Abstract

A new pump, called the hybrid airlift-jet pump, is developed by reinforcing the advantages and minimizing the demerits of airlift and jet pumps. First, a basic design of the hybrid airlift-jet pump is schematically presented. Subsequently, its performance characteristics are numerically investigated by varying the operating conditions of the airlift and jet parts in the hybrid pump. The compressible unsteady Reynolds-averaged Navier-Stokes equations, combined with the homogeneous mixture model for multiphase flow, are used as the governing equations for the two-phase flow in the hybrid pump. The pressure-based methods combined with the Pressure-Implicit with Splitting of Operators (PISO) algorithm are used as the computational fluid dynamics techniques. The validity of the present numerical methods is confirmed by comparing the predicted mass flow rate with the measured ones. In total, 18 simulation cases that are designed to represent the various operating conditions of the hybrid pump are investigated: eight of these cases belong to the operating conditions of only the jet part with different air and water inlet boundary conditions, and the remaining ten cases belong to the operating conditions of both the airlift and jet parts with different air and water inlet boundary conditions. The mass flow rate and the efficiency are compared for each case. For further investigation into the detailed flow characteristics, the pressure and velocity distributions of the mixture in a primary pipe are compared. Furthermore, a periodic fluctuation of the water flow in the mass flow rate is found and analyzed. Our results show that the performance of the jet or airlift pump can be enhanced by combining the operating principles of two pumps into the hybrid airlift-jet pump, newly proposed in the present study.

Highlights

  • A pump is a device that actuates liquids by mechanical actions

  • Airlift pumps operate on the air and are inserted into vertical pipes, which lowers the density of the fluid mixture and lifts it

  • Numerical simulations of 18 cases were performed to investigate the performance of the preliminary design of a hybrid airlift-jet pump under various operational conditions

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Summary

Introduction

A pump is a device that actuates liquids by mechanical actions. Numerous types of pumps exist according to methods used to actuate the fluid. Both the airlift and jet pumps can be classified into indirect types, where the direct contact of mechanical parts is not required to drive the fluid. Jet pumps (or educator-jet pumps) use a jet, often of steam, to create a low pressure. This lower pressure draws in the target fluid and propels it into a higher-pressure region. The primary merit of these types of pumps is their simple operating mechanism due to their simple structure, and they can operate on ill-conditioned target liquids and are durable. Our aim is to develop a new pump concept by combining

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