Centrifugal compressors, theory

The reciprocating compressor is a positive-displacement compressor. It is cheaper to purchase and install than a centrifugal compressor. Also—in theory—far more efficient (90 percent) than a centrifugal compressor (70 percent). Certainly, reciprocating compressors are more simple to understand and engineer than centrifugal machines. Best of all, they are not subject to surge. 

Centrifugal compressors have head-capacity curves similar to those of the more familiar centrifiigal-pump curves. Within the lower limit necessary to avoid surge and the upper limit of impeller capacity, each unit can in theory operate at any point on its curve. 

The above compressor control theory is applied in the following example [15]. For more details on centrifugal compressors and their control, the interested reader is again directed to the Gas Processors Suppliers Association s Engineering Data Book [17] or the ISA Instructional Resource Package on Centrifugal and Axial Compressor Control [18]. 

Stepanoff, A.J. (1955). Turboblowers. Theory, Design and Application of Centrifugal and Axial Flow Compressors and Fans, John Wiley, New York and Chapman Hall. London. 

Stepanov, A. I. Centrifugal and axial-flow compressors, blowing machines and ventilating fans. The Theory, a Build and Application. M. Engineering Industry 1960. 

---