A STUDY OF AERODYNAMICS AROUND ROTATING BLADES IN A LAWNMOWER DECK

摘要

The objective of this study is to investigate the flow behavior within a triple-blade lawnmower deck. The test section was constructed for velocity measurement with an open bottom and side-discharge. Velocity measurements were collected at several different tangential and axial sections inside the deck. The flow behaviors are observed using Laser Doppler Velocimetry (LDV) and a high-speed video camera capturing 2000 frames per second. Several different visualization techniques have been attempted: particle feeding, water vapor injection, tuft method, and others. To further enhance the experimental accuracy, fresh sod was fed into the system simulating normal cutting conditions. Along with the extensive velocity analysis, strain and static pressure were also examined at various surface locations along the blade using linear strain gages, piezoresistive pressure transducers, and Finite Element Analysis (FEA) methods. Validation of the above analyses was performed using Computational Fluid Dynamics (CFD) investigation. It has been observed that the deck and blade configurations share equal significance in the resultant flow profiles.