This challenge is exacerbated in high-performance military and aerospace applications such as radar, computer vision, and electronic warfare, where computational requirements directly conflict with low-SWaP systems that must cool these next-generation embedded computing technologies. To overcome this thermal hurdle, liquid flow-through (LFT) cooling becomes critical for mission-critical electronics as it provides vastly superior heat dissipation compared to air-cooling or conduction-cooling, ensuring that high-performance components can operate reliably without overheating or throttling.
Beyond the Heat with LFT
Modern GPUs, such as the NVIDIA Blackwell RTX Pro™ 5000, which can generate hundreds of watts of heat, are an excellent example of technology driving the need for innovation in the domain of SWaP management. GPUs consist of thousands of compute cores with dedicated architectures to render graphics, perform matrix operations, and accelerate sensor processing, often requiring an intricate thermal management solution to make use of the hardware’s full capabilities. With air cooling and conduction cooling nearing practical limits, liquid flow through (LFT) is being closely examined, particularly in applications where fluid is readily available. LFT, defined by the VITA 48.4 specification, leverages convection through fluid motion to draw heat away from high-power components, preventing damage and increasing performance capabilities. With the ability to manage hundreds of watts of thermal output, LFT cooling has become an increasingly sought-after technology in the domain of embedded systems.
The Next Generation Embedded Cooling Solution
At the card level, conduction and air cooling have served the vast majority of military and aerospace applications. Innovation that pushes the limits of these technologies, such as embedded heat pipes, vapor chambers, and processor shunts, has allowed these approaches to continue to meet cooling needs for many applications. However, newer hardware, such as GPUs, will challenge the ability of conduction and air-based convection to keep device temperatures below maximum limits, particularly with commonly specified boundary conditions (e.g., 85 °C card edge temperature, 70 °C inlet air temperature). For current and future generations of products, LFT is being deployed as the prime successor.
Single-phase LFT cooling is a relatively straightforward approach to remove heat and transfer it to an external medium through a working fluid with high thermal conductivity and heat capacity, such as polyalphaolefin (PAO). In an example system, Fig. 1, circuit cards with LFT coldplates are housed in a chassis that supplies liquid coolant via a manifold fed by a pump. Heat is removed by the coldplate and liquid is transferred to the return manifold. The warm fluid can then be routed to a heat exchanger integral to the chassis or to an external heat exchanger. Efficient cooling of such a system is largely dictated by the areas where heat transfer takes place, namely the coldplates and the liquid-to-air or liquid-to-liquid heat exchanger.
Modern LFT coldplate implementations resemble standard conduction cooled solutions but add quick disconnects (QD), liquid connectors for coolant intake and output. The VITA 48.4 specification stipulates the envelope dimensions and other basic requirements for LFT modules, including the locations of QD and mass flow rates. The internal design of the coldplate is left undefined for engineering innovation, with the standard calling for a minimum capability to cool 400 W and a target heat dissipation of 600 W. Based on testing from Curtiss-Wright with partner Parker Hannifin, LFT successfully demonstrated the ability to cool a 650 W 6U VPX card that integrated four high power heat loads using 55 °C inlet coolant (PAO).
A Mass Effect
Liquid flow-through (LFT) cooling offers a refined approach to thermal management in embedded systems. By optimizing the internal fluid channel architecture, LFT assemblies can reduce overall mass by up to 35 percent compared to traditional conduction-cooled designs. This improvement supports better SWaP performance for platforms where weight and efficiency are critical. Although implementation depends on the presence of a fluid source, heat exchanger, and pump, LFT provides a practical and effective solution for systems that must operate at high computational loads under demanding conditions.
As processing requirements continue to advance, LFT cooling provides the thermal capacity needed to maintain consistent, reliable performance. Engineering evaluations show measurable improvements in cooling efficiency, thermal stability, and system optimization. Developed in alignment with the VITA 48.4 standard and validated across rugged VPX architectures, Curtiss-Wright’s LFT solutions enable integrators to manage higher thermal loads while maintaining compliance with environmental and operational requirements. Products such as the VPX6-731, CHAMP-XD4, CHAMP-FX7, and VPX6-682E demonstrate the scalability and reliability of LFT cooling technology for next-generation mission-critical computing.
Reference Articles:
Overcoming 3U VPX Form Factor Thermal Management Constraints
Achieving Optimal Thermal Management in OpenVPX Systems - Atrenne
Cooling the beast: Heat-dissipation techniques for next-gen processors - Military Embedded Systems
Thermal Management Challenges in SOSA Systems - LCR Embedded Systems
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Thomas King
Product Manager for GPU and Edge Compute Solutions
Thomas King is a Product Manager at Curtiss-Wright Defense Solutions, managing the GPU compute and graphics product line. Thomas has a degree in Aerospace Engineering from Carleton University with a specification in Space Systems Design. With a background in technical sales and applications engineering, he has experience supporting customer integration of embedded electronics. Thomas is interested in new and innovative solutions regarding sensor, AI, RF, and compute technology.
