Electronics cooling

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

Inherently Safe Looped Thermosyphon Cooling System for Aircraft Applications using Dielectric Fluid H-Galden

Abstract: This paper presents experimental results of an inherently safe liquid cooling system. A test rig is operated at Hamburg University of Technology in order to prove the concept and gather first data for electronics cooling in modern civil aircraft. The cooling system uses a dielectric working fluid for the natural circulation in a looped thermosyphon operating in both oneand two-phase mode. First the mass flow of this natural circulation system is investigated comparing the measurement data to calculations. After that the cooling performance of the system is evaluated by taking a closer look at the heat loads and corresponding temperatures. Finally heat transfer coefficients in the cold plate are calculated. The results are discussed with respect to the following parameters, which are varied in the test series conducted: heat load, the heat sink temperature and the system orientation. 1. INHERENTLY SAFE COOLING SYSTEMS The power densities of electronic components are increasing continuously, thus conventional air cooling systems are replaced with liquid cooling to remove the waste heat (Dietl et al., 2008). Liquid cooling systems can transfer much higher waste heat flux densities. State-of-the-art liquid cooling systems use a closed cooling loop basically consisting of a cold plate and a cooler connected with pipes. The liquid is circulated by a pump. In the cold plate the waste heat from the electronic components is transferred to the working fluid. This hot liquid is pumped to the cooler, where the waste heat is discharged in most cases to sink the ambient air acting as the final heat. 1.1 Objective in Aircraft Applications Crucial flight systems (e.g. avionics) need highly reliable cooling systems. In common civil aircraft these systems are air cooled using forced convection. The electronics are air-ventilated by fans. Nevertheless the cooling systems are designed to ensure a minimum cooling performance without fans for some time to allow a safe landing at the nearest airport. With increasing power densities of microprocessors and power electronics the waste heat flux densities increase and air cooling has to be replaced by liquid cooling systems like described above. The reliability is a critical issue for these active liquid cooling systems compared to the conventional air cooling. With a failure in a coolant pump, which can have many reasons, the liquid stops circulating and the electronics get overheated very quickly. Thus, analogically to air cooling, it is the aim of an inherently safe liquid cooling system to ensure a minimum cooling performance without a coolant pump. In this passive configuration the circulation of the working fluid has to be actuated by buoyancy forces, which result from density differences. In one-phase operation this is a critical issue, as the density does not vary much for most liquids. A significant change in density is achieved by evaporating the working fluid. Therefore two-phase operation is highly attractive for inherently safe liquid cooling and will be the main focus of this paper.

The effect of fan-reliability and cooling-performance on electronic-chassis reliability

Abstract: A tractable model for predicting the failure rates of electronic chassis cooled by fans with finite failure rates is developed. The model accounts for two regimes prior to electronics failure: the electronic chassis is operated at a temperature which occurs with a fan that is operational and the electronic chassis is operated at a temperature which occurs when the fan has failed. Fan failures alone do not constitute a failure of the chassis. Such a model applies where cooling fans are not actively monitored, and where their failure is noticed only during the maintenance associated with an electronic failure of the chassis, i.e., the model accounts for the fact that the electronics in general continues to operate for a period of time following a fan failure. The model directly applies to cost/benefit studies in electronics packaging, including the determination of the improvement in mean time between failures (MTBF) to be anticipated when a chassis is implemented with a cooling fan, and the determination of the performance benefit to be anticipated when fans are actively monitored and replaced upon failure. >

Microfluidic Cooling of a 14-nm 2.5-D FPGA With 3-D Printed Manifolds for High-Density Computing: Design Considerations, Fabrication, and Electrical Characterization

Abstract: The 2.5-D integration is becoming a common method of tightly integrating heterogeneous dice with dense interconnects for efficient, high-bandwidth inter-die communication. While this tight integration improves performance, it also increases the challenge of heat extraction by increasing aggregate package powers and introducing thermal crosstalk between the adjacent dice. In this article, a microfluidic heat sink is used to cool a 2.5-D Stratix 10 GX field-programmable gate array (FPGA) consisting of an FPGA die surrounded by four transceiver dice. The heat sink utilizes a heterogeneous micropin-fin array with micropin-fin densities that are tailored to the local heat fluxes of the underlying dice. Enabled through a 3-D printed enclosure for fluid delivery, the assembled heat sink has a total height of 6.5 mm, including the tubes used for fluid delivery. The heat sink is tested in an open-loop system with deionized water as a coolant, and thermal performance is compared against a high-end air-cooled heat sink. Improvements in die temperatures, computational density, and thermal coupling between the dice are observed. The effect of the FPGA power on the surrounding transceiver die temperatures was reduced by a factor of ${10}\times$ to over ${100}\times$ when compared with the air-cooled heat sink.