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14 Radial Compressors
rotors must be stronger as well. Rotor casting, as typical for pumps, is not feasible.
Welding of the shroud is normally possible, as the rotor channels are rather open.
Fig. 14.6 renders a radial compressor with ten stages and an integrated gearbox (integrally geared compressor). This arrangement is an alternative to an inline
construction. The objective is to obtain a sufficiently high and approximately equal
peripheral speed of the successive stages with decreasing diameter for compressors
with rather small rotor dimensions. Figure 14.7 shows a diesel engine turbocharger
with a radial compressor for high work and an axial turbine. Further, radial compressors are often used as the last stage of the compressor of a small gas turbine
for helicopter rotor drive. The general appearance is then somewhat similar to the
Fig. 14.4 Radial air compressor with integrated coolers (courtesy MAN Diesel & Turbo)