High-temperature turbulent environment particle ignition combustion testing device based on rotational flow flame stabilization

Abstract

The invention discloses a high-temperature turbulent environment particle ignition combustion testing device based on rotational flow flame stabilization, and belongs to the field of combustion testing. The burner is composed of an external rotational flow flame stabilizing device, a central premixing burner, an adjustable turbulence intensity pore plate and a central powder supply pipe. High-temperature and high-speed methane turbulence flames are generated through the central premixing burner, flame stabilization is conducted on the high-temperature and high-speed turbulence flames through the external rotational flow flame stabilization device, and the turbulence intensity of the flames is improved. A high-speed turbulent flow field and a high-temperature flue gas range are constructed through high-temperature and high-speed methane flames, combustion of aluminum particles in the turbulent flow field is achieved, and the combustion rule of the aluminum particles in a complex flow field is researched and tested. The turbulence intensity of high-temperature and high-speed turbulence flame is changed by changing the pore density and the pore diameter of the adjustable turbulence intensity pore plate, and the gas ratio in the central premixing combustor, so that simulation of different fuel gas oxygen enrichment degrees, turbulence intensities and flame temperatures is realized, and test analysis of different turbulence intensities on the combustion process of condensed phase particles is realized.

Description

Technical Field

[0001] The invention relates to a high-temperature turbulent environment particle ignition and combustion testing device based on swirl flame stabilization, and belongs to the field of combustion testing. Background Art

[0002] In power systems such as solid rocket engines and powder ramjets, solid particles usually burn in the form of particle clouds, and the interactions and transport patterns between particles are complex. Solid particles such as Al, B, coal powder, and biomass undergo phase change, agglomeration, ignition, and combustion in the engine. In addition, factors such as complex flow field structures and turbulence make engine combustion research very challenging.

[0003] The engine is usually a complex turbulent environment, and the interaction and transport laws between particles and high-temperature airflow are quite complex. Due to the high-temperature, high-pressure turbulent conditions and thick smoke obscuration in the engine, it is currently impossible to use reliable experimental methods to capture the combustion details of solid particles in the engine. In actual engineering tests, the pressure of the combustion chamber and the two-phase flow field outside the engine outlet are mainly measured. The research on the ignition and combustion process of aluminum particles in the combustion chamber is relatively scarce, and it is impossible to conduct effective experimental research on the influence of strong turbulence effects in the combustion chamber flow field area and the nozzle diving section on the combustion flow process of condensed phase particles. When studying the influence of complex flow fields on particle combustion, it is difficult to flexibly control the turbulence intensity by directly conducting engine tests, and the experimental difficulty and cost are high. Summary of the invention

[0004] In order to solve the problem that it is difficult to directly explore the combustion law of aluminum particles in a complex flow field through engine tests, the purpose of the present invention is to provide a high-temperature turbulent environment particle ignition combustion test device based on swirl flame stabilization, which consists of four parts: an external swirl flame stabilization device, a central premixed burner, an adjustable turbulence intensity orifice plate, and a central powder supply tube. A high-temperature and high-speed methane turbulent flame is generated by the central premixed burner, and the high-temperature and high-speed turbulent flame is stabilized by the external swirl flame stabilization device, while the turbulence intensity of the flame is increased. The device constructs a high-speed turbulent field and a high-temperature flue gas range through a high-temperature and high-speed methane flame, thereby realizing the combustion of aluminum particles in a turbulent field, and studying and testing the combustion law of aluminum particles in a complex flow field. The device can change the turbulence intensity of the high-temperature and high-speed turbulent flame by changing the hole density and aperture of the adjustable turbulence intensity orifice plate, and can simulate different fuel gas oxygen enrichment, turbulence intensity, and flame temperature by changing the gas ratio in the central premixed burner, and realize the analysis of the combustion process of condensed phase particles with different turbulence intensities, and realize the independent adjustment of each operating condition parameter. The invention also has the advantages of low experimental cost, convenient operation and high realization efficiency.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The invention discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization, comprising a coaxially mounted external swirl flame stabilization device, a central premixing burner, an adjustable turbulence intensity orifice plate and a central powder supply pipe.

[0007] The external swirl flame stabilization device is a hollow square structure, including four external swirl flame stabilization inlets and four external swirl flame stabilization outlets. The external swirl flame stabilization inlets are evenly distributed along the tangential direction, and the external swirl flame stabilization outlets are coaxial with the external swirl flame stabilization inlets.

[0008] The central premix burner is a hollow cylindrical structure, including two radial inlets of the burner and one burner outlet. The two radial inlets of the burner are symmetrically distributed along the radial direction and are located at the front end of the adjustable turbulence intensity orifice plate; the burner outlet is arranged along the axial direction.

[0009] The adjustable turbulence intensity orifice plate is a hollow cylinder with uniform holes, which can adjust the turbulence intensity.

[0010] The central powder supply pipe is a hollow cylindrical structure with a mounting seat, and has a powder supply inlet and a powder supply outlet. The hollow cylinder in the direction of the powder supply outlet passes through the center of the adjustable turbulence intensity orifice plate.

[0011] The powder supply outlet of the central powder supply pipe is flush with the burner outlet of the central premixing burner, and the two form an annular outlet of the axial jet; the external swirl flame stabilization outlet is located above the burner outlet.

[0012] The high-velocity flame is stabilized by using external air swirl, and the Reynolds number can be controlled by changing the center gas velocity. The turbulence intensity of the flame can be adjusted to a specified value by changing the hole density and hole size of the adjustable turbulence intensity orifice plate inside the center premixed burner, thereby achieving a stable and controllable turbulent flame:

[0013]

[0014] Where I is the turbulence intensity, ρ, v, μ are the density, velocity and viscosity coefficient of the fluid, d is the characteristic length, and α is the conversion coefficient between the Reynolds number Re and the turbulence intensity. The turbulence intensity can be changed by changing the hole density x and hole size r of the adjustable turbulence intensity orifice plate. Thereby changing the turbulence intensity, where L is the gas volume flow rate.

[0015] Preferably, the number of the adjustable turbulence intensity orifice plate is at least one.

[0016] Preferably, when the number of adjustable turbulence intensity orifice plates is 2, the two porous plates are respectively located behind the burner outlet and in front of the air inlet; the adjustable turbulence intensity orifice plates are a porous plate with a thickness of 10 mm and a thickness of 5 mm, and the 35 holes of the porous plate are evenly distributed from the inside to the outside, and the hole diameter is 1 mm.

[0017] The method for performing a combustion test using the device comprises the following steps:

[0018] Step 1: The fuel is introduced into the burner along the radial inlet of the burner from one side of the central premixing burner, and the oxidant and air are introduced into the burner along the radial inlet of the burner from the other side of the central premixing burner, and ignited at the combustion chamber outlet at the same time to form a premixed jet flame.

[0019] Step 2: Air is introduced into the external swirl flame stabilization device from the external swirl flame stabilization device's ...

[0020] Step three: increase the volume flow rates of fuel, air and oxidant introduced into the central premix burner according to predetermined conditions; then, increase or decrease the volume flow rate of air introduced into the external swirl flame stabilizing device according to predetermined conditions. By increasing or decreasing the mass flow rate of air in the mixed gas of fuel and oxidant introduced into the central premix burner, the oxygen concentration can be controlled, stable combustion between oxygen-poor and oxygen-rich can be achieved, and the flame temperature can be changed, thereby forming a high-temperature or ultra-high-temperature flame.

[0021] Step 4: When the flame reaches the specified experimental conditions and stabilizes, the solid particles to be analyzed are introduced through the central powder supply pipe, the particles are ignited, and the combustion morphology of the particles is analyzed.

[0022] Beneficial effects:

[0023] 1. The present invention discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization. The device utilizes the combustion characteristics and flow characteristics of a premixed flame to radially introduce fuel and oxidant to form a premixed flame. A controlled and stable turbulent flame is formed through two adjustable turbulence intensity orifice plates inside the burner to ensure the mixing degree of the premixed flame. By adjusting the hole density, hole diameter and porous plate thickness of the two internal adjustable turbulence intensity orifice plates, a turbulent flame with the required turbulence intensity can be formed according to experimental conditions.

[0024] 2. The present invention discloses a high-temperature turbulent environment particle ignition combustion test device based on swirl flame stabilization. The external swirl flame stabilization device introduces air through four external swirl flame stabilization inlets and ejects it from the central axis to form a stable air swirl. The formed air swirl can ensure that the turbulent flame can also suck in enough oxidant at the root of the flame for combustion under the condition of high flow rate. At the same time, the stable swirl gas with adjustable flow rate can also increase the turbulence of the turbulent flame, thereby obtaining the turbulence intensity required by the experimental conditions.

[0025] 3. The present invention discloses a high-temperature turbulent environment particle ignition combustion test device based on swirl flame stabilization, in which the flame temperature can be controlled by changing the oxygen concentration. By changing the fuel / air ratio introduced into the central premix burner and adjusting the oxygen concentration of the fuel gas, stable combustion under oxygen-poor to oxygen-rich conditions can be achieved, forming stable turbulent flames of different temperatures.

[0026] 4. The present invention discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization, which can change the Reynolds number of the turbulent flame by changing the gas flow rate entering the central premixed burner to obtain the required experimental conditions.

[0027] 5. The present invention discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization. Through reasonable premixed combustion structure design and premixing ratio of oxidant and fuel, the combustion efficiency is effectively improved to achieve the effect of saving fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization;

[0029] Figure 2 This is a right view of a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization;

[0030] Figure 3 This is a schematic diagram of the central premix burner structure;

[0031] Figure 4 It is a schematic diagram of the structure of the orifice plate with adjustable turbulence intensity;

[0032] Figure 5 A three-dimensional schematic diagram of a turbulent burner.

[0033] Among them, 1-external swirl flame stabilization device, 2-adjustable turbulence intensity orifice plate, 3-central premixing burner, 4-central powder supply pipe, 5-powder supply inlet, 6-burner radial inlet, 7-external swirl flame stabilization inlet, 8-external swirl flame stabilization outlet, 9-powder supply outlet, 10-burner outlet. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose and advantages of the present invention, the specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings.

[0035] Embodiment 1:

[0036] The present embodiment discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization. The flow characteristics and stability of swirl gas are used to introduce air from the external swirl flame stabilization inlet of the external swirl flame stabilization device, and the air swirl is ejected from the external swirl flame stabilization outlet. The flow characteristics of the tangential swirl can ensure that the air swirl formed by the external swirl flame stabilization device can ensure that the central premixed flame can draw in enough air for combustion during the combustion process, thereby preventing the flame from being extinguished due to the low oxidant concentration at the flame root when the gas flow rate is too fast. At the same time, the high-speed swirl gas can also speed up the gas flow rate of the central flame, thereby adjusting the required turbulence intensity. In addition, the cold high-speed When the swirl gas provides oxidant to the central turbulent flame, it can effectively prevent the heat generated by the flame from being transferred to the combustion device, further achieving a self-cooling effect, fundamentally avoiding the problem of flame ablation of the burner, and significantly extending the service life of the burner; using two adjustable turbulence intensity orifice plates inside the central premix burner to enhance the turbulence intensity and mixing effect of the turbulent flame, maintain stable combustion, and adjust the required turbulence intensity according to experimental conditions; by increasing or decreasing the mass flow rate of air in the mixture of fuel and oxidant entering the central premix burner, the oxygen concentration can be controlled to achieve stable combustion between oxygen-poor and oxygen-rich, and change the flame temperature, thereby forming a high-temperature or ultra-high-temperature flame.

[0037] Embodiment 2:

[0038] like Figure 1 As shown, this embodiment discloses a high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization, including an external swirl flame stabilization device 1, an adjustable turbulence intensity orifice plate 2, a central premix burner 3, and a central powder supply pipe 4.

[0039] Among them, the external tangential swirl flame stabilization device 1 is a hollow square structure, including four external swirl flame stabilization inlets 7 and four external swirl flame stabilization outlets 8. The external swirl flame stabilization inlet 7 is evenly distributed along the tangent, is rectangular, and is coaxial with the external swirl flame stabilization outlet 8; the central premixing burner 3 is a hollow cylindrical structure, including two burner radial inlets 6 and a burner outlet 10. The two burner radial inlets 6 are symmetrically distributed along the radial direction, and the burner outlet 10 is along the axial direction; the adjustable turbulence intensity orifice plate 2 is a porous plate with a thickness of 10 mm and a thickness of 5 mm. The 35 holes of the porous plate are evenly distributed from the inside to the outside, and the aperture is 1 mm; the central powder supply pipe 4 is a hollow cylindrical structure, including a powder supply inlet 5 and a powder supply outlet 9, both of which are distributed along the axial direction and are circular.

[0040] The powder supply outlet 9 of the central powder supply pipe 4 is flush with the burner outlet 10 of the central premixing burner 3 , and the two form an annular outlet for axial jet. The two adjustable turbulence intensity orifice plates 2 are respectively located behind the burner outlet 10 and in front of the radial inlet 6 of the burner. The external swirl flame stabilizing outlet 8 of the external swirl flame stabilizing device 1 is located above the burner outlet 10 of the central premixing burner 3 .

[0041] The external swirl flame stabilizing device 1, the adjustable turbulence intensity orifice plate 2, the central premixing burner 3, and the central powder supply pipe 4 are coaxially installed.

[0042] The working method of a high-temperature turbulent environment particle ignition combustion test device based on swirl flame stabilization disclosed in this embodiment is as follows: first, a small amount of fuel, air and oxidant are introduced into the central premix burner 3, and ignited at the combustion chamber outlet 10 at the same time to form a premixed jet flame; then, air is introduced into the external swirl flame stabilization device 1; then, the volume flow rate of the fuel, air and oxidant introduced into the central premix burner 3 is increased according to predetermined conditions; finally, the volume flow rate of air introduced into the external swirl flame stabilization device 1 is increased or decreased according to predetermined conditions. The premixed flame generated inside the central premix burner 3 and the swirl gas generated by the external swirl flame stabilization device 1 eventually form a stable turbulent flame.

[0043] By reducing the mass flow rate of air in the mixture of fuel and oxidant entering the central premix burner 1, the oxygen concentration can be controlled, stable combustion from oxygen-poor to oxygen-rich can be achieved, and the flame temperature can be increased, thereby forming a high-temperature or ultra-high-temperature flame.

[0044] The flow characteristics of the tangential swirl can ensure that the air swirl formed by the external swirl flame stabilizing device 1 can ensure that the central premixed flame can draw in enough air for combustion during the combustion process, preventing the flame from being extinguished due to the low oxidant concentration at the root of the flame when the gas flow rate is too fast. At the same time, the high-speed swirl gas can also speed up the gas flow rate of the central flame, thereby regulating the required turbulence intensity. In addition, when providing oxidants to the central turbulent flame, the cold high-speed swirl gas can effectively prevent the heat generated by the flame from being transferred to the combustion device, further achieving a self-cooling effect, fundamentally avoiding the problem of flame ablation of the burner, and significantly extending the service life of the burner.

[0045] In this embodiment, methane is used as the fuel of the axial turbulent flame, oxygen is used as the oxidant of the axial turbulent flame, air is used as the diluent of the axial turbulent flame, and air is used as the external swirl gas. The two radial inlets 6 of the central premixing burner 3 are respectively introduced into the mixed gas of methane, oxygen and air, and air is introduced into the external swirl flame stabilizing device 1.

[0046] The present embodiment discloses a high temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization, including start-up and shutdown operations, wherein the start-up operation includes the following steps:

[0047] Step 1: Install the pipelines, and connect the adapter and the gas pipeline to the external swirl flame stabilizing device 1 and the central premixing burner 3 respectively;

[0048] Step 2: A small amount of premixed gas of methane, oxygen and air is introduced into the central premix burner 3, with the volume flow rates of methane, oxygen and air being 1 L / min, 0.2 L / min and 4.6 L / min respectively, and electric spark ignition is used near the burner outlet 10;

[0049] Step 3: introducing air into the external swirl flame stabilizing device 1;

[0050] Step 4: gradually increase the volume flow rates of methane, oxygen and air introduced into the central premix burner 3 to a ratio of 1:2.8:4.2;

[0051] This volume flow rate ratio can ensure oxygen-rich combustion, and the oxygen content in the combustion exhaust gas is about 20-21%. The temperature of the turbulent flame finally formed can reach 2100K.

[0052] The shutdown operation includes the following steps:

[0053] Step 1: gradually reducing the volume flow rates of oxygen and methane / carbon dioxide mixture introduced into the central premix burner 3 to zero at the same time;

[0054] Step 2: gradually reduce the volume flow rate of air entering the external swirl flame stabilizing device 1 to zero, and stop the burner.

[0055] Furthermore, the present invention can change the oxygen concentration by changing the volume flow rate of the oxidant, thereby achieving stable combustion from oxygen-poor to oxygen-rich flames to meet different temperature requirements.

[0056] The above description further illustrates the purpose, method and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention, which is used to explain the present invention and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization, characterized by: It includes a coaxially mounted external swirl flame stabilizing device, a central premixing burner, an adjustable turbulence intensity orifice plate and a central powder supply pipe; The external swirl flame stabilization device is a hollow square structure, including four external swirl flame stabilization inlets and four external swirl flame stabilization outlets. The external swirl flame stabilization inlets are evenly distributed along the tangential direction, and the external swirl flame stabilization outlets are coaxial with the external swirl flame stabilization inlets. The central premix burner is a hollow cylindrical structure, including two radial inlets of the burner and one burner outlet. The two radial inlets of the burner are symmetrically distributed along the radial direction and are located at the front end of the adjustable turbulence intensity orifice plate. The burner outlet is arranged in the axial direction; The adjustable turbulence intensity orifice plate is a hollow cylinder with uniform holes, which plays a role in regulating the flame; The central powder supply pipe is a hollow cylindrical structure with a mounting seat, having a powder supply inlet and a powder supply outlet, and the hollow cylinder in the direction of the powder supply outlet passes through the center of the adjustable turbulence intensity orifice plate; The powder supply outlet of the central powder supply pipe is flush with the burner outlet of the central premixing burner, and the two form an annular outlet of the axial jet; the external swirl flame stabilization outlet is located above the burner outlet.

2. A high temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization as claimed in claim 1, characterized in that: The high-velocity flame is stabilized by using external air swirl, and the Reynolds number can be controlled by changing the center gas velocity. The turbulence intensity of the flame is adjusted to a specified value by changing the hole density and hole size of the adjustable turbulence intensity orifice plate inside the center premixed burner, thereby achieving a stable and controllable turbulent flame: Where I is the turbulence intensity, ρ, υ, μ are the density, velocity and viscosity coefficient of the fluid, d is the characteristic length, and α is the conversion coefficient between the Reynolds number Re and the turbulence intensity. The turbulence intensity can be changed by changing the hole density x and hole size r of the central adjustable turbulence intensity orifice plate. Thereby changing the turbulence intensity, where L is the gas volume flow rate.

3. A high temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization as claimed in claim 2, characterized in that: The number of the adjustable turbulence intensity orifice plate is at least one.

4. A high temperature turbulent environment particle ignition and combustion test device based on swirl flame stabilization as claimed in claim 2, characterized in that: When the number of adjustable turbulence intensity orifice plates is 2, the two porous plates are located behind the burner outlet and in front of the air inlet respectively; the adjustable turbulence intensity orifice plates are a porous plate with a thickness of 10 mm and a thickness of 5 mm, and the 35 holes of the porous plate are evenly distributed from the inside to the outside, and the hole diameter is 1 mm.

5. A method for performing a combustion test using the device according to any one of claims 1 to 4, characterized in that: The following steps are included: Step 1: The fuel is introduced into the burner from one side of the central premixing burner along the radial inlet of the burner, and the oxidant and air are introduced into the burner from the other side of the central premixing burner along the radial inlet of the burner, and ignited at the burner outlet at the same time to form a premixed jet flame; Step 2: Air is introduced from the external swirl flame stabilization inlet of the external swirl flame stabilization device, and the air swirl is ejected from the external swirl flame stabilization outlet. The flow characteristics of the tangential swirl enable the air swirl formed by the external swirl flame stabilization device to ensure that the central premixed flame can draw in enough air for combustion during the combustion process, thereby preventing the flame from being extinguished due to the low oxidant concentration at the root of the flame when the gas flow rate is too fast. At the same time, the high-speed swirl gas can also accelerate the gas flow rate of the central flame, thereby regulating the required turbulence intensity; in addition, the cold high-speed swirl gas can effectively prevent the heat generated by the flame from being transferred to the combustion device when providing oxidant to the central turbulent flame, further achieving a self-cooling effect, avoiding flame ablation of the burner, and significantly extending the service life of the burner; Step 3: increasing the volume flow rates of fuel, air and oxidant introduced into the central premix burner according to predetermined conditions; then, increasing or decreasing the volume flow rate of air introduced into the external swirl flame stabilizing device according to predetermined conditions, by increasing or decreasing the mass flow rate of air in the mixed gas of fuel and oxidant introduced into the central premix burner, the oxygen concentration can be controlled, stable combustion between oxygen-poor and oxygen-rich can be achieved, the flame temperature can be changed, and a high temperature or ultra-high temperature flame can be formed; Step 4: When the flame reaches the specified experimental conditions and stabilizes, the solid particles to be analyzed are introduced through the central powder supply pipe, the particles are ignited, and the combustion morphology of the particles is analyzed.

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