Method for forecasting noise value of propeller in uneven inflow

A numerical forecasting and propeller technology, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as few successful simulations, no better cavitation model and turbulence model

Active Publication Date: 2014-01-22
SOUTHEAST UNIV
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Problems solved by technology

[0002] The propeller noise includes cavitation noise and non-cavitation noise. The non-cavitation state is the propeller load noise, and the cavitation state includes cavitation noise and load noise. The viscous numerical simulation of propeller cavitation is controlled by the multiphase flow model , turbulence model, cavitation model, and the influence of phase transition critical pressure. There are few successful simulations of sheet cavitation at home and abroad, and there are no better cavitation models and turbulence models. Successful simulations of sheet cavitation are all for uniform Inflow; the study of propeller cavitation radiation noise is limited to the ideal combination of surface element method and single pulse spherical cavity radiation noise theory, or the use of FW-H equations to convert the cavitation pulsating volume into noise, these methods are not very good Therefore, the propeller cavitation monopole radiation noise in non-uniform inflow is a research problem. At present, the successful simulation of propeller noise is limited to exploratory research, and there is no comparison and verification with actual data. Therefore, accurate numerical prediction of propeller radiation noise It is also a research problem

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  • Method for forecasting noise value of propeller in uneven inflow
  • Method for forecasting noise value of propeller in uneven inflow
  • Method for forecasting noise value of propeller in uneven inflow

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Experimental program
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Embodiment 1

[0119] The verified propeller model is a DTMB4119 propeller, a three-blade propeller with no skew and no pitch distribution, the propeller diameter is 0.305m, the disk-to-surface ratio is 0.6, the blade cut surface is NACA-66, and the hub diameter ratio is 0.2. The CFD calculation area model is as follows: the upstream distance is 0.7D, the downstream distance is 3.75D, the radius of the rotating area is 0.16165m, the length is 0.14m, the radius of the static area is 1.471D, Gambit is used to divide the grid, and the rotating area is For unstructured grid division, the number of grids is 572382, and the static area is divided into structured grids, with the number of grids being 1762748. The parameters for CFD calculation are set as follows: the static pressure is 101325Pa, the inlet inflow velocity is 5.808m / s, the propeller speed is 20rps, the sliding grid technology is adopted, and the k-εRNG model is used for the turbulence model. The value comparison is shown in Table 1. ...

Embodiment 2

[0128] The geometric parameters of a civil ship propeller are as follows: the number of blades is 4, the diameter of the propeller is 0.2482m, the disc-to-surface ratio is 0.55, and the side slope angle is 32 degrees.

[0129] Figure 7 This is the comparison and verification diagram of the cavitation simulation of the circumferential blade of the civilian ship propeller, and the uniform inflow velocity U in the axial direction is 0 is 3.25m / s, the ambient pressure is 113000Pa, the propeller speed n is 25rps and 28rps respectively, and the iteration time of each step is 0.0005 seconds. The advance coefficients J corresponding to the two different speeds are 0.5238 and 0.4677 respectively, and the cavitation exponents σ are respectively 5.747, 4.58, calculate the radiation sound pressure of the blade cavitation monopole sound source, where r=1. Figure 9 It is the sound pressure distribution map within 0.04 seconds of a propeller rotation. Spectrograms of cavitation noise sou...

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Abstract

The invention discloses a method for forecasting the noise value of a propeller noise value in uneven inflow. The method for forecasting the noise value of the propeller in the uneven inflow comprises the steps that firstly, a CFD computation grid is divided, steady iterative computation is conducted so that the water flowing performance parameter and the water speed of an inflow opening can be worked out and the accuracy of a model is verified; secondly, CFD unsteady computation is conducted, the period state of blade cavitation and the blade cavitation area change of the propeller are recoded; thirdly, through CFD flow field data, acoustic boundary element value computation is conducted, and load noise of the propeller is worked out; finally, the noise of the propeller is worked out through the blade cavitation monopole radiation noise of the propeller and the load noise of the propeller.

Description

technical field [0001] The invention relates to a method for numerical prediction of propeller noise based on non-uniform inflow, and belongs to the technical field of numerical prediction of propeller radiation noise. Background technique [0002] The propeller noise includes cavitation noise and non-cavitation noise. The non-cavitation state is the propeller load noise, and the cavitation state includes cavitation noise and load noise. The viscous numerical simulation of propeller cavitation is controlled by the multiphase flow model , turbulence model, cavitation model, and the influence of phase transition critical pressure. There are few successful simulations of sheet cavitation at home and abroad, and there are no better cavitation models and turbulence models. Successful simulations of sheet cavitation are all for uniform Inflow; the study of propeller cavitation radiation noise is limited to the ideal combination of surface element method and single pulse spherical ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCY02T90/00
Inventor 方世良曹红丽
Owner SOUTHEAST UNIV
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