Fuel on-line water injection system and method for fuel icing test

Abstract

Embodiments of the present application provide an online water injection system and method for fuel icing test, relating to the field of aero-engine fuel icing test. It aims to improve the problem of unstable water content of fuel distribution in fuel icing test. It includes main oil supply path, steady-state water injection cylinder, steady-state nozzle, transient water injection cylinder, transient nozzle, bypass solenoid valve, oil supply pressure sensor and test piece; the steady-state water injection cylinder is connected with the steady-state nozzle, and the transient water injection cylinder is connected with the transient nozzle; the bypass solenoid valve is connected with the test piece in parallel, and the bypass solenoid valve is connected with the oil supply pressure sensor. Through the parallel connection scheme of the bypass electric control valve and the test piece, the transition state water-containing fuel oil supply is converted into steady-state supply, solving the problem that the water injection flow cannot quickly follow the change of fuel flow during the transition state of the test piece, and further providing stable water-containing fuel oil, realizing the continuous supply of stable water-containing fuel oil under the transition condition.

Description

Technical Field

[0001] This invention relates to the field of fuel icing tests for aero-engines, and more specifically, to an online fuel water injection system and method for fuel icing tests. Background Technology

[0002] When conducting fuel icing tests, configuring fuel containing water that meets specifications and design requirements is a prerequisite for a successful test. Current water injection schemes include offline water injection based on SAE ARP1401B and online water injection based on SAE ARP6340.

[0003] The offline water injection method involves adding the required amount of water to the fuel at room temperature and mixing thoroughly before cooling the fuel to its operating point for testing. This method results in water being distributed throughout the fuel supply system, including the tank, lines, and valves. As the fuel temperature decreases, some water adheres to and accumulates on the inner surfaces of these components and fuel lines, leading to lower than expected water content and poor uniformity during testing, thus failing to meet the test requirements. The online water injection method, on the other hand, involves injecting pure water or high-water-content fuel into the low-temperature fuel supply line at the test specimen's inlet at a specific ratio, ensuring the required fuel water content ratio. Compared to the offline method, online water injection offers higher stability and consistency in water content.

[0004] As aero-engine design becomes increasingly sophisticated, the fuel temperature at the lubricating oil cooler outlet is above 0°C under most steady-state operating conditions. This prevents fuel icing and filter blockage from causing a loss of fuel supply to the combustion chamber, resulting in thrust loss or even combustion chamber shutdown. However, during transient operating conditions, rapid changes in fuel flow rate prevent the water injection flow rate from dynamically adapting to these changes. Consequently, a stable water-fuel ratio cannot be achieved, and excessively low or high water content in the low-temperature fuel may prevent the aircraft from passing fuel icing airworthiness verification. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] The present invention includes, for example, providing an online water injection system for fuel oil icing tests that can improve the problem of unstable water content in fuel oil during fuel oil icing tests.

[0007] The present invention also aims to provide an online water injection method for fuel icing tests, which can improve the problem of unstable water content in fuel icing tests.

[0008] The embodiments of the present invention can be implemented as follows:

[0009] An embodiment of the present invention provides an online fuel water injection system for fuel icing tests, comprising a main fuel supply line, a steady-state water injection cylinder, a steady-state nozzle, a transient water injection cylinder, a transient nozzle, a bypass solenoid valve, a fuel supply pressure sensor, and a test piece; the steady-state nozzle, the transient nozzle, the fuel supply pressure sensor, and the test piece are sequentially arranged on the main fuel supply line, and the fuel supply pressure sensor is used to measure the inlet pressure of the test piece;

[0010] The steady-state water injection cylinder is connected to the steady-state nozzle and is used to inject water into the steady-state nozzle during a steady-state fuel icing test. The transient water injection cylinder is connected to the transient nozzle and is used to inject water into the transient nozzle during a transient fuel icing test. The bypass solenoid valve is connected to the main fuel supply circuit and is connected in parallel with the test piece. The bypass solenoid valve is connected to the fuel supply pressure sensor and is used to adjust according to the measurement data of the fuel supply pressure sensor.

[0011] In addition, the online water injection system for fuel oil icing tests provided in the embodiments of the present invention may also have the following additional technical features:

[0012] Optionally, the online fuel water injection system for fuel icing tests further includes a main fuel supply pump and a main flow meter; the main fuel supply pump and the main flow meter are installed on the main fuel supply line and are located upstream of the steady-state nozzle; the main fuel supply pump and the main flow meter are connected, and the main fuel supply pump is used to adjust according to the measurement data of the main flow meter.

[0013] Optionally, the main flow meter is connected to the steady-state water injection cylinder, which is used to adjust the flow based on the measurement data of the main flow meter and the fuel water content ratio.

[0014] Optionally, the online water injection system for fuel icing test further includes a working flow meter, which is installed on the main fuel supply line and located downstream of the test specimen; the working flow meter is connected to the transient water injection cylinder, which is used to adjust according to the measurement data of the working flow meter and the fuel water content ratio.

[0015] Optionally, the online fuel water injection system for fuel icing tests further includes a protective oil tank, a protective oil pump, a heater, and a two-position three-way valve. The protective oil tank, the protective oil pump, and the heater are connected in sequence. The two-position three-way valve is connected to the heater, the steady-state nozzle, and the transient nozzle. The two-position three-way valve is used to control the connection between the heater and the steady-state nozzle, or to control the connection between the heater and the transient nozzle, so as to heat the steady-state nozzle or the transient nozzle.

[0016] Optionally, the steady-state nozzle is provided with a first fuel channel, a first protective oil channel, and a first water supply channel. The first fuel channel is connected to the main fuel supply line, the first protective oil channel is disposed within the first fuel channel, and the first protective oil channel is connected to the outlet of the two-position three-way valve. One end of the water supply line is connected to the steady-state water injection cylinder, and the other end of the water supply line extends into the first protective oil channel, which is used to heat the water supply line.

[0017] Optionally, the transient nozzle is provided with a second fuel channel, a second protective oil channel, and a second water supply channel. The second fuel channel is connected to the main fuel supply line, the second protective oil channel is disposed within the second fuel channel, and the second protective oil channel is connected to the outlet of the two-position three-way valve. One end of the water supply line is connected to the steady-state water injection cylinder, and the other end of the water supply line extends into the second protective oil channel, which is used to heat the water supply line.

[0018] Optionally, the online fuel water injection system for fuel icing tests further includes a temperature sensor; both the steady-state nozzle and the transient nozzle are equipped with temperature sensors at their outlets, the temperature sensors are connected to the heater, and the heater is used to adjust according to the measurement data of the temperature sensors so that the outlet temperature of the steady-state nozzle is 1-3℃ under steady-state conditions, or the outlet temperature of the transient nozzle is 1-3℃ under transient conditions.

[0019] Optionally, the online fuel water injection system for fuel icing tests further includes a static mixer; the static mixer is disposed on the main fuel supply line and is located between the steady-state nozzle and the transient nozzle.

[0020] Embodiments of the present invention also provide an online water injection method for fuel icing tests. The online water injection method for fuel icing tests is implemented using an online water injection system for fuel icing tests.

[0021] In the case of steady-state fuel icing test, the steady-state water injection cylinder is activated, and the steady-state water injection cylinder injects water into the steady-state nozzle at a stable water injection rate;

[0022] In the case of transient fuel icing test, the transient water injection cylinder is activated, and the transient water injection cylinder injects water into the transient nozzle at a continuously varying injection rate.

[0023] The beneficial effects of the online water injection system and method for fuel icing tests according to embodiments of the present invention include, for example:

[0024] The online fuel water injection system for fuel icing tests includes a main fuel supply line, a steady-state water injection cylinder, a steady-state nozzle, a transient water injection cylinder, a transient nozzle, a bypass solenoid valve, a fuel supply pressure sensor, and a test piece. The steady-state nozzle, transient nozzle, fuel supply pressure sensor, and test piece are sequentially arranged on the main fuel supply line. The fuel supply pressure sensor measures the inlet pressure of the test piece. The steady-state water injection cylinder is connected to the steady-state nozzle and is used to inject water into the steady-state nozzle during steady-state fuel icing tests. The transient water injection cylinder is connected to the transient nozzle and is used to inject water into the transient nozzle during transient fuel icing tests. The bypass solenoid valve is connected to the main fuel supply line and is connected in parallel with the test piece. The bypass solenoid valve is also connected to the fuel supply pressure sensor and is used to adjust based on the measurement data from the fuel supply pressure sensor.

[0025] By connecting the bypass electronic control valve in parallel with the test specimen, the transition state water-containing fuel supply is transformed into a steady state fuel supply. This solves the problem that the water injection flow cannot quickly follow the changes in fuel flow during the transition state of the test specimen, thus failing to provide a stable water-containing fuel ratio. This achieves a continuous supply of stable water-containing fuel under transition conditions.

[0026] The online water injection method for fuel used in fuel icing tests, implemented using the above-described system, can improve the problem of unstable water content in fuel water during fuel icing tests. Attached Figure Description

[0027] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0028] Figure 1 This is a structural schematic diagram of an online water injection system for fuel icing tests provided in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the steady-state nozzle in an online water injection system for fuel icing tests provided in an embodiment of the present invention.

[0030] Icons: Low-temperature fuel tank-1; Main fuel pump-2; Main flow meter-3; Steady-state nozzle-4; Static mixer-5; Fuel supply temperature sensor-6; Fuel supply pressure sensor-7; Transient nozzle-8; Steady-state water injection cylinder-9; Transient water injection cylinder-10; Test piece-11; Working flow meter-12; Return fuel tank-13; Bypass solenoid valve-14; Protective oil tank-15; Protective oil supply pump-16; Heater-17; Two-position three-way valve-18; First check valve-19; Second check valve-20; First fuel passage-30; First protective oil passage-31; First water supply passage-32. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0032] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," or "vertical" appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, and does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0033] At the same time, it should be noted that the terms "first" and "second" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.

[0034] In the description of this invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] The following is combined with Figures 1 to 2 This embodiment provides a detailed description of the online water injection system and method for fuel icing tests.

[0036] Please refer to Figure 1This invention provides an online fuel water injection system for fuel icing tests, comprising a main fuel supply line, a steady-state water injection cylinder 9, a steady-state nozzle 4, a transient water injection cylinder 10, a transient nozzle 8, a bypass solenoid valve, a fuel supply pressure sensor 7, and a test piece 11. The steady-state nozzle 4, the transient nozzle 8, the fuel supply pressure sensor 7, and the test piece 11 are sequentially arranged on the main fuel supply line. The fuel supply pressure sensor 7 is used to measure the inlet pressure of the test piece 11. The steady-state water injection cylinder 9 is connected to the steady-state nozzle 4 and is used to inject water into the steady-state nozzle 4 during a steady-state fuel icing test. The transient water injection cylinder 10 is connected to the transient nozzle 8 and is used to inject water into the transient nozzle 8 during a transient fuel icing test. The bypass solenoid valve is connected to the main fuel supply line and is connected in parallel with the test piece 11. The bypass solenoid valve is also connected to the fuel supply pressure sensor 7 and is used to adjust according to the measurement data from the fuel supply pressure sensor 7.

[0037] It should be noted that: Online water injection: This involves directly injecting room-temperature pure water or fuel with high water content into low-temperature fuel to achieve a specific water content fuel configuration; Transition state condition: During engine operation, the flow and pressure of various parts of the fuel system continuously change; the state during this change is called the transition state condition; Fuel icing test bench: This is used to support the engine control system in conducting fuel icing tests, using the engine fuel control system as the test object for system integration verification; it verifies the reliable operation capability of the fuel control system under different ice / water content conditions at low ambient temperatures and low fuel temperatures.

[0038] Reference Figure 1 In this embodiment, the online fuel water injection system for the fuel icing test further includes a cryogenic fuel supply tank 1 and a return fuel tank 13. The upstream end of the main fuel supply line is connected to the cryogenic fuel supply tank 1, and the downstream end of the main fuel supply line is connected to the return fuel tank 13. The steady-state nozzle 4, the transient nozzle 8, the fuel supply pressure sensor 7, and the test piece 11 are arranged between the cryogenic fuel supply tank 1 and the return fuel tank 13.

[0039] The low-temperature fuel is supplied in a single loop through the low-temperature fuel supply tank 1, steady-state nozzle 4, transient nozzle 8, fuel supply pressure sensor 7, test piece 11 and return tank 13. Pure water is injected into the main fuel supply circuit at the steady-state nozzle 4 or transient nozzle 8 according to the steady-state or transient operating conditions. The pure water is atomized into tiny water particles by the nozzle and enters the low-temperature fuel, where it quickly freezes. The tiny ice crystals are evenly mixed into the fuel to achieve a fuel configuration with a specific water content.

[0040] The bypass solenoid valve 14 achieves stable control of the fuel supply pressure of the test piece 11 through closed-loop control with the fuel supply pressure sensor 7. In particular, it can ensure the stability of the main fuel supply line pressure and fuel water content when the test piece 11 undergoes transitional fuel flow changes.

[0041] With a constant flow rate in the main fuel supply circuit, during the transition state of test piece 11, the working flow rate decreases while the flow rate of the bypass solenoid valve 14 increases; conversely, when the working flow rate increases, the flow rate of the bypass solenoid valve 14 decreases. By connecting the bypass solenoid valve 14 in parallel with test piece 11, the transition state water-containing fuel supply is transformed into a steady-state supply. This solves the problem that the water injection flow rate cannot quickly follow the changes in fuel flow rate during the transition state of test piece 11, thus failing to provide a stable water-containing fuel ratio. This achieves a continuous supply of stable water-containing fuel under transition conditions.

[0042] Reference Figure 1 In this embodiment, the fuel online water injection system for fuel icing test also includes a main fuel supply pump 2 and a main flow meter 3; the main fuel supply pump 2 and the main flow meter 3 are installed on the main fuel supply line and are located upstream of the steady-state nozzle 4; the main fuel supply pump 2 and the main flow meter 3 are connected, and the main fuel supply pump 2 is used to adjust according to the measurement data of the main flow meter 3.

[0043] The main fuel supply pump 2 and the main flow meter 3 are installed between the low-temperature fuel tank 1 and the steady-state nozzle 4. The main fuel supply pump 2 and the main flow meter 3 operate in a closed-loop control system to stabilize the fuel flow rate in the main fuel supply line. With a constant main fuel supply flow rate, when the test piece 11 is in a transitional state, the working flow rate decreases, and the flow rate of the bypass solenoid valve 14 increases; conversely, when the working flow rate increases, the flow rate of the bypass solenoid valve 14 decreases. This fuel icing test water injection scheme provides a continuous and stable supply of water-mixed fuel to control the fuel icing test. It solves the problem of unstable water content in the fuel mixture during the fuel icing test, improves the efficiency of the fuel icing test, ensures the validity of the test results, and reduces the test cost.

[0044] Reference Figure 1 In this embodiment, the main flow meter 3 is connected to the steady-state water injection cylinder 9, which is used to adjust the flow based on the measurement data of the main flow meter 3 and the fuel water content ratio.

[0045] With a fixed flow rate in the main oil supply line, the required water injection flow rate can be calculated based on the flow rate measured by the main flow meter 3 and the required fuel water content. The water injection flow rate can be converted into the steady-state water injection cylinder 9 speed to achieve the steady-state fuel water content ratio. At this time, regardless of whether the test piece 11 is in a steady state or a transitional state, the fuel water content supplied to the test piece 11 is stable.

[0046] Reference Figure 1In this embodiment, the online water injection system for fuel icing test also includes a working flow meter 12, which is installed on the main fuel supply line and located downstream of the test piece 11. The working flow meter 12 is connected to the transient water injection cylinder 10, which is used to adjust according to the measurement data of the working flow meter 12 and the fuel water content ratio.

[0047] The required water injection flow rate can be calculated based on the flow rate measured by the working flow meter 12 and the required water content of the fuel. The water injection flow rate can be converted into the transient water injection cylinder 10 speed to achieve the transient water-containing fuel ratio.

[0048] Reference Figure 1 In this embodiment, the online fuel water injection system for fuel icing test also includes a protective oil tank 15, a protective oil pump, a heater 17, and a two-position three-way valve 18. The protective oil tank 15, the protective oil pump, and the heater 17 are connected in sequence. The two-position three-way valve 18 is connected to the heater 17, the steady-state nozzle 4, and the transient nozzle 8. The two-position three-way valve 18 is used to control the heater 17 to connect with the steady-state nozzle 4, or to control the heater 17 to connect with the transient nozzle 8, so as to heat the steady-state nozzle 4 or the transient nozzle 8.

[0049] During the steady-state fuel icing test, the two-position three-way valve 18 is connected to the steady-state nozzle 4, supplying protective oil to the steady-state nozzle 4 to prevent icing at the outlet of the steady-state nozzle 4. During the transient fuel icing test, the two-position three-way valve 18 is connected to the transient nozzle 8, supplying protective oil to the transient nozzle 8 to prevent icing at the outlet of the transient nozzle 8.

[0050] Reference Figure 2 In this embodiment, the steady-state nozzle 4 is provided with a first fuel channel 30, a first protective oil channel 31 and a first water supply channel 32. The first fuel channel 30 is connected to the main fuel supply line, the first protective oil channel 31 is located in the first fuel channel 30 and is connected to the outlet of the two-position three-way valve; one end of the water supply line is connected to the steady-state water injection cylinder 9, and the other end of the water supply line extends into the first protective oil channel 31, which is used to heat the water supply line.

[0051] The steady-state nozzle 4 uses a double-layer design. The outer first protective oil channel 31 is connected to high-temperature protective oil, and the inner first water supply channel 32 is connected to the steady-state water injection cylinder 9, which can prevent pure water from freezing at the nozzle and clogging the nozzle.

[0052] Reference Figure 2In this embodiment, the transient nozzle 8 is provided with a second fuel channel, a second protective oil channel and a second water supply channel. The second fuel channel is connected to the main fuel supply line, the second protective oil channel is located in the second fuel channel and is connected to the outlet of the two-position three-way valve; one end of the water supply line is connected to the steady-state water injection cylinder 9, and the other end of the water supply line extends into the second protective oil channel, which is used to heat the water supply line.

[0053] The transient nozzle 8 uses a double-layer design. The outer second protective oil channel is connected to high-temperature protective oil, and the inner second water supply channel is connected to the steady-state water injection cylinder 9, which can prevent pure water from freezing at the nozzle and clogging the nozzle.

[0054] Reference Figure 1 In this embodiment, the online fuel water injection system for fuel icing test also includes a temperature sensor; both the steady-state nozzle 4 and the transient nozzle 8 are equipped with temperature sensors at their outlets. The temperature sensors are connected to the heater 17, which is used to adjust according to the measurement data of the temperature sensors so that the outlet temperature of the steady-state nozzle 4 is 1-3℃ under steady-state conditions, or the outlet temperature of the transient nozzle 8 is 1-3℃ under transient conditions.

[0055] Temperature sensors are installed at the outlets of steady-state nozzle 4 and transient nozzle 8, and are controlled in a closed loop with heater 17. Under steady-state conditions, the temperature at the outlet of steady-state nozzle 4 is kept between 1 and 3°C, and under transient conditions, the temperature at the outlet of transient nozzle 8 is kept between 1 and 3°C, further ensuring that pure water will not freeze at the nozzle and clog the nozzle.

[0056] Reference Figure 1 In this embodiment, the online water injection system for fuel icing tests also includes a static mixer 5. The static mixer 5 is located on the main fuel supply line, between the steady-state nozzle 4 and the transient nozzle 8. The static mixer 5 uniformly mixes tiny ice crystals into the fuel, achieving a fuel configuration with a specific water content. The static mixer 5 is connected after the steady-state nozzle 4, making the water-containing fuel more uniformly mixed after passing through the static mixer 5.

[0057] Reference Figure 1 In this embodiment, the online fuel water injection system for fuel icing test also includes fuel supply temperature sensor 6, first check valve 19 and second check valve 20. The fuel supply temperature sensor 6 is installed on the main fuel supply line and is located between the transient nozzle 8 and the fuel supply pressure sensor 7. The first check valve 19 is installed between the two-position three-way valve 18 and the steady-state nozzle 4, and the second check valve 20 is installed between the two-position three-way valve 18 and the transient nozzle 8.

[0058] Embodiments of the present invention also provide an online water injection method for fuel icing tests. The online water injection method for fuel icing tests is implemented using an online water injection system for fuel icing tests.

[0059] Under the condition of steady-state fuel icing test, steady-state water injection cylinder 9 is started, and steady-state water injection cylinder 9 injects water into steady-state nozzle 4 at a stable water injection rate;

[0060] In the case of transient fuel icing test, the transient water injection cylinder 10 is activated, and the transient water injection cylinder 10 injects water into the transient nozzle 8 at a continuously varying water injection rate.

[0061] According to the embodiment provided, an online water injection system for fuel icing tests is provided. The working principle of the online water injection system for fuel icing tests includes:

[0062] Low-temperature fuel is supplied via a single loop through a low-temperature fuel tank 1, a main fuel pump 2, a main flow meter 3, a steady-state nozzle 4, a static mixer 5, a fuel supply temperature sensor 6, a fuel supply pressure sensor 7, a transient nozzle 8, a test piece 11, a working flow meter 12, and a return fuel tank 13. Pure water is injected into the main fuel supply line at either the steady-state nozzle 4 or the transient nozzle 8 according to the steady-state or transient operating conditions. The pure water is atomized into tiny water particles by the nozzle and enters the low-temperature fuel, where it quickly freezes. The static mixer 5 evenly mixes the tiny ice crystals into the fuel to achieve a specific water content in the fuel mixture.

[0063] The low-temperature fuel supply tank 1 provides the test specimen 11 with low-temperature fuel with very low water content. The main fuel supply pump 2 and the main flow meter 3 are under closed-loop control to provide a stable fuel supply to the main fuel supply line. The bypass solenoid valve 14 is connected in parallel with the test specimen 11. The inlet pressure of the test specimen 11 is stabilized through the closed-loop control of the bypass solenoid valve 14 and the fuel supply pressure sensor 7. The main fuel supply line flow rate (the flow rate after passing through the flow meter) is constant. When the test specimen 11 is in a transition state, the working flow rate decreases and the flow rate of the bypass solenoid valve 14 increases; when the working flow rate increases, the flow rate of the bypass solenoid valve 14 decreases. With the main fuel supply line flow rate stable, the water supply flow rate of the steady-state water injection cylinder 9 also remains stable when the fuel with a fixed water content is mixed, thus keeping the fuel water content constant. The high water content fuel is stored in the return fuel tank 13 and will be dehydrated after the test for recycling.

[0064] During the steady-state fuel icing test, the two-position three-way valve 18 introduces heated protective oil into the steady-state nozzle 4. The required water injection flow rate can be calculated based on the flow rate measured by the main flow meter 3 and the required fuel water content. The water injection flow rate is converted into the speed of the steady-state water injection cylinder 9 to achieve the steady-state water-containing fuel ratio. At this time, regardless of whether the test piece 11 is in a steady state or a transition state, the fuel water content supplied to the test piece 11 is stable.

[0065] During the transient fuel icing test, the water injection time is generally within a few seconds. Since the state of the test piece 11 changes little within a few seconds, it can be regarded as a steady state. The two-position three-way valve 18 introduces the heated protective oil into the transient nozzle 8. The required water injection flow rate can be calculated based on the flow rate measured by the working flow meter 12 and the required fuel water content. The water injection flow rate is converted into the speed of the transient water injection cylinder 10 to achieve the ratio of transient water-containing fuel.

[0066] The online water injection system for fuel oil icing tests provided in this embodiment has at least the following advantages:

[0067] By connecting the bypass electronic control valve 14 in parallel with the test piece 11, the transition state water-containing fuel supply is transformed into a steady state fuel supply. This solves the problem that the water injection flow rate cannot quickly follow the change in fuel flow rate during the transition state of the test piece 11, thus failing to provide a stable water-containing fuel ratio. This achieves a continuous supply of stable water-containing fuel under transition conditions.

[0068] It can perform steady-state fuel icing tests and transient fuel icing tests, and has wide applicability and strong practicality in the fields of aero-engine fuel control systems and mechanical systems. The application of fuel icing tests can verify the thermal management design of the fuel lubricating oil system, thereby improving the validity of the test results.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An online water injection system for fuel oil icing tests, characterized in that, include: Main fuel supply line; Steady-state water injection cylinder, steady-state nozzle, transient water injection cylinder, transient nozzle, bypass solenoid valve, oil supply pressure sensor and test piece; The steady-state nozzle, the transient nozzle, the oil supply pressure sensor, and the test piece are sequentially arranged on the main oil supply line, and the oil supply pressure sensor is used to measure the inlet pressure of the test piece; The steady-state water injection cylinder is connected to the steady-state nozzle and is used to inject water into the steady-state nozzle during a steady-state fuel icing test. The transient water injection cylinder is connected to the transient nozzle and is used to inject water into the transient nozzle during a transient fuel icing test. The bypass solenoid valve is connected to the main fuel supply circuit and is connected in parallel with the test piece. The bypass solenoid valve is connected to the fuel supply pressure sensor and is used to adjust according to the measurement data of the fuel supply pressure sensor.

2. The online water injection system for fuel oil icing tests according to claim 1, characterized in that, The online fuel water injection system for fuel icing tests also includes a main fuel supply pump and a main flow meter; the main fuel supply pump and the main flow meter are installed on the main fuel supply line and are located upstream of the steady-state nozzle; the main fuel supply pump and the main flow meter are connected, and the main fuel supply pump is used to adjust according to the measurement data of the main flow meter.

3. The online water injection system for fuel oil icing tests according to claim 2, characterized in that, The main flow meter is connected to the steady-state water injection cylinder, which is used to adjust the flow based on the measurement data of the main flow meter and the fuel water content ratio.

4. The online water injection system for fuel oil icing tests according to any one of claims 1-3, characterized in that, The online water injection system for fuel icing tests also includes a working flow meter, which is installed on the main fuel supply line and located downstream of the test specimen. The working flow meter is connected to the transient water injection cylinder, which is used to adjust the system according to the measurement data of the working flow meter and the fuel water content ratio.

5. The online water injection system for fuel oil icing tests according to any one of claims 1-3, characterized in that, The online fuel water injection system for fuel icing tests further includes a protective oil tank, a protective oil pump, a heater, and a two-position three-way valve. The protective oil tank, the protective oil pump, and the heater are connected in sequence. The two-position three-way valve is connected to the heater, the steady-state nozzle, and the transient nozzle. The two-position three-way valve is used to control the connection between the heater and the steady-state nozzle, or to control the connection between the heater and the transient nozzle, so as to heat the steady-state nozzle or the transient nozzle.

6. The online water injection system for fuel oil icing tests according to claim 5, characterized in that, The steady-state nozzle is provided with a first fuel channel, a first protective oil channel, and a first water supply channel. The first fuel channel is connected to the main fuel supply line, the first protective oil channel is disposed in the first fuel channel, and the first protective oil channel is connected to the outlet of the two-position three-way valve. One end of the water supply line is connected to the steady-state water injection cylinder, and the other end of the water supply line extends into the first protective oil channel, which is used to heat the water supply line.

7. The online water injection system for fuel oil icing tests according to claim 6, characterized in that, The transient nozzle is provided with a second fuel channel, a second protective oil channel, and a second water supply channel. The second fuel channel is connected to the main fuel supply line, and the second protective oil channel is located inside the second fuel channel and is connected to the outlet of the two-position three-way valve. One end of the water supply line is connected to the steady-state water injection cylinder, and the other end of the water supply line extends into the second protective oil channel, which is used to heat the water supply line.

8. The online water injection system for fuel oil icing tests according to claim 5, characterized in that, The online fuel water injection system for fuel icing tests also includes a temperature sensor; both the steady-state nozzle and the transient nozzle are equipped with temperature sensors at their outlets. The temperature sensors are connected to the heater, which is used to adjust the heater based on the measurement data from the temperature sensors, so that the outlet temperature of the steady-state nozzle is 1-3°C under steady-state conditions, or the outlet temperature of the transient nozzle is 1-3°C under transient conditions.

9. The online water injection system for fuel oil icing tests according to claim 1, characterized in that, The online water injection system for fuel icing tests also includes a static mixer; the static mixer is located on the main fuel supply line and is situated between the steady-state nozzle and the transient nozzle.

10. A method for online water injection into fuel for fuel icing tests, characterized in that, The online water injection method for fuel icing test is implemented using the online water injection system for fuel icing test as described in any one of claims 1-9; In the case of steady-state fuel icing test, the steady-state water injection cylinder is activated, and the steady-state water injection cylinder injects water into the steady-state nozzle at a stable water injection rate; In the case of transient fuel icing test, the transient water injection cylinder is activated, and the transient water injection cylinder injects water into the transient nozzle at a continuously varying injection rate.

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