A high-temperature turbulent environment particle ignition and combustion testing device based on cyclone stable flame

Abstract

The application discloses a kind of high-temperature turbulent flow environment particle ignition combustion test device based on cyclone stable flame, belong to combustion test field.The present application is composed of external cyclone stable flame device, central premix burner, adjustable turbulent intensity orifice plate, center powder supply tube four parts.By central premix burner to generate high-temperature high-speed methane turbulent flame, by external cyclone stable flame device to carry out stable flame to high-temperature high-speed turbulent flame, increase the turbulent intensity of flame.By high-temperature high-speed methane flame to construct high-speed turbulent field and high-temperature flue gas range, realize the combustion of aluminum particles in turbulent field, and the combustion law of aluminum particles in complex flow field is researched and tested.By changing the hole density and aperture of adjustable turbulent intensity orifice plate, the turbulent intensity of high-temperature high-speed turbulent flame is changed, by changing the gas ratio in central premix burner, the simulation of different fuel gas oxygen enrichment degree, turbulent intensity and flame temperature is realized, and the test analysis of different turbulent intensity on condensed phase particle combustion process is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame, belong to combustion test field. BACKGROUND

[0002] In power systems such as solid rocket engine and powder ramjet engine, solid particles usually burn in the form of particle cloud, and the interaction and transport law between particles is complex. Al, B, coal powder, biomass and other solid particles undergo phase change, agglomeration, ignition and combustion processes in the engine, combined with complex flow field structure and turbulence, making the engine combustion research very challenging.

[0003] The engine is usually a complex turbulent environment, and the interaction and transport law of particles and high-temperature gas flow is quite complex. Due to the high-temperature and high-pressure turbulent conditions in the engine and the smoke shielding, it is currently impossible to capture the details of the combustion of solid particles in the engine using reliable experimental methods. In actual engineering testing, the pressure of the combustion chamber and the two-phase flow field outside the engine outlet are mainly measured, and the study of the ignition and combustion process of aluminum particles in the combustion chamber is relatively scarce. The influence of the combustion chamber flow field region and the strong turbulent effect of the nozzle submerged section on the combustion flow process of condensed phase particles cannot be effectively studied experimentally. When studying the influence of complex flow field on particle combustion, direct engine testing is difficult to flexibly control the turbulent intensity, and the experiment is difficult and costly. SUMMARY

[0004] To solve the problem of difficult to directly explore the aluminum particle combustion law in complex flow field through engine test, the purpose of the present application is to provide a kind of high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame. The device is composed of external cyclone stable flame device, center premix burner, adjustable turbulent intensity orifice plate and center powder supply pipe. The high-temperature and high-speed methane turbulent flame is generated by the center premix burner, and the external cyclone stable flame device is used to stabilize the high-temperature and high-speed turbulent flame and increase the turbulent intensity of the flame. The device constructs a high-speed turbulent field and a high-temperature smoke range by high-temperature and high-speed methane flame, so as to realize the combustion of aluminum particles in the turbulent field and study the combustion law of aluminum particles in complex flow field. By changing the orifice density and orifice diameter of the adjustable turbulent intensity orifice plate, the turbulent intensity of the high-temperature and high-speed turbulent flame can be changed. By changing the gas ratio in the center premix burner, different fuel gas oxygen enrichment degree, turbulent intensity and flame temperature can be simulated, the analysis of the combustion process of condensed phase particles under different turbulent intensity can be realized, and the independent adjustment of various working condition parameters can be realized. The present application also has the advantages of low experimental cost, easy operation and high implementation efficiency.

[0005] The purpose of the present application is realized by the following technical solutions:

[0006] The application discloses a high-temperature turbulent environment particle ignition and combustion testing device based on cyclone stable flame, which comprises an external cyclone stable flame device, a center premix burner, an adjustable turbulent intensity orifice plate and a center powder supply pipe which are coaxially arranged.

[0007] The external cyclone stable flame device is a hollow square structure, comprising four external cyclone stable flame inlets and four external cyclone stable flame outlets; the external cyclone stable flame inlets are uniformly distributed along the tangential direction; and the external cyclone stable flame outlets are coaxial with the external cyclone stable flame inlets.

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

[0009] The adjustable turbulent intensity orifice plate is a hollow cylinder with uniform holes, which has an adjusting effect.

[0010] The center powder supply pipe is a hollow cylindrical structure with a mounting seat, comprising one powder supply inlet and one powder supply outlet; the hollow cylinder of the powder supply outlet passes through the center of the adjustable turbulent intensity orifice plate.

[0011] The powder supply outlet of the center powder supply pipe is flush with the burner outlet of the center premix burner, and the two form an annular outlet of axial jet; and the external cyclone stable flame outlet is located above the burner outlet.

[0012] The external air cyclone is used for stabilizing the high-flow-rate flame, the Reynolds number can be controlled by changing the center gas flow rate, the turbulent intensity of the flame can be adjusted to a specified value by changing the hole density and hole size of the adjustable turbulent intensity orifice plate in the center premix burner, so that the stable and controllable turbulent flame is realized.

[0013]

[0014] Wherein, I is the turbulent intensity, ρ, v and μ are the density, flow rate and viscosity coefficient of the fluid, d is the characteristic length, and α is the conversion coefficient of the Reynolds number Re and the turbulent intensity; the turbulent intensity can be changed by changing the hole density x and hole size r of the adjustable turbulent intensity orifice plate. So as to change the turbulent intensity, wherein L is the gas volume flow rate.

[0015] As preferred, the number of the adjustable turbulent intensity orifice plate is at least one.

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

[0017] A method for conducting a combustion test using the device, comprising the following steps:

[0018] Step one: pass fuel into the burner from one side of the central premix burner along the radial inlet of the burner, pass oxidant and air into the burner from the other side of the central premix burner along the radial inlet of the burner, and ignite at the outlet of the combustion chamber to form a premix jet flame.

[0019] Step two: pass air into the outer swirl stabilizer inlet of the outer swirl stabilizer, and the air swirl is ejected from the outer swirl stabilizer outlet, the tangential flow characteristics of the air swirl formed by the outer swirl stabilizer can ensure that the central premix flame can absorb enough air for combustion in the process of combustion, prevent the flame from being extinguished due to the too low oxidant concentration at the flame root in the case of too fast gas flow rate, and 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 transmitted to the combustion device when providing oxidant for the central turbulent flame, further realizing the self-cooling effect and avoiding the ablation problem of the flame to the burner, thereby significantly prolonging the service life of the burner.

[0020] Step three: increase the volume flow rate of fuel, air and oxidant passed into the central premix burner according to predetermined conditions; then, increase or decrease the air volume flow rate passed into the outer swirl stabilizer according to predetermined conditions, and by increasing or decreasing the mass flow rate of air in the mixture of fuel and oxidant passed into the central premix burner, the oxygen concentration can be controlled, stable combustion between lean oxygen and rich oxygen can be realized, the flame temperature can be changed, and therefore high-temperature or ultrahigh-temperature flame can be formed.

[0021] Step four: when the flame reaches the specified conditions and is stable, pass the solid particles to be analyzed along the central powder supply pipe, ignite the particles, and analyze the combustion form of the particles.

[0022] Advantages:

[0023] 1. The high-temperature turbulent environment particle ignition combustion test device based on swirl flame stabilization disclosed in the application utilizes the combustion characteristics and flow characteristics of the premix flame, passes fuel and oxidant into the burner along the radial direction to form a premix flame, forms a controlled and stable turbulent flame through two adjustable turbulent intensity orifice plates inside the burner, ensures the mixing degree of the premix flame, and adjusts the orifice density, orifice size and thickness of the two internal adjustable turbulent intensity orifice plates, so that the turbulent flame with the required turbulent intensity can be formed according to the experimental conditions.

[0024] 2. The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame, wherein the external cyclone stable flame device is connected with air through four external cyclone stable flame inlets and sprays the air from the center axis to form stable air cyclone; the formed air cyclone can ensure that the turbulent flame can also suck enough oxidant at the flame root to burn under the condition of high flow rate, and the stable cyclone gas with adjustable flow rate can also increase the turbulent degree of the turbulent flame, so that the required turbulent intensity of the experimental condition is obtained.

[0025] 3. The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame, wherein the flame temperature is controlled by changing the oxygen concentration; the stable combustion under the condition of lean oxygen to rich oxygen can be realized by changing the fuel / air ratio in the center premixing combustor to adjust the oxygen concentration of the fuel gas, and the stable turbulent flame with different temperatures is formed.

[0026] 4. The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame, wherein the Reynolds number of the turbulent flame can be changed by changing the flow rate of the fuel gas in the center premixing combustor, so that the required experimental condition is obtained.

[0027] 5. The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame, wherein the combustion efficiency is effectively improved by reasonably designing the premixing combustion structure and by premixing the ratio of the oxidant and the fuel, so that the fuel saving effect is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a structure schematic view of the high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame.

[0029] Figure 2 It is a right view of the high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame.

[0030] Figure 3 It is a structure schematic view of the center premixing combustor.

[0031] Figure 4 It is a structure schematic view of the adjustable turbulent intensity orifice plate.

[0032] Figure 5 It is a three-dimensional schematic view of the turbulent combustor.

[0033] 1-external cyclone stable flame device, 2-adjustable turbulent intensity orifice plate, 3-center premixing combustor, 4-center powder supply pipe, 5-powder supply inlet, 6-combustor radial inlet, 7-external cyclone stable flame inlet, 8-external cyclone stable flame outlet, 9-powder supply outlet, 10-combustor outlet. DETAILED DESCRIPTION

[0034] For a better understanding of the present application, together with other and further advantages thereof, reference is made to the following

[0035] Example 1

[0036] The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame disclosed in this embodiment utilizes the flow characteristics and stability of the cyclone gas, and air is introduced from the outside of the external cyclone stable flame device through the external cyclone stable flame inlet, and the air cyclone is sprayed out from the external cyclone stable flame outlet. The flow characteristics of the tangential cyclone can ensure that the air cyclone formed by the external cyclone stable flame device can ensure that the central premixed flame can absorb enough air for combustion in the process of combustion, prevent the flame from being extinguished due to the too low oxidant concentration at the flame root in the case of too fast gas flow rate, and at the same time, the high-speed cyclone gas can also speed up the gas flow rate of the central flame, so as to adjust the required turbulent intensity. In addition, the cold high-speed cyclone gas can effectively prevent the heat generated by the flame from being transmitted to the combustion device when providing the oxidant for the central turbulent flame, further realizing the self-cooling effect, fundamentally avoiding the ablation problem of the flame to the burner, and significantly prolonging the service life of the burner. Two adjustable turbulent intensity orifice plates inside the central premixed burner are used to enhance the turbulent intensity and mixing effect of the turbulent flame, maintain stable combustion, and adjust the required turbulent intensity according to the experimental conditions. By increasing or reducing the mass flow rate of air in the mixed gas of fuel and oxidant introduced into the central premixed burner, the oxygen concentration can be controlled, stable combustion between lean oxygen and rich oxygen can be realized, the flame temperature can be changed, and high-temperature or ultrahigh-temperature flame can be formed.

[0037] Example 2

[0038] As shown in Figure 1 The high-temperature turbulent environment particle ignition combustion test device based on cyclone stable flame disclosed in this embodiment includes an external cyclone stable flame device 1, an adjustable turbulent intensity orifice plate 2, a central premixed burner 3, and a central powder supply pipe 4.

[0039] The external tangential cyclone stable flame device 1 is a hollow square structure, including four external cyclone stable flame inlets 7 and four external cyclone stable flame outlets 8. The external cyclone stable flame inlets 7 are uniformly distributed along the tangential direction and are rectangular, coaxial with the external cyclone stable flame outlets 8. The central premixed 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 turbulent intensity orifice plate 2 is a multi-orifice plate with a thickness of 10 mm and a thickness of 5 mm. The 35 orifices of the multi-orifice plate are uniformly distributed from the inside to the outside, and the orifice diameter 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 tube 4 is level with the burner outlet 10 of the central premix burner 3, and the two form an annular outlet of axial jet flow. Two adjustable turbulence intensity orifice plates 2 are respectively located behind the burner outlet 10 and in front of the burner radial inlet 6. The outer swirl stabilizing outlet 8 of the outer swirl stabilizing device 1 is located above the burner outlet 10 of the central premix burner 3.

[0041] The outer swirl stabilizing device 1, the adjustable turbulence intensity orifice plate 2, the central premix burner 3, and the central powder supply tube 4 are coaxially installed.

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

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

[0044] The flow characteristics of the tangential swirl can ensure that the air swirl generated by the outer swirl stabilizing device 1 can ensure that the central premix flame can absorb enough air for combustion during the combustion process, preventing the flame from being extinguished due to the excessively low oxidant concentration at the flame root in the case of excessively high gas flow rate. In addition, 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 transmitted to the combustion device when providing oxidant for the central turbulent flame, further achieving a self-cooling effect, and fundamentally avoiding the ablation problem of the flame to the burner, thereby significantly prolonging the service life of the burner.

[0045] In the 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 outer swirl gas. The mixed gas of methane, oxygen, and air is introduced into the two burner radial inlets 6 of the central premix burner 3, and air is introduced into the outer swirl stabilizing device 1.

[0046] The embodiment discloses a high-temperature turbulent environment particle ignition and combustion test device based on a cyclone stable flame, and comprises starting and stopping operations.

[0047] Step one: pipeline installation is performed, and an adapter and a gas pipeline are connected to the external cyclone stable flame device 1 and the center premix burner 3 respectively.

[0048] Step two: a small amount of premixed gas of methane, oxygen and air is introduced into the center premix burner 3, the volume flow rates of the methane, oxygen and air are 1 L / min, 0.2 L / min and 4.6 L / min respectively, and an electric spark is used for ignition near the burner outlet 10.

[0049] Step three: air is introduced into the external cyclone stable flame device 1.

[0050] Step four: the volume flow rates of the methane, oxygen and air introduced into the center premix burner 3 are gradually increased to a ratio of 1:2.8:4.2.

[0051] The ratio of the volume flow rates can ensure oxygen-rich combustion, and the oxygen accounts for about 20-21% in the combustion tail gas, and finally the formed turbulent flame has a temperature of 2100K.

[0052] The stopping operation comprises the following steps.

[0053] Step one: the volume flow rates of the oxygen and the methane / carbon dioxide mixed gas introduced into the center premix burner 3 are simultaneously gradually reduced to zero.

[0054] Step two: the volume flow rate of the air introduced into the external cyclone stable flame device 1 is gradually reduced to zero, and the burner stops working.

[0055] Further, the present application can change the oxygen concentration by changing the volume flow rate of the oxidant, so as to realize stable combustion of lean-oxygen to oxygen-rich flame, and achieve different temperature requirements.

[0056] The above description further describes the purpose, method and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application, which is used to explain the present application and does not limit the protection scope of the present application, and any modification, equivalent replacement, improvement and the like within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high temperature turbulent environment particle ignition and combustion test apparatus based on cyclone stabilized flame, characterized in that: The external swirl stabilizer, the center premix burner, the adjustable turbulence intensity orifice plate and the center powder supply tube are coaxially installed; The external swirl stabilizer is a hollow square structure, including four external swirl stabilizer inlets and four external swirl stabilizer outlets, the external swirl stabilizer inlets are uniformly distributed along the tangential direction, and the external swirl stabilizer outlets are coaxial with the external swirl stabilizer inlets; The center premix burner is a hollow cylindrical structure, including two burner radial inlets and one burner outlet, the two burner radial inlets are symmetrically distributed along the radial direction, and the two adjustable turbulence intensity orifice plates are respectively located behind the burner outlet and in front of the burner radial inlet; the burner outlet is arranged along the axial direction; The adjustable turbulence intensity orifice plate is a hollow cylinder with uniform holes, which adjusts the flame; The center powder supply tube is a hollow cylindrical structure with a mounting seat, having one powder inlet and one powder outlet, and the hollow cylinder of the powder outlet direction passes through the center of the adjustable turbulence intensity orifice plate; The powder outlet of the center powder supply tube is flush with the burner outlet of the center premix burner, and the two form an annular outlet of axial jet; the external swirl stabilizer outlet is located above the burner outlet; The external air swirl is used to stabilize the high flow rate flame, and the Reynolds number can be controlled by changing the center gas flow rate; the turbulence intensity of the flame is adjusted to a specified value by changing the hole density and size of the adjustable turbulence intensity orifice plate in the center premix burner, so that a stable and controllable turbulent flame is realized: the turbulence intensity, the density, the flow rate and the viscosity coefficient of the fluid, d being the characteristic length, the Reynolds number the conversion factor with the turbulence intensity; by varying the hole density x and the hole size r of the adjustable turbulence intensity orifice plate it is possible to vary the turbulence intensity, where L is the gas volume flow.

2. The high temperature turbulent flow environment particle ignition and combustion test device based on cyclone stabilized flame according to claim 1, characterized in that: The number of adjustable turbulence intensity orifice plates is at least one.

3. The high temperature turbulent flow environment particle ignition and combustion test device based on cyclone stabilized flame according to claim 1, characterized in that: When the number of adjustable turbulence intensity orifice plates is two, the two adjustable turbulence intensity orifice plates are respectively located behind the burner outlet and in front of the burner radial inlet; the adjustable turbulence intensity orifice plates are a porous plate with a thickness of 10 mm and a porous plate with a thickness of 5 mm, and 35 holes of the porous plates are uniformly distributed from inside to outside, with a hole diameter of 1 mm.

4. Method for carrying out a combustion test using a device according to any one of claims 1 to 3, characterized in that: The method comprises the following steps, Step one: the fuel is introduced into the burner from the center premix burner side through the radial burner radial inlet, the oxidant and air are introduced into the burner from the other side of the center premix burner through the radial burner radial inlet, and the flame is ignited at the burner outlet to form a premix jet flame; Step two: air is introduced into the external swirl stabilizer through the external swirl stabilizer inlet, and the air swirl is ejected from the external swirl stabilizer outlet; the flow characteristics of the tangential swirl enable the air swirl formed by the external swirl stabilizer to ensure that the center premix flame can absorb enough air for combustion during the combustion process, preventing the flame from being extinguished due to the low oxidant concentration at the flame root when the gas flow rate is too high; in addition, the cold high-speed swirl gas can effectively prevent the heat generated by the flame from being transmitted to the combustion device when providing oxidant for the center turbulent flame, further realizing the self-cooling effect, avoiding the ablation of the flame to the burner, and significantly prolonging the service life of the burner; Step three: increase the volume flow rate of fuel, air and oxidant into the central premix burner according to predetermined conditions; then, increase or decrease the volume flow rate of air into the external swirl stabilizer according to predetermined conditions, and control the oxygen concentration by increasing or decreasing the mass flow rate of air in the mixture of fuel and oxidant into the central premix burner, so as to realize stable combustion between lean oxygen and rich oxygen, change the flame temperature, and form a high-temperature or ultrahigh-temperature flame; Step four: when the flame reaches the specified conditions and is stable, the solid particles to be analyzed are fed into the central powder feeding pipe, and the particles are ignited for analysis of the combustion form of the particles.

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