed to model and simulate a 20-ft standard reefer container, in which seven cargo stacking modes are emulated to numerically analyze the internal temperature distribution inside the container. The stacking cargo is assumed as solid stack without heat release and the variables, such as stack number, height, length and gap, are considered in seven simulation cases. The results show that the temperature distributions become disordered along with increase in the stack height; the temperature difference increase along with increase in the stack length; the temperature tends to be isothermal when the gap of the stacks or the space between the stack and sidewall surface is enlarging. The simulation results are in very good agreement with the experimental results.

Experimental Analysis and Numerical Modeling of Microwave Reheating of Cylindrically Shaped Instant Rice

2014 ◽  
Vol 10 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Daming Fan ◽  
Chunxiang Li ◽  
Yi Li ◽  
Wei Chen ◽  
Jianxin Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Internal Temperature ◽  
Microwave Application ◽  
Cooked Rice ◽  
Temperature Distributions ◽  
Rice Samples ◽  
Good Agreement

Abstract The purpose of this study was to develop a numerical model to predict the temperature distribution in cylindrically shaped cooked rice samples during microwave reheating and to give impetus to a uniform microwave-heating design. Cylindrically shaped instant rice was reheated by continuous microwave application, and the sample temperature was measured to determine the internal temperature profile which resulted in a desired uniformity of temperature observed using the non-uniformity temperature evaluation. A finite difference method was used to predict the temperature distribution of the cylindrical rice during microwave reheating and applying Lambert’s law to calculate the microwave power absorption in a large sample of cylindrically shaped instant rice. In order to solve the numerical model of heat transfer, the thermal and dielectric properties of instant rice were measured with respect to temperature. Our results showed that the temperature had a significant effect on the specific heat and dielectric loss of rice, while the thermal conductivity and dielectric constant were unaffected. The numerically predicted temperature distributions were in good agreement with the measured ones of instant rice.

Simulation and Analysis of the Temperature Rising for Cylindrical Power Batteries

2012 ◽  
Vol 512-515 ◽  
pp. 982-985
Author(s):  
Peng Liang ◽  
Mao De Li
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
Thermal Model ◽  
Cfd Simulation ◽  
Internal Resistance ◽  
Operating Conditions ◽  
High Rate ◽  
Simulation Tool ◽  
Internal Temperature ◽  
Temperature Range

Whatever types of batteries, when they work out of the normal temperature range, their performances greatly worsen. When the battery charges or discharges in a high rate, it would be quite possible to arouse thermal runaway had the heat generated not dissipated properly. This article commits itself to take the variation of the battery internal resistance into account to revise the overall temperature rising curve based on a simplified battery thermal model. By carrying out necessary experiments and using CFD simulation tool we get a better battery temperature rising curve and contour of internal temperature distribution under different operating conditions. It is applicable to provide reference for the thermal management of power batteries.

Error in Temperature Measurements Due to Conduction Along the Sensor Leads

1976 ◽  
Vol 98 (3) ◽  
pp. 491-495 ◽  
Author(s):  
B. S. Singh ◽  
A. Dybbs
Keyword(s):  
Temperature Distribution ◽  
The Body ◽  
True Temperature ◽  
Measured Temperature ◽  
Internal Temperature ◽  
Sensing Element ◽  
First Approximation ◽  
Immersion Thermocouple ◽  
Thermocouple Wire ◽  
Good Agreement

When a sensor is embedded in a solid body to measure its internal temperature, any conduction to, or from, its sensing element may cause the indicated temperature to be different from the true temperature. This paper describes an analysis of the error caused by conduction when there is an arbitrary temperature distribution in thebbody along the sensor. The sensor is modeled as a cylindrical fin and the appropriate conduction equation is solved. The solution gives a correction for the error which depends on such parameters as, depth of immersion, thermocouple wire and insulation properties, contact between the sensor and the body, and temperature distribution in the body. The latter may not be known, but the measured temperature distribution can be used as a first approximation. The corrected value can then be used to obtain a better estimate of the error. The results show good agreement with experimental observations.

Correlation of Electronic and Thermal Properties of Short Channel nMOSFETS

1999 ◽  
Author(s):  
M. Palaniappan ◽  
V. Ng ◽  
R. Heiderhoff ◽  
J.C.H. Phang ◽  
G.B.M. Fiege ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Hot Spots ◽  
Light Emission ◽  
Photon Emission ◽  
Thermal Image ◽  
Short Channel ◽  
Physical Phenomena ◽  
Backside Illuminated

Abstract Light emission and heat generation of Si devices have become important in understanding physical phenomena in device degradation and breakdown mechanisms. This paper correlates the photon emission with the temperature distribution of a short channel nMOSFET. Investigations have been carried out to localize and characterize the hot spots using a spectroscopic photon emission microscope and a scanning thermal microscope. Frontside investigations have been carried out and are compared and discussed with backside investigations. A method has been developed to register the backside thermal image with the backside illuminated image.

scholarly journals Simulation of Thermal and Electric Field Distribution in Packaged Sausages Heated in a Stationary Versus a Rotating Microwave Oven

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1622
Author(s):  
Wipawee Tepnatim ◽  
Witchuda Daud ◽  
Pitiya Kamonpatana
Keyword(s):  
Temperature Distribution ◽  
Electric Field ◽  
Three Dimensional ◽  
Development Stage ◽  
Microwave Oven ◽  
Computational Time ◽  
Plastic Package ◽  
Heating Uniformity ◽  
The Cost ◽  
Good Agreement

The microwave oven has become a standard appliance to reheat or cook meals in households and convenience stores. However, the main problem of microwave heating is the non-uniform temperature distribution, which may affect food quality and health safety. A three-dimensional mathematical model was developed to simulate the temperature distribution of four ready-to-eat sausages in a plastic package in a stationary versus a rotating microwave oven, and the model was validated experimentally. COMSOL software was applied to predict sausage temperatures at different orientations for the stationary microwave model, whereas COMSOL and COMSOL in combination with MATLAB software were used for a rotating microwave model. A sausage orientation at 135° with the waveguide was similar to that using the rotating microwave model regarding uniform thermal and electric field distributions. Both rotating models provided good agreement between the predicted and actual values and had greater precision than the stationary model. In addition, the computational time using COMSOL in combination with MATLAB was reduced by 60% compared to COMSOL alone. Consequently, the models could assist food producers and associations in designing packaging materials to prevent leakage of the packaging compound, developing new products and applications to improve product heating uniformity, and reducing the cost and time of the research and development stage.

Analysis of Tempering and Rehardening for Grinding of Hardened Steels

1991 ◽  
Vol 113 (4) ◽  
pp. 388-394 ◽  
Author(s):  
O. B. Fedoseev ◽  
S. Malkin
Keyword(s):  
Thermal Properties ◽  
Heat Source ◽  
Hardened Steel ◽  
Temperature History ◽  
Hardness Distribution ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Reaction Equations ◽  
Rate Controlling Step ◽  
Good Agreement

An analysis is presented to predict the hardness distribution in the subsurface of hardened steel due to tempering and rehardening associated with high temperatures generated in grinding. The grinding temperatures are modeled with a triangular heat source at the grinding zone and temperature-dependent thermal properties. The temperature history, including the effect of multiple grinding passes, is coupled with thermally activated reaction equations for tempering and for reaustenitization which is the rate controlling step in rehardening. Experimental results from the literature are found to be in good agreement with the analytical predictions.

Electrothermal analysis of integrated circuits: a realization by infrared thermography

2021 ◽  
Author(s):  
Farnoos Farrokhi
Keyword(s):  
Temperature Distribution ◽  
Integrated Circuits ◽  
Power Dissipation ◽  
Electronic Device ◽  
Power Measurement ◽  
Device Under Test ◽  
Distribution Analysis ◽  
Ir Thermography ◽  
Temperature Dependent ◽  
Run Time

The International Technology Roadmap for Silicon (ITRS) predicted that by the year 2016, a high-performance chip could dissipate as much as 300 W/cm² of heat. Another more noticeable thermal issue in IC's is the uneven temperature distribution. Increased power dissipation and greater temperature variation highlight the need for electrothermal analysis of electronic components. The goal of this research is to develop an experimental infrared measurement technique for the thermal and electrothermal analysis of electronic circuits. The objective of the electrothermal analysis is to represent the behavior of the temperature dependent characteristics of electronic device in near real work condition. An infrared (IR) thermography setup to perform the temperature distribution analysis and power dissipation measurement of the device under test is proposed in this reasearch. The system is based on a transparent oil heatsink which captures the thermal profile and run-time power dissipation from the device under test with a very fine degree of granularity. The proposed setup is used to perform the thermal analysis and power measurement of an Intel Dual Core E2180 processor. The power dissipation of the processor is obtained by calculating and measuring the heat transfer coefficient of the oil heatsink. Moreover, the power consumption of the processor is measured by isolating the current used by the CPU at run time. A three-dimensional fininte element thermal model is developed to simulate the thermal properties of the processor. The results obtained using this simulation is compared to the experimental results from IR thermography. A methodology to perform electrothermal analysis on integrated circuits is introduced. This method is based on coupling a standard electrical simulator, which is often used in the design process, and IR thermography system through an efficient interface program. The proposed method is capable of updating the temperature dependent parameters of device in near real time. The proposed method is applied to perform electrothermal analysis of a power MOSFET to measure the temperature distribution and the device performance. The DC characteristics of the device are investigated. The obtained results indicated that the operating point, I-V characteristics and power dissipation of the MOSFET vary significantly with temperature.

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