To the calculation of energy efficiency indicators of single-screw pumps

Abstract

Test results from manufacturers of single screw pumps were studied. The expended power of a single-screw pump is directly proportional to the rotor speed. The proportionality coefficient represents the mechanical work of a single screw pump per revolution and increases linearly with increasing pressure drop. Energy efficiency and Specific energy consumption indicators were calculated for the Vulcan series single screw pump. Both indicators improve with increasing rotor speed: energy efficiency increases, specific energy consumption decreases. No maximum efficiency was found when the rotor speed changed in the studied range. If the frequency is fixed, then there is a maximum efficiency at a certain pressure drop. At higher pressure values, both indicators worsen. At lower pressure values, the energy efficiency indicator decreases, and the specific energy consumption indicator shows better energy efficiency. Therefore, when selecting single-screw pumps for operation under these conditions, the specific energy consumption indicator, and not the efficiency, should be taken into account.