A ground experimental system for a supersonic combustion chamber injecting supercritical kerosene

Abstract

This application belongs to the field of combustion chamber experiment technology and relates to a supersonic combustion chamber ground experiment system for injecting supercritical kerosene. The system comprises: a supersonic combustion chamber, a fuel supply device, and a fuel injection device. The fuel supply device is connected to the fuel injection device so that the fuel supply device supplies fuel to the fuel injection device. The fuel injection device is located near a concave cavity on the isolation section of the supersonic combustion chamber to inject supercritical kerosene. The system also comprises: a nitrogen purge device connected to the fuel supply device. The fuel supply device comprises: a kerosene fuel storage tank, a kerosene fuel pipeline, and a kerosene heater. The kerosene fuel storage tank is connected to the kerosene fuel pipeline to enable kerosene fuel transmission. The kerosene heater is spaced outside the kerosene fuel pipeline so that the kerosene heater heats the supercritical kerosene in the kerosene fuel pipeline. The kerosene fuel pipeline is also connected to the fuel injection device. This application enables precise control of kerosene temperature.

Description

Technical Field

[0001] The present application relates to the field of combustion chamber experimental technology, and in particular to a ground experimental system for a supersonic combustion chamber injecting supercritical kerosene. Background Art

[0002] With the progress of science and the development of technology, kerosene injection technology in supersonic combustion chambers has been increasingly studied.

[0003] In a study of the injection and combustion characteristics of vaporized kerosene in a supersonic airflow, the kerosene was heated using a gas generator. During the hot kerosene preparation process, the oxidant and fuel are fully combusted within the gas generator's combustion chamber to generate high-temperature fuel gas. This high-temperature fuel gas flows through the gas generator nozzle into the heat exchange chamber and exchanges heat with the kerosene through the heat exchange tubes, thereby heating the kerosene. However, this existing heating method, which relies on combustion, makes it difficult to precisely control the kerosene temperature, and the hot kerosene suffers from significant temperature losses during flow.

[0004] In the study of the ignition and combustion characteristics of vaporized kerosene in supersonic airflow, a two-stage electric heating device was used to heat the kerosene. During the experimental preparation phase, kerosene that had not reached the desired temperature after primary heating was directed through a control valve into a cooling and exhaust path. Once the heating stabilized, a pipeline switch allowed the heated kerosene to enter the secondary heating section, ensuring the supply of hot kerosene within the supersonic combustion chamber. However, due to experimental constraints, this technology resulted in a high time and cost for preparing the hot kerosene and a lack of effective insulation. Furthermore, the maximum kerosene outlet temperature could only reach 700K, limiting the scope of research on the supercritical temperature range and cracked kerosene.

[0005] Another study also used a two-stage electric heating system to prepare supercritical kerosene. The first-stage heater heated kerosene at a flow rate of 15 g / s to 520 K with negligible coking. A second-stage heater rapidly heated the kerosene to 760 K within 1 second. Furthermore, a heating band with a maximum temperature of 600°C was used to compensate for heat loss between the heater outlet and the nozzle inlet. However, this method limited the temperature compensation range and made it difficult to precisely control the final kerosene injection temperature.

[0006] Therefore, the existing technology still has the following problems: (1) Traditional gas generators prepare supercritical kerosene by combustion heating. Since it is difficult to accurately control the three components during the preparation process, the temperature and state of the kerosene at the heater outlet cannot be guaranteed to be consistent with the expected conditions, thereby affecting the final experimental results; (2) Providing supercritical kerosene for the supersonic combustion chamber requires connecting it to the kerosene heater through a stainless steel pipeline and using a sonic nozzle to achieve injection. However, a large heat loss will be generated during the transportation of the supercritical kerosene, so that the kerosene temperature at the heater outlet and the combustion chamber inlet is very different. Summary of the Invention

[0007] Based on this, it is necessary to provide a ground experimental system for a supersonic combustion chamber that injects supercritical kerosene to address the above technical problems, which can achieve precise control of the temperature and state of kerosene in the supersonic combustion chamber, and at the same time insulate and temperature compensate the fuel pipeline.

[0008] A supersonic combustion chamber ground experimental system for injecting supercritical kerosene, comprising: a supersonic combustion chamber, a fuel supply device, and a fuel injection device;

[0009] The fuel supply device is connected to the fuel injection device so that the fuel supply device provides fuel to the fuel injection device;

[0010] The fuel injection device is arranged on the isolation section of the supersonic combustion chamber near the concave cavity to inject supercritical kerosene.

[0011] In one embodiment, the invention further comprises: a nitrogen blowing device;

[0012] The nitrogen blowing device is connected to the fuel supply device.

[0013] In one embodiment, the fuel supply device includes: a kerosene fuel storage tank, a kerosene fuel pipeline, and a kerosene heater;

[0014] The kerosene fuel storage tank is connected to the kerosene fuel pipeline to achieve the transmission of kerosene fuel;

[0015] The kerosene heater is arranged between the kerosene fuel storage tank and the fuel injection device, and is spaced and sleeved on the outside of the kerosene fuel pipeline, so that the kerosene heater heats the liquid kerosene in the kerosene fuel pipeline to a supercritical state;

[0016] The kerosene fuel pipeline is also connected to the fuel injection device, and the outer side of the kerosene fuel pipeline is provided with a multifunctional flexible heat insulation sleeve.

[0017] In one embodiment, the kerosene heater comprises: a kerosene heater furnace and a kerosene heater resistance wire;

[0018] The kerosene heater resistance wire is sleeved at intervals on the outside of the kerosene fuel pipeline, and the kerosene heater furnace is sleeved at intervals on the outside of the kerosene heater resistance wire to heat the kerosene to a supercritical state.

[0019] In one embodiment, the kerosene heater is an integrated thermal medium type electric heater.

[0020] In one embodiment, the fuel injection device includes: a connecting structure, a sonic nozzle, and a pipe joint connected in sequence;

[0021] The connecting structure is connected to the fuel injection device;

[0022] A fuel channel is provided inside the sonic nozzle to allow kerosene heated to a supercritical state to enter the supersonic combustion chamber;

[0023] The pipe joint is connected to the fuel supply device.

[0024] In one embodiment, the sonic nozzle is a transverse fuel nozzle.

[0025] In one embodiment, the fuel injection device further comprises: a heat-insulating structure;

[0026] The heat insulation structure is arranged inside the sonic nozzle to reduce heat loss during the fuel injection process.

[0027] In one embodiment, the thermal insulation structure uses nitrogen or silica aerogel.

[0028] In one embodiment, the fuel injection device further comprises: a temperature measurement structure;

[0029] The temperature measurement structure is arranged on the side wall of the sonic nozzle to monitor the fuel temperature of the sonic nozzle in real time to ensure that it meets the experimental requirements.

[0030] The above-mentioned supersonic combustion chamber ground experimental system for injecting supercritical kerosene addresses the problems of large fuel heat loss and difficulty in controlling the outlet temperature and kerosene state during the injection of supercritical kerosene in traditional supersonic combustion chamber ground experimental systems. The kerosene is heated by an integrated heat medium type electric heater. The electric heater can accurately control the temperature and flow of the hot kerosene through numerical control equipment. The insulation and heating process has the advantages of small size, easy installation and use, and long service life, thereby ensuring that the kerosene at the inlet of the combustion chamber can reach the ideal state. A flexible insulation sleeve is used to insulate and temperature compensate the fuel pipeline, and a sonic transverse fuel nozzle is used in combination with an insulation structure and a temperature measurement structure for injection in the supersonic combustion chamber, thereby reducing the experimental The heat loss of the test system during the supply of supercritical kerosene has a good insulation effect, which can achieve precise control of the temperature and state of kerosene in the supersonic combustion chamber, thereby enhancing the mixing efficiency of hydrocarbon fuel scramjet engines and improving combustion performance; at the same time, the system also includes a high-pressure nitrogen purge device, which is connected between the kerosene heater and the kerosene storage tank. It can purge the residual and coked kerosene in the pipeline before and after use to ensure that the heating system is unobstructed and the fuel nozzle flow coefficient is stable; in addition, flow meters, thermocouples and other components can be used to connect the heater CNC system to achieve precise control of the supercritical kerosene flow and temperature. During the experiment, the error between the heater set temperature and the supersonic combustion chamber inlet temperature does not exceed ±5%. This application can conduct cold flow field and combustion flow field ground experiments of supercritical kerosene injection in supersonic combustion chambers, and can keep the fuel warm throughout the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a ground experimental system for a supersonic combustion chamber injecting supercritical kerosene according to an embodiment;

[0032] Figure 2 A schematic diagram of a fuel injection device of a ground experimental system for a supersonic combustion chamber that injects supercritical kerosene according to an embodiment;

[0033] Figure 3 The figure is a schematic diagram of the dimensions of a fuel injection device of a ground experimental system for a supersonic combustion chamber that injects supercritical kerosene in one embodiment.

[0034] Reference numerals:

[0035] 1 supersonic combustion chamber, 1-1 isolation section, 1-2 concave cavity, 1-3 expansion section;

[0036] 2 fuel supply device, 2-1 kerosene fuel pipeline, 2-2 kerosene fuel storage tank, 2-3 kerosene heater furnace, 2-4 kerosene heater resistance wire;

[0037] 3 fuel injection device, 3-1 connection structure, 3-2 fuel channel, 3-3 insulation structure, 3-4 pipe joint, 3-5 temperature measurement structure, 3-6 sonic nozzle;

[0038] 4. Nitrogen blowing device;

[0039] d0 sonic nozzle orifice diameter, d1 fuel channel diameter, d2 insulation structure thickness, d3 connecting structure diameter, d4 sonic nozzle diameter. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in this application without creative work are within the scope of protection of this application.

[0041] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the terms "first," "second," and so on, used in this application are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "multiple groups" means at least two groups, such as two groups, three groups, and so on, unless otherwise specifically defined.

[0043] In this application, unless otherwise specified or limited, the terms "connect," "fix," etc. should be understood in a broad sense. For example, "fix" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two elements or an interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0044] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0045] This application provides a ground experimental system for a supersonic combustion chamber injecting supercritical kerosene, such as Figures 1 to 3 As shown, in one embodiment, it includes: a supersonic combustion chamber, a fuel injection device, a fuel supply device and a nitrogen purge device.

[0046] The supersonic combustion chamber is connected to a fuel injection device so that the fuel injection device injects supercritical kerosene into the supersonic combustion chamber. The supersonic combustion chamber includes an isolation section, a concave cavity and an expansion section which are connected in sequence.

[0047] The fuel injection device is connected to the supersonic combustion chamber and the fuel supply device respectively. Specifically, the fuel injection device is located near the concave cavity on the isolation section of the supersonic combustion chamber, for example, near the concave cavity downstream of the isolation section, to inject supercritical kerosene. The fuel injection device includes: a connecting structure, a sonic nozzle, a pipe joint, a thermal insulation structure, and a temperature measurement structure. The connecting structure, sonic nozzle, and pipe joint are connected in sequence. The connecting structure is connected to the supersonic combustion chamber, and a sonic nozzle orifice is provided in the center of the connecting structure. A fuel channel is provided inside the sonic nozzle, connected to the sonic nozzle orifice, so that kerosene heated to a supercritical state can enter the supersonic combustion chamber. The pipe joint is connected to the fuel supply device and can use a DN4 pipe joint. The thermal insulation structure is divided into two layers and embedded in the sonic nozzle and located outside the fuel channel to reduce heat loss during fuel injection. The temperature measurement structure is located on the side wall of the sonic nozzle to monitor the fuel temperature in the sonic nozzle in real time to ensure that it meets experimental requirements.

[0048] Preferably, the sonic nozzle is a transverse fuel nozzle.

[0049] Further preferably, the thermal insulation structure uses nitrogen or silica aerogel.

[0050] More preferably, the temperature measurement structure adopts a K-type thermocouple to achieve a temperature measurement range of -200 to 1300°C and a temperature measurement accuracy of ≤±1°C.

[0051] The fuel supply device is connected to the fuel injection device and the nitrogen purge device, respectively, to supply fuel to the fuel injection device. The fuel supply device includes a kerosene fuel storage tank, a kerosene fuel pipeline, and a kerosene heater. The kerosene fuel storage tank is connected to the kerosene fuel pipeline to enable the transmission of kerosene fuel. The kerosene fuel pipeline is annularly coiled and also connected to the fuel injection device. The outer surface of the kerosene fuel pipeline is sheathed with a multifunctional flexible thermal insulation sleeve. The kerosene heater is located between the kerosene fuel storage tank and the fuel injection device and is spaced apart and sheathed on the outer surface of the kerosene fuel pipeline. The kerosene heater heats the liquid kerosene in the kerosene fuel pipeline to a supercritical state, with a maximum temperature of 1200°C. The kerosene heater includes: a kerosene heater resistance wire and a kerosene heater furnace; the kerosene heater resistance wire is spaced and arranged on the outside of the kerosene fuel pipeline, and the kerosene heater furnace is spaced and arranged on the outside of the kerosene heater resistance wire, that is, the kerosene heater resistance wire is arranged on the inner wall of the kerosene heater furnace, and is distributed on the left and right sides of the furnace for heating to heat the kerosene to a supercritical state.

[0052] Preferably, the kerosene heater adopts an integrated heat medium electric heater, which is a high-quality, long-life heating device that can insulate and heat flowing liquid and gaseous media. When the heating medium passes through the heating cavity of the electric heater under pressure, it evenly takes away the huge heat generated by the electric heating element during operation, so that the temperature of the heated medium reaches the requirement and the temperature loss during the fuel transmission process is reduced.

[0053] Further preferably, the resistance wire of the kerosene heater is made of OCr27Al7Mo2 material.

[0054] More preferably, the kerosene heater furnace adopts a lightweight alumina zirconium fiber furnace to achieve better thermal insulation performance and higher tensile strength.

[0055] More preferably, the multifunctional flexible thermal insulation sleeve consists of a temperature compensation layer, an oxide fiber layer, an aerogel layer, and an insulating rubber layer. The temperature compensation layer is placed in the innermost layer of the multifunctional flexible thermal insulation sleeve, in direct contact with the kerosene fuel pipeline. The material is preferably a glass fiber electric heating tape, preferably 5mm thick. The oxide fiber layer is wrapped around the temperature compensation layer, preferably made of alumina fiber, preferably 5mm thick. The aerogel layer is wrapped around the oxide fiber layer, preferably made of silica aerogel, preferably 5mm thick. The insulating rubber layer is wrapped around the aerogel layer, reinforcing the flexible thermal insulation sleeve as a whole, and preferably has a thickness of 10mm.

[0056] The nitrogen purge device is connected to the fuel supply device to clean the residual and coked kerosene in the pipeline before and after the kerosene heater is operated, ensuring that the hot kerosene at the outlet of the kerosene heater will not be affected by the previous operation. Specifically, the nitrogen purge device is located between the kerosene fuel storage tank and the kerosene fuel pipeline. The upstream gas source pressure of the nitrogen purge device is 2.0MPa≤P N ≤3.0MPa, preferably 2.5MPa, to ensure that residual fuel and coking materials inside the pipeline can be removed and that the device will not be damaged due to excessive purge gas pressure.

[0057] In a specific embodiment, the total length of the annularly coiled kerosene fuel pipeline inside the kerosene heater satisfies 16000mm≤10≤17000mm, preferably 16500mm, to ensure that the fuel has sufficient time to be heated during transportation, and the space occupied by the internal pipeline of the heater does not exceed the furnace limit; the length of the pipeline between the kerosene heater and the supersonic combustion chamber satisfies 1000mm≤11≤2000mm, preferably 1500mm, to ensure that the heater and the combustion chamber do not interfere with each other during operation, the transported fuel will not increase heat loss and generate additional costs due to the excessive length of the pipeline, and a multifunctional flexible insulation sleeve must be externally packaged for insulation; The nozzle hole diameter of the supersonic nozzle satisfies 0.3mm≤d0≤1.0mm, preferably 0.5mm, to ensure that it can meet the simulation of the common engine working equivalence ratio; the fuel channel diameter d1 is preferably 2mm; the insulation structure thickness d2 is preferably 2mm; the connection structure diameter d3 is preferably 7mm, and its outer surface must be tapped with M7 threads to match the screw holes at the bottom of the supersonic combustion chamber. A copper gasket can be used at its lower end to seal the matching gap to ensure good airtightness during the experiment; the sonic nozzle diameter d4 is preferably 10mm, and a screw-type mounting structure is selected to pass through the sonic nozzle and the insulation structure, so that the temperature probe can directly enter the fuel channel for measurement.

[0058] The above-mentioned supersonic combustion chamber ground experimental system for injecting supercritical kerosene addresses the problems of large fuel heat loss and difficulty in controlling the outlet temperature and kerosene state during the injection of supercritical kerosene in traditional supersonic combustion chamber ground experimental systems. The kerosene is heated by an integrated heat medium type electric heater. The electric heater can accurately control the temperature and flow of the hot kerosene through numerical control equipment. The insulation and heating process has the advantages of small size, easy installation and use, and long service life, thereby ensuring that the kerosene at the inlet of the combustion chamber can reach the ideal state. A flexible insulation sleeve is used to insulate and temperature compensate the fuel pipeline, and a sonic transverse fuel nozzle is used in combination with an insulation structure and a temperature measurement structure for injection in the supersonic combustion chamber, thereby reducing The experimental system has a good insulation effect in the process of supplying supercritical kerosene, which can achieve precise control of the temperature and state of kerosene in the supersonic combustion chamber, thereby enhancing the mixing efficiency of hydrocarbon fuel scramjet engines and improving combustion performance. At the same time, the system also includes a high-pressure nitrogen purge device, which is connected between the kerosene heater and the kerosene storage tank. It can purge residual and coked kerosene in the pipeline before and after use to ensure that the heating system is unobstructed and the fuel nozzle flow coefficient is stable. In addition, flow meters, thermocouples and other components can be used to connect the heater CNC system to achieve precise control of the supercritical kerosene flow and temperature. During the experiment, the error between the heater set temperature and the supersonic combustion chamber inlet temperature does not exceed ±5%. This application can conduct cold flow field and combustion flow field ground experiments of supercritical kerosene injection in supersonic combustion chambers, and can keep the fuel warm throughout the experiment.

[0059] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A ground experimental system for a supersonic combustion chamber injecting supercritical kerosene, characterized in that: include: Supersonic combustion chamber, fuel supply device and fuel injection device; The fuel supply device is connected to the fuel injection device so that the fuel supply device provides fuel to the fuel injection device; The fuel injection device is arranged on the isolation section of the supersonic combustion chamber near the concave cavity to inject supercritical kerosene; Also included: a nitrogen purge device; The nitrogen blowing device is connected to the fuel supply device; The fuel supply device includes: a kerosene fuel storage tank, a kerosene fuel pipeline and a kerosene heater; The kerosene fuel storage tank is connected to the kerosene fuel pipeline to achieve the transmission of kerosene fuel; The kerosene heater is arranged between the kerosene fuel storage tank and the fuel injection device, and is spaced and sleeved on the outside of the kerosene fuel pipeline, so that the kerosene heater heats the liquid kerosene in the kerosene fuel pipeline to a supercritical state; The kerosene fuel pipeline is also connected to the fuel injection device, and the outer side of the kerosene fuel pipeline is provided with a multifunctional flexible heat insulation sleeve; The kerosene heater comprises: a kerosene heater furnace and a kerosene heater resistance wire; The kerosene heater resistance wire is sleeved at intervals on the outside of the kerosene fuel pipeline, and the kerosene heater furnace is sleeved at intervals on the outside of the kerosene heater resistance wire to heat the kerosene to a supercritical state; The fuel injection device includes: a connecting structure, a sonic nozzle, a pipe joint, a thermal insulation structure, and a temperature measurement structure, wherein the connecting structure, the sonic nozzle, and the pipe joint are connected in sequence; the connecting structure is connected to the supersonic combustion chamber, and a sonic nozzle nozzle hole is provided in the center of the connecting structure; a fuel channel is provided inside the sonic nozzle, connected to the sonic nozzle nozzle hole, so that kerosene heated to a supercritical state can enter the supersonic combustion chamber; the pipe joint is connected to the fuel supply device; the thermal insulation structure is divided into two layers and embedded in the sonic nozzle and located outside the fuel channel to reduce heat loss during the fuel injection process; the temperature measurement structure is provided on the side wall of the sonic nozzle to monitor the fuel temperature of the sonic nozzle in real time to ensure that it meets the experimental requirements; The multifunctional flexible thermal insulation sleeve consists of a temperature compensation layer, an oxide fiber layer, an aerogel layer and a thermal insulation rubber layer. The temperature compensation layer is placed in the innermost layer of the multifunctional flexible thermal insulation sleeve, the oxide fiber layer is wrapped around the temperature compensation layer, the aerogel layer is wrapped around the oxide fiber layer, and the thermal insulation rubber layer is wrapped around the aerogel layer.

2. A supersonic combustion chamber ground experimental system for injecting supercritical kerosene according to claim 1, characterized in that: The kerosene heater adopts an integrated thermal medium type electric heater.

3. A supersonic combustion chamber ground experimental system for injecting supercritical kerosene according to claim 1 or 2, characterized in that: The sonic nozzle is a transverse fuel nozzle.

4. A supersonic combustion chamber ground experimental system for injecting supercritical kerosene according to claim 1 or 2, characterized in that: The thermal insulation structure adopts nitrogen or silicon dioxide aerogel.

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