Flow Characterization and Noise Reduction in a Tumble Dryer Using MRV

This study presents an magnetic resonance velocimetry (MRV)-based approach to reduce flow-induced noise and improve energy efficiency in the machine room of a tumble dryer. A 0.4-scale MRV-compatible water model replicating the internal flow path was fabricated using stereolithography 3D printing, with flow conditions matched to the actual system via dynamic similarity. Three-dimensional mean velocity and turbulent kinetic energy (TKE) fields were measured using MRV. Flow analysis of the reference model revealed non-uniform velocity profiles, strong secondary flows, and high TKE regions associated with flow-induced noise generation. Based on these insights, structural modifications were introduced to create an improved model. The modified design exhibited more uniform flow, suppressed secondary motions, and significantly reduced TKE. These improvements led to a 3 dB reduction in sound pressure level and lower vibration amplitudes, confirmed by microphone and accelerometer measurements. The results highlight the potential of MRV as a systematic tool for identifying flow noise sources and guiding design modifications to enhance both acoustic and flow performance in an industrial system including household appliances.