Investigation of flows around a rotating blade in a lawn mower deck

The experimental and computational studies were performed for the double-spindle lawn mower decks. Two different types of mower model were tested separately in this study. The first type is the mulching type 42-inch mower deck with 1.076m width and the second type is the side discharge type 44-inch mower deck with 1.20m width.;Experiments were performed to determine the effects of different blade designs on a flow pattern inside a double-spindle mulching type 42-inch mower deck. Two blade models were tested and air velocities were measured by using a forward-scatter LDV (Laser Doppler Velocimetry) system. The velocity measurements were taken place at several different azimuth and axial sections inside the deck. The velocity measurements in this experimental study clarified the air flow pattern caused by blades and the effects of deck and blade design. The high-speed video camera was also used for observing the flow pattern. Furthermore the noise level of blades was measured by using a sound level meter. The experimental results were compared with computational results.;Experiments were also performed for the discharge type 44-inch mower deck model. The LDV system and high-speed video camera were used for velocity measurements and air flow visualizations. A computational modeling of two-dimensional blade model and three-dimensional full deck model were also developed by using the FLUENT code in the numerical part of the study. The redesigned deck does not have a 'V-notch' in the rear of the deck, but incorporates a smooth continuous passage instead was also analyzed with the same experimental tools and the results for these two different designs were compared.;The experimental data obtained from different mower deck models supported the results predicted by using the computational models. Therefore, it is concluded that the research methods and the computational models developed in the present study can become useful tools for designs of new lawn mowers and for analysis of flow characteristics in other types of existing lawn mowers. In addition, this database can further be used for studies in turbo-machinery and many other aerodynamic applications.