Next-Generation Rocket Engine Thermal Management Using Monel K-500

The initial gas duct design incorporated spiral channels and a flow distributor plate, providing a strong starting point. Conflux identified an opportunity to deliver greater efficiency than the current standard, with lower pressure drop for the same heat exchange.

Conflux’s enhanced design is a custom, integrated heat exchanger device that replaced the previous spiral channel system, resulting in significantly lower helium pressure drop while allowing for a thinner duct wall, reducing the overall weight of the assembly.

 

 

What is Monel K-500?

Monel K-500 is a nickel-copper alloy that combines the excellent corrosion resistance of Monel 400 with greater strength and hardness. This is achieved through the addition of aluminum and titanium.

The alloy is highly valued in various industrial sectors, including space exploration, due to its ability to maintain structural integrity under extreme conditions.

 

Its exceptional resistance to corrosion, high strength, and durability make it an ideal material for aerospace components exposed to harsh environments.

The versatility and reliability of Monel K-500 ensure it meets stringent aerospace application requirements, contributing to the success and safety of space missions.

Challenges of Using Monel K-500 in Additive Manufacturing

Introducing Monel K-500—a high-strength, corrosion-resistant nickel-copper alloy—as the desired material for the heat exchanger created some significant hurdles for Conflux. Early challenges centered on insufficient material characterization data and addressing print defects such as micro-cracking and porosity.

 

To overcome these, Conflux undertook extensive microscopic and CT scanning analyses to refine printing parameters and eliminate micro-cracks. Through multiple iterative loops of printing, testing and parameter adjustments our team developed new techniques to address these issues.

Heat Treatment of Monel K-500 and Machining of Thin-Walled Geometries

Heat treating Monel K-500 posed significant difficulties, particularly for thin-walled geometries critical to the heat exchanger’s design. To address this, Conflux developed and validated specialized heat treatment processes. These processes ensured optimal mechanical properties without distortion.

Additionally, innovative machining techniques were implemented to meet the strict tolerances required for aerospace components.

 

Our successful implementation of Monel K-500 in a heat exchanger delivered superior thermal and structural performance. The project demonstrated five key advantages:

 

1. Enhanced Thermal Performance with Monel K-500

   The final heat exchanger design met and exceeded RFA’s target helium outlet temperatures, surpassing initial thermal performance expectations.

2. Reduced Pressure Drop for Improved Efficiency

   The Monel K-500 design significantly lowered pressure losses relative to the original spiral-wound configuration. This enhanced overall energy efficiency and reduced mechanical stress on downstream rocket engine components.

3. Additive Manufacturing Innovation in Aerospace
   

   This project sets a new standard for aerospace heat exchangers by applying Monel K-500 in an additive manufacturing context, achieving both performance and manufacturability.

4. Validated AM Process Expertise with Monel K-500
   

   The program confirmed Conflux’s capabilities in material parameter development, thermal post-processing, and precision machining – critical elements in delivering repeatable, high-performance AM components.

5. Scalable Design Methodology for Larger Aerospace Systems
   

   The validated manufacturing and design processes are now transferable to larger-scale rocket engines and other advanced aerospace systems, enabling broader adoption of Monel K-500 in AM applications.