Introduction

ColdStream 2026.09 delivers a major update to the ColdStream experience alongside significant advances in thermal physics and topology optimization. The release combines a faster, more user-friendly interface with fully integrated nucleate boiling for standard and custom designs, and improved topology optimization physics through turbulent treatment at fluid-solid interfaces.

Faster, More User-Friendly ColdStream Experience

ColdStream has been rebuilt on a new platform architecture, delivering a faster and more responsive user experience together with a cleaner, more intuitive interface. New capabilities make it easier to inspect, compare, measure, export and manage engineering cases.

Customer Value

• Faster and more responsive interaction with ColdStream.
• Compare case setups and highlight differences, including across projects.
• Measure distances directly on the 3D geometry with persistent measurements and labels.
• Export setup and results information to Excel/CSV.
• Access case files and per-iteration result files directly from the case.
• Improved organization and member management.

Representative views of the updated ColdStream experience.

Fully Integrated Nucleate Boiling

ColdStream 2026.09 introduces nucleate boiling based on the Rohsenow correlation, with a unique implementation fully integrated into ColdStream’s topology optimization physics. Nucleate boiling can be used in both topology-optimized custom designs and standard parametric designs, allowing boiling heat transfer to influence the design directly during optimization.

Customer Value

• Model and optimize designs involving nucleate boiling heat transfer.
• Apply nucleate boiling to both topology-optimized custom designs and standard parametric designs.
• Account for boiling heat transfer directly during design generation and optimization, enabling applications such as high heat-flux and immersion-cooled electronics.

Representative Nucleate boiling results

Improved Thermal and Topology Optimization Physics

The thermal solver has been updated to solve the energy equation directly in terms of temperature rather than enthalpy. The fluid momentum and energy equations are equipped with monolithic implementation. ColdStream 2026.09 also introduces turbulent treatment at the evolving fluid-solid interface, improving the physical accuracy of heat transfer within topology optimization.

Customer Value

• Improved physical accuracy of topology-optimized designs in turbulent flow applications.
• More representative treatment of heat transfer at evolving fluid-solid interfaces.
• Temperature-based formulation supporting advanced thermal physics.
• Monolithic implementation further improves stability and convergence.

Representative ColdStream Result

The Modular Cold Plate case provides a representative topology-optimized custom design generated with ColdStream 2026.09.