Cryocoolers are essential systems in many space exploration missions to maintain propellants at cryogenic temperatures. Cryogenic recuperators are a key component of these cryocoolers and dictate the performance of the system. NASA is seeking to reduce the cost and increase the performance of cryogenic recuperators (also called Heat Exchangers) by utilizing Additive Manufacturing (AM) technologies.
Key problem(s) to be solved or system(s) to be designed.
Traditional shell and tube recuperator designs used in cryogenic systems are labor intensive to fabricate and manufacturing defects are a common problem. Can the GrabCAD community generate cryocooler recuperator designs with topologies that take advantage of the latest AM techniques to simplify the recuperator fabrication process without sacrificing performance?
Fig: Example of a Shell and Tube Recuperator
High-level requirements, assumptions and/or constraints.
Designs using AM technologies can take advantage of complex geometries with internal structures and channel sizes that would be difficult or impossible to fabricate with traditional methods.
In addition to cost reductions, designers should also seek to improve the thermal heat exchange efficiency, reduce mass and volume, reduce pressure drops, and consider innovative materials and material properties that can be produced through additive manufacturing.
Background:
NASA’s endeavors in cis-lunar, lunar, and Martian exploration all benefit from being able to use cryogenic propellants. However, maintaining the cryogenic temperatures that those propellants require poses a significant challenge as the vacuum and intense temperature variations in space render cryogenic cooling difficult. This challenge remains an obstacle for its efficient use as a mode of in-space travel.
NASA has identified that using advanced manufacturing techniques such as selective laser sintering, laser powder bed fusion, directed energy deposition, or others, could enable a reimagining of the traditional design of many propulsion system components. By applying these manufacturing practices, the goal is to enable novel design concepts that show improved manufacturability, performance, and/or mass.
Challenge Details:
The state of the art for recuperative heat exchangers is focused on increased heat transfer efficiency, compact designs, advanced materials, and integration with other cryocooler systems.
Some drawbacks to traditionally designed and manufactured components is the difficulty in the process and the manufacturing limitations. Traditional shell and tube models require precision engineering and energy recovery systems. Designs should reduce assembly and joining operations.
Innovations such as advanced coatings, 3D printing, optimized fluid flow management, microchannels, thermally anisotropic materials, and lattice structures can enable these devices to operate more efficiently than realized in current practice.
NASA has advanced many additive manufacturing technologies and is seeking innovative designs of an optimized recuperator that can take advantage of them https://www.nasa.gov/centers-and-facilities/glenn/nasa-additive-manufacturing-project-shapes-future-for-agency-industry-rocket-makers/. It is hoped that the winning designs from this challenge can be prototyped and tested to see how they compare to traditional designs. Advancing the state of the art of cryogenic systems is a key technology shortfall that NASA has identified for enabling long term storage of cryogens in orbit and in deep space.
Detailed requirements, assumptions and/or constraints.
The requirements for this concept are flexible to account for design innovation but are expected to be approximately as follows:
Reduced fabrication costs: ~50% (high priority)
Power Density: ~100 W/Kg
Effectiveness: >0.97
Operating temperatures: Cold side 90K, Hot Side 300K
Operating pressure: ~150psi
Secondary objectives would be to facilitate a working fluid (neon) at a rate >20 gm/s, and to minimize pressure drop.
Available CAD models, data, or other references.
While we can’t supply any specific models or data, some methods to meet requirements may include the use of topology optimization or generative designs with lattices, gyroids, or other complex geometries.
https://doi.org/10.1016/j.ijheatmasstransfer.2021.121600
https://cdn.techscience.cn/uploads/attached/file/20230628/20230628151101_64112.pdf
Key Criteria: Must be included in the submissions
In addition to the CAD Models, submissions should include a one or two page description document of the models that discusses materials, AM methods that are expected to be used and any other key information that may not be evident from the models alone.
Predicted thermal performance/CFD analysis are not required but are encouraged.
Evaluation Criteria and Weighting Factors
1. Feasibility of manufacturing, fabrication, and assembly of recuperator design and ability to lower production costs. (20%)
2. Incorporation of new or novel manufacturing technologies in model description. (15%)
3. Ability to meet efficiency requirements demonstrated by design. Bonus points may be awarded for CFD analysis. (10%)
4. Ability to meet power density requirements and demonstrated in a compact design. (15%)
5. Ability to meet operating temperature constraints demonstrated by design. (15%)
6. Ability to meet operating pressure constraints demonstrated by design. (15%)
7 . Quality and fidelity of the 3D models and renderings. (5%)
8 . How innovative the concept is when compared to other submissions. (5%)
Awards:-
Total Prizes: $7,000
1st Place
$3,000
2nd Place
$1,800
3rd Place
$1,200
4th Place
$750
5th Place
$250
Deadline:- 03-05-2025
