Numerical Analysis of PIN Fin Configurations for Liquid Cooled Cold Plates for Aircraft Power Converters
This study utilizes CFD simulations to evaluate circular, diamond, and NACA 0030 aerofoil pin fin configurations for liquid-cooled aircraft cold plates, revealing that the staggered aerofoil design offers the best thermal performance index for weight-constrained avionics while the staggered circular design provides superior pure cooling with minimal pressure penalty.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Modern aircraft are undergoing a quiet revolution. To reduce emissions and improve efficiency, designers are replacing heavy hydraulic and pneumatic systems with electrical ones, creating what engineers call "More Electric" or even "All Electric" aircraft. This shift places a massive burden on the power converters that manage electricity, devices that must operate reliably within the cramped, hot confines of the avionics bay. As these components generate more heat, the systems designed to cool them must become far more effective without adding excessive weight or requiring powerful pumps that drain fuel. The challenge is to move heat away from sensitive electronics as quickly as possible while using the least amount of energy to push the cooling fluid through the system.
To solve this, researchers at Munster Technological University turned to a method called computational fluid dynamics, essentially using powerful computers to simulate how liquid flows over tiny obstacles inside a cooling plate. They focused on a specific design feature: pin fins. These are small, pillar-like structures arranged in rows inside the channels where the coolant flows. As the liquid moves past these pins, it swirls and mixes, which helps pull heat away from the metal walls of the plate. The team wanted to know which shape of pin fin works best. They tested three distinct shapes: a simple circle, a diamond, and a streamlined airfoil shape similar to the cross-section of an airplane wing. They also tested two ways of arranging these pins: one where the pins in each row line up perfectly with the ones behind them, and another where the pins in the second row sit in the gaps between the first row, creating a staggered pattern.
The researchers built a detailed digital model of a cold plate made from aluminum, the same material used in real aircraft, and filled it with a mixture of water and ethylene glycol, a common coolant. They simulated the flow of this liquid at three different speeds, ranging from a slow crawl to a fast rush, while applying a heavy, steady heat load to the top of the plate to mimic the intense conditions of a real power converter. In total, they ran eighteen different simulations, testing every combination of the three shapes, two patterns, and three speeds. The goal was to measure two competing factors: how well the system cooled the plate and how much resistance the fluid felt as it tried to move through the pins. A design that cools well but requires a powerful pump to push the fluid through is not useful for an aircraft, where every ounce of weight and every drop of fuel counts.
The results revealed that there is no single "perfect" shape for every situation, but there were clear winners depending on what the aircraft designer prioritized. When the goal was purely to remove heat as fast as possible, the circular pins arranged in a staggered pattern performed the best. At the highest flow speed, this configuration improved the cooling efficiency by just over two percent compared to a standard baseline design. However, this slight gain came with a small increase in the effort required to pump the fluid. The diamond-shaped pins, which some previous studies had suggested might be superior, consistently performed the worst in this specific setup, failing to meet expectations in both cooling and fluid flow.
The most significant finding, however, came from the airfoil-shaped pins. While they did not remove heat quite as aggressively as the circular pins, they offered a far better balance. Because their shape is streamlined, the fluid flowed around them with much less resistance, requiring significantly less pumping power. When the researchers combined the cooling performance with the energy needed to move the fluid into a single score, the airfoil pins arranged in a staggered pattern emerged as the clear champion. This configuration achieved the highest overall performance score, proving that it could keep the electronics cool while saving energy and reducing the strain on the aircraft's pumping systems.
The study confirmed that the speed of the coolant was the most powerful factor influencing the results, with faster flow always leading to better cooling, regardless of the pin shape. However, the shape and arrangement of the pins dictated how efficiently that speed was used. The airfoil design was particularly attractive for the aviation industry because it minimized the pressure drop, meaning the pumps could be smaller and lighter. The researchers noted that while their computer models were highly detailed and validated against real-world experiments, the airfoil shapes were the most difficult to simulate due to their sharp, curved edges, requiring careful adjustments to ensure the digital results were accurate. Ultimately, for the constrained environment of an aircraft's avionics bay, where weight and power are at a premium, the streamlined airfoil pin fin offers the most promising path forward for cooling the next generation of electric aircraft.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.