ABSTRACT

Radial inflow turbines have a long history and predate axial machines by many years. The oldest turbine was that Hero’s turbine that dates back to 150 BC. The other old one is the Ljungstrom outward flow type which dates back to 1894. This chapter deals solely with radial inflow turbines working with compressible fluids. Radial inflow turbines are not as common as radial flow (centrifugal) compressors. Like the latter, most radial inflow turbines are machines with relatively low specific speed suitable for applications with low flow rates and large pressure drops. They are also simpler and cheaper than axial turbines and so are used when weight and cost are more important than efficiency. The inward-flow radial (IFR) turbine covers tremendous ranges of power, rates of mass flow, and rotational speeds, and their uses range from very large Francis turbines used in hydroelectric power generation and developing hundreds of megawatts down to tiny closed cycle gas turbines employed in aerospace applications requiring power generation of a few kilowatts [1].