Numerical Analysis of Two-Phase Flow in the Cavitation Process of a Waterjet Propulsion Pump System

Advances in Materials Science and Engineering

et al. 2020

The rotating stall is a kind of flow phenomenon in the impeller harming the navigation speed of vessels propelled by a waterjet propulsion device when the waterjet propulsion device operates at the small flow rate conditions. The numerical simulated hydraulic performance was compared with experimental results so that the reliability of the CFD method was verified. The grooves are proposed before the inlet of an impeller to suppress the rotating stall. The orthogonal experiment is designed to seek the appropriate values of the parameters such as the length, width, depth, and number of the groove. The results show that the width of groove has the greatest influence on the performance of the device, followed by the number, the depth, and the length. The width, number, depth, and length of the selected groove scheme are 3.10 × 10−2D, 72, 3.10 × 10−2D, and 7.75 × 10−2D, respectively. At the rotating stall conditions, the selected groove scheme is numerically calculated. In contradistinction to the original scheme, it is found that the groove can improve the flow in the impeller and enhance the head of valley point condition, but the efficiency drops due to the increasing local hydraulic loss near the groove. When the groove is installed, the positive slop region on the flow rate-head curve disappears related to the static pressure difference on the blade, especially depending on the static pressure on the suction side. The flow pattern on the span surface of the vortex core is smooth, and then, the head increases. On the contrary, the head decreases. The outcome is beneficial to improve the performance of the waterjet propulsion device and enrich the rotating stall theory.

Section: Introductionmentioning

confidence: 99%

Investigation of Rotating Stall Phenomenon and Optimization in Mixed-Flow Waterjet Propulsion Device

Luo

Advances in Materials Science and Engineering

et al. 2020

“…e results could help to establish the design requirements for a waterjet-propelled ship type. e design and optimization method of the inlet passage is an important part of the hydraulic optimization of the waterjet propulsion system, and its hydraulic performance directly affects the overall performance of the waterjet propulsion system [38][39][40]. e uneven outflow of the inlet passage will cause periodic pulsation of the propulsion pump, induce vibration, and reduce the efficiency of the propulsion pump.…”

Section: Introductionmentioning

confidence: 99%

Optimal Design of Inlet Passage for Waterjet Propulsion System Based on Flow and Geometric Parameters

Jiao

Cheng

Advances in Materials Science and Engineering

et al. 2019

As an important overcurrent component in a waterjet propulsion system, the inlet passage is used to connect the propulsion pump and the bottom of the propulsion ship. e anticavitation, vibration, and noise performance of the waterjet propulsion pump are significantly affected by the hydraulic performance of the inlet passage. e hydraulic performance of the inlet passage directly affects the overall performance of the waterjet propulsion system, thus the design and optimization method of the inlet passage is an important part of the hydraulic optimization of the waterjet propulsion system. In this study, the hydraulic characteristics of the inlet passage in the waterjet propulsion system with different flow parameters and geometric parameters were studied by a combination of numerical simulation and experimental verification. e model test was used to verify the hydraulic characteristics of the waterjet propulsion system, and the results show that the numerical results are in good agreement with the test results. e numerical results are reliable. e hydraulic performance of the inlet passage is significantly affected by the inlet velocity ratio.ere is a certain correlation between the hydraulic performance of the inlet passage and ship speed, and the hydraulic performance of the inlet passage is limited by ship speed. e geometric parameters of the best optimization case are as follows: the inflow dip angle α is 35°, the length L is 6.38D 0 , and the upper lip angle is 4°. e optimal operating conditions are the conditions of IVR 0.69-0.87.

“…Jiao et al [6] studied the three-dimensional cavitation flow in a waterjet propulsion pump based on Zwart-Gerber-Belamri cavitation model and the RNG (Renormalization Group) k-ε model. The study demonstrates that the potential dangerous regions of cavitation are the lip of the inlet passage and the upper and lower connecting curved section of the inlet passage.…”

Section: Smart Flow Control In Pumpsmentioning

confidence: 99%

Special Issue: Smart Flow Control in Micro Scale

Qian

et al. 2020

Processes