Design of an Ultra-low Noise Ventilation Fan for Space Applications

Ventilation fans play a critical role in spacecraft and space habitats, functioning as a key component in environmental control and life support systems. However, these fans have been grappling with operational noise issues, causing significant annoyance to astronauts and interfering with communication equipment. Over the past decade, NASA has actively engaged in noise mitigation efforts, particularly focusing on reducing noise related to rotor-stator interaction using techniques commonly employed in turbofan engines. In this program, Whisper Aero proposes maturation of a solution that leverages their novel ultrasonic fan design to create a highly efficient and ultra-quiet fan. The intended benefits include alleviating the production of annoying blade passing frequency tones, reducing structural-borne vibratory noise, cutting down fan weight and associated imbalance noise, and simplifying the mechanical layout for an extended operational lifecycle. Phase I activities involved sizing and designing the fan based on NASA's requirements, utilizing Whisper's multidisciplinary optimization software toolkit. Further, Whisper conducted testing across a large experimental test matrix exploring the effect of discrete single design variable sweeps along the most critical directions in the design space, resulting in testing on over 10 unique fan designs. Under this Phase II effort, Whisper will conduct testing on an even broader design space with additional instrumentation, will perform targeted technology infusion into a chosen design point, will mature the design through preliminary design, will build a functionally conforming engineering verification prototype, and will conduct extensive testing in a representative environment.