Before selecting or designing a turbomachine, one must master the underlying physics. Turbomachines are defined as devices that transfer energy between a rotor and a fluid. This energy transfer is governed by the , the cornerstone of turbomachine theory.

A core concept in turbomachinery theory is the construction of velocity triangles. At the inlet and outlet of a rotor, vectors representing the fluid velocity are drawn to visualize the relationship between:

: Graphical analysis of absolute, relative, and tangential velocities at the inlet and outlet sections. 3. Selection and Preliminary Design

O.E. Baljé’s Turbomachines: A Guide to Design, Selection and Theory (1981) provides a foundational approach to machinery selection using Specific Speed ( Nscap N sub s ) and Specific Diameter ( Dscap D sub s

To maximize your learning, do not just download a PDF and archive it. Work through the example problems. Redraw the velocity triangles. Calculate the specific speed for a machine you encounter daily. Turbomachines are the ultimate fusion of art and science—and with the right guide, you can master both.

: Fluid moves parallel to the axis of rotation (e.g., jet engine compressors). Radial (Centrifugal) Flow