| 초록 |
The tumble flow of the reciprocating engine was evaluated through the steady-flow bench and PIV and compared. PIV was conducted in parallel with 3D and 2D, and the results of these two evaluations were also compared. As a result of 2D measurement, it was confirmed that a high-speed flow of 50 m/sec or more existed on the wall opposite to the intake port, and a reverse flow along the wall was observed in a plane perpendicular to the suction direction. Looking at the 3D measurement result, it is macroscopically consistent with the 2D result, but there is a difference in the detailed distribution. Specifically, the axial velocity measured in 3D is generally lower than that in 2D, which is determined to be due to the passage of particles in a shorter time than the laser pulse interval when the flow speed is high, and thus not measured. In particular, in the case of 3D, the area where flow measurement is impossible near the wall is larger than that of 2D. Due to these various factors, there are differences depending on the method in calculating the flow rate and tumble value. However, despite these limitations, 3D PIV measurements provide sufficient qualitative information on flow characteristics and distribution.
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