An engine thrust measurement device and method suitable for small test benches

Abstract

This invention discloses an engine thrust measurement device and method suitable for small test benches, belonging to the field of engine thrust measurement technology. It includes: a clamping test mechanism with multiple symmetrically distributed T-shaped connecting rods, each equipped with a T-shaped clamping plate; the T-shaped clamping plates and I-shaped clamping plates mounted on them are used to clamp engine components; the engine components include a first engine component and a second engine component; the engine flange of the second engine component is clamped between the T-shaped clamping plates and the I-shaped clamping plates, and a pressure sensor is installed between the engine flange and the I-shaped clamping plates; a leveling mechanism is connected to the tail end of the clamping test mechanism. This invention enables the engine thrust, initial friction force, and the tension of the leveling mechanism to be on the same horizontal axis, achieving self-balancing of the thrust measurement force system, eliminating measurement deviations caused by torque and non-axial friction, improving measurement accuracy, and solving the problem of low accuracy in thrust measurement of small engines.

Description

Technical Field

[0001] This invention belongs to the field of engine thrust measurement technology, and more specifically, this invention relates to an engine thrust measurement device and method suitable for small test benches. Background Technology

[0002] Precise measurement of engine thrust is a core challenge in propulsion system testing technology. Currently, the mainstream method uses an electro-optical vector balance, which simultaneously acquires electrical signals of six components: Fx, Fy, Fz, Mx, My, and Mz. These signals are then processed by an internal algorithm to obtain the engine's positive thrust value. This method is highly accurate and reliable, and has become the industry standard for high-precision thrust testing. However, electro-optical vector balances are expensive, with domestically produced equipment generally costing over one million yuan and imported equipment costing tens of millions of yuan. Furthermore, their use and maintenance are complex, and testing schedules are tight, resulting in extremely low ownership rates in domestic research institutes and universities, making it difficult to meet the widespread exploratory testing needs of small engines.

[0003] Currently, exploratory tests of small engines commonly employ a force measurement scheme combining pressure sensors with steel cables and a weighing pan. This involves placing a lifting ring above the engine flange, with the steel cable connected to the ring above the engine via a fixed pulley, creating a horizontal, rightward tension. Simultaneously, a pressure sensor is positioned directly below the flange to measure the support reaction force, and the thrust is calculated using initial friction compensation. However, this method suffers from significant accuracy errors. The axes of the steel cable tension, engine thrust, and the pressure measured by the sensor do not coincide, failing to form a coaxial force system. This introduces additional torque and non-axial friction components during measurement. The combined effect of these two errors leads to inaccurate initial friction compensation, making it difficult to obtain an accurate engine thrust value. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these and other advantages according to the invention, the invention provides an engine thrust measurement device suitable for small test benches, comprising: The clamping and testing mechanism has multiple sets of symmetrically distributed T-shaped connecting rods fixedly installed at its front end. Each T-shaped connecting rod has a T-shaped clamping piece detachably installed at its end. The T-shaped clamping piece has an I-shaped clamping piece detachably installed on it. The T-shaped clamping piece and the I-shaped clamping piece constitute a clamping station for clamping engine components. An engine assembly includes: a first engine assembly; a second engine assembly detachably connected to the first engine assembly, wherein the first engine assembly and the second engine assembly are axially relative to each other; the engine flange of the second engine assembly is clamped between the T-shaped clamping piece and the I-shaped clamping piece, and a pressure sensor is provided between the engine flange and the I-shaped clamping piece; A leveling mechanism is detachably mounted at the tail end of the clamping and testing mechanism.

[0006] Preferably, the first engine assembly and the second engine assembly are detachably connected by a limiting bolt, and both ends of the limiting bolt are provided with space for relative sliding of the first engine assembly and the second engine assembly.

[0007] Preferably, a sealing groove is provided between the first engine assembly and the second engine assembly.

[0008] Preferably, the clamping test mechanism further includes: The clamping mechanism flange, wherein the T-shaped connecting rod is welded and fixed to the clamping mechanism flange; The T-shaped clamping piece is detachably mounted on the end of the T-shaped connecting rod via a first bolt assembly, and the I-shaped clamping piece is detachably connected to the T-shaped clamping piece via a second bolt assembly.

[0009] Preferably, the T-shaped clamping piece and the I-shaped clamping piece are each provided with a plurality of adjustable bolt holes.

[0010] Preferably, the leveling mechanism comprises the following structure: Leveling mechanism flange; Two sets of double-headed connecting rods are provided with a first loop hole at their center position and a second loop hole at the end of the double-headed connecting rod. The double-headed connecting rods are installed on the leveling mechanism flange through the first loop hole. The leveling mechanism flange is detachably installed on the clamping mechanism flange. A steel cable, one end of which is threaded through the first loop hole, and the other end of which is connected to a weighing pan, on which a standard weight is placed. A fixed pulley is provided with a slide rail, and the steel cable is wound around the slide rail of the fixed pulley.

[0011] Preferably, in the two sets of double-ended connecting rods, a flat gasket of the same width as the double-ended connecting rod is provided between the right-side double-ended connecting rod and the flange of the leveling mechanism.

[0012] A method for measuring engine thrust suitable for small test benches includes the following steps: Step 1, Axis Leveling Stage: Using a level, adjust the positions of the two sets of double-ended connecting rods and the fixed pulley to ensure that the steel cable between the double-ended connecting rods and the fixed pulley is horizontal, and the steel cable between the fixed pulley and the weighing pan is perpendicular to the horizontal ground along the direction of gravity. Then, adjust the axis position of the engine assembly. When the axis of the first engine assembly and the second engine assembly are not aligned, the values ​​of the symmetrically distributed pressure sensors will be inconsistent. Adjust the installation posture and clamping preload of each flange and support structure of the engine system according to the differences in the values ​​of each pressure sensor. When the values ​​of multiple pressure sensors are close to being consistent, the axis adjustment of the engine assembly is considered complete, thereby ensuring that the engine thrust, initial friction force, and the pulling direction of the leveling mechanism are kept on the same horizontal axis. Step 2, Initial Friction Measurement Stage: By adjusting the number of standard weights, the initial friction force is calculated using the relationship between the horizontal backward tension generated by the steel cable and the changes in the values ​​measured by each pressure sensor. F 0; Step 3, Formal Test Measurement Phase: Remove the leveling mechanism and calculate the engine thrust value based on the pressure sensor readings from the formal test phase, combined with the initial friction compensation.

[0013] Preferably, in step three, the engine thrust... F The calculation formula is: F=nF 1 +F 0 in, n For the number of pressure sensors, n =4 k , k It is an integer greater than or equal to 1; F 1 represents the pressure value measured by a single pressure sensor during the formal test; F 0 represents the initial frictional force; During the initial friction force measurement phase, as the number of standard weights is increased, when the first engine assembly and the second engine assembly just begin to slide relative to each other axially, the number of standard weights at this point is recorded as _____. a， The pressure sensor readings begin to change; the change in pressure measured by a single pressure sensor is [value missing]. ∆F The mass of the weighing pan is m 1. The mass of a single standard weight is m 2. The acceleration due to gravity is g The pulling force generated by the standard weights and the mass of the weighing pan through the fixed pulley is ( ). m 1+ am 2) g , F 0 and ( m 1+ am 2) gThe following relationship must be satisfied: F 0+ n∆F =( m 1+ am 2) g Therefore, the engine thrust is obtained. F The calculation formula is: F = nF 1+( m 1+ am 2) g - n∆F .

[0014] This invention offers at least the following advantages: It designs an engine thrust measurement device suitable for small test benches, achieving force self-balancing through structural innovation. The leveling mechanism, aided by a spirit level, adjusts the positions of two sets of double-ended connecting rods and fixed pulleys to ensure the steel cable between the connecting rods and pulleys is horizontal. The steel cable between the pulleys and the weighing pan is perpendicular to the horizontal ground along the direction of gravity. Then, the engine assembly's axis position is adjusted, ensuring the engine thrust, initial friction force, and the leveling mechanism's tension direction are all on the same horizontal axis. Furthermore, four pressure sensors are symmetrically arranged around the circumference of the clamping testing mechanism. The convergence of their output values ​​reflects the offset of the engine system's axis. By coordinating the adjustment of the installation posture of the engine system's flanges and support structures, as well as the clamping preload, the measured values ​​of the four sensors are made nearly uniform. This ensures that the cable tension, the combined pressure sensor force, and the engine thrust are collinear and all on the same horizontal axis, effectively eliminating measurement deviations caused by torque and non-axial friction, significantly improving thrust measurement accuracy, and solving the problem of low thrust measurement accuracy in small engines.

[0015] The engine thrust measuring device of the present invention, applicable to small test benches, has a simple structure and stable operation. It can keep the engine thrust, initial friction force, and leveling mechanism tension on the same horizontal axis, achieving self-balancing of the force system for thrust measurement. The engine thrust measuring device of the present invention can effectively suppress interference from multi-axis coupling of the force system and eliminate the influence of torque on the measurement results, and has the advantages of high measurement accuracy and high reliability. The engine thrust measurement device of the present invention, applicable to small test benches, does not require the use of expensive photoelectric vector balances and can measure relatively accurate engine thrust under ordinary test environments, effectively reducing the test entry threshold; the engine thrust measurement device of the present invention, applicable to small test benches, can be used repeatedly and quickly, avoiding long test scheduling and effectively reducing overall time costs. The engine thrust measurement device of the present invention, applicable to small test benches, adopts a modular structure design. Each component can be quickly disassembled and replaced, and the operation is simple. It is particularly suitable for the technical needs of frequent configuration changes and multiple rounds of performance verification in small engine exploration tests. After changing the configuration, only simple leveling is required to restore the measurement function, which can effectively shorten the test preparation cycle. The engine thrust measurement device of the present invention, applicable to small test benches, has low manufacturing cost and requires no special maintenance, making it highly economical. It is suitable for high-frequency verification test scenarios of small engines and meets the conventional thrust measurement accuracy requirements.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the rear structure of the engine thrust measuring device suitable for a small test bench in Example 1; Figure 2 A schematic diagram of the front side of an engine thrust measurement device suitable for small test benches; Figure 3 This is a schematic diagram of the engine assembly in Example 1; Figure 4 This is a schematic diagram of the clamping test mechanism; Figure 5 This is a schematic diagram of the structure of the T-shaped clamping piece and the I-shaped clamping piece; Figure 6 This is a schematic diagram of the leveling mechanism; Figure 7 This is a schematic diagram showing that the axis of the engine assembly and the horizontal section of the steel cable are not on the same horizontal axis.

[0018] The corresponding labels for each structure in the diagram are as follows: First engine assembly 101; Sealing groove 102; Second engine assembly 103; Limit bolt 104; Engine flange 105; T-shaped clamping piece 201; Second bolt assembly 202; I-shaped clamping piece 203; Pressure sensor 204; Adjustable bolt hole 205; Clamping mechanism flange 206; T-shaped connecting rod 207; First bolt assembly 208; Leveling mechanism flange 301; Double-headed connecting rod 302; First loop hole 303; Slide rail 304; Standard weight 305; Weighing pan 306; Steel cable 307; Fixed pulley 308; Steel cable lock 309; Second loop hole 310; Flat gasket 311. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0020] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof. Example 1 like Figures 1-6 As shown, an engine thrust measuring device suitable for a small test bench includes: The clamping testing mechanism has four sets of symmetrically distributed T-shaped connecting rods 207 welded and fixed to its clamping mechanism flange 206. Each T-shaped connecting rod 207 has a T-shaped clamping piece 201 detachably mounted at its end via a first bolt assembly 208. The T-shaped clamping piece 201 has an I-shaped clamping piece 203 detachably mounted via a second bolt assembly 202. The T-shaped clamping piece 201 and the I-shaped clamping piece 203 constitute a clamping station for clamping the engine assembly. The T-shaped clamping piece 201 and the I-shaped clamping piece 203 are respectively provided with three adjustable bolt holes 205, which are used to adjust the relative positions of the T-shaped clamping piece 201 and the I-shaped clamping piece 203. The engine assembly includes: a first engine assembly 101; and a second engine assembly 103, which is detachably connected to the first engine assembly 101 via a limiting bolt 104. The first engine assembly 101 and the second engine assembly 103 can slide relative to each other axially. Both ends of the limiting bolt 104 are reserved with space for the first engine assembly 101 and the second engine assembly 103 to slide relative to each other. During formal testing, the first engine assembly 101 and the second engine assembly 103 slide relative to each other within the limited space reserved by the limiting bolt 104, thereby preventing the second engine assembly 103 from flying out along the thrust direction and causing a safety accident. The engine flange 105 of the second engine assembly 103 is clamped between the T-shaped clamping piece 201 and the I-shaped clamping piece 203. A pressure sensor 204 is provided between the engine flange 105 and the I-shaped clamping piece 203. The two sides of the pressure sensor 204 abut against the engine flange 105 and the I-shaped clamping piece 203 respectively. A sealing groove 102 is provided between the first engine assembly 101 and the second engine assembly 103. During the formal test, when the second engine assembly 103 and the first engine assembly 101 slide axially relative to each other, the sealing groove 102 is used to ensure the airtightness of the aerodynamic area of ​​the engine assembly. A leveling mechanism, detachably mounted at the tail end of the clamping mechanism flange 206, includes: Leveling mechanism flange 301; Two sets of double-headed connecting rods 302 are provided with a first loop hole 303 at their center position and a second loop hole 310 at the end of the double-headed connecting rods 302. The double-headed connecting rods 302 are installed on the leveling mechanism flange 301 through the first loop hole 303. The leveling mechanism flange 301 is detachably installed on the clamping mechanism flange 206 by bolts. A steel cable 307 has one end threaded through the first loop hole 303 and fixed with a steel cable buckle 309. The other end of the steel cable 307 is connected to a weighing pan 306, on which a standard weight 305 is placed. A fixed pulley 308 is provided with a slide rail 304, and the steel cable 307 is wound around the slide rail 304 of the fixed pulley 308. When the fixed pulley 308 is placed at the test site, it should be ensured that the steel cable 307 between the double-ended connecting rod 302 and the fixed pulley 308 is on the same horizontal axis as the axis of the engine assembly, and the steel cable 307 between the fixed pulley 308 and the weighing pan 306 is perpendicular to the horizontal ground along the direction of gravity.

[0021] In the two sets of double-headed connecting rods 302, a flat gasket 311 of the same width as the double-headed connecting rod 302 is provided between the right double-headed connecting rod 302 and the leveling mechanism flange 301; the flat gasket 311 ensures that the right double-headed connecting rod 302 and the left double-headed connecting rod 302 maintain a parallel position relationship.

[0022] Working principle: The engine thrust measuring device suitable for a small test bench is placed horizontally on the test bench (not shown). The first engine assembly 101 is fixedly mounted on the engine under test. The engine flange 105 of the second engine assembly 103 is clamped between the T-shaped clamping piece 201 and the I-shaped clamping piece 203. The pressure sensor 204 is positioned between the engine flange 105 and the I-shaped clamping piece 203 of the second engine assembly 103, with its two sides abutting against the engine flange 105 and the I-shaped clamping piece 203, respectively. After determining the positions of the engine flange 105 and the pressure sensor 204, the first bolt assembly 208 is tightened to fix the T-shaped clamping piece 201, so that the engine flange 105 of the second engine assembly 103 is clamped between the T-shaped clamping piece 201 and the pressure sensor 204. The pressure sensor 204 is not only used to measure the pressure value acting on it, but the degree of convergence of the output values ​​of each pressure sensor 204 can also reflect the offset state of the engine system's shaft center, which is used for shaft center leveling.

[0023] First, the shaft center is leveled. Using a level, the positions of the two sets of double-ended connecting rods 302 and the fixed pulleys 308 are adjusted to ensure that the steel cable between the double-ended connecting rods 302 and the fixed pulleys 308 is horizontal, and the steel cable 307 between the fixed pulleys 308 and the weighing pan 306 is perpendicular to the horizontal ground along the direction of gravity. Next, the shaft center position of the engine assembly is adjusted. When the shaft centers of the first engine assembly 101 and the second engine assembly 103 are not aligned, the values ​​of the four symmetrically distributed pressure sensors 204 will be inconsistent. Based on the differences in the values ​​of each pressure sensor 204, the installation posture and clamping preload of each flange and support structure of the engine system are adjusted accordingly. When the values ​​of the four pressure sensors 204 are nearly identical, the shaft center adjustment of the engine assembly is considered complete, thus ensuring that the engine thrust, initial friction force, and the pulling force of the leveling mechanism remain on the same horizontal axis. Then, by adjusting the number of standard weights 305, the initial friction force is calculated using the relationship between the horizontal backward tension generated by the steel cable 307 and the changes in the values ​​measured by each pressure sensor 204. F 0; Finally, the leveling mechanism was removed, and the engine thrust value was calculated based on the value measured by pressure sensor 204 during the formal test phase, combined with the initial friction compensation.

[0024] Example 2 A method for measuring engine thrust suitable for small test benches, which uses the engine thrust measuring device suitable for small test benches in Example 1, includes the following steps: Step 1, Axis Leveling Stage: Using a level, adjust the positions of the two sets of double-ended connecting rods 302 and fixed pulleys 308 to ensure that the steel cable between the double-ended connecting rods 302 and fixed pulleys 308 is horizontal, and the steel cable between the fixed pulleys and the weighing pan is perpendicular to the horizontal ground along the direction of gravity. Then, adjust the axis position of the engine assembly. When the axis of the first engine assembly 101 and the second engine assembly 103 is inconsistent, the values ​​of the four symmetrically distributed pressure sensors 204 will be inconsistent. Adjust the installation posture and clamping preload of each flange and support structure of the engine system according to the difference in the values ​​of each pressure sensor 204. When the values ​​of the four pressure sensors 204 are close to being consistent, the axis adjustment of the engine assembly is considered to be complete, thereby ensuring that the engine thrust, initial friction force, and the pulling direction of the leveling mechanism are kept on the same horizontal axis. like Figure 7The diagram illustrates a possible scenario where the engine assembly shaft and the horizontal section of the steel cable 307 are not on the same horizontal axis, causing the engine to tilt. In this case, the lower pressure sensor 204 will be compressed, resulting in a higher pressure reading than the upper pressure sensor 204. This situation may occur because the bolts connecting the support member (not shown) of the first engine assembly 101 to the test bench are too tight, or the bolts connecting the support member (not shown) of the second engine assembly 103 to the test bench are too loose; or the bolts clamping the lower end of the engine flange 105 of the clamping test mechanism are too tight, or the bolts clamping the upper end of the engine flange 105 of the clamping test mechanism are too loose. The shaft position of the engine assembly can be adjusted accordingly. When the values ​​of the four pressure sensors 204 are nearly identical, the engine assembly shaft adjustment is considered complete, thus ensuring that the engine thrust, initial friction force, and the pulling direction of the leveling mechanism are kept on the same horizontal axis. Step 2, Initial Friction Measurement Stage: By adjusting the number of standard weights, the initial friction force is calculated using the relationship between the horizontal backward tension generated by the steel cable and the values ​​measured by each pressure sensor 204. F 0 ; Step 3, Formal Test Measurement Stage: Remove the leveling mechanism and calculate the engine thrust value based on the value measured by pressure sensor 204 during the formal test stage, combined with the initial friction compensation.

[0025] In step three, engine thrust F The calculation formula is: F= 4 F 1 +F 0 in, F 1 represents the pressure value measured by a single pressure sensor during the formal test; F 0 represents the initial frictional force; During the initial friction force measurement phase, as the number of standard weights 305 is increased, when the first engine assembly 101 and the second engine assembly 103 just begin to slide relative to each other axially, the number of standard weights 305 at this point is recorded as follows: a， The pressure sensor 204 reading begins to change; the change in pressure measured by a single pressure sensor 204 is [value missing]. ∆F The mass of weighing pan 306 is m 1. The mass of a single standard weight 305 is m 2. The acceleration due to gravity is g The pulling force generated by the standard weight 305 and the weighing pan 306 through the fixed pulley 308 is ( ). m 1+ am 2) g , F 0 and (m 1+ am 2) g The following relationship must be satisfied: F 0+4 ∆F =( m 1+ am 2) g Therefore, the engine thrust is obtained. F The calculation formula is: F =4 F 1+( m 1+ am 2) g -4 ∆F .

[0026] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0027] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An engine thrust measuring device suitable for small test benches, characterized in that, include: The clamping and testing mechanism has multiple sets of symmetrically distributed T-shaped connecting rods fixedly installed at its front end. Each T-shaped connecting rod has a T-shaped clamping piece detachably installed at its end. The T-shaped clamping piece has an I-shaped clamping piece detachably installed on it. The T-shaped clamping piece and the I-shaped clamping piece constitute a clamping station for clamping engine components. An engine assembly includes: a first engine assembly; a second engine assembly detachably connected to the first engine assembly, wherein the first engine assembly and the second engine assembly are axially relative to each other; the engine flange of the second engine assembly is clamped between the T-shaped clamping piece and the I-shaped clamping piece, and a pressure sensor is provided between the engine flange and the I-shaped clamping piece; A leveling mechanism is detachably mounted at the tail end of the clamping and testing mechanism.

2. The engine thrust measuring device suitable for small test benches as described in claim 1, characterized in that, The first engine assembly and the second engine assembly are detachably connected by a limiting bolt, and the two ends of the limiting bolt are reserved with space for relative sliding of the first engine assembly and the second engine assembly.

3. The engine thrust measuring device suitable for small test benches as described in claim 1, characterized in that, A sealing groove is provided between the first engine assembly and the second engine assembly.

4. The engine thrust measuring device suitable for small test benches as described in claim 1, characterized in that, The clamping test mechanism also includes: The clamping mechanism flange, wherein the T-shaped connecting rod is welded and fixed to the clamping mechanism flange; The T-shaped clamping piece is detachably mounted on the end of the T-shaped connecting rod via a first bolt assembly, and the I-shaped clamping piece is detachably connected to the T-shaped clamping piece via a second bolt assembly.

5. The engine thrust measuring device suitable for small test benches as described in claim 1, characterized in that, The T-shaped clamping piece and the I-shaped clamping piece are respectively provided with multiple adjustable bolt holes.

6. The engine thrust measuring device suitable for small test benches as described in claim 3, characterized in that, The structure of the leveling mechanism includes: Leveling mechanism flange; Two sets of double-headed connecting rods are provided with a first loop hole at their center position and a second loop hole at the end of the double-headed connecting rod. The double-headed connecting rods are installed on the leveling mechanism flange through the first loop hole. The leveling mechanism flange is detachably installed on the clamping mechanism flange. A steel cable, one end of which is threaded through the first loop hole, and the other end of which is connected to a weighing pan, on which a standard weight is placed. A fixed pulley is provided with a slide rail, and the steel cable is wound around the slide rail of the fixed pulley.

7. The engine thrust measuring device suitable for small test benches as described in claim 6, characterized in that, In the two sets of double-headed connecting rods, a flat gasket of the same width as the double-headed connecting rod is provided between the right-side double-headed connecting rod and the flange of the leveling mechanism.

8. A method for measuring engine thrust on a small test bench, comprising using the engine thrust measuring device for a small test bench as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1, Axis Leveling Stage: Using a level, adjust the positions of the two sets of double-ended connecting rods and the fixed pulley to ensure that the steel cable between the double-ended connecting rods and the fixed pulley is horizontal, and the steel cable between the fixed pulley and the weighing pan is perpendicular to the horizontal ground along the direction of gravity. Then, adjust the axis position of the engine assembly. When the axis of the first engine assembly and the second engine assembly are not aligned, the values ​​of the symmetrically distributed pressure sensors will be inconsistent. Adjust the installation posture and clamping preload of each flange and support structure of the engine system according to the differences in the values ​​of each pressure sensor. When the values ​​of multiple pressure sensors are close to being consistent, the axis adjustment of the engine assembly is considered complete, thereby ensuring that the engine thrust, initial friction force, and the pulling direction of the leveling mechanism are kept on the same horizontal axis. Step 2, Initial Friction Measurement Stage: By adjusting the number of standard weights, the initial friction force is calculated using the relationship between the horizontal backward tension generated by the steel cable and the changes in the values ​​measured by each pressure sensor. F 0; Step 3, Formal Test Measurement Phase: Remove the leveling mechanism and calculate the engine thrust value based on the pressure sensor readings from the formal test phase, combined with the initial friction compensation.

9. The engine thrust measurement method suitable for small test benches as described in claim 8, characterized in that, In step three, the engine thrust F The calculation formula is: F=nF 1 +F 0 in, n For the number of pressure sensors, n =4 k , k It is an integer greater than or equal to 1; F 1 represents the pressure value measured by a single pressure sensor during the formal test; F 0 represents the initial frictional force; During the initial friction force measurement phase, as the number of standard weights is increased, when the first engine assembly and the second engine assembly just begin to slide relative to each other axially, the number of standard weights at this point is recorded as _____. a， The pressure sensor readings begin to change; the change in pressure measured by a single pressure sensor is [value missing]. ∆F The mass of the weighing pan is m 1. The mass of a single standard weight is m 2. The acceleration due to gravity is g The pulling force generated by the standard weights and the mass of the weighing pan through the fixed pulley is ( ). m 1+ am 2) g , F 0 and ( m 1+ am 2) g The following relationship must be satisfied: F 0+ n∆F =( m 1+ am 2) g Therefore, the engine thrust is obtained. F The calculation formula is: F = nF 1+( m 1+ am 2) g - n∆F 。

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