Appendix I - Turbomachinery Fundamentals

Summary

Introduction

This book discusses six basic types of turbomachines directly: axial flow compressors, axial flow pumps, radial flow compressors, centrifugal pumps, axial flow gas turbines, and axial flow hydraulic turbines. Two other basic types are used in practice that are not covered in this text because of their limited application in propulsion: radial inflow gas turbines and radial inflow hydraulic turbines. The basic derivations of the equations for each machine type are covered in this appendix rather than in the chapters in which the machines are discussed. As will be shown, the resulting fundamental equations apply to all types of turbomachines, regardless of categorization. Application of the equations with complementing velocity polygons is, however, different for the different turbomachines. Advanced details can be found in texts, including Balje (1981), Cohen et al. (1996), Dixon (1998, 1975), Hah (1997), Hill and Peterson (1992), Howell (1945a, 1945b), Japikse and Baines (1994), Logan (1993), Osborn (1977), Shepherd (1956), Stodola (1927), Turton (1984), Vavra (1974), Wallis (1983), Whittle (1981), and Wilson (1984). Furthermore, Rhie et al. (1998), LeJambre et al. (1998), Adamczyk (2000), and Elmendorf et al. (1998) show how modern computational fluid dynamic (CFD) tools can effectively be used for the complex three-dimensional analysis and design of turbomachines.

Single-Stage Energy Analysis

In this section, the equations are derived so that the internal fluid velocities can be related to the pressure change, power, and other important turbomachine characteristics.