scholarly journals Numerical simulation of heat transfer and temperature distribution in a printed circuit board enclosure model for different geometries and Reynolds numbers

2014 ◽  
Author(s):  
S. Varela ◽  
G. Usera ◽  
A. Vernet ◽  
J. A. Ferré
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Distribution ◽  
Printed Circuit Board ◽  
Reynolds Numbers ◽  
Circuit Board ◽  
Printed Circuit

Numerical Simulation of Conjugate Heat Transfer From Multiple Electronic Module Packages Cooled by Air

2003 ◽  
Author(s):  
Hideo Yoshino ◽  
Motoo Fujii ◽  
Xing Zhang ◽  
Masud Behnia
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Conjugate Heat Transfer ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Heat Transfer Area ◽  
Printed Circuit ◽  
Effective Heat ◽  
Parallel Arrangement

This paper reports on the numerical simulation of conjugate heat transfer from multiple electronic module packages (45 × 45 × 2.4 mm) on a printed circuit board placed in a duct. The dimensions of the modules are the same as a single module package previously studied. In the series arrangement, two module packages are installed on the center of the printed circuit board along the airflow direction. In the parallel arrangement, two and/or four module packages are installed normal to the airflow direction. In the numerical simulations, the interval between the module packages was varied and three values were considered (45, 22.5 and 9 mm). The variation of the printed circuit board thermal conductivity was also considered and 0.3, 3 and 20 W/m/K were used with the mean velocity in the duct also at three different values (0.33, 0.67 and 1 m/s). In order to derive a non-dimensional correlation from the numerical results, the concept of the effective heat transfer area previously used for a single module package was used for the multiple module packages. For the series arrangement, the effects of the interval on the effective heat transfer area are relatively low, and the numerical results can be summarized with the same correlation obtained from the single module package. On the other hand, the effective heat transfer area for the parallel arrangement is strongly affected by the parallel interval and the thermal conductivity of printed circuit board. When the interval increases, the temperature of the module packages greatly reduces as the thermal conductivity of the printed circuit board increases.

Separation of Natural Convection and Radiation by Changing Rotational Acceleration

Volume 1 ◽  
2004 ◽  
Author(s):  
Arnout Willockx ◽  
Gilbert De Mey ◽  
Michel De Paepe ◽  
Boguslaw Wiecek ◽  
Mariusz Felczak ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Centripetal Force ◽  
Rotational Acceleration ◽  
Governing Equations ◽  
Total Heat Transfer ◽  
Closed Cavity ◽  
Printed Circuit

The objective is to separate natural convection and radiation experimentally. Therefore a heat source is placed inside a closed cavity and the acceleration inside the cavity can be changed. A centrifuge is used to change the acceleration. A flat resistor etched on a printed circuit board of 10mm × 48mm, is placed in a hermetically sealed cylinder, which hangs under the arm of the centrifuge. The resistor is powered by a battery, dissipates 0,35W and has a surface temperature of 60°C at 1g. Natural convection is maintained inside the cylinder. Conduction is reduced to a negligible amount by construction of the experiment, thus convection and radiation are the main modes of heat transfer. The rotational speed of the centrifuge determines the centrifugal force in the cylinder. When the centripetal force increases, the temperature of the resistor decreases due to the increase of natural convection. The amount of radiation and total heat transfer can be determined from the experiment, so the amount of natural convection can also be determined. The experimental results are compared with the governing equations to validate the experiment. The reproducibility of the experiment is also checked.

Thermal Performance of Microelectronic Substrates With Submillimeter Integrated Vapor Chamber

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Sangbeom Cho ◽  
Yogendra Joshi
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Printed Circuit Board ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Circuit Board ◽  
Working Fluid ◽  
Vapor Chamber ◽  
Conduction Model ◽  
Printed Circuit

We develop a vapor chamber integrated with a microelectronic packaging substrate and characterize its heat transfer performance. A prototype of vapor chamber integrated printed circuit board (PCB) is fabricated through successful completion of the following tasks: patterning copper micropillar wick structures on PCB, mechanical design and fabrication of condenser, device sealing, and device vacuuming and charging with working fluid. Two prototype vapor chambers with distinct micropillar array designs are fabricated, and their thermal performance tested under various heat inputs supplied from a 2 mm × 2 mm heat source. Thermal performance of the device improves with heat inputs, with the maximum performance of ∼20% over copper plated PCB with the same thickness. A three-dimensional computational fluid dynamics/heat transfer (CFD/HT) numerical model of the vapor chamber, coupled with the conduction model of the packaging substrate is developed, and the results are compared with test data.

Studying heat transfer on inclined printed circuit boards during vapour phase soldering

2017 ◽  
Vol 29 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Attila Geczy ◽  
Daniel Nagy ◽  
Balazs Illes ◽  
Laszlo Fazekas ◽  
Oliver Krammer ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Vapour Phase ◽  
Circuit Board ◽  
Efficient Production ◽  
Content Type ◽  
Printed Circuit ◽  
Heat Transfer Efficiency ◽  
Uneven Heating

Purpose The paper aims to present an investigation of heating during vapour phase soldering (VPS) on inclined printed circuit board (PCB) substrates. The PCB is a horizontal rectangular plate from the aspect of filmwise condensation with a given inclination setting. Design/methodology/approach The paper focuses on the measurement of temperature distribution on the PCBs with a novel setup immersed in the saturated vapour space. The measuring instrumentation is optimized to avoid and minimize vapour perturbing effects. Findings The inhomogeneity of the heating is presented according to the lateral dimensions of the PCB. The inclination improves temperature uniformity, improves heat transfer efficiency; however, a minor misalignment may affect the flow and result in uneven heating. Practical implications The results can be implemented for practical improvements in industrial ovens with the use of intended inclination. The improvements may consequently point to more efficient production and better joint quality. Originality/value The novel method can be used for deeper investigation of inclination during and can be complemented with numerical calculations. The results highlight the importance of precise PCB holding instrumentation in VPS ovens.

scholarly journals Modelling of temperature distribution along PCB thickness in different substrates during reflow

Circuit World ◽  
2019 ◽  
Vol 46 (2) ◽  
pp. 85-92
Author(s):  
Daniel Straubinger ◽  
István Bozsóki ◽  
David Bušek ◽  
Balázs Illés ◽  
Attila Géczy
Keyword(s):  
Heat Transfer ◽  
Printed Circuit Board ◽  
Vapour Phase ◽  
Circuit Board ◽  
Transfer Coefficients ◽  
Content Type ◽  
Printed Circuit ◽  
Heat Transfer Coefficients ◽  
Significant Temperature ◽  
The Difference

Purpose In this paper, analytical modelling of heat distribution along the thickness of different printed circuit board (PCB) substrates is presented according to the 1 D heat transient conduction problem. This paper aims to reveal differences between the substrates and the geometry configurations and elaborate on further application of explicit modelling. Design/methodology/approach Different substrates were considered: classic FR4 and polyimide, ceramics (BeO, Al2O3) and novel biodegradables (polylactic-acid [PLA] and cellulose acetate [CA]). The board thicknesses were given in 0.25 mm steps. Results are calculated for heat transfer coefficients of convection and vapour phase (condensation) soldering. Even heat transfer is assumed on both PCB sides. Findings It was found that temperature distributions along PCB thicknesses are mostly negligible from solder joint formation aspects, and most of the materials can be used in explicit reflow profile modelling. However PLA shows significant temperature differences, pointing to possible modelling imprecisions. It was also shown, that while the difference between midplane and surface temperatures mainly depend on thermal diffusivity, the time to reach solder alloy melting point on the surface depends on volumetric heat capacity. Originality/value Results validate the applicability of explicit heat transfer modelling of PCBs during reflow for different heat transfer methods. The results can be incorporated into more complex simulations and profile predicting algorithms for industrial ovens controlled in the wake of Industry 4.0 directives for better temperature control and ultimately higher soldering quality.

The restoration of temperature distribution in a two-dimensional domain by a tomographic method by using the results of measurements for electric resistance of oriented conductors

2018 ◽  
Author(s):  
В.А. Деревянко ◽  
А.Ф. Латыпов
Keyword(s):  
Mathematical Model ◽  
Temperature Distribution ◽  
Real Time ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Two Dimensional ◽  
Electronic Unit ◽  
Resistance Thermometer ◽  
Printed Circuit ◽  
Radio Electronic

Рассмотрена возможность использования “термометра сопротивления” для измерения распределения температуры в двумерной области. Создана математическая модель датчика, сводящаяся к решению томографической задачи. Важной особенностью модели является то, что число уравнений в системе линейных алгебраических уравнений (СЛАУ) больше числа переменных. Это позволяет уменьшить ошибки в исходных данных. Создана программа для определения решения СЛАУ с плохо обусловленной матрицей, позволяющая обрабатывать результаты измерений в реальном масштабе времени. Выполнен тестовый расчет. При малом числе ракурсов измерений получена удовлетворительная точность восстановления температуры. Purpose. To ensure a long period of active lifetime of space vehicles, it is necessary to use effective methods and means to control physical processes leading to premature failure of on-board radio electronic equipment both at the stage of ground testing and during active operation of the spacecraft in space. Long-term testing experience for electronic equipment shows that monitoring compliance with necessary temperature conditions of onboard equipment plays the main role in ensuring reliability. Ideally, the thermal control should be performed for all elements of radio electronic units in real time. Method. The possibility of using a “two-dimensional resistance thermometer” for recording the thermal field of a printed circuit board of an electronic unit is considered. The principle of operation of the thermometer is based on the measurement of integral resistances of extended mutually intersecting conductors in a medium with inhomogeneous temperature distribution. The registration of the integral resistances of individual conductors is possible with the help of an automated measuring system by solving the tomographic problem aimed to obtain the temperature distribution on the surface of the printed circuit board. Result. The design of the “two-dimensional temperature sensor” is considered. The sensor is technologically compatible with the design of the printed circuit board of the radio electronic unit. A mathematical model of the sensor is developed. It is reduced to the solution of a tomographic problem. A program for solving a system of linear equations with an ill-conditioned matrix is developed that provides the real-time processing for measurement results. The test calculation is performed. A satisfactory accuracy of the temperature restoration is achieved. Conclusion. A “two-dimensional resistance thermometer” can be used to measure a two-dimensional temperature field for a printed circuit board of a radio electronic unit in real time. The mathematical model allows adapting the thermometer design to a specific radio electronic unit and selecting the required accuracy of the temperature field restoration.

Evaluation of Effective Thermal Conductivity of Multilayer Printed Circuit Board

2011 ◽  
Author(s):  
Toshio Tomimura ◽  
Yoshihiro Shiotsu ◽  
Yasushi Koito ◽  
Masaru Ishizuka ◽  
Tomoyuki Hatakeyama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Printed Circuit Board ◽  
Evaluation Method ◽  
Circuit Board ◽  
Printed Circuit ◽  
Plane Direction ◽  
Simple Evaluation

To perform a rational thermal design of a printed circuit board (PCB) with highly anisotropic heat transfer nature in its initial stage, effective thermal conductivities in thickness direction and in in-plane direction must be given depending on the electric circuit of the board. However, a simple evaluation method for the effective thermal conductivities of such PCB has not been developed yet. In this study, as the first step to propose a simple evaluation method, the heat transfer coefficient by natural convection around a horizontal disk, which is indispensable for measuring the effective thermal conductivity, has been evaluated. Furthermore, the thermal conductivity of the glass epoxy resin in in-plane direction has been evaluated by applying the evaluated heat transfer coefficient, and then, the validity of the proposed thermal conductivity measurements of the anisotropic PCB has been confirmed.

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