Author Contributions
Investigation, L.Y.; data curation, L.Y.; methodology, L.Y. and H.Z.; validation, L.Y. and H.Z.; writing—original draft preparation, L.Y.; writing—review and editing, H.C., Z.Z., and S.L.; supervision, H.C., Z.Z., and S.L.; funding acquisition, H.C., Z.Z., and S.L. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Computational domain.
Figure 1.
Computational domain.
Figure 2.
Mesh of the inducer.
Figure 2.
Mesh of the inducer.
Figure 3.
Schematic of the blade profile. (Left one for the equal pitch inducer and the right one for the varying pitch inducer).
Figure 3.
Schematic of the blade profile. (Left one for the equal pitch inducer and the right one for the varying pitch inducer).
Figure 4.
Schematics of the studied casings: (a) Step casing; (b) straight casing.
Figure 4.
Schematics of the studied casings: (a) Step casing; (b) straight casing.
Figure 5.
The variation of the nondimensional cavity area over time on three blades of Model O.
Figure 5.
The variation of the nondimensional cavity area over time on three blades of Model O.
Figure 6.
The variation of the nondimensional cavity area over time on Blade 1 of Model O and OE (cases with the equal pitch inducer).
Figure 6.
The variation of the nondimensional cavity area over time on Blade 1 of Model O and OE (cases with the equal pitch inducer).
Figure 7.
The variation of the nondimensional cavity area over time on Blade 1 of Model A and AE (cases with the varying pitch inducer).
Figure 7.
The variation of the nondimensional cavity area over time on Blade 1 of Model A and AE (cases with the varying pitch inducer).
Figure 8.
The 3D cavity structures of (a) Model O and(b) Model OE.
Figure 8.
The 3D cavity structures of (a) Model O and(b) Model OE.
Figure 9.
The variation of cavities over time at S1. (a) Schematic of S1, (b) Model O, and (c) Model OE.
Figure 9.
The variation of cavities over time at S1. (a) Schematic of S1, (b) Model O, and (c) Model OE.
Figure 10.
The variation of cavities over time at S2. (a) Schematic of S2, (b) Model O, and (c) Model OE.
Figure 10.
The variation of cavities over time at S2. (a) Schematic of S2, (b) Model O, and (c) Model OE.
Figure 11.
The variation of cavities over time at S3. (a) Schematic of S3, (b) Model O, and (c) Model OE.
Figure 11.
The variation of cavities over time at S3. (a) Schematic of S3, (b) Model O, and (c) Model OE.
Figure 12.
The 3D cavity structures of (a) Model A and (b) Model AE.
Figure 12.
The 3D cavity structures of (a) Model A and (b) Model AE.
Figure 13.
The variation of cavities over time at S1. (a) Schematic of S1, (b) Model A, and (c) Model AE.
Figure 13.
The variation of cavities over time at S1. (a) Schematic of S1, (b) Model A, and (c) Model AE.
Figure 14.
The variation of cavities over time at S2. (a) Schematic of S2, (b) Model A, and (c) Model AE.
Figure 14.
The variation of cavities over time at S2. (a) Schematic of S2, (b) Model A, and (c) Model AE.
Figure 15.
The variation of cavities over time at S3. (a) Schematic of S3, (b) Model A, and (c) Model AE.
Figure 15.
The variation of cavities over time at S3. (a) Schematic of S3, (b) Model A, and (c) Model AE.
Figure 16.
Blade loading along the streamwise direction at a 95% span for a certain blade in Models O and OE.
Figure 16.
Blade loading along the streamwise direction at a 95% span for a certain blade in Models O and OE.
Figure 17.
Blade loading along the streamwise direction at a 95% span for a certain blade in Models A and AE.
Figure 17.
Blade loading along the streamwise direction at a 95% span for a certain blade in Models A and AE.
Figure 18.
Flow fields at S2. (a) Model O and (b) Model OE.
Figure 18.
Flow fields at S2. (a) Model O and (b) Model OE.
Figure 19.
Flow fields at S2. (a) Model A and (b) Model AE.
Figure 19.
Flow fields at S2. (a) Model A and (b) Model AE.
Table 1.
Geometrical parameters of the cases with the equal pitch inducer.
Table 1.
Geometrical parameters of the cases with the equal pitch inducer.
Model | Inlet Blade Angle β1 | Outlet Blade Angle β2 | Pitch Variation | Casing Geometry |
---|
O | β | β | Constant | Straight |
OE | β | β | Constant | Step |
Table 2.
Geometrical parameters of the cases with the varying pitch inducer.
Table 2.
Geometrical parameters of the cases with the varying pitch inducer.
Model | Inlet Blade Angle β1 | Outlet Blade Angle β2 | Pitch Variation | Casing Geometry |
---|
A | β − 1.8° | β + 0.6° | Linear | Straight |
AE | β − 1.8° | β + 0.6° | Linear | Step |
Table 3.
Geometrical parameters of the studied inducers.
Table 3.
Geometrical parameters of the studied inducers.
Model | Region | θ | Δθ | (Δr)max | (Δz)max |
---|
O | I | 75°~85° | 10° | 11.9% | 13.5% |
II | 85°~160° | 75° |
OE | I | 80°~90° | 10° | 19.8% | 11.1% |
II | 90°~170° | 80° |
Table 4.
Geometrical parameters of the studied inducers.
Table 4.
Geometrical parameters of the studied inducers.
Model | Region | θ | Δθ | (Δr)max | (Δz)max |
---|
A | I | 75°~93° | 18° | 11.9% | 9.0% |
II | 93°~146° | 53° |
AE | I | 80°~150° | 70° | 4.1% | 6.8% |
Table 5.
Characteristic parameters of clearance flow in the cases with the equal pitch inducer.
Table 5.
Characteristic parameters of clearance flow in the cases with the equal pitch inducer.
Model | Δp (Pa) | Average Velocity at the Clearance (m/s) | Leakage Flow Rate (kg/s) |
---|
O | 1.11 × 106 | −16.18 | 0.094 |
OE | 1.04 × 106 | −10.69 | 0.230 |
Table 6.
Characteristic parameters of clearance flow in the cases with the varying pitch inducer.
Table 6.
Characteristic parameters of clearance flow in the cases with the varying pitch inducer.
Model | Δp (Pa) | Average Velocity at the Clearance (m/s) | Leakage Flow Rate (kg/s) |
---|
A | 8.40 × 105 | −7.45 | 0.045 |
AE | 6.70 × 105 | −1.33 | 0.070 |