On the space-time decomposition and reconstruction of the pump-jet propulsor flow field

Li, Shizhong; Li, Fuzheng; Huang, Qiaogao; Pan, Guang; Wang, Shixian; Tian, Xushun

doi:10.1016/j.oceaneng.2023.115521

Cited by 5 publications

(1 citation statement)

References 18 publications

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“…The morphology and evolutionary characteristics were investigated using the SPOD and DMD methods. Li et al [108] DMD and SPOD are utilized to decouple the complex coherent structure of high-speed jets in liquid ring pump ejectors. Jiang et al [109] The POD and SPOD methods were introduced to analyze the complex spatiotemporal evolution of the flow field in the liquid ring pump injector.…”

Section: Liu Et Al [63]mentioning

confidence: 99%

Data-Driven Modal Decomposition Methods as Feature Detection Techniques for Flow Fields in Hydraulic Machinery: A Mini Review

Xu,

Zhang,

Zhang

et al. 2024

JMSE

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Cavitation is a quasi-periodic process, and its non-stationarity leads to increasingly complex flow field structures. On the other hand, characterizing the flow field with greater precision has become increasingly feasible. However, accurately and effectively extracting the most representative vibration modes and spatial structures from these vast amounts of data has become a significant challenge. Researchers have proposed data-driven modal decomposition techniques to extract flow field information, which have been widely applied in various fields such as signal processing and fluid dynamics. This paper addresses the application of modal decomposition methods, such as dynamic mode decomposition (DMD), Proper Orthogonal Decomposition (POD), and Spectral Proper Orthogonal Decomposition (SPOD), in cavitation feature detection in hydraulic machinery. It reviews the mathematical principles of these three algorithms and a series of improvements made by researchers since their inception. It also provides examples of the applications of these three algorithms in different hydraulic machinery. Based on this, the future development trends and possible directions for the improvement of modal decomposition methods are discussed.

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Section: Liu Et Al [63]mentioning

confidence: 99%

Data-Driven Modal Decomposition Methods as Feature Detection Techniques for Flow Fields in Hydraulic Machinery: A Mini Review

Xu,

Zhang,

Zhang

et al. 2024

JMSE

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Research on hydraulic optimization design method of water-jet propulsion pump considering hump index

Long,

Zheng,

Han

et al. 2024

J Braz. Soc. Mech. Sci. Eng.

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：In order to improve the efficiency of water-jet pump and reduce or eliminate the hump phenomenon, it is necessary to optimize the impeller design. In this paper, the optimization of waterjet propulsion pump is studied by combining numerical simulation and experiment.The orthogonal optimization design scheme is established. Based on the numerical simulation method, the hydraulic performance indexes such as energy coefficient, torque coefficient and efficiency of the design points of different design schemes are obtained. The final optimization design is completed by further optimizing the profile and spatial position of the optimal efficiency factor level combination A2B1C1D1 at different spanwise heights.Then, based on the results of numerical simulation by CFX, using Python and LabVIEW programming software, a pump flow head curve fitting and hump judgment program is developed, which can realize the function of curve fitting of flow head, giving the position of trough and peak, and calculating the value of hump climbing coefficient Chump. The influence of different blade structure parameters on the hydraulic performance and energy characteristic curve hump of the water-jet pump is analyzed, and the optimization design of the high-performance water-jet pump considering the hump index is completed.In summary, This method is not only applicable to the hydraulic optimization of the water-jet propulsion pump, but also the research results can provide theoretical basis and technical support for the high-performance and low-vibration design of the water jet propulsion pump.

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Numerical analysis of the influence of hull-modulated inflow on unsteady force fluctuations and vortex dynamics of pump-jet propulsor

Xue,

Yang,

Zou

et al. 2023

Physics of Fluids

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The influence of the hull-modulated inflow on the propulsion performance of the propeller is related to the matching design of the propeller–hull system. In the present study, considering the working conditions of the pump-jet propulsor in uniform inflow and two types of hull-modulated inflow, based on improved delay detached eddy simulation, the influence of hull-modulated inflow on unsteady force fluctuations and vortex dynamics of pump-jet propulsor under design conditions is carried out. The results show that the hull-modulated inflow increases the propulsion efficiency of the pump-jet propulsor to varying degrees within the range of the calculated advance coefficient and has a significant influence on the frequency characteristics of the unsteady force spectra characteristics of each component of the pump-jet propulsor. It also shows changes in the magnitude characteristics, that is, the energy transfer process of an individual rotor blade from the stator blade passing frequency to other harmonics of the shaft rotation frequency, and the thrust spectrum of an individual stator blade presents broad-spectrum characteristics in the high-frequency range. Furthermore, the application of hull-modulated inflow directly affects the shape of the stator shedding vortex, causing some of the stator blade shedding vortices to separate early and aggravating its short-wave instability. More secondary vortices are induced to accelerate the instability of the rotor blade tip clearance vortex. The energy transfer mechanism from the rotor blade passing frequency and its harmonics to the broadband spectra appears in the wake field of the pump-jet propulsor.

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On the space-time decomposition and reconstruction of the pump-jet propulsor flow field

Cited by 5 publications

References 18 publications

Data-Driven Modal Decomposition Methods as Feature Detection Techniques for Flow Fields in Hydraulic Machinery: A Mini Review

Data-Driven Modal Decomposition Methods as Feature Detection Techniques for Flow Fields in Hydraulic Machinery: A Mini Review

Research on hydraulic optimization design method of water-jet propulsion pump considering hump index

Numerical analysis of the influence of hull-modulated inflow on unsteady force fluctuations and vortex dynamics of pump-jet propulsor

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