A Novel Package-integrated Cyclone Cooler for the Thermal Management of Power Electronics

2021 ◽  
Author(s):  
Rinaldo Miorini ◽  
Darin J Sharar ◽  
Arun V. Gowda ◽  
Cathleen Hoel ◽  
Bryan Whalen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power Electronics ◽  
Power Density ◽  
High Power ◽  
Two Phase Flow ◽  
Junction Temperature ◽  
Phase Flow ◽  
Two Phase ◽  
Temperature Reduction ◽  
The Impact

Abstract In order for electronics packaging power density to increase, innovations and improvements in heat transfer are required. Electrification of transportation has the potential for significant fuel and energy savings. Changing to an electrified drive train requires reliable and efficient power electronics to provide power conversion between AC motors and DC energy storage. For high power transportation systems like aircraft or heavy vehicles, the power density of these power electronics needs to be improved. Power density is also an enabler for high power military devices that must be used and transported via air, ground, and sea. This paper summarizes the outcome of a collaborative and multi-disciplinary research effort aimed at co-designing novel electronics cooling device that utilizes two-phase fluid flow. Two-phase flow cooling has been known for decades as well as the risks associated with it: critical heat flux, dry-out and thermal runaway. Our research de-risks the two-phase cooling phenomenon by swirling the flow to remove the bubbles from the wall and confining them at the core of the cooler. The combined effects of gas phase removal, enhanced nucleation and dramatic liquid film agitation and rupture have been quantified by our experiments: double the heat transfer coefficient with only 13% increase in pressure drop. Besides advanced fluid-dynamics, our Package Integrated Cyclone Cooler (PICCO) utilizes cutting edge packaging and additive manufacturing technology such as direct deposition of a metal substrate and circuits (dies) on a complex helical cooler that can only be manufactured via 3D printing. By co-designing and testing the cooler we have quantified the impact of the swirled flow on the junction temperature with respect to a conventional (non-swirl) two-phase-flow-cooled power electronics package. At steady state, our post-test thermal simulations predict a junction temperature reduction from 185°C to 75°C at the same power dissipation. When the heat load is unsteady (EPA Urban Drive Cycle), the junction temperature reduction is 140°C to 60°C.

Numerical and experimental investigation on the effect of the two-phase flow pattern on heat transfer of piston cooling gallery

2019 ◽  
Vol 20 (5) ◽  
pp. 507 ◽  
Author(s):  
Lijun Deng ◽  
Jian Zhang ◽  
Guannan Hao ◽  
Jing Liu
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Unstable Wave ◽  
Fluid Viscosity ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Process ◽  
The Impact ◽  
Piston Cooling

To study factors affecting the formation and conversion of two-phase flow pattern as well as the heat transfer of piston cooling gallery, a transient visual target test bench was set up to research the oscillatory flow characteristics in the cooling gallery under idle condition of the engine. The computational fluid dynamics (CFD) was employed while dynamic mesh technology, SST k–ω turbulence model and volume of fluid (VOF) two-phase flow model were applied to simulate the flow process of piston cooling gallery so as to predict the distribution pattern of two-phase flow. Simulation results were in good agreement with that experimentally obtained. It was observed that in the reciprocating movement of the piston, the action of two-phase flow oscillation was severe, forming some unstable wave flows and slug flows. Results show that under the same pipe diameter, the increase of fluid viscosity results in the decrease of amplitude and the increase of the liquid slugs number as well as the enhancement on heat transfer effect. In addition, it was revealed that injection pressure has little effect on the two-phase flow pattern. However, when the pressure is reduced, the change of the liquid phase is weakened and the locations of flow pattern transition move towards to the behind, thus the impact on the heat transfer is also faint.

Analytical and Numerical Simulation of the Two Phase Flow Heat Transfer in the Vent and Scavenge Pipes of the Clean Engine Demonstrator

2008 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Numerical Models ◽  
Environmentally Friendly ◽  
The Other ◽  
Analytical Models ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Heat ◽  
The Impact

Advanced aircraft engine development dictates high standards of reliability for the lubrication systems, not only in terms of the proper lubrication of the bearings and the gears, but also in terms of the removal of the large amounts of the generated heat. Heat is introduced both internally through the rotating hardware and externally through radiation, conduction and convection. In case where the bearing chamber is in close proximity to the engine’s hot section, the external heat flux may be significant. This is, for example, the case when oil pipes pass through the turbine struts and vanes on their way to the bearing chamber. There; the thermal impact is extremely high, not only because of the hot turbine gases flowing around the vanes, but also because of the hot cooling air which is ingested into the vanes. The impact of this excessive heat on the oil may lead to severe engine safety and reliability problems which can range from oil coking with blockage of the oil tubes to oil fires with loss of part integrity, damage or even failure of the engine. It is therefore of great importance that the oil system designer is capable of predicting the system’s functionality. As part of the European Research program EEFAE (Efficient and Environmentally Friendly Aero Engine), the project CLEAN (Component vaLidator for Environmentally-friendly Aero-eNngine) [1], [2] was initiated with the goal to develop future engine technologies. Within the scope of this program, MTU Aero Engines has designed the lubrication system and has initiated an investigation of the heat transfer in the scavenge and vent tubes passing through the high thermally loaded TCF (Turbine Center Frame). The objective was to evaluate analytical and numerical models for the heat transfer into the air and oil mixtures and benchmark them. Three analytical models were investigated. A model which was based on the assumption that the flow of air and oil is a homogeneous mixture which was applied on the scavenge flow. The other two models assumed annular two-phase flows and were applied on the vent flows. Additionally, the two phase flow in the scavenge and vent pipes was simulated numerically using the ANSYS CFX package. The evaluation of the models was accomplished with test data from the heavily instrumented test engine with special emphasis on the TCF. Both the analytical and the numerical models have demonstrated strengths and weaknesses. The homogeneous flow model correlation and the most recent correlation by Dr. Busam for vent flows have demonstrated very good agreement between test and computed results. On the other hand the numerical analysis produced remarkable results, however at the expense of significant modeling and computing efforts. This particular work is unique compared to published investigations since it was conducted in a real engine environment and not in a simulating rig. Nevertheless, research in two-phase flow heat transfer will continue in order mitigate any deficiencies and to further improve the correlations and the CFD tools.

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