Gas turbine exhaust ejector ejection coefficient measurement device and method

Abstract

The present invention discloses a device for measuring the ejection coefficient of a gas turbine exhaust ejector, which is arranged at the orifice of the exhaust ejector duct and is characterized by comprising: a sliding mechanism mounted on the orifice of the exhaust ejector duct and slidably connected thereto; a driving base structure fixed to the sliding mechanism; a rotary driving structure arranged on the driving base structure and connected to the exhaust ejector duct for transmission, enabling the driving base structure to move circumferentially about the orifice of the exhaust ejector duct; a wind speed probe; and a wind speed probe driving structure arranged on the driving base structure for driving the wind speed probe to move radially about the orifice of the exhaust ejector duct. A measurement method is also disclosed. After installation, the device of the present invention can automatically set and collect multi-point velocities. The more angles and radii are divided, the higher the accuracy of the data obtained, and the more accurate the ejection coefficient obtained, allowing the precise determination of the velocity distribution at the ejector outlet.

Description

Technical Field

[0001] The present invention relates to the technical field of exhaust ejector performance testing, and in particular to a device and method for measuring the ejection coefficient of an exhaust ejector of a gas turbine. Background Art

[0002] An exhaust ejector is a device that ejects a secondary fluid through a mainstream fluid. It first appeared on aircraft engines to reduce the engine exhaust temperature. After modification, it was applied to the exhaust system of marine gas turbines. Due to its simple structure, effective reduction of exhaust temperature and no consumption of other energy, it has been widely used in gas turbine exhaust systems. Ships equipped with exhaust ejectors effectively reduce the intensity of infrared signals and improve their survivability at sea.

[0003] The ejection coefficient is a key metric for evaluating exhaust ejector performance. It is defined as the ratio of the mass flow rate of the ejected fluid to the mass flow rate of the mainstream exhaust gas. A larger value indicates a stronger ejector. Typically, the velocity at the exhaust ejector outlet surface exhibits peaks and significant non-uniformity, particularly at the outlet of multi-nozzle exhaust ejectors. Therefore, the ejection coefficient is typically measured by taking the average of the velocities at multiple points on the ejector outlet surface. This method results in significant measurement errors and fails to accurately capture the velocity distribution at the outlet surface. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the background technology, the first purpose of the present invention is to disclose a gas turbine exhaust ejector ejection coefficient measuring device;

[0005] The second object is to disclose a measurement method using the above-mentioned gas turbine exhaust ejector ejection coefficient measurement device;

[0006] Through the rotation of the measuring device and the forward and backward extension of the probe, the automatic collection of multi-point velocities on the ejector outlet surface is realized, and the ejection coefficient is obtained by establishing a coordinate system and fitting and integrating the surface equation, providing a technical reference for the measurement of the exhaust ejector ejection coefficient.

[0007] Technical solution: The gas turbine exhaust ejector ejection coefficient measuring device of the present invention is arranged at the pipe mouth of the exhaust ejector pipe and is characterized by comprising:

[0008] A sliding mechanism is mounted on the exhaust ejector pipe orifice and is slidably connected thereto;

[0009] A driving base structure fixed to the sliding mechanism;

[0010] The rotary drive structure is provided on the drive base structure and is connected to the exhaust ejector pipe for transmission, so as to realize the circumferential movement of the drive base structure at the pipe opening of the exhaust ejector pipe;

[0011] Wind speed probe;

[0012] The wind speed probe driving structure is arranged on the driving basic structure and drives the wind speed probe to move radially along the pipe opening of the exhaust ejector pipe.

[0013] Furthermore, the sliding mechanism includes a sliding fixing frame and an inner sliding guide plate and an outer sliding guide plate connected thereto. The sliding fixing frame is parallel to the outer end of the pipe mouth. The inner sliding guide plate and the outer sliding guide plate have the same curvature as the exhaust ejector pipe. The two are fixed at a distance to form a sliding guide groove structure for inserting the exhaust ejector pipe. The sliding fixing frame is mounted on the outer end of the exhaust ejector pipe through the inner sliding guide plate and the outer sliding guide plate.

[0014] Furthermore, the rotary drive structure includes a ring gear mounted on the exhaust ejector pipe, and also includes a first motor mounted on the driving base structure. The first motor is engaged with the ring gear through a first gear set, and the sliding mechanism is driven by the first motor to move circumferentially around the pipe mouth of the exhaust ejector pipe.

[0015] Furthermore, the first gear set includes a first bevel gear connected to the first motor drive end and a first transmission shaft arranged on the drive base structure, and the first transmission shaft is fixed with a second bevel gear meshing with the first bevel gear and a first cylindrical gear meshing with the ring gear.

[0016] Furthermore, the wind speed probe driving structure includes a second motor and a probe rack arranged on the driving base structure. The wind speed probe is fixed at the end of the probe rack. The second motor is engaged with the probe rack through a second gear set and driven by the second motor to move radially along the pipe mouth of the exhaust ejector duct.

[0017] Furthermore, the second gear set includes a third bevel gear connected to the second motor drive end and a second transmission shaft arranged on the drive base structure, and the second transmission shaft is fixed with a fourth bevel gear meshing with the third bevel gear and a second cylindrical gear meshing with the probe rack.

[0018] Furthermore, a first limit frame is provided on the side of the second cylindrical gear, and a second limit frame is also provided on the driving base structure. A positioning shaft is provided in the second limit frame, and a third cylindrical gear is provided on the positioning shaft. The probe rack passes through the first limit frame and the second limit frame to limit the transmission direction, and is engaged with the second cylindrical gear and the third cylindrical gear.

[0019] Furthermore, the wind speed probe is bent and extended inwardly along the axial direction of the exhaust ejector pipe at the end of the probe rack.

[0020] Furthermore, the driving infrastructure is detachably connected to the sliding mechanism.

[0021] A method for measuring the ejection coefficient of a gas turbine exhaust ejector, using the above-mentioned gas turbine exhaust ejector ejection coefficient measuring device, comprises the following steps:

[0022] S1. Establish a three-dimensional rectangular coordinate system Oxyz with the center of the exhaust ejector pipe outlet surface as the center. Divide the outlet surface into several spider-web-shaped areas by angle and radius. Assume that the angle is divided into m parts and the radius is divided into n parts. By controlling the first motor, the device is rotated in angle. By controlling the second motor, the position of the wind speed probe is changed in diameter. By repeatedly changing the position of the wind speed probe, the speed of each spider web point is finally measured, a total of m×n, that is, the speed at (x i ,y j ) coordinates, f(x, y), i = 1, 2 ... m, j = 1, 2 ... n;

[0023] S2. Fit the above data with a bivariate polynomial to obtain the most accurate surface equation that satisfies all the data. Take the quadratic polynomial as an example to solve f(x, y)=c 00 +c 10 x+c 01 y+c 20 x 2 +c 11 xy+c 02 y 2 The fitting coefficient c in 00 、c 10 、c 01 、c 20 、c 11 、c 02 ;

[0024] S3. According to Q = ρvA, in order to obtain the mass flow rate, vA needs to be obtained. In a physical sense, vA is the volume enclosed by the fitted surface equation and the xOy plane. The mass flow rate value can be obtained by double integration of the surface equation.

[0025]

[0026] Where Q is the mass flow rate at the exhaust ejector outlet, and ρ is the density;

[0027] S4, when the mainstream mass flow is Q in When , the ejection coefficient of the gas turbine exhaust ejector is:

[0028]

[0029] Where η is the ejection coefficient, Q in is the mass flow rate of the ejector exhaust mainstream.

[0030] Beneficial effects: Compared with the prior art, the advantages of the present invention are: after installation, multi-point speeds can be automatically set and collected, the more the angle and radius are divided, the higher the data accuracy is, the more accurate the obtained ejection coefficient is, and the velocity distribution of the ejector outlet can be accurately grasped; at the same time, in order to meet the ejection coefficient measurement of exhaust ejectors of different sizes, the present invention provides a detachable sliding mechanism, which can adapt to the measurement of exhaust ejectors of different sizes by simply changing the size of the sliding mechanism, and has the advantages of good adaptability and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is an overall diagram of the device of the present invention;

[0032] Figure 2 It is a structural diagram of the sliding mechanism of the present invention;

[0033] Figure 3 This is a structural diagram of the rotary drive structure of the present invention;

[0034] Figure 4 This is a structural diagram of the wind speed probe drive structure of the present invention;

[0035] Figure 5 This is a structural diagram of the probe rack of the present invention;

[0036] Figure 6 It is a schematic diagram of the spider-web-shaped area division of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1 The gas turbine exhaust ejector ejection coefficient measuring device shown is arranged at the pipe mouth of the exhaust ejector pipe 1, and includes:

[0039] The sliding mechanism 2 is mounted on the outlet of the exhaust ejector pipe 1 and is slidably connected thereto;

[0040] A driving base structure 3 is fixed to the sliding mechanism 2;

[0041] The rotary drive structure 4 is provided on the driving base structure 3 and is connected to the exhaust ejector pipe 1 for transmission, so as to realize the circumferential movement of the driving base structure 3 at the pipe opening of the exhaust ejector pipe 1;

[0042] Wind speed probe 5;

[0043] The wind speed probe driving structure 6 is provided on the driving base structure 3 , and drives the wind speed probe 5 to move radially along the pipe opening of the exhaust ejector duct 1 .

[0044] like Figure 2As shown, the sliding mechanism 2 includes a sliding fixed frame 201 and an inner sliding guide plate 202 and an outer sliding guide plate 203 connected thereto. The sliding fixed frame 201 is parallel to the outer end of the pipe mouth, and the inner sliding guide plate 202 and the outer sliding guide plate 203 have the same curvature as the exhaust ejector pipe 1. The two are fixed at intervals to form a sliding guide groove structure for inserting the exhaust ejector pipe 1. The sliding fixed frame 201 is mounted on the outer end of the exhaust ejector pipe 1 through the inner sliding guide plate 202 and the outer sliding guide plate 203.

[0045] The driving basic structure 3 is detachably connected to the sliding mechanism 2. Different sliding mechanisms 2 are used according to the diameter of the exhaust ejector pipe 1 to ensure that the measuring device is suitable for exhaust ejectors of different sizes.

[0046] like Figure 1 and 3 As shown, the rotary drive structure 4 includes a ring gear 401 mounted on the exhaust ejector duct 1, and also includes a first motor 402 mounted on the drive base structure 3. The first motor 402 is engaged with the ring gear 401 through a first gear set, and the first motor 402 drives the sliding mechanism 2 to move circumferentially around the nozzle of the exhaust ejector duct 1. The first gear set includes a first bevel gear 403 connected to the drive end of the first motor 402, and a first transmission shaft 404 mounted on the drive base structure 3. The first transmission shaft 404 is fixed with a second bevel gear 405 engaged with the first bevel gear 403, and a first cylindrical gear 406 engaged with the ring gear 401.

[0047] like Figure 4 and 5 As shown, the wind speed probe driving structure 6 includes a second motor 601 and a probe rack 602 arranged on the driving base structure 3, and the wind speed probe 5 is fixed at the end of the probe rack 602. The wind speed probe 5 is bent and extended inward along the axial direction of the exhaust ejector duct 1 at the end of the probe rack 602.

[0048] The second motor 601, through a second gear set, meshes with the probe rack 602 for transmission, driving the probe rack 602 radially along the nozzle of the exhaust ejector duct 1. The second gear set includes a third bevel gear 603 connected to the drive end of the second motor 601 and a second transmission shaft 604 mounted on the drive base structure 3. A fourth bevel gear 605 meshing with the third bevel gear 603 and a second cylindrical gear 606 meshing with the probe rack 602 are fixed to the second transmission shaft 604. A first limiting bracket 607 is attached to the side of the second cylindrical gear 606. A second limiting bracket 608 is also mounted on the drive base structure 3. A positioning shaft 609 is mounted within the second limiting bracket 608, which is mounted on a third cylindrical gear 610. The probe rack 602 passes through the first and second limiting brackets 607 and 608 to limit transmission direction and mesh with the second and third cylindrical gears 606 and 610.

[0049] A method for measuring the ejection coefficient of a gas turbine exhaust ejector comprises the following steps:

[0050] S1, such as Figure 6 As shown, a three-dimensional rectangular coordinate system Oxyz is established with the center of the exhaust ejector pipe outlet surface as the center, and the outlet surface is divided into several spider-web-shaped areas by angle and radius. Assuming that the angle is divided into m parts and the radius is divided into n parts, the device is rotated in angle by controlling the first motor, and the position change of the wind speed probe in diameter is achieved by controlling the second motor. By repeatedly changing the position of the wind speed probe, the speed of each spider web point is finally measured, a total of m×n, that is, the speed of each spider web point is obtained at (x i ,y j ) coordinates, f(x, y), i = 1, 2 ... m, j = 1, 2 ... n;

[0051] S2. Fit the above data with a bivariate polynomial to obtain the most accurate surface equation that satisfies all the data. Take the quadratic polynomial as an example to solve f(x, y)=c 00 +c 10 x+c 01 y+c 20 x 2 +c 11 xy+c 02 y 2 The fitting coefficient c in 00 、c 10 、c 01 、c 20 、c 11 、c 02 ;

[0052] S3. According to Q = ρvA, in order to obtain the mass flow rate, vA needs to be obtained. In a physical sense, vA is the volume enclosed by the fitted surface equation and the xOy plane. The mass flow rate value can be obtained by double integration of the surface equation.

[0053]

[0054] Where Q is the mass flow rate at the exhaust ejector outlet, and ρ is the density;

[0055] S4, when the mainstream mass flow is Q in When , the ejection coefficient of the gas turbine exhaust ejector is:

[0056]

[0057] Where η is the ejection coefficient, Q in is the mass flow rate of the ejector exhaust mainstream.

Claims

1. A method for measuring the ejection coefficient of a gas turbine exhaust ejector, characterized in that: A gas turbine exhaust ejector ejection coefficient measuring device is used, and the gas turbine exhaust ejector ejection coefficient measuring device is arranged at the pipe mouth of the exhaust ejector pipe (1), comprising: A sliding mechanism (2) is mounted on the pipe opening of the exhaust ejector pipe (1) and is slidably connected thereto; A driving base structure (3) is fixed to the sliding mechanism (2); The rotary drive structure (4) is provided on the driving base structure (3) and is connected to the exhaust ejector pipe (1) for transmission, so as to realize the circumferential movement of the driving base structure (3) at the pipe opening of the exhaust ejector pipe (1); Wind speed probe (5); The wind speed probe driving structure (6) is arranged on the driving base structure (3) and drives the wind speed probe (5) to move radially at the pipe opening of the exhaust ejector pipe (1); The sliding mechanism (2) includes a sliding fixed frame (201) and an inner sliding guide plate (202) and an outer sliding guide plate (203) connected thereto, the sliding fixed frame (201) is parallel to the outer end of the pipe mouth, the inner sliding guide plate (202) and the outer sliding guide plate (203) have the same curvature as the exhaust ejector pipe (1), and are fixed at intervals to form a sliding guide groove structure for inserting the exhaust ejector pipe (1), and the sliding fixed frame (201) is mounted on the outer end of the exhaust ejector pipe (1) through the inner sliding guide plate (202) and the outer sliding guide plate (203); The rotary drive structure (4) includes a gear ring (401) sleeved on the exhaust ejector pipe (1), and also includes a first motor (402) provided on the driving base structure (3); the first motor (402) is meshed with the gear ring (401) through a first gear set, and the first motor (402) drives the sliding mechanism (2) to move circumferentially around the pipe opening of the exhaust ejector pipe (1); The first gear set comprises a first bevel gear (403) connected to the driving end of the first motor (402) and a first transmission shaft (404) provided on the driving base structure (3); a second bevel gear (405) meshing with the first bevel gear (403) and a first cylindrical gear (406) meshing with the ring gear (401) are fixed on the first transmission shaft (404); The wind speed probe driving structure (6) comprises a second motor (601) and a probe rack (602) provided on the driving base structure (3); the wind speed probe (5) is fixed to the end of the probe rack (602); the second motor (601) is meshed with the probe rack (602) through a second gear set, and the probe rack (602) is driven by the second motor (601) to move radially along the pipe opening of the exhaust ejector pipe (1); The method for measuring the ejection coefficient of a gas turbine exhaust ejector comprises the following steps: S1. Establish a three-dimensional rectangular coordinate system Oxyz with the center of the exhaust ejector pipe outlet surface as the center. Divide the outlet surface into several spider-web-shaped areas by angle and radius. Assume that the angle is divided into m parts and the radius is divided into n parts. By controlling the first motor, the device is rotated in angle. By controlling the second motor, the position of the wind speed probe is changed in diameter. By repeatedly changing the position of the wind speed probe, the speed of each spider web point is finally measured, a total of m×n, that is, the speed at (x i ,y j ) coordinates, f(x, y), i = 1, 2 ... m, j = 1, 2 ... n; S2. Fit the f(x, y) data with a bivariate polynomial to obtain the most accurate surface equation that satisfies all the data. Take the quadratic polynomial as an example to solve f(x, y) = c 00 +c 10 x+c 01 y+c 20 x 2 +c 11 xy+c 02 y 2 The fitting coefficient c in 00 、c 10 、c 01 、c 20 、c 11 、c 02 ; S3. According to Q = ρvA, in order to obtain the mass flow rate at the exhaust ejector outlet, vA needs to be obtained. In a physical sense, vA is the volume enclosed by the fitted surface equation and the xOy plane. The mass flow rate value can be obtained by double integrating the surface equation. Where Q is the mass flow rate at the exhaust ejector outlet, and ρ is the density; S4, when the mass flow rate of the ejector exhaust mainstream is Q in When , the ejection coefficient of the gas turbine exhaust ejector is: Where η is the ejection coefficient, Q in is the mass flow rate of the ejector exhaust mainstream.

2. The method for measuring the ejection coefficient of a gas turbine exhaust ejector according to claim 1, wherein: The second gear set includes a third bevel gear (603) connected to the driving end of the second motor (601) and a second transmission shaft (604) provided on the driving base structure (3); a fourth bevel gear (605) meshing with the third bevel gear (603) and a second cylindrical gear (606) meshing with the probe rack (602) are fixed on the second transmission shaft (604).

3. The method for measuring the ejection coefficient of a gas turbine exhaust ejector according to claim 2, wherein: A first limiting frame (607) is provided on the side of the second cylindrical gear (606), and a second limiting frame (608) is also provided on the driving base structure (3). A positioning shaft (609) is provided inside the second limiting frame (608), and a third cylindrical gear (610) is provided on the positioning shaft (609). The probe rack (602) passes through the first limiting frame (607) and the second limiting frame (608) to achieve transmission direction limitation, and is engaged with the second cylindrical gear (606) and the third cylindrical gear (610).

4. The method for measuring the ejection coefficient of a gas turbine exhaust ejector according to claim 3, wherein: The wind speed probe (5) is bent and extended inwardly along the axial direction of the exhaust ejector pipe (1) at the end of the probe rack (602).

5. The method for measuring the ejection coefficient of a gas turbine exhaust ejector according to claim 1, wherein: The driving infrastructure (3) is detachably connected to the sliding mechanism (2).

Images