Comparison of hydrodynamic performance and wake vortices of two typical types of pumpjet propulsor

Qin, Denghui; Huang, Qiaogao; Shi, Yuejun; Pan, Guang; Shi, Yue; Dong, Xinguo

doi:10.1016/j.oceaneng.2021.108700

Cited by 32 publications

(15 citation statements)

References 32 publications

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“…Here, f1 and f2 are the torque and thrust coefficient, respectively, for the two types of meshes [19,53]. P denotes the accuracy of algorithm (p = 2 herein).…”

Section: Vertification Of the Grid Independencementioning

confidence: 99%

Prediction of Cavitation Performance over the Pump-Jet Propulsor Using Computational Fluid Dynamics and Hybrid Deep Learning Method

Qiu

Huang

Pan

2022

JMSE

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The cavitation performance of an oblique flow field is different from that under a pure axial flow field. This study analyzed the hydrodynamic performance, bearing force, and tip clearance flow field under different rotating speeds and different cavitation numbers in an oblique flow field. Furthermore, this study proposed a hybrid deep learning model CNN-Bi-LSTM to quickly and accurately predict the bearing force of a pump-jet propulsor (PJP), which will solve the problem of time-consuming calculation and consumption of considerable computing resources in traditional computational fluid dynamics. The Shear–Stress–Transport model and Reynolds-averaged Navier–Stokes equations were utilized to procure the training and testing datasets. The training and testing datasets were reasonably divided in the ratio of 7:3. The results show that the propulsion efficiency decreased more obviously under higher rotating speed conditions, with a maximum decrease of up to 13.59%. The small cavitation numbers 1.4721 and high oblique angle significantly impacted the efficiency reduction; the maximum efficiency loss exceeded 20%. Thus, a small cavitation number 1.4721 is extremely detrimental to the propulsion efficiency of the PJP due to the large cavitation area. Moreover, the intensity of the tip clearance vortex continuously increased with the rotating speed. The CNN-Bi-LSTM deep model successfully predicted the phase difference and trend change of the propulsor bearing force under different conditions. The prediction difference was large at the crest and trough of the bearing force, but it is within the acceptable error range.

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“…Here, f1 and f2 are the torque and thrust coefficient, respectively, for the two types of meshes [19,53]. P denotes the accuracy of algorithm (p = 2 herein).…”

Section: Vertification Of the Grid Independencementioning

confidence: 99%

Prediction of Cavitation Performance over the Pump-Jet Propulsor Using Computational Fluid Dynamics and Hybrid Deep Learning Method

Qiu

Huang

Pan

2022

JMSE

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“…According to the relative position of the stator and rotor, the PJP can be divided into two categories: the "pre-swirl PJP" (the stator is in front of the rotor) and the "post-swirl PJP" (the stator is behind the rotor). 1 In this study, the hydrodynamic performance of a pre-swirl PJP is studied. For the pre-swirl PJP, the front stator can pre-swirl the incoming flow to improve the working conditions of the rotor.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the front stator reduces the inlet flow of the rotor, leading to a reduction of the radiated noise of the PJP. 1 Therefore, since the birth of the PJP, it has received extensive attention, and research of PJP has grown rapidly. 2 The experimental test is an essential means to study the flowfield characteristics of PJP.…”

Section: Introductionmentioning

confidence: 99%

“…Sun et al 13 simulated the flow of PJP (with a nine-bladed stator and seven-bladed rotor) using LES. Denghui et al 1 discussed the difference of hydrodynamic performance between the pre-swirl PJP (with an eight-bladed stator and six-bladed rotor) and the post-swirl PJP (with an 11-bladed stator and nine-bladed rotor). The three-dimensional structure of vortices of rotor tip vortices of the two PJPs are compared.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the odd and even number of blades on the hydrodynamic performance of a pre-swirl pumpjet propulsor

et al. 2022

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A numerical study based on detached eddy simulations is conducted to investigate the effects of the odd and even number of rotor/stator blades, that is, nr/ ns, on the hydrodynamic performance of a pre-swirl pumpjet propulsor (PJP). In this paper, six PJPs, the PJP 6-4 ( ns– nr), 8-6, 10-8, 7-5, 9-7, and 11-9, are created. The hydrodynamic performance, the unsteady force of blades, and the wake structure of the PJPs are compared. The results show that the frequency of the fluctuating force of the whole rotor highly depends on the number or, more specifically, the parity of nr. When the parameter nr is the even number, it can be found that the total unsteady force of the rotor blades will be strengthened at the k-order stator-blades-passing frequency ([Formula: see text]). Moreover, it indicates that the superposition-enhancement coefficient (is defined as [Formula: see text]) at [Formula: see text] equals to nr, at least from the present tests. In terms of both the rotor and stator numbers are even, a phenomenon of the rotor–stator resonance occurs at [Formula: see text], where fn represents the hub rotational frequency. This work is expected to give some insight in the design of a PJP.

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“…According to the position of the stator, there are two types of PJP: pre-swirl PJP and post-swirl PJP. The submarines and some offshore vessels generally adopt the former for noise reduction [1]. In contrast, underwater vehicles such as torpedoes typically employ post-swirl PJP, for the post-stator can recover part of the wake energy that is lost with conventional propellers.…”

Section: Introductionmentioning

confidence: 99%

Influence of Various Stator Parameters on the Open-Water Performance of Pump-Jet Propulsion

Huang

Pan

et al. 2021

JMSE

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In order to improve the hydrodynamic performance of pump-jet propulsion (PJP) when matching stator with the rotor, the RANS method with SST k-ω turbulence model is employed to study the influence of six kinds of stator parameters, which are classified into three groups, i.e., stator solidity, stator angles and rotor–stator spacing (S). Results show that the stator solidity involves the blade number (Ns) and chord length (L), has an obvious acceleration effect at and after stator, and produces a higher thrust and torque with a slight efficiency change. Further comparing Ns and L results, we find greater distinctions between the two cases when stator solidity is greatly adjusted. Three stator angles, i.e., stagger angle (α), lean angle (γ), and sweep angle (β), are studied. The α has the biggest effect on the thrust, torque, and efficiency; meanwhile, it shifts the advance number that corresponds to maximum efficiency. The effect of γ is similar to α, but its influence is far less than α. However, there is little difference between various β cases except for off-design conditions, where the efficiency drops dramatically as β increases. The S has a slight effect on PJP performance. Even though S decreases 34% relative to the original PJP, the rotor thrust and torque increase by less than 1%. In addition, we compare torque balance locations under various parameters, and each component force is analyzed in detail to explain the reason for performance variation. The present work is conducive to future optimization in PJP design.

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Comparison of hydrodynamic performance and wake vortices of two typical types of pumpjet propulsor

Cited by 32 publications

References 32 publications

Prediction of Cavitation Performance over the Pump-Jet Propulsor Using Computational Fluid Dynamics and Hybrid Deep Learning Method

Prediction of Cavitation Performance over the Pump-Jet Propulsor Using Computational Fluid Dynamics and Hybrid Deep Learning Method

Effect of the odd and even number of blades on the hydrodynamic performance of a pre-swirl pumpjet propulsor

Influence of Various Stator Parameters on the Open-Water Performance of Pump-Jet Propulsion

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