Explosion experiment device for fluid rapid premixing and droplet diameter control

Abstract

The invention provides a fluid rapid premixing and droplet diameter control explosion experiment device, which comprises an explosion container, a scattering assembly, an ignition system and a control system, and is characterized in that the scattering assembly comprises a Venturi mixing tube, a first sample tank, a second sample tank and an ultrasonic atomization spray head, and the ultrasonic atomization spray head is connected with the explosion container; optical glass is arranged on the two sides of the explosion container, and a high-speed camera is arranged outside the optical glass; the Venturi mixing pipe realizes mixing by depending on fluid kinetic energy, so that sufficient premixing of materials is ensured, blockage can be avoided, the secondary flow suction volume is stabilized, the mixing proportion is maintained to be constant without a filter element, and the energy consumption is lower than that of mechanical stirring; the ultrasonic atomization nozzle can directly utilize the kinetic energy of the mixed liquid to accelerate the gas-liquid mass transfer and chemical reaction rate; the corrosion-resistant material ensures long-term operation, accurately regulates and controls particle size distribution of fog drops, ensures uniform coverage, realizes complete burning and explosion of the mixed fuel, and records the explosion process of the fluid fuel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluid explosion characteristics research, in particular to a fluid rapid premixing and droplet diameter control explosion experiment device. BACKGROUND

[0002] In the experimental research of fuel combustion and explosion characteristics such as combustible gas / liquid vapor explosion, cloud explosion, etc., the key prerequisite for obtaining accurate and repeatable experimental data is to achieve rapid and uniform premixing of fuels. Due to technical limitations, traditional mixing methods such as mechanical stirring, static mixing in a premixing chamber, or simple jet injection often have problems such as low premixing degree and poor mixing uniformity. Non-uniform mixing can lead to local fuel concentration being too high or too low, resulting in incomplete combustion, insufficient energy release, and the inability to form ideal blast waves, affecting the reliability of experimental results and making it difficult to accurately evaluate key parameters such as fuel explosion power.

[0003] In addition, in explosion experiments involving the formation of liquid fuel clouds, droplet diameter is one of the core parameters affecting cloud atomization, evaporation, flame propagation, and final explosion intensity. Different sizes of droplets have different evaporation rates and combustion characteristics. Small droplets are easy to vaporize and mix with air, while larger droplets may delay combustion or even fail to burn completely. Currently, most experimental devices only focus on achieving mixing functions, and generally lack effective, accurate, and controllable means of adjusting droplet diameter. Researchers can only passively accept the droplet distribution produced by a specific atomization device, and cannot actively and systematically study the influence of droplet diameter on the explosion process, limiting the in-depth exploration of the micro-mechanism of liquid fuel explosion.

[0004] Therefore, there is an urgent need for an integrated experimental device that can rapidly and highly uniformly mix fuels, ensure that the mixed fuel can be completely and efficiently combusted, and accurately regulate droplet diameter to provide technical support for studying the influence of droplet size on explosion intensity and flame propagation characteristics, filling the gap in current research methods. SUMMARY

[0005] The present application aims to provide a fluid rapid premixing and droplet diameter control explosion experiment device that can uniformly mix fuels, make them completely combust, and also study the influence of droplet diameter on the combustion effect of mixed fuels.

[0006] To this end, the technical scheme of the present application is as follows: a fluid rapid premixing and droplet diameter control explosion experiment device, comprising an explosion container, a throwing assembly arranged at a feeding port of the explosion container, an ignition system arranged at a top of the explosion container, and a control system for controlling the throwing assembly and the ignition system to start or stop, the throwing assembly comprising a Venturi mixing pipe, a first sample tank connected with the Venturi mixing pipe, a second sample tank, and an ultrasonic atomizing nozzle, the ultrasonic atomizing nozzle being connected with the explosion container through an electromagnetic valve, optical glass being arranged at both sides of the explosion container for observing a flame propagation process of fluid fuel, a high-speed camera being arranged outside the optical glass for recording the flame propagation process of the fluid fuel, and a pressure sensor being further arranged on the explosion container for monitoring a pressure change process.

[0007] As a preferred solution of the above-mentioned scheme, the explosion container is made of stainless steel in a spherical shape.

[0008] Further preferably, the Venturi mixing pipe is composed of two symmetrical conical pipes and a throat pipe in the middle, one end of which is a main fluid inlet connected with the first sample tank, the throat pipe in the middle section is connected with the second sample tank through a secondary fluid inlet, and the other end is a mixed fluid outlet connected with the ultrasonic atomizing nozzle, a bend pipe is arranged on the Venturi mixing fluid outlet and connected with the ultrasonic atomizing nozzle, the main fluid is high-pressure fluid, and the secondary fluid is low-pressure fluid.

[0009] Further preferably, the ultrasonic atomizing nozzle comprises a feeding end connected with the bend pipe and a discharging end connected with the explosion container, and a piezoelectric transducer is arranged between the feeding end and the discharging end.

[0010] Further preferably, the ultrasonic atomizing nozzle is made of titanium alloy.

[0011] Further preferably, the ignition system comprises an ignition electrode arranged at a top end of the explosion container, the ignition electrode extending from the top end of the explosion container to a middle position of the explosion container.

[0012] Further preferably, the pressure sensor is arranged at a middle position of a side surface of the explosion container, a vacuum extraction pipeline is further arranged at a side surface of the top end of the explosion container, and a pressure gauge and a control valve are arranged on the vacuum extraction pipeline.

[0013] The Venturi mixing pipe has no moving parts, relies on fluid kinetic energy to realize mixing, ensures that materials are fully premixed, provides homogeneous input for subsequent atomization, and has low energy consumption compared with mechanical stirring. The ultrasonic atomization nozzle can directly utilize the kinetic energy of the mixed liquid to accelerate gas-liquid mass transfer and chemical reaction rate. The Venturi mixing pipe has no filter core to avoid blockage, and the ultrasonic atomization nozzle uses a nozzle made of corrosion-resistant material to ensure long-term operation. The Venturi mixing pipe can stabilize the secondary flow suction amount and maintain a constant mixing ratio. By controlling the ultrasonic frequency range, the size of the liquid droplets is controlled, the mixed fuel is finely atomized during the throwing process, micron-level liquid droplets of a specific size and uniform size are formed, and the droplet size distribution is accurately controlled (for example, 7±2 μm), the control system controls the ignition system to ignite, and finally realizes complete combustion and explosion of the mixed fuel, records the explosion process of the fluid fuel, records the explosion parameter curve, and analyzes the explosion characteristic parameters. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structural schematic diagram of the present application.

[0015] Figure 2 is a structural schematic diagram of the Venturi mixing pipe of the present application.

[0016] Figure 3 is a cross-sectional view of the internal structure of the Venturi mixing pipe of the present application.

[0017] Figure 4 is a structural schematic diagram of the ultrasonic atomization nozzle of the present application.

[0018] Figure 5 is a cross-sectional view of the internal structure of the ultrasonic atomization nozzle of the present application. DETAILED DESCRIPTION

[0019] The present application will be further described below in conjunction with the drawings and examples.

[0020] As shown in Figures 1-5 , a fluid rapid premixing and droplet diameter control explosion experiment device includes an explosion container 1, a throwing assembly arranged at the feeding port of the explosion container 1, an ignition system arranged at the top of the explosion container 1, and a control system (not shown in the figure) for controlling the start or stop of the throwing assembly and the ignition system. The explosion container 1 is made of stainless steel and is spherical. In this embodiment, the volume of the explosion container 1 is 20L, which can be adjusted according to experimental requirements in actual use. The control system is connected to the signal receiving target of the ignition system and the throwing assembly through a signal transmitter, so as to control the opening or closing of the ignition system and the throwing assembly (this is prior art, which will not be described here).

[0021] The spraying assembly comprises a Venturi mixing tube 2, a first sample tank (not shown in the figure) connected with the Venturi mixing tube 2, a second sample tank (not shown in the figure) and an ultrasonic atomizing nozzle 3 connected with the explosion container 1 through an electromagnetic valve (not shown in the figure), the Venturi mixing tube 2 is composed of two symmetrical conical tubes and a throat 202 in the middle, one end is a main fluid inlet 201 connected with the first sample tank, the throat 202 in the middle is connected with the second sample tank through a secondary fluid inlet 203, and the other end is a mixed fluid outlet 204 connected with the ultrasonic atomizing nozzle 3, a bend pipe 205 is arranged on the Venturi mixed fluid outlet 204 and connected with the ultrasonic atomizing nozzle 3, the main fluid is a high-pressure fluid and can be in a gas phase or a liquid phase, and the secondary fluid is a low-pressure fluid and can also be in a gas phase or a liquid phase.

[0022] The Venturi mixing tube 2 utilizes the pressure-velocity conversion caused by Bernoulli effect when the fluid flows through the Venturi tube to realize efficient and rapid mixing (suitable for pre-mixing of gas-gas, gas-liquid or low-viscosity liquid-liquid). The core is to actively induce the secondary fluid through the strong negative pressure area artificially created at the throat 202, and to realize instantaneous dispersion by high shear turbulent flow.

[0023] The specific process is as follows:

[0024] ① Throat 202 acceleration and negative pressure induction: the main fluid as the driving fluid (gas or high-speed liquid) flows through the throat 202 from the main fluid inlet 201, the cross-sectional area of the pipeline gradually decreases, the flow rate increases dramatically and the static pressure drops sharply, forming a local strong negative pressure area at the throat 202; the negative pressure difference induces the secondary fluid (gas or liquid) through the secondary fluid inlet 203, and the two-phase fluid is preliminarily contacted in the narrow channel of the throat 202.

[0025] ② High shear breaking and turbulent flow generation (rapid mixing core stage): the conical tube connected at the end of the throat 202 serves as a mixing chamber to mix the two-phase fluid, the bend pipe 205 and the mixing chamber arranged adjacent thereto drive the high-speed driving fluid to collide with the low-speed induced fluid; the huge velocity gradient and fluid viscosity generate extreme shear force and strong turbulent flow field: the mixed fluid passes through the mixed fluid outlet 204 and enters the ultrasonic atomizing nozzle 3 through the bend pipe 205.

[0026] Gas-liquid / liquid-liquid mixing: the shear force tears the liquid column instantaneously to generate smaller liquid droplets / liquid groups;

[0027] ③ Turbulent flow reinforced mixing (uniformity guarantee):

[0028] The high-intensity turbulent flow in the mixing chamber stretches the vortex, collides and diffuses through turbulent flow: continuously refines the dispersed phase size (droplet / bubble); violently disturbs the fluid clusters to accelerate the interphase mass transfer and energy exchange.

[0029] ④ Diffusion section homogenization and pressure recovery:

[0030] The mixing chamber simultaneously serves as a diffusion section. After the fluid enters the diffusion section, the cross-sectional area is enlarged, the average flow velocity is reduced, and the static pressure is partially restored. The reduced flow velocity causes the turbulent kinetic energy to be converted into mixing energy. The secondary flow and backflow prolong the residence time. The turbulent diffusion and molecular diffusion work together to completely eliminate the concentration / temperature gradient.

[0031] ⑤Output:

[0032] The mixed fluid output port 204 obtains a uniformly dispersed and homogeneous mixture (gas phase premixed gas, gas-liquid emulsion, or homogeneous liquid phase), meeting the feeding requirements of the rapid reaction process.

[0033] Optical glass 4 is provided on both sides of the explosion vessel 1 for observing and recording the flame propagation process of the fluid fuel through the explosion vessel 1. The optical glass 4 is externally recorded by a high-speed camera (not shown in the figure) to record the flame propagation process of the fluid fuel and the pressure change process, facilitating subsequent research.

[0034] The ultrasonic atomizing nozzle 3 includes a feed end 301 connected with the elbow pipe 205 and a discharge end 302 connected with the explosion vessel 1. A piezoelectric transducer 303 is arranged between the feed end 301 and the discharge end 302.

[0035] The piezoelectric transducer 303 can convert high-frequency electrical energy into mechanical vibration energy to generate axial vibration waves. The ultrasonic atomizing nozzle 3 is made of titanium alloy.

[0036] The ultrasonic atomizing nozzle 3 is vibrated by high-frequency sound waves generated by an ultrasonic generator, causing the liquid to undergo intense physical changes on its surface, thereby forming fine droplets. By changing the atomization intensity and controlling the droplet diameter, the problem of coarse atomization and uneven distribution of liquid droplets during the spraying process is solved, thereby ensuring complete combustion of the mixed fluid. The influence of different atomization degrees on the experimental results can also be studied, and the ultrasonic atomizing nozzle 3 can directly utilize the kinetic energy of the mixed liquid.

[0037] The ignition system includes an ignition electrode 5 arranged at the top end of the explosion vessel 1. The ignition electrode 5 extends from the top end of the explosion vessel 1 to the middle position of the explosion vessel 1.

[0038] A pressure sensor is arranged at the middle position of the side of the explosion vessel 1. A vacuum extraction pipeline 6 is also arranged at the side of the top end of the explosion vessel 1. The vacuum extraction pipeline 6 is provided with a pressure gauge 601 and a control valve.

[0039] The ignition electrode 5 and chemical ignition are arranged in two ways. Different ways of igniting can be used for different mixed fluids by controlling the system operation point of the ignition system. Chemical ignition is achieved by wrapping an ignition head on the ignition electrode.

[0040] The Venturi mixing pipe 2 has no moving parts and relies on fluid kinetic energy to achieve mixing, ensuring that the material is fully premixed to provide homogeneous input for subsequent atomization; and the energy consumption of the Venturi mixing pipe 2 is lower than that of mechanical stirring, and the ultrasonic atomization nozzle 3 can directly utilize the kinetic energy of the mixed liquid to accelerate the gas-liquid mass transfer and chemical reaction rate; the Venturi mixing pipe 2 has no filter core to avoid clogging, the ultrasonic atomization nozzle 3 uses a nozzle made of corrosion-resistant material to ensure long-term operation; the Venturi mixing pipe 2 can stabilize the secondary flow suction amount and maintain a constant mixing ratio, the mixed fluid fuel is finely atomized during the throwing process by the ultrasonic atomization nozzle 3, forming micron-sized droplets of a specific size and uniform size, and in a uniform and dispersed distribution state, the droplet size distribution is accurately controlled (such as 7±2 μm), ensuring uniform coverage, the ignition system is controlled by the control system to ignite, and finally the complete combustion and explosion of the mixed fuel is realized, and the explosion process of the fluid fuel is recorded, the explosion parameter curve is recorded, and the explosion characteristic parameters are analyzed.

[0041] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. An explosion experimental apparatus for rapid fluid premixing and droplet diameter control, characterized in that: The device includes an explosion container (1), a scattering assembly located at the inlet of the explosion container (1), an ignition system located on the top of the explosion container (1), and a control system for controlling the start-up or shutdown of the scattering assembly and the ignition system. The scattering assembly includes a Venturi mixing tube (2), a first sample container, a second sample container, and an ultrasonic atomizing nozzle (3) connected to the Venturi mixing tube (2). The ultrasonic atomizing nozzle (3) is connected to the explosion container (1) via a solenoid valve. Optical glass (4) is provided on both sides of the explosion container (1) for observing the propagation process of the fluid fuel flame through the explosion container (1). A high-speed camera is provided outside the optical glass (4) to record the propagation process of the fluid fuel flame. A pressure sensor is also provided on the explosion container (1) for monitoring the pressure change process.

2. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 1, characterized in that: The explosion container (1) is made of stainless steel and is spherical.

3. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 1, characterized in that: The Venturi mixing tube (2) consists of two symmetrical conical tubes and a throat (202) in the middle. One end is the main fluid inlet (201) connected to the first sample container, the throat (202) in the middle section is connected to the second sample container through the secondary fluid inlet (203), and the other end is the mixed fluid outlet (204) connected to the ultrasonic atomizing nozzle (3). The Venturi mixed fluid outlet (204) is provided with a bend (205) connected to the ultrasonic atomizing nozzle (3). The main fluid is a high-pressure fluid, and the secondary fluid is a low-pressure fluid.

4. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 3, characterized in that: The ultrasonic atomizing nozzle (3) includes a feed end (301) connected to the bend (205) and a discharge end (302) connected to the explosion container (1), and a piezoelectric transducer (303) is provided between the feed end (301) and the discharge end (302).

5. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 4, characterized in that: The ultrasonic atomizing nozzle (3) is made of titanium alloy.

6. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 3, characterized in that: The ignition system includes an ignition electrode (5) disposed at the top of the explosion container (1), the ignition electrode (5) extending from the top of the explosion container (1) to the middle of the explosion container (1).

7. The explosion experimental apparatus for rapid fluid premixing and droplet diameter control according to claim 3, characterized in that: The pressure sensor is located at the middle of the side of the explosion container (1). A vacuum pipe (6) is also provided on the top side of the explosion container (1). A pressure gauge (601) and a control valve (602) are provided on the vacuum pipe (6).

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