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Contents
13.3.4 Forcing of the Vortex Distribution ..................................... 485
13.3.5 Effect of End Wall Boundary Layers ................................. 487
13.3.6 Three-dimensional Blade Design ....................................... 488
13.4 Compressor Blade Profiles ............................................................... 491
13.4.1 Subsonic and Supercritical Cascades ................................. 491
13.4.2 Transonic Cascades ............................................................ 494
13.4.3 Supersonic Cascades and Transonic Cascades with
High Inlet Mach Number ................................................... 496
13.5 Performance Characteristics and Operating Range .......................... 497
13.5.1 General Shape of a Characteristic Curve ........................... 497
13.5.2 Rotating Stall ...................................................................... 498
13.5.3 Choking .............................................................................. 499
13.5.4 Surge .................................................................................. 501
13.5.5 Operating Range ................................................................. 502
13.6 Exercises .......................................................................................... 505
References ................................................................................................. 506
14 Radial Compressors ................................................................................ 509
14.1 Construction Forms and Applications .............................................. 509
14.1.1 Rotor Types ........................................................................ 509
14.1.2 General Shape of a Radial Compressor ............................. 511
14.1.3 Comparison Between Radial and Axial Compressors ....... 512
14.1.4 Examples of Radial Compressors ...................................... 513
14.2 Kinematic Parameters ...................................................................... 516
14.3 Pressure Ratio ................................................................................... 519
14.4 Rotor Shape ...................................................................................... 521
14.4.1 Number of Blades .............................................................. 521
14.4.2 Inducer ................................................................................ 523
14.5 Diffusers ........................................................................................... 525
14.5.1 Flow Non-homogeneity at Rotor Outlet ............................ 525
14.5.2 Mixing Zone ....................................................................... 526
14.5.3 Vaneless Diffusers .............................................................. 527
14.5.4 Vaned Diffusers .................................................................. 527
14.6 Performance Characteristics ............................................................. 528
14.6.1 Flow Instability .................................................................. 528
14.6.2 Choking .............................................................................. 528
14.6.3 Operating Characteristics and Operating Range ................ 529
14.7 Exercises .......................................................................................... 531
14.7.1 Velocity Variation at Constant Radius in a Rotor ............... 531
14.7.2 Variable Geometry ............................................................. 533
References ................................................................................................. 533
15 Axial and Radial Turbines for Gases ..................................................... 535
15.1 Axial Turbines .................................................................................. 535
15.1.1 Kinematic Parameters ........................................................ 535
15.1.2 Radial Variation of Flow Parameters ................................. 541