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Abstract(s)
A constante evolução da microeletrónica, bem como a tendência de construir equipamentos com cada vez menor volume e maior poder de processamento, faz com que surjam problemas na gestão da carga térmica dos SoC’s (system on a chip) em situações nas quais que e necessário proteger os equipamentos dentro de uma caixa. Este trabalho estuda o desempenho térmico de um Raspberry Pi 3b+, em várias situações, tentando criar uma caixa que potencie a transmissão de calor por convecção natural. Primeiramente, o equipamento foi testado sem caixa e foi elaborado um modelo Computational Fluid Dynamics (CFD) que represente bem o seu comportamento térmico. Deste modelo, foram deduzidas as potencias térmicas dissipadas nos diversos componentes do Raspberry Pi 3b+. Sabendo as potencias térmicas dissipadas, testou-se o Raspberry Pi 3b+ dentro da caixa original, para perceber que problemas térmicos aparecem. No caso, o processador atinge a temperatura limite de 80oC e ativa um processo que limita a sua velocidade (throttling). Para tentar resolver esse problema, desenvolveram-se mais duas caixas, Caixa P1 e Caixa P2. A Caixa P1 tem o mesmo volume que a caixa original, tendo-se apenas criado grelhas para promover a circulação do ar. Segundo as simulações, a Caixa P1, ainda nao e capaz de evitar o throttling do processador, apesar de as temperaturas atingidas serem inferiores as atingidas com a caixa original. A Caixa P2, tem um volume superior, o que permite aumentar ainda mais a área das grelhas. Analisando os resultados, verifica-se que as temperaturas atingidas com esta caixa já evitam o throttling do processador. Por fim, utilizou-se uma impressora 3D para imprimir a Caixa P2 e testou-se o seu desempenho, confirmando os dados obtidos via CFD.
This work studies the thermal performance of a Raspberry Pi 3b+, in different conditions, trying to project a box that stimulates the heat transfer via natural convection. Firstly, the equipment was tested wihtout a box and a CFD (Computational Fluid Dynamics) model, that accurately represents it’s thermal behaviour, was developed. The thermal power dissipated in the Raspberry Pi 3b+ componentes was determined from this model. Knowing the power dissipated, the Raspberry Pi 3b+ was tested inside it’s original box, to understand what thermal problems appear. In this case, the processor reaches the limit temperature of 80oC and starts to throttle. To try and solve that problem, two more boxes were developed, Box P1 and Box P2. Box P1 has the same volume as the original box, only being added to grids to promote air circulation. According to the simulation results, Box P1, still isn’t capable of preventing throttling, although, the temperatures reached are lower than those reached using the original box. Box P2, has a bigger volume, which allows for bigger grid areas. Analysing results, it’s confirmed that the temperatures reached prevent the processor from throttling. Finally, Box P2 was 3D printed and tested, thus proving the CFD results.
This work studies the thermal performance of a Raspberry Pi 3b+, in different conditions, trying to project a box that stimulates the heat transfer via natural convection. Firstly, the equipment was tested wihtout a box and a CFD (Computational Fluid Dynamics) model, that accurately represents it’s thermal behaviour, was developed. The thermal power dissipated in the Raspberry Pi 3b+ componentes was determined from this model. Knowing the power dissipated, the Raspberry Pi 3b+ was tested inside it’s original box, to understand what thermal problems appear. In this case, the processor reaches the limit temperature of 80oC and starts to throttle. To try and solve that problem, two more boxes were developed, Box P1 and Box P2. Box P1 has the same volume as the original box, only being added to grids to promote air circulation. According to the simulation results, Box P1, still isn’t capable of preventing throttling, although, the temperatures reached are lower than those reached using the original box. Box P2, has a bigger volume, which allows for bigger grid areas. Analysing results, it’s confirmed that the temperatures reached prevent the processor from throttling. Finally, Box P2 was 3D printed and tested, thus proving the CFD results.
Description
Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica.
Keywords
Edge computing Raspberry Pi 3b+ Desempenho térmico Transmissão de calor Convecção natural CFD Prototipagem rápida SoC Edge computing Raspberry Pi 3b+ Thermal performance Heat transfer Natural convection CFD Rapid prototyping SoC
Citation
GUIA, Eduardo - Projeto de caixa estanque para gestão de carga térmica em microeletrónica. Lisboa: Instituto Superior de Engenharia de Lisboa, 2022. Dissertação de Mestrado.