Investigation of Key Parameters for Hydraulic Optimization of an Inlet Duct Based on a Whole Waterjet Propulsion Pump System

Abstract

The hydraulic performance of an inlet duct directly affects the overall performance of a waterjet propulsion system. Key parameters for the hydraulic optimization of the inlet duct are explored using the computational fluid dynamics (CFD) technology to improve the hydraulic performance of the waterjet propulsion system. In the CFD simulation and experiment, an inlet duct with different flow and geometric parameters is simulated. By comparing grid sensitivity and different turbulence models, a suitable grid size and a turbulence model are determined. The comparison between the numerical simulation and the experiment shows that the numerical results are reliable. The results of the calculation and analysis of different speed cases show that the ship speed affects the efficiency of the waterjet propulsion system. In particular, the system efficiency increases first and then decreases with an increase in the ship speed. Under the conditions of constant ship speed and rotational speed, the influence of the length and dip angle of the inlet duct on the waterjet propulsion system is investigated using a single factor method. The results show that the dip angle has an obvious effect on the hydraulic performance of the inlet duct, and an extremely small angle of inclination will lead to poor flow patterns in the inlet passage. When the length is approximately six times the inlet duct outlet diameter, and the dip angle is 30°-35°, the hydraulic performance of the waterjet propulsion pump system is satisfactory.

Experiment on Influence of Blade Angle on Hydraulic Characteristics of the Shaft Tubular Pumping Device

“…Firstly, due to the low head of the shaft tubular pump, the performance of the device largely depends on the loss of the passage. Zhou et al [8], Zhang et al [9], Jiao et al [10], and Gao et al [11] carried out in-depth research on the optimal design of the inlet and outlet channels of the pumping device, and put forward optimization suggestions on the type and profile of the channel. Secondly, with the development of China's South-to-North Water Transfer Project and the renewal and reconstruction project of small-and medium-sized pumping stations, in order to further optimize the performance of vertical shaft tubular pump devices, Shi et al [12] used CFD to perform unsteady simulation calculations on full tubular and axial flow pumps based on the RNG k-ε turbulence model, and the results show that the pressure pulsation of the full tubular pump is less than that of the axial flow pump under design and large flow conditions.…”

Design and Analysis of a Stiffness-Enhanced 3-PPS Parallel Mechanism for Fault-Tolerant Underwater Vectored Thrusters

“…To improve the motion performance of underwater vehicles, there are mainly two approaches, i.e., a vector water-jet propulsion system [5,6] and vector propulsion system based on a propeller [7,8], to realize vector propulsion. However, the complex mechanical structure of the vector water jet propulsion reduces the system's reliability [9]. In comparison, the vector propulsion system based on the propeller not only has the priorities of flexible assemble mode and high propulsion efficiency, but also maintains high maneuverability and a certain reliability [10,11].…”