An optimization method for pressure ratio distribution of low-pressure compressor stages of marine gas turbines under flow structure constraints

Abstract

The purpose of the present invention is to provide a method for optimizing the stage pressure ratio distribution of a low-pressure compressor of a marine gas engine under the constraint of a flow structure, to design the step-by-step distribution law of the load coefficient ψ without substantially changing the geometric constraint of the compressor flow structure, and to achieve different stage pressure ratio distribution schemes by controlling the load of each stage of the compressor. The present invention realizes the customized distribution of the pressure ratio of each stage of the low-pressure compressor, effectively improves the aerodynamic optimization effect of the existing model of the low-pressure compressor, and fully utilizes the structural advantages and processing and manufacturing process of the prototype compressor, inherits the advantages of the prototype compressor to the greatest extent, effectively solves the performance improvement and optimization problem of the low-pressure compressor of the existing model of the marine gas engine, and is very suitable for practical engineering applications. At the same time, the present invention is not only limited to the low-pressure compressor of the marine gas engine, but is also applicable to the aerodynamic optimization process of axial flow compressors with a wide range of working conditions.

Description

Technical Field

[0001] The present invention relates to a gas turbine control method, in particular to a compressor control method. Background Art

[0002] As one of the three most important core components of a marine gas turbine, the performance of the compressor plays a decisive role in the realization of the technical and economic indicators of the entire unit. As the most widely used layout form of marine gas turbines, the three-rotor gas turbine has a very wide range of common operating conditions for its low-pressure compressor, and at the same time has extremely high efficiency requirements within a wide range of operating conditions. The aerodynamic design technology of high-efficiency and wide-margin low-pressure compressors has become one of the most important core technologies in the design system of marine gas turbines. Among them, the pressure ratio distribution of each stage plays a key role in the inter-stage matching of the low-pressure compressor.

[0003] On the other hand, in order to improve the performance indicators of existing marine gas turbines, aerodynamic optimization using existing compressors as prototypes has become the most commonly used improvement method in current engineering. In order to make full use of the structural advantages of the prototype compressor and inherit the processability of the unit's processing and manufacturing, it is usually required that the aerodynamic optimization of the compressor must maintain the original structural characteristics as much as possible and maintain the geometric parameter constraints unchanged, which makes the design of the compressor more difficult. At present, achieving compressor performance improvement under the premise of limited flow changes and almost unchanged structural constraints has become the most difficult of the difficulties. Therefore, it is necessary to explore and develop advanced aerodynamic optimization methods based on new ideas and new methods, create more groundbreaking compressor aerodynamic optimization design technology, and thus effectively promote the performance improvement of the low-pressure compressor of the existing unit. Summary of the invention

[0004] The purpose of the present invention is to provide a method for optimizing the stage pressure ratio distribution of a low-pressure compressor of a marine gas engine under flow structure constraints, which can solve the performance improvement optimization problem of the low-pressure compressor of a marine gas engine under the condition that the geometric constraints of the flow structure remain unchanged.

[0005] The object of the present invention is achieved in that:

[0006] The present invention provides a method for optimizing the pressure ratio distribution of a low-pressure compressor stage of a marine gas engine under the constraint of a flow structure, which is characterized by:

[0007] (1) Determine the flow structure constraints, including geometric parameters such as flow channel size, number of stages, and axial position of each row of blades;

[0008] (2) Determine the compressor optimization design parameters, including compressor inlet conditions, speed, flow rate, and pressure ratio;

[0009] (3) Selecting a stage load control parameter, using the load coefficient ψ as the stage load control parameter, and realizing different stage pressure ratio distribution schemes by controlling the load of each stage of the compressor;

[0010] (4) Design of the load factor ψ distribution law for each level, given the relationship between the load factor ψ and the level number i;

[0011] (5) Solving the one-dimensional inverse problem: Using the geometric parameters, aerodynamic parameters and load coefficient distribution results obtained in the above steps as input variables, solving the one-dimensional inverse problem and obtaining the distribution scheme of the pressure ratio of each stage of the low-pressure compressor.

[0012] The present invention may also include:

[0013] 1. The relationship between the given load factor ψ and the level number i described in step (4) is as follows:

[0014] Determine the first-stage load factor ψ based on the compressor speed, pressure ratio, and the inner and outer diameters of the first-stage moving blades. 1 ; Then determine the load coefficients ψ at each level through the following relationship i :

[0015]

[0016] The advantages of the present invention are:

[0017] 1. The present invention realizes customized distribution of pressure ratios of each stage of low-pressure compressor by designing the step-by-step distribution law of load coefficient without substantially changing the geometric constraints of the compressor flow structure, thereby parameterizing the aerodynamic optimization work of the existing model of low-pressure compressor and effectively improving the aerodynamic optimization effect of the compressor.

[0018] 2. While achieving the improvement of the performance of the low-pressure compressor, the present invention fully utilizes the structural advantages and processing and manufacturing processability of the prototype compressor, inherits the advantages of the prototype compressor to the greatest extent, and effectively solves the performance improvement and optimization problem of the low-pressure compressor of the existing model of marine gas turbine, and is very suitable for practical engineering applications.

[0019] 3. The present invention is not limited to low-pressure compressors of marine gas engines, but is also applicable to aerodynamic optimization processes of axial flow compressors in a wide range of operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in more detail below with reference to the accompanying drawings:

[0022] Combination Figure 1The specific implementation method of the present invention for optimizing the pressure ratio distribution of a low-pressure compressor stage of a marine gas engine under the constraint of a flow structure is achieved by the following steps:

[0023] Step 1: Determine the flow structure constraints. Clearly optimize the structural constraints of the flow section of the compressor. Common constraints are generally geometric parameters such as flow channel size, number of stages, and axial position of each row of blades.

[0024] Step 2: Determine the compressor optimization design parameters. According to the index requirements, determine the aerodynamic parameters of the compressor optimization design, including compressor inlet conditions, speed, flow rate, pressure ratio, etc.

[0025] Step 3: Select stage load control parameters. Use the load coefficient ψ as the stage load control parameter to achieve different stage pressure ratio distribution schemes by controlling the load of each stage of the compressor.

[0026] The load factor ψ is defined as follows:

[0027] Among them C 1u,m , C 2u,m , U m It is the absolute tangential velocity at the inlet, the absolute tangential velocity at the outlet and the circumferential velocity at the average radius of the moving blades of each stage of the compressor.

[0028] Step 4: Design the step-by-step distribution rule of load coefficient ψ.

[0029] The relationship between the given load factor ψ and the level number i is as follows:

[0030] Determine the first-stage load factor ψ based on the compressor speed, pressure ratio, and the inner and outer diameters of the first-stage moving blades. 1 ; Then determine the load factor ψ at each level through the following relationship i :

[0031]

[0032] Step 5: Solve the one-dimensional inverse problem. The geometric parameters, aerodynamic parameters and load coefficient distribution results obtained in the above steps are used as input variables to solve the one-dimensional inverse problem and obtain the distribution plan of the pressure ratio of each stage of the low-pressure compressor.

[0033] The method for optimizing the pressure ratio distribution of a low-pressure compressor stage of a marine gas engine under the constraint of a flow structure proposed in the present invention is universal and is not limited to the low-pressure compressor of a marine gas engine, but is also applicable to the aerodynamic optimization process of axial flow compressors in a wide range of operating conditions.

Claims

1. A method for optimizing the pressure ratio distribution of a low-pressure compressor stage of a marine gas turbine under the constraints of a flow structure, characterized by: (1) Determine the flow structure constraints, including geometric parameters such as flow channel size, number of stages, and axial position of each row of blades; (2) Determine the compressor optimization design parameters, including compressor inlet conditions, speed, flow rate, and pressure ratio; (3) Selecting a stage load control parameter, using the load coefficient ψ as the stage load control parameter, and realizing different stage pressure ratio distribution schemes by controlling the load of each stage of the compressor; (4) Design of the load factor ψ distribution law for each level, given the relationship between the load factor ψ and the level number i; (5) Solving a one-dimensional inverse problem: using the geometric parameters, aerodynamic parameters, and load coefficient distribution results obtained in the above steps as input variables, solving a one-dimensional inverse problem to obtain a distribution scheme for the pressure ratio of each stage of the low-pressure compressor; The relationship between the given load factor ψ and the level number i described in step (4) is as follows: According to the compressor speed, pressure ratio, and the inner and outer diameters of the first-stage moving blades, the first-stage load factor ψ1 is determined; then the load factors of each stage ψ are determined by the following relationship i :

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