Operating Characteristics of Multi-Injection Type Underwater Jet Pump

摘要

A method of installing a jet pump at the bottom of a contaminated lake or river and stirring the contaminated area with a jet of large flow rate generated by the jet pump to promote water purification has attracted attention. By stirring the contaminated area, dissolved oxygen in the water is supplied to the stagnant area. As a result, the activity of the bacteria in the water is enhanced, and the decomposition and removal of the contaminants is promoted. In this study, the structure and operating conditions of a jet pump capable of generating a jet flow of larger flow rate with less energy consumption was pursued. In particular, the operation efficiency of the jet pump in the case of adopting the multi-nozzle injection method as the supply method of the primary jet was experimentally evaluated by precise flow rate measurement in a large tank experiment. In addition, quantitative evaluation of energy consumed by constituent equipments such as electric motors, pumps, pipelines and so on constituting the jet pump system was performed, and the total energy efficiency of the jet pump system was also evaluated. As a result, it became clear that the multi-injection method of the primary jet shows superior energy efficiency compared with the jet pump of the conventional structure.