Experimental and Numerical Study of Swirling ... - Solid Mechanics

Experimental and Numerical Study of Swirling Flow in Scavenging Process for 2-Stroke
Marine Diesel Engines
2.3.6 Helical Vortex Structures .................................................................................... 24
2.4 CFD Modeling Challenges .................................................................................. 28
3 Experimental Setup ................................................................................... 31
3.1 Scavenging Flow Test Model ................................................................................ 31
3.1.1 Cylinder .............................................................................................................. 32
3.1.2 Inlet Section (Swirl Generator) ........................................................................... 32
3.1.3 Outlet Section ...................................................................................................... 33
3.2 Experimental Setup ............................................................................................. 34
3.3 Differences between Test Model and Real Engine Scavenging process ................. 35
3.4 Smoke Visualization ........................................................................................... 36
3.5 Stereoscopic PIV Setup ........................................................................................ 40
3.5.1 Alignment and Calibration ................................................................................ 42
3.5.2 Seeding Setup ...................................................................................................... 43
3.5.3 Data Acquisition and Processing ......................................................................... 44
3.6 LDA Setup ........................................................................................................... 44
4 Swirling Flow in a Pipe .......................................................................... 47
4.1 LDA Measurements (Inlet Section) ..................................................................... 49
4.2 PIV Experimental Results (L3) ............................................................................ 54
4.2.1 Mean Velocity Field ............................................................................................ 54
4.2.2 Tangential Velocity Profile ................................................................................. 57
4.2.3 Axial Velocity Profile .......................................................................................... 58
4.2.4 Mean Axial Vorticity ........................................................................................... 59
4.2.5 Reynolds Normal Stresses .................................................................................... 63
4.2.6 Reynolds Shear Stresses ....................................................................................... 75
4.2.7 Average Turbulent Kinetic Energy ...................................................................... 84
4.3 Effect of Cylinder Length .................................................................................... 87
4.3.1 Tangential Velocity Profile ................................................................................. 88