CN-122021439-A - Gas turbine exhaust passage pneumatic noise calculation method

CN122021439ACN 122021439 ACN122021439 ACN 122021439ACN-122021439-A

Abstract

The invention relates to the field of gas turbines, in particular to a gas turbine exhaust passage aerodynamic noise calculation method, which comprises the steps of establishing an exhaust passage flow field calculation domain model and drawing flow field grids by taking an exhaust passage actual engineering drawing or three-dimensional scanning data as a basis; calculating steady-state flow fields according to inlet and outlet boundary conditions in a given calculation domain, deriving speed data, establishing an acoustic calculation area model of an exhaust passage by using three-dimensional modeling software, drawing an acoustic grid, setting monitoring points and a solver, deriving a direct frequency response calculation file, calculating the derived direct frequency response calculation file, and obtaining a spectrogram of the monitoring points after calculation is completed. According to the invention, through the accurate connection of the flow field and acoustic calculation, the noise spectrum data of key monitoring points can be directly obtained, the noise intensity characteristics under different frequencies are clearly presented, the noise distribution rules in the exhaust passage and in the far field are intuitively reflected, and accurate data support is provided for noise control.

Inventors

ZHANG KAIHONG
GUAN CHAOYANG
YU XINJIA
LI XIANG
WANG YU
ZHANG ZEYU
JIN GANG
ZHAO CHUNKAI
HE SHUAI
BAI ZHENG

Assignees

中国船舶集团有限公司第七〇三研究所

Dates

Publication Date: 20260512
Application Date: 20260202

Claims (9)

1. The method for calculating the aerodynamic noise of the exhaust passage of the gas turbine is characterized by comprising the following specific steps: s1, establishing an exhaust passage flow field calculation domain model and drawing flow field grids according to an exhaust passage actual engineering drawing or three-dimensional scanning data; s2, calculating a steady-state flow field under the inlet and outlet boundary conditions in a given calculation domain, calculating a transient flow field by taking a steady-state calculation result as a primary field after calculation convergence, and deriving speed data; s3, establishing an acoustic calculation area model of the exhaust passage by using three-dimensional modeling software, wherein two stages of silencers exist in the acoustic calculation area model of the exhaust passage; s4, drawing an acoustic grid; s5, utilizing a ICFD module in Actran to carry out Fourier transform on data of a flow field, guiding an acoustic grid into Actran, setting a bulk sound source, an infinite element plane, a sandwich structure, a microperforated panel and sound absorbing materials, setting monitoring points and a solver, and guiding out a direct frequency response calculation file; s6, calculating the derived direct frequency response calculation file, and acquiring a spectrogram of the monitoring point after calculation is completed.
2. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 1, wherein S1 further comprises the steps of reserving a core channel through which fuel gas flows by the established exhaust passage flow field calculation domain model, discharging a two-stage silencer, a sandwich structure and non-runner accessory parts, and deleting non-key features in the exhaust passage flow field calculation domain model.
3. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 1, wherein in S1, a polyhedral grid is selected as the flow field grid drawn.
4. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 1, wherein in S2, the inlet-outlet boundary condition setting includes: the mass flow inlet is adopted, the design flow of the exhaust passage is input, and the inlet gas temperature and the total pressure are designated at the same time; adopting a pressure outlet, setting the pressure outlet as the ambient pressure, and setting the reflux coefficient of the outlet as 0; setting the wall surface boundary as a slip-free wall surface, and setting the wall surface temperature to be according to the actual working condition and/or the adiabatic boundary.
5. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 4, wherein in S2, after the convergence is calculated, the convergence judgment includes: The residual errors of the continuity equation and the momentum equation are lower than 1e-6, and the energy equation; the average flow velocity and the static pressure fluctuation amplitude of the outlet section are less than or equal to 1%, and the continuous 30 iteration steps have no obvious change; after obtaining the steady state calculation result, the initial field calculation transient flow field comprises: and calling a convergence result of steady-state calculation as an initial field, fixedly starting large vortex simulation, and after calculation, deriving speed data, wherein the format is stored as a format compatible with the CFD software and Actran.
6. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 1, wherein the acoustic calculation region model of the exhaust passage in the step S3 uses a basic flow field domain model of the flow field calculation region model established in the step S1, an ellipsoid region exists around the flow field calculation region model, the length of the long axis of the ellipsoid is 1.5-2 times of the maximum length of the flow field calculation region, the short axis is 1.5-2 times of the maximum width of the flow field calculation region, the center of the ellipsoid coincides with the center of the flow field calculation region, and the direction of an ellipsoid outlet faces the far-field noise monitoring direction.
7. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 6, wherein the acoustic grid in S4 is a hexahedral grid, and the area grid density comprises a silencer interior, an interlayer interior and an infinite element area, wherein the silencer interior and the interlayer interior are encrypted according to the multiple of the basic grid size, and the infinite element area gradually transits and enlarges the grid from a sound source area to the outside; the acoustic mesh is derived in Actran compatible formats.
8. The method for calculating aerodynamic noise of an exhaust passage of a gas turbine according to claim 1, wherein S5 specifically comprises: importing Actran the exported speed data file, and selecting ICFD module for Fourier transformation; introducing an acoustic grid into Actran, defining a primary flow field calculation domain as a LIGHTHILL-volume sound source, defining the outer surface of an ellipsoidal infinite element region as InfiniteFluid, applying a micropunching plate to the outer surface of a two-stage silencer and the inner wall of an interlayer, and filling sound absorption materials into the interlayer structure and the silencer; setting monitoring points, wherein the monitoring points cover key areas, and a solver selects direct frequency response solution; A direct frequency response calculation file is generated containing all parameter configurations.
9. The method of calculating aerodynamic noise of a gas turbine exhaust passage according to claim 8, wherein said step S6 further comprises, in the calculation: Observing residual curve and monitoring point sound pressure level change through Actran calculation monitoring interface, suspending calculation, checking grid quality and parameter configuration when residual divergence and sound pressure level mutation exist; And the calculation result is automatically saved every 100 frequency steps.

Description

Gas turbine exhaust passage pneumatic noise calculation method Technical Field The invention relates to the field of gas turbines, in particular to a gas turbine exhaust passage pneumatic noise calculation method. Background As core equipment in the fields of energy supply and power output, exhaust noise generated in the operation process of a gas turbine has become a key problem affecting the surrounding environment of equipment and personnel comfort. The exhaust passage is used as a core passage for discharging the fuel gas, the internal gas flow state is complex, the internal gas flow state is influenced by factors such as the structure form of a flow passage, the gas flow characteristics and the like, a turbulent vortex structure is easy to form, and the internal gas flow state becomes a main generation source of aerodynamic noise based on a vortex-sound interaction principle. In order to reduce the influence of exhaust noise, the noise control scheme of arranging a silencer inside an exhaust passage, arranging a sandwich structure outside the exhaust passage, filling sound absorbing materials and matching with a microperforated plate is commonly adopted in the existing engineering. However, in the noise calculation link, the industry depends on general technical manuals, and the estimation is performed by inquiring standard sound insulation data of parts such as sound absorption materials, plates and the like. The traditional calculation mode can only acquire the approximate level of the whole noise, can not accurately reflect the noise frequency distribution characteristics of specific monitoring positions, and is difficult to reveal the propagation path and intensity distribution rule of the noise in the exhaust passage. The limitation leads to structural design and arrangement modes of the silencer, selection and filling schemes of sound absorbing materials and the like, targeted optimization is difficult to achieve, the problem that noise control effect is not as expected or design redundancy often exists, and the requirement on accurate noise control in engineering practice cannot be met. Disclosure of Invention The invention provides a gas turbine exhaust passage pneumatic noise calculation method aiming at the technical problems in the prior art. The technical scheme for solving the technical problems is as follows, the method for calculating the aerodynamic noise of the exhaust passage of the gas turbine comprises the following specific steps: s1, establishing an exhaust passage flow field calculation domain model and drawing flow field grids according to an exhaust passage actual engineering drawing or three-dimensional scanning data; S2, calculating a steady-state flow field by using inlet and outlet boundary conditions in a Fluent and/or Star-CCM+ given calculation domain, calculating a transient flow field by taking a steady-state calculation result as an initial field after calculation convergence, and deriving speed data; s3, establishing an acoustic calculation area model of the exhaust passage by using three-dimensional modeling software, wherein two stages of silencers exist in the acoustic calculation area model of the exhaust passage; s4, drawing an acoustic grid; s5, utilizing a ICFD module in Actran to carry out Fourier transform on data of a flow field, guiding an acoustic grid into Actran, setting a bulk sound source, an infinite element plane, a sandwich structure, a microperforated panel and sound absorbing materials, setting monitoring points and a solver, and guiding out a direct frequency response calculation file; s6, calculating the derived direct frequency response calculation file, and acquiring a spectrogram of the monitoring point after calculation is completed. In a preferred embodiment, the S1 further comprises the step of reserving a core channel through which fuel gas flows by the established exhaust passage flow field calculation domain model, discharging a two-stage silencer, a sandwich structure and non-runner accessory parts, avoiding the interference of an irrelevant structure on flow field calculation, deleting small chamfers, threaded holes and other non-key features in the exhaust passage flow field calculation domain model, and reducing grid division difficulty. In a preferred embodiment, in the step S1, the drawn flow field grid is a polyhedral grid, and the core advantage is that the nodes are uniformly distributed, so that the node correspondence of the subsequent acoustic grid can be perfectly matched, and interpolation errors during data transmission are avoided. In a preferred embodiment, in S2, the inlet/outlet boundary condition setting includes: the mass flow inlet is adopted, the design flow of the exhaust passage is input, and the inlet gas temperature and the total pressure are designated at the same time; The pressure outlet is adopted, the ambient pressure is set, the reflux coefficient of the outlet is set to 0, and the reverse flow interfer