Large integral oil tank efficient pressurizing device with internal pressure feedback function

Abstract

The invention relates to a large integral oil tank efficient pressurizing device with an internal pressure feedback function, and relates to the technical field of aviation part sealing detection. Comprising a separated tool, a ball screw, an angle sensor, an inflation connector, a first nut, a second nut and a third nut. The ball screw penetrates through the separated tool, penetrates through the angle sensor and is fixed through a sealing joint, the ball screw is in threaded connection with a first nut, a second nut and a third nut are welded to the two sides of the first nut, a pressure sensor is installed at the bottom of the second nut, and a temperature sensor is installed at the bottom of the third nut; and an inflation interface is arranged on the separated tool in a penetrating manner. The pressure sensor and the temperature sensor of the separated tool are arranged in the oil tank through the ball screw mechanism, free movement of the sensors in the inflation direction is achieved, meanwhile, the depth of the sensors can be calculated and monitored in real time in combination with the angle sensor, and the efficiency and reliability of airtightness detection of the large overall oil tank are improved; and the sealing quality of the large integral oil tank is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of aviation component sealing detection, in particular to a large-scale integral oil tank high-efficiency pressurizing device with internal pressure feedback. Background Art

[0002] After the assembly process of the large integral fuel tank of the aircraft is completed, it needs to be tested for overall air tightness. The existing air tightness testing process is to fill the tank to be tested with nitrogen or compressed air, balance it after the pressure reaches near the set value, disconnect the air source and stop supplying air after the pressure stabilizes at the set value, and perform a pressure holding test. By observing whether there is a pressure drop after a certain period of pressure holding, the overall air tightness of the tank is judged. The air tightness testing process of the large integral fuel tank of the aircraft has formulated different test standards such as test pressure and pressure holding time according to the volume of the tank to be tested.

[0003] The aircraft's integral fuel tank is large in size and the air tightness test process takes a long time. The time consumption mainly comes from the inflation time, balancing time and pressure holding test time. The pressure holding test time is generally limited by process requirements and cannot be optimized and shortened. The existing air tightness test inflation tooling simply fixes the pressure sensor on the inflation plug, and the default pressure value at the inflation position is the internal overall pressure value. For large-sized aviation seals such as integral fuel tanks, on the one hand, during the inflation process, the pressure change in the tank is affected by the spatial position and the duration of gas flow, and has a certain hysteresis. The pressure data obtained by the sensor at the inflation port cannot represent the actual average pressure of the gas medium after the tank is balanced, resulting in inaccurate pressure value detection and a decrease in pressure value after balancing; on the other hand, if the inflation flow rate is too large, the gas pressure in the tank is unstable, and the balancing time required is longer. If the flow rate is small, the inflation time is longer, resulting in low detection efficiency.

[0004] Therefore, how to provide a large-scale integral oil tank high-efficiency pressurizing device with internal pressure feedback has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In order to solve at least one technical problem in the background technology, the present invention provides a high-efficiency pressurizing device for a large integral oil tank with internal pressure feedback. The pressure sensor and temperature sensor of a separate tooling are arranged inside the oil tank through a ball screw mechanism to realize the free movement of the sensor along the inflation direction. At the same time, it can be combined with an angle sensor to calculate and monitor the sensor depth in real time, thereby improving the efficiency and reliability of air tightness detection of large integral oil tanks and ensuring the sealing quality of large integral oil tanks.

[0006] To achieve the above-mentioned purpose, the present invention provides a large-scale integral oil tank high-efficiency pressurizing device with internal pressure feedback, comprising:

[0007] Separate tooling, a ball screw, an angle sensor, an inflation interface, nut one, nut two and nut three; the ball screw passes through the separate tooling, the part of the ball screw located at the upper part of the separate tooling passes through the angle sensor and is fixed by a sealing joint, the part of the ball screw located at the lower part of the separate tooling is threadedly connected with nut one, the nut two and nut three are respectively welded on both sides of the nut one, a pressure sensor is installed at the bottom of the nut two, and a temperature sensor is installed at the bottom of the nut three; an inflation interface is arranged through the separate tooling.

[0008] Furthermore, the separable tooling comprises a tooling outer cover and a tooling inner cover, wherein the tooling outer cover and the tooling inner cover are fixedly connected by clamping bolts; and the tooling outer cover is provided with a U-shaped groove for avoiding the ball screw and the inflation interface.

[0009] Furthermore, an outer cover sealing gasket is bonded to the bottom of the tooling outer cover, and an inner cover sealing gasket is bonded to the top of the tooling inner cover.

[0010] Furthermore, the top and bottom ends of the tooling inner cover are both fixed with mounting handrails, and the tooling outer cover is provided with slots for avoiding the mounting handrails.

[0011] Further, the pressurizing device is installed by the following steps:

[0012] Step S1: Rotate the ball screw to return it to zero;

[0013] Step S2: Turn on the power of the pressure sensor and the temperature sensor, check the communication, and ensure that there is no abnormality in the communication;

[0014] Step S3: Grab the installation handrail and install the tooling inner cover into the oil tank so that the inner cover gasket is in close contact with the inner surface of the oil tank. During the installation process, pay attention to the collision between the ball screw and the inner and outer walls of the oil tank;

[0015] Step S4: insert the tooling outer cover into the tooling inner cover through the clamping bolts and the installation arm, so that the tooling outer cover is installed on the outer surface of the fuel tank, and the outer cover sealing gasket is closely attached to the outer surface of the fuel tank;

[0016] Step S5: tighten the clamping bolts in sequence, and then tighten the ball screw sealing joint to complete the sealing of the inflation device;

[0017] Step S6: connecting the inflation connector to the airtight test bench through the air intake pipeline;

[0018] Step S7: Rotate the rotating end of the ball screw mechanism to control nut one to drive nut two and nut three to move along the inflation direction, read the angle sensor data in real time, determine the nut displacement in real time through the lead, and determine the oil tank depth where the pressure sensor and temperature sensor are located.

[0019] Furthermore, the method for determining the optimal detection position of the pressure sensor is as follows:

[0020] Step D1: After the inflation time t is over, the gas mass m flowing into the fuel tank and the internal gas pressure reach the average absolute pressure p required for detection;

[0021] Step D2: The average absolute pressure required for the test is p. The pressure value at the inflation position is the largest. At a certain moment during the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the actual pressure value of the point. A calculation formula for the actual pressure value of the calculation point in the fuel tank is proposed. According to formula (1), the hydrostatic pressure p of each point on each cross section is calculated. ij ;

[0022]

[0023] Among them, p0 is the inflation gas source pressure, (x ij ,y ij ,z ij ) is the spatial position coordinate of the calculation point, (x0, y0, z0) is the coordinate of the inflation position, x, y, z are the length, width, and height of the inflation tank respectively;

[0024] Step D3: The required inflation flow rate is φ. The mass of the fluid particle at the inflation position is the largest. At a certain moment in the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the mass of the fluid particle at that point. A calculation formula for the mass of the fluid particle at the calculation point in the fuel tank is proposed. According to formula (2), the mass of the fluid particle at each point on each cross section is calculated: ij ;

[0025]

[0026] Where V is the inflation volume;

[0027] Step D4: Calculate the average absolute pressure p on each cross section based on the flow average function formula (3): i ;

[0028]

[0029] Among them, i represents the divided section, j represents the divided calculation point on the section, and n is the number of divided calculation points on the section;

[0030] Step D5: Select the section where the average absolute pressure on the section is equal to or closest to the average absolute pressure p inside the tank as the optimal pressure detection position, and calculate the section depth d according to formula (4): i ;

[0031]

[0032] Wherein, d is the length of the entire fuel tank in the inflation direction, and k is the number of divided sections.

[0033] Furthermore, the variable flow inflation method for minimizing inflation and balancing time is as follows:

[0034] Step E1: When the inflation is performed at a constant flow rate φ, the inflation time is t and the inflation volume is V; the relationship between the inflation volume V, the inflation flow rate φ and the inflation time t is shown in formula (5);

[0035] V=φt (5)

[0036] When the inflation reaches time t′, the flow valve begins to adjust the inflation flow rate from φ to 0 in a linearly decreasing inflation method. The adjusted inflation time is t1, and the large integral fuel tank is full of gas at time t1. The relationship between the adjusted inflation volume V, the inflation flow rate φ and the inflation time t1 is shown in formula (6);

[0037] V=(t′+t1)φ / 2 (6)

[0038] The adjusted inflation time t1 is calculated by equation (5) and equation (6), and the inflation time t1 corresponding to different t′ is obtained, as shown in equation (7);

[0039] t1=2t-t′ (7)

[0040] Step E2: by performing multiple airtightness detection tests with variable flow rate inflation, starting to record the equilibrium time t2 at time t1 after the inflation is completed, and obtaining the equilibrium time t2 corresponding to different t′;

[0041] Step E3: by calculating and testing the data sets of t′, t1 and t2, fitting the mapping relationship between t′ and t1+t2, obtaining the variable flow time t′ corresponding to the minimum inflation balance time t1+t2, and calculating the gas pressure p′ corresponding to the variable flow time by formula (8);

[0042]

[0043] The beneficial effects of the present invention are:

[0044] 1. The present invention designs a large-scale integral oil tank inflation device with internal pressure feedback, in which the pressure sensor and temperature sensor of the tooling are arranged inside the oil tank through a ball screw mechanism to realize the free movement of the sensor along the inflation direction, and can also be combined with an angle sensor to calculate and monitor the sensor depth in real time.

[0045] 2. The present invention divides the detection section and calculation nodes, solves and calculates the fluid static pressure and fluid particle mass at each node, calculates and compares the cross-sectional average pressure and the internal average pressure according to the flow average function, determines the optimal detection position, and improves the accuracy and reliability of large integral oil tank air tightness detection.

[0046] 3. The present invention aims to shorten the inflation time and the balancing time, and proposes a variable flow inflation method that minimizes the inflation and balancing time during the inflation stage of the oil tank air tightness detection, thereby shortening the total inflation and balancing time during the air tightness detection process of large integral oil tanks and improving the air tightness detection efficiency of large integral oil tanks. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of the present invention;

[0048] Figure 2 It is a schematic diagram of the cross section and calculation point division of the present invention;

[0049] Figure 3 It is the corresponding relationship curve of flow rate change moment and inflation balance time of the present invention.

[0050] Among them, 1-tooling outer cover, 2-tooling inner cover, 3-outer cover sealing gasket, 4-inner cover sealing gasket, 5-pressure sensor, 6-temperature sensor, 7-installation handrail, 8-clamping bolt, 9-inflation interface, 10-ball screw, 11-nut one, 12-nut two, 13-nut three, 14-angle sensor, 15-sealing joint. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0054] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0055] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0056] In order to solve the problems existing in the prior art, it is necessary to consider the difference in pressure values ​​in large integral fuel tanks caused by spatial position differences during the inflation process, judge the optimal pressure detection position, accurately monitor the actual pressure value in the fuel tank at the optimal pressure detection position during inflation, and adjust the inflation pressurization strategy based on the accurately monitored gas pressure value to shorten the inflation time and balancing time to the greatest extent, so as to achieve high-efficiency and high-reliability detection of the air tightness of large integral fuel tanks.

[0057] The present invention designs a large-scale integral oil tank inflation device with internal pressure feedback, proposes a method for calculating the optimal pressure detection position in the oil tank, moves the pressure sensor to the optimal detection position to monitor the internal pressure value in real time, and provides reliable parameters for the air tightness detection of the large-scale integral oil tank, and proposes a variable flow inflation and pressurization method that minimizes the total inflation and balancing time, calculates the variable flow moment and performs variable flow inflation when the corresponding pressure value is reached, shortens the total inflation and balancing time, and improves the detection efficiency.

[0058] To achieve the above purpose, Figure 1 As shown, the present invention provides a large-scale integral oil tank high-efficiency pressurizing device with internal pressure feedback, comprising:

[0059] Separate tooling, ball screw 10, angle sensor 14, inflation interface 9, nut 11, nut 2 12 and nut 3 13; the ball screw 10 passes through the separate tooling, the part of the ball screw 10 located at the upper part of the separate tooling passes through the angle sensor 14 and is fixed by a sealing joint 15, the part of the ball screw 10 located at the lower part of the separate tooling is threadedly connected with nut 11, the nut 2 12 and the nut 3 13 are respectively welded on both sides of the nut 11, the bottom of the nut 2 12 is installed with a pressure sensor 5, and the bottom of the nut 3 13 is installed with a temperature sensor 6; the separate tooling is penetrated by an inflation interface 9. The specifications of nut 11, nut 2 12 and nut 3 13 are consistent and the welding positions are at the same horizontal line, which ensures that the moving mechanism and the installation surfaces of the pressure sensor 5 and the temperature sensor 6 are at the same height inside the oil tank; the pressure sensor 5 and the temperature sensor 6 are both wirelessly transmitted to avoid the complex internal wiring affecting the installation.

[0060] The ball screw 10 of the large integral oil tank inflation device is designed with an angle sensor 14 at the active rotating end, which can read the rotation angle value of the ball screw 10 in real time. Combined with the lead parameter P of the ball screw 10, the depth information of nut 11, nut 2 12 and nut 3 13 can be determined in real time, and the depth values ​​of the pressure sensor 5 and the temperature sensor 6 can be determined; a sealing joint 15 is designed between the ball screw 10 and the angle sensor 14 to play a connecting and sealing role, thereby avoiding new leakage due to the introduction of the ball screw 10 mechanism.

[0061] The separate tooling includes a tooling outer cover 1 and a tooling inner cover 2, and the tooling outer cover 1 and the tooling inner cover 2 are fixedly connected by clamping bolts 8; and the tooling outer cover 1 is provided with a U-shaped groove for avoiding the ball screw 10 and the inflation interface 9, leaving space for the installation of the tooling outer cover 1 and the tooling inner cover 2 to avoid interference and collision during the installation process.

[0062] To further optimize the technical solution, the bottom of the tooling outer cover 1 is bonded with an outer cover sealing gasket 3, and the top of the tooling inner cover 2 is bonded with an inner cover sealing gasket 4. While playing a sealing role, it can effectively prevent the inner and outer covers from scratching the inner and outer surfaces of the fuel tank during installation; the tooling inner cover 2 is designed to be convex, and the tooling outer cover 11 is designed to be concave according to the convex shape of the inner cover. The inner and outer covers can be installed in a tight fit. After installation, the filling inside of the inflation tooling is good, avoiding the hollow inside of the inflation tooling, and the overall strength is high, which can ensure stability under high-pressure inflation.

[0063] To further optimize the technical solution, the top and bottom of the tooling inner cover 2 are fixed with mounting handrails 7, and the tooling outer cover 1 is provided with slots for avoiding the mounting handrails 7. Key slots and threaded holes are provided at corresponding positions on the tooling outer cover 1, and the tooling outer cover 1 and the tooling inner cover 2 are clamped to the surface of the oil tank and the bolts are tightened to complete the installation.

[0064] The pressurization device is installed by following the steps below:

[0065] Step S1: Rotate the ball screw 10 to return the ball screw 10 to zero;

[0066] Step S2: Turn on the power of the pressure sensor 5 and the temperature sensor 6, check the communication, and ensure that there is no abnormality in the communication;

[0067] Step S3: Grab the installation handrail 7, install the tooling inner cover 2 into the oil tank, make the inner cover gasket 4 close to the inner surface of the oil tank, and pay attention to the collision between the ball screw 10 and the inner and outer walls of the oil tank during the installation process;

[0068] Step S4: insert the tooling outer cover 1 into the tooling inner cover 2 through the clamping bolts 8 and the mounting handrail 7, so that the tooling outer cover 1 is installed on the outer surface of the fuel tank, and the outer cover sealing gasket 3 is closely attached to the outer surface of the fuel tank;

[0069] Step S5: tighten the clamping bolts 8 in sequence, and then tighten the ball screw 10 and the sealing joint 15 to complete the sealing of the inflation device;

[0070] Step S6: connecting the inflation connector to the airtight test bench through the air intake pipeline;

[0071] Step S7: Rotate the rotating end of the ball screw 10 mechanism, control nut 1 11 to drive nut 2 12 and nut 3 13 to move along the inflation direction, read the angle sensor 14 data in real time, determine the nut displacement in real time through the lead, and determine the oil tank depth where the pressure sensor 5 and the temperature sensor 6 are located.

[0072] The method for determining the optimal detection position of the pressure sensor is as follows:

[0073] Step D1: After the filling time t is over, the gas mass m flowing into the tank and the internal gas pressure reach the average absolute pressure p required for the test. Figure 2 , cut k equally spaced sections of the tank along the inflation direction, and the section is represented by i. For the several sections cut, select the same number of calculation points along the same direction, and the points on the section are represented by ij. The number of sections and the number of calculation points are determined according to the actual situation. The more the number, the more accurate the test results, but the calculation cost will be higher.

[0074] Step D2: The average absolute pressure required for the test is p. The pressure value at the inflation position is the largest. At a certain moment during the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the actual pressure value of the point. A calculation formula for the actual pressure value of the calculation point in the fuel tank is proposed. According to formula (1), the hydrostatic pressure p of each point on each cross section is calculated. ij ;

[0075]

[0076] Among them, p0 is the inflation gas source pressure, (x ij ,y ij ,z ij ) is the spatial position coordinate of the calculation point, (x0, y0, z0) is the coordinate of the inflation position, x, y, z are the length, width, and height of the inflation tank respectively, and k equally spaced sections of the tank are cut along the inflation direction. The section is represented by i. For the several sections cut, the same number of calculation points are selected along the same direction, and the points on the section are represented by ij;

[0077] Step D3: The required inflation flow rate is φ. The mass of the fluid particle at the inflation position is the largest. At a certain moment in the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the mass of the fluid particle at that point. A calculation formula for the mass of the fluid particle at the calculation point in the fuel tank is proposed. According to formula (2), the mass of the fluid particle at each point on each cross section is calculated: ij ;

[0078]

[0079] Where V is the inflation volume;

[0080] Step D4: Calculate the average absolute pressure p on each cross section based on the flow average function formula (3): i ;

[0081]

[0082] Among them, i represents the divided section, j represents the divided calculation point on the section, and n is the number of divided calculation points on the section;

[0083] Step D5: Select the section where the average absolute pressure on the section is equal to or closest to the average absolute pressure p inside the tank as the optimal pressure detection position, and calculate the section depth d according to formula (4): i ;

[0084]

[0085] Wherein, d is the length of the entire fuel tank in the inflation direction, and k is the number of divided sections.

[0086] The variable flow inflation method that minimizes inflation and balancing time is as follows:

[0087] Step E1: When the inflation is performed at a constant flow rate φ, the inflation time is t and the inflation volume is V; the relationship between the inflation volume V, the inflation flow rate φ and the inflation time t is shown in formula (5);

[0088] V=φt (5)

[0089] When the inflation reaches time t′, the flow valve begins to adjust the inflation flow rate from φ to 0 in a linearly decreasing inflation method. The adjusted inflation time is t1, and the large integral fuel tank is full of gas at time t1. The relationship between the adjusted inflation volume V, the inflation flow rate φ and the inflation time t1 is shown in formula (6);

[0090] V=(t′+t1)φ / 2 (6)

[0091] The adjusted inflation time t1 is calculated by equation (5) and equation (6), and the inflation time t1 corresponding to different t′ is obtained, as shown in equation (7);

[0092] t1=2t-t′ (7)

[0093] Step E2: The balance time t2 of the gas in the fuel tank is related to the degree of disorder of the internal gas before the balance, and the degree of disorder of the gas is related to the inflation method used. It cannot be derived by theoretical formula and needs to be measured by experimental means. Through multiple variable flow inflation airtightness detection tests, the balance time t2 is recorded from the time t1 after the inflation is completed, and the balance time t2 corresponding to different t′ is obtained;

[0094] Step E3: by calculating and testing the data sets of t′, t1 and t2, fitting the mapping relationship between t′ and t1+t2, obtaining the variable flow time t′ corresponding to the minimum inflation balance time t1+t2, and calculating the gas pressure p′ corresponding to the variable flow time by formula (8);

[0095]

[0096] The present invention proposes a large-scale integral oil tank inflation device with internal pressure feedback, which has built-in pressure sensors and temperature sensors, and can monitor the gas pressure and temperature inside the oil tank in real time during the airtightness detection process. The pressure sensor and temperature sensor are designed on the ball screw and can move along the inflation direction. At the same time, an angle sensor is designed to calculate and monitor the sensor depth information in real time. Compared with the existing integral oil tank inflation tooling, the present invention realizes the built-in, internal movement and position monitoring of the pressure sensor and temperature sensor.

[0097] The present invention proposes a method for calculating the optimal detection position of the internal pressure of the oil tank, divides the detection section and the calculation nodes on the section, solves and calculates the fluid static pressure and fluid particle mass at each node, calculates the average pressure of each section through the flow average function, and determines the optimal pressure detection position. Before the airtightness detection, the present invention determines the optimal pressure detection position, moves the pressure sensor to the corresponding detection position and then starts the detection. Compared with the existing detection method, this method improves the detection reliability and accuracy.

[0098] The present invention proposes a variable flow inflation method that minimizes the inflation and balancing time. The relationship between the flow change moment and the inflation time is theoretically calculated, the relationship between the flow change moment and the balancing time is determined through experiments, a mapping relationship between the flow change moment and the total inflation balancing time is established, the flow change moment corresponding to the minimum inflation balancing time is determined, and variable flow inflation is performed when the pressure value corresponding to the change moment is reached. Compared with the existing fixed flow inflation method, the present invention shortens the total inflation and balancing time and improves the efficiency of airtightness detection.

[0099] Example

[0100] The embodiment of the present invention discloses a large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback, comprising:

[0101] 1) Large integral tank inflation device with internal pressure feedback

[0102] It includes an outer cover 1, an inner cover 2, an outer cover gasket 3, an inner cover gasket 4, a pressure sensor 5, a temperature sensor 6, an installation handrail 7, a clamping bolt 8, an inflation interface 9, a ball screw 10, a nut 11, a nut 2 12, a nut 3 13, an angle sensor 14 and a sealing joint 15. The pressure sensor 5 and the temperature sensor 6 are arranged inside the oil tank through a ball screw and can move along the inflation direction. Follow the steps below to install:

[0103] Step 1: Rotate the ball screw to return it to zero;

[0104] Step 2: Turn on the power of the pressure sensor 5 and the temperature sensor 6, check the communication, and ensure that there is no abnormality in the communication;

[0105] Step 3: Grab the installation handrail 7, install the tooling inner cover 2 into the oil tank, make the inner cover gasket 4 close to the inner surface of the oil tank, and pay attention to the collision between the ball screw 10 and the inner and outer walls of the oil tank during the installation process;

[0106] Step 4: Insert the tooling outer cover 1 into the tooling inner cover 2 through the clamping bolts 8 and the mounting handrails 7, so that the tooling outer cover 1 is installed on the outer surface of the fuel tank, and the outer cover sealing gasket 3 is closely attached to the outer surface of the fuel tank;

[0107] Step 5: Tighten the clamping bolts 8 in sequence, and then tighten the sealing joint 15 to complete the sealing of the inflation device;

[0108] Step 6: Connect the inflation connector 9 to the airtight test bench through the air intake pipeline;

[0109] Step 7: Rotate the rotating end of the ball screw mechanism to control nut 1 11 to drive nut 2 12 and nut 3 13 to move along the inflation direction, read the angle sensor data in real time, determine the nut displacement in real time through the lead, and determine the oil tank depth where the pressure sensor 5 and the temperature sensor 6 are located.

[0110] 2) Calculation method for the optimal detection position of the internal pressure of the fuel tank

[0111] Step 1: The volume of the integral fuel tank of a certain type of aircraft wing is 4000L, 4m long, 1m wide and 1m high. The air tightness test pressure of the fuel tank of the wing of this type of aircraft is 25kPa, and the inflation pressure is 25kPa. Nine equally spaced sections S1, S2, S3, S4 and S5 are cut and sealed along the inflation direction. For the five cut sections, four calculation points are selected along the same direction, namely k 11 -k 14 , k 21 -k 24 ……k 51 -k 54 , and obtain the inflation position coordinates (0, 0.8, 0.6) and all calculation point coordinates. The position coordinates of the calculation points of each section are shown in Table 1:

[0112]

[0113] Table 1

[0114] Step 2: Calculate the static pressure p of the fluid at each point on each cross section according to formula (1) ij The static pressure of the fluid at each cross-section calculation point (unit: kPa) is shown in Table 2:

[0115]

[0116] Table 2

[0117] Step 3: Calculate the mass M of the fluid particle at each point on each cross section according to formula (2): ij The mass of fluid particles at each cross-section calculation point is shown in Table 3:

[0118]

[0119] Table 3

[0120] Step 4: Calculate the average absolute pressure p on each section according to formula (3): i The average absolute pressure of each section (unit: kPa) is shown in Table 4:

[0121]

[0122] Table 4

[0123] Step 5: The internal average absolute pressure value is 25 kPa. The section average absolute pressure is equal to or closest to the internal average absolute pressure p of the tank is section 3. According to formula (4), the depth of the detection section is 2 m.

[0124] 3) Variable flow inflation method to minimize inflation and balancing time

[0125] Step 1: When inflating at a constant flow rate of 80L / min, the inflation time is 50min and the inflation volume is 4000L. When the inflation reaches time t', the flow valve begins to adjust the inflation flow rate from 80L / min to 0 in a linear decreasing inflation method. The adjusted inflation time is t1, and the wing integral fuel tank is full of air at time t1. The adjusted inflation time t1 can be calculated by formula (5)(6)(7) to obtain the inflation time t1 corresponding to different t'. The corresponding relationship between some t' and t1 is shown in Table 5:

[0126]

[0127] Table 5

[0128] Step 2: Through multiple variable flow rate inflation airtightness test, start recording the equilibrium time t2 at time t1 after the inflation is completed, and obtain the equilibrium time t2 corresponding to different t′. The corresponding relationship between some t′ and t2 is shown in Table 6:

[0129]

[0130] Table 6

[0131] Step 3: Fit the mapping relationship between t′ and t1+t2 Figure 3 As shown in the figure, the variable flow time t′ corresponding to the minimum total inflation balance time t1+t2 is 33.57 min. The pressure value corresponding to the variable flow time is calculated by formula (8) to be 16.79 kPa. From the calculation results, it can be seen that the total inflation balance time after the change is shortened from 100 min to 81.09 min, which saves about 19 min compared with the original method.

[0132] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A large-scale integral oil tank high-efficiency pressurizing device with internal pressure feedback, characterized in that: include: Separate tooling, a ball screw, an angle sensor, an inflation interface, nut one, nut two and nut three; the ball screw passes through the separate tooling, the part of the ball screw located at the upper part of the separate tooling passes through the angle sensor and is fixed by a sealing joint, the part of the ball screw located at the lower part of the separate tooling is threadedly connected with nut one, the nut two and nut three are respectively welded on both sides of the nut one, a pressure sensor is installed at the bottom of the nut two, and a temperature sensor is installed at the bottom of the nut three; an inflation interface is arranged through the separate tooling.

2. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 1, characterized in that: The separate tooling comprises a tooling outer cover and a tooling inner cover, wherein the tooling outer cover and the tooling inner cover are fixedly connected by clamping bolts; and the tooling outer cover is provided with a U-shaped groove for avoiding the ball screw and the inflation interface.

3. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 2, characterized in that: An outer cover sealing gasket is bonded to the bottom of the tooling outer cover, and an inner cover sealing gasket is bonded to the top of the tooling inner cover.

4. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 3, characterized in that: The top and bottom ends of the tooling inner cover are both fixed with mounting handrails, and the tooling outer cover is provided with slots for avoiding the mounting handrails.

5. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 4, characterized in that: The pressurization device is installed by following the steps below: Step S1: Rotate the ball screw to return it to zero; Step S2: Turn on the power of the pressure sensor and the temperature sensor, check the communication, and ensure that there is no abnormality in the communication; Step S3: Grab the installation handrail and install the tooling inner cover into the oil tank so that the inner cover gasket is in close contact with the inner surface of the oil tank. During the installation process, pay attention to the collision between the ball screw and the inner and outer walls of the oil tank; Step S4: insert the tooling outer cover into the tooling inner cover through the clamping bolts and the installation arm, so that the tooling outer cover is installed on the outer surface of the fuel tank, and the outer cover sealing gasket is closely attached to the outer surface of the fuel tank; Step S5: tighten the clamping bolts in sequence, and then tighten the ball screw sealing joint to complete the sealing of the inflation device; Step S6: connecting the inflation connector to the airtight test bench through the air intake pipeline; Step S7: Rotate the rotating end of the ball screw mechanism to control nut one to drive nut two and nut three to move along the inflation direction, read the angle sensor data in real time, determine the nut displacement in real time through the lead, and determine the oil tank depth where the pressure sensor and temperature sensor are located.

6. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 5, characterized in that: The method for determining the optimal detection position of the pressure sensor is as follows: Step D1: After the inflation time t is over, the gas mass m flowing into the fuel tank and the internal gas pressure reach the average absolute pressure p required for detection; Step D2: The average absolute pressure required for the test is p. The pressure value at the inflation position is the largest. At a certain moment during the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the actual pressure value of the point. A calculation formula for the actual pressure value of the calculation point in the fuel tank is proposed. According to formula (1), the hydrostatic pressure p of each point on each cross section is calculated. ij ; Among them, p0 is the inflation gas source pressure, (x ij ,y ij ,z ij ) is the spatial position coordinate of the calculation point, (x0, y0, z0) is the coordinate of the inflation position, x, y, z are the length, width, and height of the inflation tank respectively; Step D3: The required inflation flow rate is φ. The mass of the fluid particle at the inflation position is the largest. At a certain moment in the inflation process, the farther the point in the fuel tank is from the inflation position, the lower the mass of the fluid particle at that point. A calculation formula for the mass of the fluid particle at the calculation point in the fuel tank is proposed. According to formula (2), the mass of the fluid particle at each point on each cross section is calculated: ij ; Where V is the inflation volume; Step D4: Calculate the average absolute pressure p on each cross section based on the flow average function formula (3): i ; Among them, i represents the divided section, j represents the divided calculation point on the section, and n is the number of divided calculation points on the section; Step D5: Select the section where the average absolute pressure on the section is equal to or closest to the average absolute pressure p inside the tank as the optimal pressure detection position, and calculate the section depth d according to formula (4): i ; Wherein, d is the length of the entire fuel tank in the inflation direction, and k is the number of divided sections.

7. A large-scale integrated oil tank high-efficiency pressurizing device with internal pressure feedback as claimed in claim 6, characterized in that: The variable flow inflation method that minimizes inflation and balancing time is as follows: Step E1: When the inflation is performed at a constant flow rate φ, the inflation time is t and the inflation volume is V; the relationship between the inflation volume V, the inflation flow rate φ and the inflation time t is shown in formula (5); V=φt (5) When the inflation reaches time t′, the flow valve begins to adjust the inflation flow rate from φ to 0 in a linearly decreasing inflation method. The adjusted inflation time is t1, and the large integral fuel tank is full of gas at time t1. The relationship between the adjusted inflation volume V, the inflation flow rate φ and the inflation time t1 is shown in formula (6); V=(t′+t1)φ / 2 (6) The adjusted inflation time t1 is calculated by equation (5) and equation (6), and the inflation time t1 corresponding to different t′ is obtained, as shown in equation (7); t1=2t-t′ (7) Step E2: by performing multiple airtightness detection tests with variable flow rate inflation, starting to record the equilibrium time t2 at time t1 after the inflation is completed, and obtaining the equilibrium time t2 corresponding to different t′; Step E3: by calculating and testing the data sets of t′, t1 and t2, fitting the mapping relationship between t′ and t1+t2, obtaining the variable flow time t′ corresponding to the minimum inflation balance time t1+t2, and calculating the gas pressure p′ corresponding to the variable flow time by formula (8);

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