Electronics cooling

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

Smart, low-cost, pumpless loop for micro-channel electronic cooling using flat and enhanced surfaces

Abstract: Two-phase cooling of a square simulated electronic device surface of 21.3 mm side was successfully carried out without the need for a pump. This smart, passive, low-cost cooling system incorporates a self-enhancing and self-sustaining mechanism, wherein the system inherently enhances its cooling capacity by increasing the velocity of the two-phase mixture along the boiling surface when an increase in heat flux is sensed. Other practical attributes of this pumpless loop are small liquid inventory requirements and absence of the incipient boiling temperature drop. It is shown small surface tension and contact angle render dielectric coolants such as FC-72 ideally suited for flow in narrow gaps. These unique properties are responsible for very small bubble size, precluding any appreciable blockage of the replenishment liquid flow even in narrow gaps. Critical heat flux (CHF) was found to generally increase with decreasing boiler gap. CHF for flat, micro-channel (with 0.2 mm rectangular fins) and mini-channel (with 1.98 mm rectangular fins) surfaces was 4.5, 5.9, and 5.7 times greater than for pool boiling from a flat surface for corresponding gaps. A pressure drop model was formulated to predict coolant mass flow rate, boiling surface inlet and exit velocities, and pressure drop components throughout the loop. The model predictions illustrate the pumpless loop's self-sustaining and self-enhancing attributes, and relate CHF trends to those of the two-phase mixture acceleration along the boiling surface.

Two-phase cooling method using R134a refrigerant to cool power electronic devices

Abstract: This paper presents a two-phase cooling method using R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PE) such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs). The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 300 days were performed on a submerged IGBT and gate-controller card to study dielectric characteristics, deterioration effects, and heat flux capability of R134a. Results from these tests illustrate that R134a has high dielectric characteristics, no deterioration on electrical components, and a heat flux of 114 W/cm 2 for the experimental configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30 kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device

Nanofluids for electronics cooling

Abstract: The goal of this study is to investigate experimentally the thermal performance of an electronics cooling system which is available in the market Selected system is a water block used for liquid cooling of a central processing unit (CPU) of a computer A suitable heater (resistance wire) is fabricated for producing heat similar to CPU System is instrumented with K-type thermocouples for the temperature measurement of certain points The experiments were carried out first with water and then with water-based Alumina nanofluid Nanofluid sample was supplied from NanoAmor Inc, with particle concentration of 633 volumetric percent and diluted to 1 volumetric percent with water, by using a probe type ultrasound for 2 minutes at 70 W During the experiments 60 W power applied to the CPU and the ambient temperature was 19 degree Celcius Our results show that nanofluids, with low volume concentration (1 percent vol) of Alumina particles decreases the maximum temperature of the system, almost 27 degree Celcius, compared to water