Navigating Thermal Management Solutions for Aviation SWaP Challenges
Thermal management solutions for aviation SWaP challenges have become increasingly critical as technological advancements push aircraft to new heights of efficiency, agility, and capability. However, these innovations introduce complex challenges, particularly in optimizing Size, Weight, and Power (SWaP). Among these, thermal management remains a critical factor in ensuring system reliability and performance. This article examines the growing thermal demands in the defense and aviation industries and explores how ACT continues to develop cutting-edge solutions as waste heat levels reach unprecedented extremes.
Thermal Management Solutions for Aviation SWaP Challenges
SWaP is critical in defense and aviation due to strict weight limits for keeping aircraft airborne. With powerful onboard electronics, managing heat without adding excessive weight is challenging. Mission phases also introduce unique thermal hurdles. Let’s explore a few examples.
Taxi & Take-Off Challenges
The Problem
During takeoff, high power demand electronics for communication and boot-up generate significant heat, but the aircraft lacks the cooling benefit of airflow at cruising speed.
The Solution
- PCM Heat Sink: A Phase Change Material (PCM) heat sink is an effective solution for managing high heat loads over short durations when immediate heat rejection is not feasible. By absorbing and storing thermal energy, PCM heat sinks enable delayed heat dissipation, leveraging increased airflow during later flight phases for cooling. As a passive system, they require no additional power and; however, their weight can be substantial depending on the required energy storage capacity. ACT utilizes advanced in-house tools and simulation software to optimize PCM heat sink size and weight for specific thermal loads.
- Fan Cooled Solution: Deploying fans during taxi and low-speed flight phases is an effective method for cooling electronics before sufficient airflow is available. While fans require additional power and wiring, they are often lighter than PCM heat sinks and eliminate the need for delayed heat rejection. ACT specializes in selecting optimal fan solutions and designing finned heat sinks to minimize SWaP impact.
Effective Thermal Management Solutions for Low Altitude Flight Challenges
Problem 1
At low altitudes, an aircraft’s velocity aids in cooling onboard electronics; however, efficiently transferring heat to the external airflow is challenging due to high G-loads from maneuvering. Additionally, solar loading can introduce significant thermal energy, further increasing the system’s heat burden despite the presence of cooler ambient air.
The Solution
- Custom Wick Heat Pipes: When worst-case G-load conditions are known, custom heat pipes provide an efficient solution for heat transfer to the designated heat sink. ACT employs advanced in-house modeling tools to optimize heat pipe design, ensuring structural integrity and thermal performance under extreme loading conditions while minimizing size and weight.
- Pulsating Heat Pipes: PHPs are an ideal solution because they can handle high g-loads than traditional heat pipes, depending on fluid selection and inner channel geometry. Unlike a heat pipe, which degrades at max g-load, PHPs stop working entirely when they reach their max g-load.
- RAM Air Flow Heat Exchangers: In some cases, directly transferring heat to the aircraft’s exterior for rejection is impractical. RAM airflow heat exchangers provide an alternative by enabling heat dissipation within the aircraft’s internal airflow. ACT optimizes heat exchanger designs by analyzing pressure drop, thermal efficiency, and fin configurations across varying altitudes and air densities to maximize cooling performance.
Problem 2
At altitude, sometimes the opposite problem occurs. Sensitive components that turn off, instead of overheating, may get too cold to operate and heat rejection needs to be minimized at times.
The Solution
- Variable Conductance Heat Pipe – A variable conductance heat pipe (VCHP) is a great way to keep things warm when the environment gets too cold while helping reject heat in warm environments. ACT has made VCHPs for a variety of battery cooling/heating applications and can help determine if it will be a good solution for you.
In Summary
In aviation, the mantra of Size, Weight, and Power (SWaP) is paramount, with thermal management playing a crucial role in ensuring system reliability, performance, and longevity. Whether in commercial aviation, military aircraft, or UAVs, the demand for innovative thermal solutions continues to drive progress. As technology evolves, implementing effective thermal management solutions for aviation SWaP challenges remains essential for advancing aviation capabilities. Facing a thermal challenge? Contact us to explore how we can help.
