Pumps and Gas- Moving Equipment

Outline Pump Power Positive-Displacement Pumps Centrifugal Pumps Comparison Centrifugal Pump Performance Characteristics and Operating Point Pumps in Series and Parallel

Outline (Continued) Scaling Laws Net Positive Suction Head Gas-Moving Machinery Power Isentropic Efficiency Two-Stage Compressor

Objectives Introduce and compare the different types of pumps. Calculate the electric and brake powers. Calculate the volumetric flowrate in the case of reciprocating pumps.

Objectives (Continued) Determine the operating point for centrifugal pump. Consider the case of pumps in series and parallel. Introduce scaling laws. Know how to avoid cavitation.

Objectives (Continued) Introduce and compare the different types of gas-moving machinery. Calculate the brakepower. Minimize power in a two-stage compressor.

Summary Head rise gained by the fluid Brake power Electric power

Summary (Continued) Positive-displacement pumps include rotary and reciprocating pumps. The different types of pumps have been discussed and compared. The operating point is found as the intersection of the pump performance curve, and the system curve.

Summary (Continued) For pumps in series and parallel, new pump curves can be calculated, which allows to calculate the new operating points knowing the single pump performance curve. Scaling laws allow to estimate the new performance curves if we change rpm or impeller diameter.

Summary (Continued) Requirement to avoid cavitation: The different types of gas-moving machinery have been discussed and compared.

Summary (Continued) Brake power Isentropic efficiency To minimize compression power, a two- stage compression is used with intercooling.