Aero-engine tip clearance test system and test method

Abstract

The application discloses an aero-engine tip clearance testing system and a testing method. The system comprises a base, a driving motor, a shaft coupling, first to third rotating shafts, first to second supporting members, first to second bearings, first to second engine simulation modules, first to second double optical fiber sensors, first to second rotating speed sensors, a collector, a three-degree-of-freedom displacement platform, a fixing rod and a control module. The application has a two-stage rotor impeller and a casing, can measure the tip clearance of multiple sections, and has good mobility and displayability. The application can meet the tip clearance measurement and calibration of multiple sections, multiple impellers and multiple measuring points under different rotating speeds and different tip clearances, and the continuous adjustment precision of the tip clearance can reach 0.02 mm. Meanwhile, the application has small volume, good mobility and displayability.

Description

Technical Field

[0001] This invention relates to the field of aero-engine blade tip clearance testing, and more particularly to an aero-engine blade tip clearance testing system and testing method. Background Technology

[0002] As a core power-generating component of an aero-engine, the operating parameters of rotating blades directly affect the overall engine system's operation, efficiency, and safety performance. The distance between the blade tip and the engine casing wall is called the tip clearance, and its parameters are directly related to the aero-engine's efficiency, pressure ratio, fuel consumption rate, and stability, making it crucial for improving aero-engine performance. Studies show that in turbine stages, approximately one-third of aerodynamic losses are caused by tip clearance flow, and for every 1% increase in turbine blade length in tip clearance, turbine aerodynamic efficiency decreases by 0.8% to 1.2%. Furthermore, excessive tip clearance can lead to slight blade surge, affecting engine stability. Conversely, insufficient tip clearance may cause blades to collide and rub against the casing, resulting in safety accidents and reducing safety margins. Therefore, monitoring tip clearance is considered a feasible strategy for achieving engine health management.

[0003] Scholars both at home and abroad have conducted extensive research on the methods and techniques for measuring blade tip clearance. Existing methods for monitoring blade tip clearance mainly include fiber optic method, capacitance method, microwave method, eddy current method, and discharge probe method. However, most existing blade tip clearance measurement devices have one or more of the following drawbacks: Firstly, they cannot perform continuous and precise blade tip clearance adjustments, typically requiring manual feeler gauge measurements or optical image detection after changing the blade tip clearance value. Secondly, these devices contain only a single blade, simulating blade tip clearance by measuring the distance between the blade tip and the sensor, which differs from the multiple blades of a real rotor. Thirdly, while measuring the blade tip clearance of multiple blades in the entire impeller, they usually only have one cross-section and only one impeller, differing from the multi-stage rotor impeller of a real aero-engine. Fourthly, these devices only measure the distance between the sensor and the blade tip, lacking a casing, resulting in differences from the blade tip clearance of a real aero-engine. Finally, these devices are too large, lacking portability and demonstrability, hindering the demonstration of blade tip clearance measurement research.

[0004] Therefore, how to construct a blade tip clearance measurement and research experimental device that can be continuously and accurately adjusted and effectively calibrated, has a multi-stage rotor impeller and mounting casing, simulates the formation of the blade tip clearance of a real aero-engine, and has good mobility and demonstrability, and has a matching blade tip clearance measurement method and system, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by providing an aero-engine blade tip clearance testing system and test method, which can perform multi-section, multi-point blade tip clearance measurement and verification, and the blade tip clearance is conveniently adjustable and can be tested at different speeds, which is more in line with the actual blade tip clearance testing conditions of aero-engines.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] An aero-engine blade tip clearance testing system includes a base, a drive motor, a coupling, first to third rotating shafts, first to second support members, first to second bearings, first to second engine simulation modules, first to second dual fiber optic sensors, first to second speed sensors, a data acquisition unit, a three-degree-of-freedom displacement platform, a fixed rod, and a control module.

[0008] The first and second engine simulation modules each include a blade disk and a casing. The blade disk includes a turntable and several blades evenly arranged on the side wall of the turntable. The casing is a hollow cylinder with openings at both ends and through holes on its side wall.

[0009] The first support member and the second support member are both fixed on the base, and each of them is provided with through holes for installing the first bearing and the second bearing;

[0010] The outer ring of the first bearing is fixedly connected to the through hole of the first support member, and the inner ring is fixedly connected to the first rotating shaft coaxially; one end of the first rotating shaft is fixedly connected to the center of one side of the turntable of the first engine simulation module coaxially, and the other end passes through the first bearing and is fixedly connected to the output shaft of the drive motor coaxially through the coupling.

[0011] One end of the second rotating shaft is coaxially fixed to the center of the other side of the turntable of the first engine simulation module, and the other end is coaxially fixed to the center of one side of the turntable of the second engine simulation module.

[0012] The outer ring of the second bearing is fixedly connected to the through hole of the second support member, and the inner ring is coaxially fixedly connected to the third rotating shaft; one end of the third rotating shaft is coaxially fixedly connected to the center of the other side of the turntable of the second engine simulation module.

[0013] The casings of the first and second engine simulation modules are respectively fitted over the blade disks of the first and second engine simulation modules, and are coaxial with the second rotating shaft and fixed on the base.

[0014] The first dual fiber optic sensor is installed in the through hole of the casing of the first engine simulation module, flush with the inner wall of the casing of the first engine simulation module, and is used to measure the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module according to the instructions of the data acquisition unit.

[0015] The three-degree-of-freedom displacement platform is fixed on the base; one end of the fixing rod is fixedly connected to the output platform of the three-degree-of-freedom displacement platform, and the other end is fixedly connected to the second dual-fiber sensor, so that the second dual-fiber sensor extends into the through hole of the second engine simulation module; the three-degree-of-freedom displacement platform is used to adjust the position of the second dual-fiber sensor by means of the fixing rod.

[0016] The second dual fiber optic sensor measures the time interval between the blade tip passing through its two probes in the second engine simulation module according to the instructions of the data acquisition unit.

[0017] The first and second speed sensors are respectively installed on the blade disks of the first and second engine simulation modules, and are used to measure the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module.

[0018] The control module is electrically connected to the drive motor, the three-degree-of-freedom displacement platform, the data acquisition unit, the first speed sensor, and the second speed sensor, respectively. It is used to control the operation of the drive motor, the three-degree-of-freedom displacement platform, and the data acquisition unit, and to calculate the distance between the first dual-fiber sensor and the blade tip in the first engine simulation module, and the distance between the second dual-fiber sensor and the blade tip in the second engine simulation module, based on the sensing data of the first dual-fiber sensor, the second dual-fiber sensor, the first speed sensor, and the second speed sensor.

[0019] As a further optimization of the aero-engine blade tip clearance testing system of the present invention, the data acquisition device adopts the NI9401 digital acquisition card and NI9178 data acquisition device base manufactured by NI.

[0020] This invention also discloses a test method for the aero-engine blade tip clearance testing system, comprising the following steps:

[0021] Step 1), the control module controls the three-degree-of-freedom displacement platform to work, so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is 0;

[0022] Step 2), the control module controls the three-degree-of-freedom displacement platform to work so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is a preset distance threshold D.

[0023] Step 3): The control module controls the drive motor to work, which drives the blade disks of the first and second engine simulation modules to rotate.

[0024] Step 4): The first speed sensor and the second speed sensor respectively sense the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module;

[0025] Step 5), the control module controls the acquisition unit to work, so that the first dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module, and the second dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the second dual fiber optic sensor in the second engine simulation module.

[0026] Step 6): The control module calculates the blade tip clearance of the first engine simulation module based on the distance between the two probes of the first dual fiber optic sensor, the included angle between the two probes of the first dual fiber optic sensor, and the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module. The control module calculates the blade tip clearance of the second engine simulation module based on the distance between the two probes of the second dual fiber optic sensor, the included angle between the two probes of the second dual fiber optic sensor, and the time interval between the blade tip passing through the two probes of the second dual fiber optic sensor in the second engine simulation module.

[0027] Step 7) Compare the calculated tip clearance of the second engine simulation module with the preset distance threshold D to verify the accuracy of the calculated tip clearance of the first engine simulation module.

[0028] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0029] This invention provides an aero-engine blade tip clearance testing system and method. The drive motor can change the rotation speed of the blade disks in two engine simulation modules, thereby enabling blade tip clearance testing at different speeds. The size of the blade tip clearance is changed by adjusting the distance between the second dual-fiber sensor and the blade tip in the second engine simulation module. Blade tip clearance testing is performed at different blade tip clearance sizes. The three-degree-of-freedom displacement platform enables the second dual-fiber sensor to have a displacement capability with an accuracy of 0.02mm, thereby allowing for the measurement and verification of blade tip clearance. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the principle of blade tip clearance measurement;

[0031] Figure 2 This is a schematic diagram of the mathematical model for the principle of blade tip clearance measurement;

[0032] Figure 3 This is a structural diagram of the first dual-fiber sensor in this invention;

[0033] Figure 4 This is a schematic diagram of voltage signal acquisition generated by the first dual-fiber sensor in this invention;

[0034] Figure 5 This is a schematic diagram of the arrival time of the blades collected by the digital acquisition card in this invention;

[0035] Figure 6 This is a schematic diagram of the structure of the present invention;

[0036] Figure 7 This is a schematic diagram illustrating the principle of testing this invention.

[0037] In the figure, 1-base, 2-coupling, 3-first support, 4-second support, 5-first rotating shaft, 6-second rotating shaft, 7-third rotating shaft, 8-casing of the first engine simulation module, 9-blade disk of the first engine simulation module, 10-first dual fiber optic sensor, 11-casing of the second engine simulation module, 12-blade disk of the second engine simulation module, 13-second dual fiber optic sensor, 14-three-degree-of-freedom displacement platform. Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0039] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0040] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from one another. Therefore, the first element, component, and / or part discussed below may be a second element, component, or part without departing from the teachings of this invention.

[0041] The principle of using a dual-fiber sensor based on laser triangulation to measure blade tip clearance is shown in the figure. Figure 1In this system, OA and OB are two fiber-optic blade tip timing sensors. When the same blade continuously sweeps across the emitted beams of the two sensors at points C and D, the receiving fibers of the sensors at points A and B successively receive the reflected light. This light is then converted into digital pulse signals via photoelectric conversion. The system obtains the times when the blade continuously sweeps across sensors OA and OB, denoted as t1 and t2, respectively. A speed synchronization sensor is then used to monitor the rotor speed in real time, allowing the computer to calculate the distance d between the sensor end face and the blade tip.

[0042] Figure 2 This is a mathematical model of a blade tip clearance measurement system based on the dual-fiber blade tip timing principle. In the figure, α represents the angle between the two sensors in the dual-fiber sensor, AB represents the distance between the centers of the tips of the two sensor probes, and CD represents the distance between the positions where the blade sweeps across the two beams of light. Let the rotor tangential velocity measured by the speed synchronization sensor be v, and the times when the blade passes through the emitted light spots of the two timing sensors be t1 and t2, respectively.

[0043] Clearly, ΔOAB is similar to ΔOCD, therefore:

[0044]

[0045] according to Figure 2 Easy to obtain:

[0046]

[0047] Combining formulas (1) and (2), the tip clearance value d can be obtained as follows:

[0048]

[0049] And:

[0050] CD=v×(t2-t1) (4)

[0051] Substituting formula (4) into formula (3) and rearranging, we get:

[0052]

[0053] The above mathematical derivation process theoretically establishes the mathematical model of the blade tip clearance measurement system based on the blade tip timing principle designed in this paper. Among them, AB and α in formula (5) are known constants of the system. Therefore, the value of blade tip clearance d can be calculated by measuring the timing signals t1 and t2 and the rotor speed v.

[0054] Mechanical blade tip clearance measurement using laser triangulation requires a specially designed dual-fiber sensor. The dual-beam fiber sensor used in this paper, such as... Figure 3As shown, it contains two fiber bundles. Each fiber-optic leaf tip timing sensor includes a transmitting fiber and multiple receiving fibers. The transmitting fiber continuously emits a light beam. When the leaf sweeps across the emitted light beam, it is reflected. The reflected light is received by the receiving fiber and transmitted to the photoelectric converter.

[0055] When the same blade passes continuously through both sensors of the dual-fiber sensor, its receiving end receives the optical signal, and the photoelectric converter converts the signal into an electrical signal, thereby generating two voltage signals V1 and V2. Figure 4 We can see that the rising edges of the two voltage signals have significant differences on the time scale, and the time difference remains basically constant. Therefore, the acquired time difference also remains basically constant. Figure 5 As shown.

[0056] As described above, two voltage pulse signals are generated when the blade sweeps across the dual fiber optic sensor. To accurately acquire the edge times of these two voltage pulse signals—that is, the precise time point when the blade sweeps across the dual sensor—high demands are placed on the data acquisition unit. Not only must the sampling frequency be very high, but the simultaneous acquisition of both signals is also required. This invention utilizes the NI9401 digital acquisition card and the NI9178 data acquisition base manufactured by NI. The combination of these two technologies allows for a sampling frequency of up to 80 MHz, fully meeting the sampling rate requirements, and enables simultaneous acquisition of multiple channels. This perfectly matches the requirements of the dual fiber optic sensor used for gap measurement based on the leaf tip timing method. The working principle of the NI 9041 acquisition card is as follows: Figure 4 As shown, whenever the rising edge of the voltage pulse signal reaches 2.5V, the data acquisition card records the time at that moment, such as... Figure 5 As shown.

[0057] like Figure 6 As shown, the present invention discloses an aero-engine blade tip clearance testing system, including a base, a drive motor, a coupling, first to third rotating shafts, first to second support members, first to second bearings, first to second engine simulation modules, first to second dual fiber optic sensors, first to second speed sensors, a data acquisition unit, a three-degree-of-freedom displacement platform, a fixing rod, and a control module;

[0058] The first and second engine simulation modules each include a blade disk and a casing. The blade disk includes a turntable and several blades evenly arranged on the side wall of the turntable. The casing is a hollow cylinder with openings at both ends and through holes on its side wall.

[0059] The first support member and the second support member are both fixed on the base, and each of them is provided with through holes for installing the first bearing and the second bearing;

[0060] The outer ring of the first bearing is fixedly connected to the through hole of the first support member, and the inner ring is fixedly connected to the first rotating shaft coaxially; one end of the first rotating shaft is fixedly connected to the center of one side of the turntable of the first engine simulation module coaxially, and the other end passes through the first bearing and is fixedly connected to the output shaft of the drive motor coaxially through the coupling.

[0061] One end of the second rotating shaft is coaxially fixed to the center of the other side of the turntable of the first engine simulation module, and the other end is coaxially fixed to the center of one side of the turntable of the second engine simulation module.

[0062] The outer ring of the second bearing is fixedly connected to the through hole of the second support member, and the inner ring is coaxially fixedly connected to the third rotating shaft; one end of the third rotating shaft is coaxially fixedly connected to the center of the other side of the turntable of the second engine simulation module.

[0063] The casings of the first and second engine simulation modules are respectively fitted over the blade disks of the first and second engine simulation modules, and are coaxial with the second rotating shaft and fixed on the base.

[0064] The first dual fiber optic sensor is installed in the through hole of the casing of the first engine simulation module, flush with the inner wall of the casing of the first engine simulation module, and is used to measure the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module according to the instructions of the data acquisition unit.

[0065] The three-degree-of-freedom displacement platform is fixed on the base; one end of the fixing rod is fixedly connected to the output platform of the three-degree-of-freedom displacement platform, and the other end is fixedly connected to the second dual-fiber sensor, so that the second dual-fiber sensor extends into the through hole of the second engine simulation module; the three-degree-of-freedom displacement platform is used to adjust the position of the second dual-fiber sensor by means of the fixing rod.

[0066] The second dual fiber optic sensor measures the time interval between the blade tip passing through its two probes in the second engine simulation module according to the instructions of the data acquisition unit.

[0067] The first and second speed sensors are respectively installed on the blade disks of the first and second engine simulation modules, and are used to measure the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module.

[0068] The control module is electrically connected to the drive motor, the three-degree-of-freedom displacement platform, the data acquisition unit, the first speed sensor, and the second speed sensor, respectively. It is used to control the operation of the drive motor, the three-degree-of-freedom displacement platform, and the data acquisition unit, and to calculate the distance between the first dual-fiber sensor and the blade tip in the first engine simulation module, and the distance between the second dual-fiber sensor and the blade tip in the second engine simulation module, based on the sensing data of the first dual-fiber sensor, the second dual-fiber sensor, the first speed sensor, and the second speed sensor.

[0069] As a further optimization of the aero-engine blade tip clearance testing system of the present invention, the data acquisition device adopts the NI9401 digital acquisition card and NI9178 data acquisition device base manufactured by NI.

[0070] like Figure 7 As shown, the present invention also discloses a test method for the aero-engine blade tip clearance test system, comprising the following steps:

[0071] Step 1), the control module controls the three-degree-of-freedom displacement platform to work, so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is 0;

[0072] Step 2), the control module controls the three-degree-of-freedom displacement platform to work so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is a preset distance threshold D.

[0073] Step 3): The control module controls the drive motor to work, which drives the blade disks of the first and second engine simulation modules to rotate.

[0074] Step 4): The first speed sensor and the second speed sensor respectively sense the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module;

[0075] Step 5), the control module controls the acquisition unit to work, so that the first dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module, and the second dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the second dual fiber optic sensor in the second engine simulation module.

[0076] Step 6): The control module calculates the blade tip clearance of the first engine simulation module based on the distance between the two probes of the first dual fiber optic sensor, the included angle between the two probes of the first dual fiber optic sensor, and the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module. The control module calculates the blade tip clearance of the second engine simulation module based on the distance between the two probes of the second dual fiber optic sensor, the included angle between the two probes of the second dual fiber optic sensor, and the time interval between the blade tip passing through the two probes of the second dual fiber optic sensor in the second engine simulation module.

[0077] Step 7) Compare the calculated tip clearance of the second engine simulation module with the preset distance threshold D to verify the accuracy of the calculated tip clearance of the first engine simulation module.

[0078] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0079] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A blade tip clearance testing system for an aero-engine, characterized in that, It includes a base, drive motor, coupling, first to third rotating shafts, first to second support components, first to second bearings, first to second engine simulation modules, first to second dual fiber optic sensors, first to second speed sensors, data acquisition unit, three-degree-of-freedom displacement platform, fixed rod, and control module; The first and second engine simulation modules each include a blade disk and a casing. The blade disk includes a turntable and several blades evenly arranged on the side wall of the turntable. The casing is a hollow cylinder with openings at both ends and through holes on its side wall. The first support member and the second support member are both fixed on the base, and each of them is provided with through holes for installing the first bearing and the second bearing; The outer ring of the first bearing is fixedly connected to the through hole of the first support member, and the inner ring is fixedly connected to the first rotating shaft coaxially; one end of the first rotating shaft is fixedly connected to the center of one side of the turntable of the first engine simulation module coaxially, and the other end passes through the first bearing and is fixedly connected to the output shaft of the drive motor coaxially through the coupling. One end of the second rotating shaft is coaxially fixed to the center of the other side of the turntable of the first engine simulation module, and the other end is coaxially fixed to the center of one side of the turntable of the second engine simulation module. The outer ring of the second bearing is fixedly connected to the through hole of the second support member, and the inner ring is coaxially fixedly connected to the third rotating shaft; one end of the third rotating shaft is coaxially fixedly connected to the center of the other side of the turntable of the second engine simulation module. The casings of the first and second engine simulation modules are respectively fitted over the blade disks of the first and second engine simulation modules, and are coaxial with the second rotating shaft and fixed on the base. The first dual fiber optic sensor is installed in the through hole of the casing of the first engine simulation module, flush with the inner wall of the casing of the first engine simulation module, and is used to measure the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module according to the instructions of the data acquisition unit. The three-degree-of-freedom displacement platform is fixed on the base; one end of the fixing rod is fixedly connected to the output platform of the three-degree-of-freedom displacement platform, and the other end is fixedly connected to the second dual-fiber sensor, so that the second dual-fiber sensor extends into the through hole of the second engine simulation module; the three-degree-of-freedom displacement platform is used to adjust the position of the second dual-fiber sensor by means of the fixing rod. The second dual fiber optic sensor measures the time interval between the blade tip passing through its two probes in the second engine simulation module according to the instructions of the data acquisition unit. The first and second speed sensors are respectively installed on the blade disks of the first and second engine simulation modules, and are used to measure the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module. The control module is electrically connected to the drive motor, the three-degree-of-freedom displacement platform, the data acquisition unit, the first speed sensor, and the second speed sensor, respectively. It is used to control the operation of the drive motor, the three-degree-of-freedom displacement platform, and the data acquisition unit, and to calculate the distance between the first dual-fiber sensor and the blade tip in the first engine simulation module, and the distance between the second dual-fiber sensor and the blade tip in the second engine simulation module, based on the sensing data of the first dual-fiber sensor, the second dual-fiber sensor, the first speed sensor, and the second speed sensor.

2. The aero-engine blade tip clearance testing system according to claim 1, characterized in that, The data acquisition device uses the NI9401 digital acquisition card and the NI9178 data acquisition base manufactured by NI.

3. The test method for the aero-engine blade tip clearance testing system according to claim 1, characterized in that, Includes the following steps: Step 1), the control module controls the three-degree-of-freedom displacement platform to work, so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is 0; Step 2), the control module controls the three-degree-of-freedom displacement platform to work so that the distance between the tips of adjacent blades in the second dual-fiber sensor and the second engine simulation module is a preset distance threshold D. Step 3), the control module controls the drive motor to work, driving the blade disks of the first and second engine simulation modules to rotate; Step 4), the first speed sensor and the second speed sensor respectively sense the speed of the blade disks of the first and second engine simulation modules and transmit it to the control module; Step 5), the control module controls the data acquisition unit to work so that the first dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the first dual fiber optic sensor in the first engine simulation module, and the second dual fiber optic sensor measures the time interval between the blade tip passing through the two probes of the second dual fiber optic sensor in the second engine simulation module. Step 6): The control module calculates the blade tip clearance of the first engine simulation module based on the distance between the two probes of the first dual-fiber sensor, the angle between the two probes of the first dual-fiber sensor, and the time interval between the blade tip passing through the two probes of the first dual-fiber sensor in the first engine simulation module. The control module calculates the blade tip clearance of the second engine simulation module based on the distance between the two probes of the second dual-fiber sensor, the angle between the two probes of the second dual-fiber sensor, and the time interval between the blade tip passing through the two probes of the second dual-fiber sensor in the second engine simulation module. Step 7) Compare the calculated tip clearance of the second engine simulation module with the preset distance threshold D to verify the accuracy of the calculated tip clearance of the first engine simulation module.

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