Next-Generation Military Weaponry
Directed Energy Weapons (DEW) are designed to damage targets at long distances using concentrated energy including lasers, microwaves, and particle beams. The energy concentration of these systems also creates an excessive amount of heat, which must be removed as the overall reliability of the system depends on keeping components within safe operating temperatures. The overall reliability of the system depends on keeping the energy source at a safe operating temperature. In many applications, the effectiveness of the laser can be negatively impacted by poor thermal management. In addition to power and thermal performance, these systems must be contained in extremely size and weight-friendly packages.
The need to incorporate high quantities of laser diodes to concentrate/combine outputs to improve laser functionality. The success of the system hinges on these diodes operating at similar temperatures throughout the array. Therefore, the thermal management system must provide temperature uniformity over long distances.
Thermal Technology Option: Pumped Two-Phase (P2P)
Pulsed Operation (on when firing, off the remainder of the time)
This leads to an opportunity to dampen the overall heat load with a thermal storage medium. If successful, all downstream components can be sized for average heat load instead of peak heat load.
Thermal Technology Option: Phase Change Material (PCM) Heat Exchanger (HX)
Extreme Waste Heat Loads Increasing Ambient Air Temperature
Next-generation military weapons with extreme heat loads and requirements to operate in any condition from arctic to desert temperatures now require custom thermal solutions to meet the needs of individual programs. Chiller technology cools the incoming ambient air to safe operating temperatures and can be combined with the above technologies to create a full thermal system solution.
Thermal Technology Option: Liquid Chiller
Thermal Solutions for Directed Energy Weapons (DEW):
Pumped two-phase (P2P) technology allows for isothermality along with the cold plate that interfaces with the laser diodes. In a P2P system, the fluid leverages the high latent heat of vaporization to create an extremely high internal heat transfer coefficient. As the fluid is pumped and vaporizes across the heat sources, it adjusts the quality (percentage of vapor to liquid) of the fluid while maintaining uniform temperature. As the cold plates contacting the laser systems grow in physical size or power densities, a single-phase system will have large temperature gradients which can affect the system performance. P2P is a strong option to create highly uniform cold plates that are capable of moving high heat flux and higher overall power. Check out this video to see a visual demonstration and performance of a P2P system.
A Phase Change Material (PCM) heat exchanger is introduced to exchange heat between the primary coolant loop (that contacts the laser system) and the secondary cooling loop (that transports heat to the radiator). This PCM heat exchanger can be used to dampen the pulsed load so that the secondary loop can be sized for the average heat load instead of maximum heat load. This can mean significant packaging advantages and lower weight for the system integrator. Check out this video for more information.
Chillers and Liquid cooling units are designed to remove heat from the coolant and provides coolant at sub-ambient conditions. The chiller utilizes a refrigeration circuit to absorb heat from the relatively cool circulating fluid which is usually a glycol water mix and rejects it to the higher ambient temperature air. For mobile applications, the chiller design and construction must withstand extreme environmental conditions often from -40F to 140F, vibration, salt, fog, and humidity conditions. Commercially available, off-the-shelf type units are not engineered for these types of rugged conditions.
Combined Technology Solutions: Chillers can also be integrated into a system solution to work alongside Phase Change Material (PCM) Heat Sinks and Pumped Two-Phase (P2P) solutions for applications such as directed energy weapons or pulsed type operations.
ACT works with customers to design and develop system-level thermal solutions for DEW programs. The technologies outlined above are several key components, but the overarching system required pumps, heat exchangers, controls, and many other components. At ACT we make sure we understand our customers’ and end-user needs to strategically implement a thermal management solution that will meet stringent thermal, mechanical and environmental requirements.