Electronics cooling

About: Electronics cooling is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 17608 citations.

Experimental measurement and modelling of heattransfer in spiral and curved channels

Abstract: Heat transfer enhancement is desired in most thermal applications. In general, there are two methods to improve the heat transfer rate: active and passive techniques Active techniques are based on external forces such as electro-osmosis, magnetic stirring, etc. to perform the augmentation. Active techniques are effective; however, they are not always easy to implement with other components in a system. They also increase the total cost of the system manufacturing. On the other hand, passive techniques employ fluid additives or special surface geometry. Using the surface geometry approach is easier, cheaper and does not interfere with other components in the system. Surface modification or additional devices incorporated in the stream are two passive augmentation techniques. With these techniques, the existing boundary layer is disturbed and the heat transfer performance is improved. However, pressure drop is also increased. Curved geometry is one of the passive heat transfer enhancement methods that fit several heat transfer applications such as: compact heat exchangers, steam boilers, gas turbine blades, electronics cooling, refrigeration and etc. This dissertation contains eight chapters.. Chapter one is the introduction and shows the originality, novelty and importance of the work. Chapter two reviews the literatures on the heat transfer and the pressure drop correlations in curved circular tubes. In chapters three and four, two heat sinks having spiral and straight channel geometry engraved on them are examined experimentally. Heat transfer and pressure drop inside them are measured, and reduced to apply two existing correlations to predict their behaviour analytically. In chapters five, six and seven, thermal and flow behaviour inside curved geometry are studied experimentally. The calculated heat transfer coefficient and pressure drop are compared to the existing models. Comparing the predicted Nusselt number from the existing models, poor accuracy was observed in the region of 5 < Pr < 15. Finally, in chapters six and seven two new asymptotic correlations are proposed to calculate the heat transfer and the pressure drop inside mini scale curved and coiled tubes.

Inline pin fin heat sink model and thermal performance analysis for central processing unit

Abstract: The thermal management issue is common in electronic products such as computers, projectors and others. The trend shows that by increasing the power density, indirectly it will increase the temperature and power dissipation in CPU processor. This is a major challenge to the product designer of electronics cooling system to find an alternative technique to solve the problem. Therefore, in order to control and minimize the heat produced by the CPU's processor, the conventional external heat sink is added to the overall thermal management mechanism. In this paper, 3D simulation inline pin fin heat sink is designed using COMSOL Multiphysics software. The outcome of this study hopefully can shed some light on how to optimize inline pin fin arrangement heat sink design.

Next-Generation Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

Abstract: The development of the Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support System (PLSS) is currently underway at NASA Johnson Space Center. The AEMU PLSS features two new evaporative cooling systems, the Reduced Volume Prototype Spacesuit Water Membrane Evaporator (RVP SWME), and the Auxiliary Cooling Loop (ACL). The RVP SWME is the third generation of hollow fiber SWME hardware, and like its predecessors, RVP SWME provides nominal crewmember and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crewmember and PLSS electronics. Major design improvements, including a 36% reduction in volume, reduced weight, and more flight like back-pressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. In addition to the RVP SWME, the Auxiliary Cooling Loop (ACL), was developed for contingency crewmember cooling. The ACL is a completely redundant, independent cooling system that consists of a small evaporative cooler--the Mini Membrane Evaporator (Mini-ME), independent pump, independent feed-water assembly and independent Liquid Cooling Garment (LCG). The Mini-ME utilizes the same hollow fiber technology featured in the RVP SWME, but is only 25% of the size of RVP SWME, providing only the necessary crewmember cooling in a contingency situation. The ACL provides a number of benefits when compared with the current EMU PLSS contingency cooling technology; contingency crewmember cooling can be provided for a longer period of time, more contingency situations can be accounted for, no reliance on a Secondary Oxygen Vessel (SOV) for contingency cooling--thereby allowing a SOV reduction in size and pressure, and the ACL can be recharged-allowing the AEMU PLSS to be reused, even after a contingency event. The development of these evaporative cooling systems will contribute to a more robust and comprehensive AEMU PLSS.