阅读说明：本技术 一种基于交错射流的湍流强化火焰加速系统及方法 (Turbulence-enhanced flame acceleration system and method based on staggered jet flow ) 是由 张博 程俊 刘洪� 于 2021-07-28 设计创作，主要内容包括：本发明提供一种基于交错射流的湍流强化火焰加速系统,包括激波管、安装于激波管上的进出气系统、点火系统、数据采集系统和射流系统,以及与所述点火系统和射流系统均相连的信号触发系统；射流系统由依次连接的二氧化碳储罐、电磁阀、单向阀以及设于激波管上的射流接口组成,电磁阀、单向阀以及射流接口的数量是多个,且多个射流接口彼此交错地设置于激波管上。本发明还提供了相应的火焰加速方法。本发明的基于交错射流的湍流强化火焰加速系统可以有效地加速火焰传播,在特定工况下极大的缩短了DDT所需的距离和时间。(The invention provides a turbulence-enhanced flame acceleration system based on staggered jet flow, which comprises a shock tube, an air inlet and outlet system, an ignition system, a data acquisition system, a jet flow system and a signal trigger system, wherein the air inlet and outlet system, the ignition system, the data acquisition system and the jet flow system are arranged on the shock tube; the jet system comprises carbon dioxide storage tank, solenoid valve, check valve and the efflux interface of locating on the shock tube that connects gradually, and the quantity of solenoid valve, check valve and efflux interface is a plurality of, and a plurality of efflux interfaces set up on the shock tube in a staggered manner each other. The invention also provides a corresponding flame acceleration method. The turbulence-enhanced flame acceleration system based on the staggered jet flow can effectively accelerate flame propagation, and greatly shortens the distance and time required by DDT under a specific working condition.)

1. A turbulence-enhanced flame acceleration system based on staggered jet flow is characterized by comprising a shock tube (1), an air inlet and outlet system (2), an ignition system (3), a data acquisition system (4), a jet flow system (5) and a signal trigger system (6) which is connected with the ignition system (3) and the jet flow system (5), wherein the air inlet and outlet system (2), the ignition system (3), the data acquisition system (4) and the jet flow system (5) are arranged on the shock tube (1); the jet system (5) is composed of a carbon dioxide storage tank (51), an electromagnetic valve (52), a one-way valve and jet interfaces (54) arranged on the shock tube (1), wherein the carbon dioxide storage tank, the electromagnetic valve (52), the one-way valve and the jet interfaces (54) are connected in sequence, the number of the electromagnetic valve (52), the one-way valve and the jet interfaces (54) is multiple, and the multiple jet interfaces (54) are arranged on the shock tube (1) in a staggered mode.

2. The turbulent-enhanced flame acceleration system based on staggered jet flow according to claim 1, characterized in that the ignition system (3) comprises an ignition head (31) installed at one end of the shock tube and a pulse igniter (32) connected with the ignition head (31), and the ignition system (3) is connected with one end of the shock tube (1) through the ignition head (31).

3. The turbulent intensified flame acceleration system based on staggered jet flow of claim 2, characterized in that the signal trigger system (6) comprises a signal trigger (61), and the signal trigger (61) is connected with the pulse igniter (32) and each solenoid valve (52) of the jet system (5).

4. The turbulent intensified flame acceleration system based on staggered jet flow of claim 1, characterized in that the number of jet flow interfaces (54) provided on the shock tube (1) is 2, the first jet flow interface (54) is 10cm from the firing end of the shock tube (1), and the second jet flow interface (54) is 20cm from the firing end of the shock tube (1).

5. The turbulent intensified flame acceleration system based on staggered jet flow of claim 1, characterized in that the gas inlet and outlet system (2) is connected with the shock tube (1) through a gas inlet and outlet interface arranged on the shock tube (1); the gas inlet and outlet system (2) comprises a methane bottle (21), an oxygen high-pressure gas bottle (22), a gas mixing tank (23) and a vacuum pump (24), wherein the methane bottle (21), the oxygen high-pressure gas bottle (22), the gas mixing tank (23) and the vacuum pump (24) are connected with the gas inlet and outlet interface through corresponding hoses and valves (25).

6. The turbulent intensified flame acceleration system based on staggered jet flow of claim 1, characterized in that the data acquisition system (4) comprises pressure sensors (41) and ion probes (42) which are installed at equal intervals in the length direction of the shock tube, and the pressure sensors (41) and the ion probes (42) are installed in a one-to-one correspondence and same section.

7. The turbulent intensified flame acceleration system based on staggered jet flow of claim 6, characterized in that the data acquisition system (4) further comprises a signal amplification circuit (43) and data acquisition hardware (44), the pressure sensor (41) is directly connected with the data acquisition hardware (44), and the ion probe (42) is connected with the data acquisition hardware (44) through the signal amplification circuit (43).

8. A turbulence-enhanced flame acceleration method based on staggered jet flow is characterized by comprising the following steps:

step S1: the turbulent flow intensified flame acceleration system based on staggered jet flow is provided, and comprises a shock tube (1), an air inlet and outlet system (2) arranged on the shock tube (1), an ignition system (3), a data acquisition system (4), a jet flow system (5) and a signal trigger system (6) connected with the ignition system (3) and the jet flow system (5); the jet system (5) consists of a carbon dioxide storage tank (51), an electromagnetic valve (52), a one-way valve and jet interfaces (54) arranged on the shock tube (1) which are sequentially connected, the number of the electromagnetic valve (52), the number of the one-way valve and the number of the jet interfaces (54) are multiple, and the multiple jet interfaces (54) are arranged on the shock tube (1) in a staggered manner;

step S2: on the premise of ensuring good air tightness of the shock tube (1), the shock tube (1) is pumped to a vacuum state by using the air inlet and outlet system (2), and then methane-oxygen combustible mixed gas or methane-air combustible mixed gas is injected, so that the shock tube (1) is in a state of pressure ranging from 20 kPa to 25 kPa; keeping the signal trigger system (6) and the data acquisition system (4) in a standby state;

step S3: setting the opening time of each electromagnetic valve (52) of the jet system (5) in the signal trigger system (6) to be prior to the ignition time of the ignition system (3);

step S4: triggering the system (6) according to the set triggering signal of the step S3 to start the shock tube detonation experiment.

9. The turbulent intensified flame acceleration system based on staggered jet flow of claim 1, characterized in that, in the step S3, the time interval between the opening time of the solenoid valve (52) and the ignition time of the ignition system (3) is controlled to be 20-40 ms, the opening time of the solenoid valve (52) is 100ms, and the ignition time of the ignition system (3) is 1S.

10. The staggered jet-based turbulent enhanced flame acceleration system of claim 1, wherein the step S3 further comprises: and adjusting the outlet pressure of a carbon dioxide storage tank (51) of the jet system (5) to ensure that the outlet pressure of the carbon dioxide storage tank (51) is 20-70 times of the air pressure in the shock tube (1).

Technical Field

The invention belongs to the technical field of deflagration/detonation application, and particularly relates to a turbulence-enhanced flame acceleration system and method based on staggered jet flow.

Background

Detonation is a combustion wave that propagates at supersonic speeds. The detonation waves release a large amount of energy in the process of propagation, and can provide required power for the propulsion of a spacecraft and a hypersonic aircraft. Just because detonation has considerable potential for development as a propulsive power, power plant models developed around detonation have become a focus of research in recent years. Detonation combustion in a natural state is very difficult to realize, and ignition energy and gas activity required by the detonation combustion are difficult to obtain under conventional conditions, so that detonation transition becomes a feasible implementation path. However, the phenomenon of detonation transition requires that the flame reaches the detonation velocity through a long distance, and the detonation velocity cannot be directly used in practical application, so that the weight of the device can be increased. Therefore, how to rapidly accelerate the flame to cause transition becomes an urgent problem to be solved.

At this stage, some studies have attempted to add a certain proportion of active gas to the fuel to provide the enormous energy required for direct detonation, but this certainly also brings about a certain safety hazard. In another part of research, the principle that the flame acceleration effect is realized by increasing the roughness of the wall of the combustion chamber pipe or adding a solid barrier in the combustion chamber is that the internal energy of combustible gas is increased in the development and dissipation process of turbulence by increasing the turbulence effect in the combustion chamber, so that the combustible mixed gas in the induction zone is easier to burn, and the purposes of exciting flame deformation and accelerating are achieved. Although this approach shortens the time and distance required for detonation transition, a large thrust loss is generated due to the blocking effect of the solid obstacle, which substantially reduces the propulsive efficiency.

In recent years, transverse jet flow excited detonation is gradually known by scholars, related experimental researches are more and more, but jet flow media of the transverse jet flow excited detonation are mostly combustible mixed gas which is the same as combustion, so that the transverse jet flow excited detonation is unsafe in practical application, local small fire disasters are easy to occur in the jet flow process, and the transverse jet flow excited detonation threatens the safety of aircrafts and the safety of personnel.

Disclosure of Invention

The invention aims to provide a turbulence-enhanced flame acceleration system and method based on staggered jet flow, so as to achieve flexible control, effectively accelerate flame propagation and greatly shorten the distance and time required by DDT under a specific working condition.

In order to achieve the aim, the invention provides a turbulence-enhanced flame acceleration system based on staggered jet flow, which comprises a shock tube, an air inlet and outlet system, an ignition system, a data acquisition system, a jet flow system and a signal trigger system, wherein the air inlet and outlet system, the ignition system, the data acquisition system and the jet flow system are arranged on the shock tube; the jet system comprises carbon dioxide storage tank, solenoid valve, check valve and the efflux interface of locating on the shock tube that connects gradually, and the quantity of solenoid valve, check valve and efflux interface is a plurality of, and a plurality of efflux interfaces set up on the shock tube in a staggered manner each other.

The ignition system comprises an ignition head arranged at one end of the shock tube and a pulse igniter connected with the ignition head, and the ignition system is connected with one end of the shock tube through the ignition head.

The signal trigger system comprises a signal trigger, and the signal trigger is connected with the pulse igniter and each electromagnetic valve of the jet system.

The number of the jet interfaces arranged on the shock tube is 2, the distance between the jet interface of the first strand and the ignition end of the shock tube is 10cm, and the distance between the jet interface of the second strand and the ignition end of the shock tube is 20 cm.

The gas inlet and outlet system is connected with the shock tube through a gas inlet and outlet interface arranged on the shock tube; the gas inlet and outlet system comprises a methane bottle, an oxygen high-pressure gas bottle, a gas mixing tank and a vacuum pump, wherein the methane bottle, the oxygen high-pressure gas bottle, the gas mixing tank and the vacuum pump are connected with the gas inlet and outlet interface through corresponding hoses and valves.

The data acquisition system comprises pressure sensors and ion probes which are arranged in the length direction of the shock tube at equal intervals, wherein the pressure sensors and the ion probes are in one-to-one correspondence and are arranged on the same section.

The data acquisition system further comprises a signal amplification circuit and data acquisition hardware, the pressure sensor is directly connected with the data acquisition hardware, and the ion probe is connected with the data acquisition hardware through the signal amplification circuit.

In another aspect, the present invention provides a turbulent flow enhanced flame acceleration method based on staggered jet, including:

s1: the turbulent flow intensified flame acceleration system based on the staggered jet flow comprises a shock tube, an air inlet and outlet system, an ignition system, a data acquisition system, a jet flow system and a signal trigger system, wherein the air inlet and outlet system, the ignition system, the data acquisition system and the jet flow system are arranged on the shock tube; the jet system consists of a carbon dioxide storage tank, an electromagnetic valve, a one-way valve and jet interfaces arranged on a shock tube which are connected in sequence, wherein the number of the electromagnetic valve, the number of the one-way valve and the number of the jet interfaces are multiple, and the multiple jet interfaces are arranged on the shock tube in a staggered manner;

s2: on the premise of ensuring good air tightness of the shock tube, pumping the shock tube to a vacuum state by using an air inlet and outlet system, and then injecting methane-oxygen combustible mixed gas or methane-air combustible mixed gas, so that the shock tube is in a state of pressure ranging from 20 kPa to 25 kPa; keeping the signal trigger system and the data acquisition system in a standby state;

s3: setting the opening time of each electromagnetic valve of the jet system in the signal trigger system before the ignition time of the ignition system;

s4: triggering the system according to the set trigger signal of the step S3 to start the shock tube detonation experiment.

In the step S3, the time interval between the opening time of the electromagnetic valve and the ignition time of the ignition system is controlled to be 20-40 ms, the opening time of the electromagnetic valve is 100ms, and the ignition time of the ignition system is 1S.

The step S3 further includes: and adjusting the outlet pressure of a carbon dioxide storage tank of the jet system, so that the outlet pressure of the carbon dioxide storage tank is 20-70 times of the air pressure in the shock tube.

The turbulence-enhanced flame acceleration system and method based on staggered jet flow increase the turbulence effect in the detonation tube and accelerate the flame propagation speed through the interaction among a plurality of transverse high-speed jet flows, and further shorten the distance required by DDT (direct double-jet) by exciting the flame propagation to realize flame acceleration and even detonation in a short time, so that a smaller blockage ratio can be achieved, and the DDT distance and time can be effectively shortened.

In addition, the flame acceleration system of the invention specifically adopts a control system of multi-strand jet flow to be matched with an ignition system, and the multi-strand high-speed carbon dioxide jet flow enters a shock tube through a plurality of electromagnetic valves at the same time or at different times, thereby realizing the control of the multi-strand high-speed jet flow; and the transverse jet flow mode based on inert gas is adopted, so that the safety and the reliability of the system are improved while the effects of exciting flame deformation and acceleration are ensured. The invention can be applied to the detonation process of rapid excitation detonation transition and has wide application prospect and research value in the fields of detonation dynamics, fluid dynamics, detonation physics and the like.

Drawings

FIG. 1 is a schematic structural diagram of a shock tube experimental system based on a turbulent enhanced flame acceleration system according to an embodiment of the invention.

FIG. 2 is a schematic view of the jet distribution pattern of the turbulent enhanced flame acceleration system based on staggered jets as shown in FIG. 1.

FIG. 3 is a schematic diagram of the timing sequence of the operation of the solenoid valve and pulse igniter of the turbulent intensified flame acceleration system based on staggered jets in accordance with one embodiment of the present invention.

FIG. 4 is a graph of the velocity of methane-oxygen flame propagation under the influence of the turbulent enhanced flame acceleration method based on staggered jets of the present invention.

Detailed Description

The present invention will be further described with reference to the following specific examples. It should be understood that the following examples are illustrative only and are not intended to limit the scope of the present invention.

Fig. 1 shows a turbulent intensified flame acceleration system based on staggered jet flow according to an embodiment of the invention, which is improved based on a shock tube experimental platform. Therefore, the turbulent flow intensified flame acceleration system based on staggered jet flow comprises a shock tube 1, an air inlet and outlet system 2, an ignition system 3, a data acquisition system 4, a jet flow system 5 and a signal trigger system 6, wherein the air inlet and outlet system 2, the ignition system 3, the data acquisition system 4 and the jet flow system 5 are arranged on the shock tube 1, and the signal trigger system 6 is connected with the ignition system 3 and the jet flow system 5.

The ignition system 3 includes an ignition head 31 mounted at one end of the shock tube and a pulse igniter 32 connected to the ignition head 31. The ignition system 3 is connected with one end of the shock tube 1 through an ignition head 31, and the ignition head 31 is powered by a pulse igniter 32.

And the air inlet and outlet system 2 is connected with the shock tube 1 through an air inlet and outlet interface arranged on the shock tube 1. The air inlet and outlet port may be disposed at any position in the length direction of the shock tube 1, and in this embodiment, the air inlet and outlet port is disposed at one end of the shock tube 1 away from the ignition system 3 in the length direction. The gas inlet and outlet system 2 comprises a methane cylinder 21, an oxygen high-pressure gas cylinder 22, a gas mixing tank 23 and a vacuum pump 24, wherein the methane cylinder 21, the oxygen high-pressure gas cylinder 22, the gas mixing tank 23 and the vacuum pump 24 are all connected with the gas inlet and outlet interface through respective corresponding hoses and valves 25. The purpose of the gas mixing tank 23 is to mix methane from the methane tank 21 and oxygen from the oxygen high pressure gas tank 22.

The data acquisition system 4 comprises pressure sensors 41(PCB 113B21 series) and ion probes 42 which are arranged in the length direction of the shock tube at equal intervals, a signal amplification circuit 43 and data acquisition hardware 44, wherein the pressure sensors 41 and the ion probes 42 are arranged in a one-to-one correspondence and same section. The pressure sensor 41 is used for acquiring a pressure signal and is directly connected with the data acquisition hardware 44; the ion probe 42 is used to acquire a flame signal and is connected to data acquisition hardware 44 via signal amplification circuitry 43. Data acquisition hardware 44 is used for acquisition and filtering of pressure and flame signal sources.

In the present embodiment, the data acquisition system 4 employs a PXIe-1071 from National Instrument corporation, and the data acquisition hardware 44 employs a BNC-2110 module.

As shown in fig. 2, the jet system 5 is composed of a carbon dioxide storage tank 51, an electromagnetic valve 52, a one-way valve (not shown), and a jet interface 54 arranged on the shock tube 1, which are connected in sequence, and is connected with the shock tube 1 through the jet interface 54. The number of the carbon dioxide storage tanks 51 is one, the number of the electromagnetic valves 52, the check valves, and the fluidic interfaces 54 is plural, and the plural fluidic interfaces 54 are alternately arranged on the shock tube 1, and the directions of the jet flows of the fluidic interfaces 54 are parallel to each other. In this embodiment, the number of the electromagnetic valves 52, the one-way valves, and the jet interfaces 54 provided on the shock tube 1 is 2, the first jet interface 54 is 10cm away from the ignition end of the shock tube 1, and the second jet interface 54 is 20cm away from the ignition end of the shock tube 1. The firing end refers to the end of shock tube 1 at which firing head 31 is located.

The check valve is connected between the electromagnetic valve 52 of the jet system 5 and the shock tube 1, so that gas can be prevented from flowing back through the jet interface 54 during ignition. The electromagnetic valve 52 of the jet system 5 is an ultra-high speed electromagnetic valve, the response time of the electromagnetic valve is 3.5MS, and the model specification of the electromagnetic valve 52 of the jet system 5 is FESTO MHE4-MS 1H-3/2G-1/4-K.

The signal trigger system 6 comprises a signal trigger 61, and the signal trigger 61 is connected with each electromagnetic valve 52 of the pulse igniter 32 and the jet system 5, so that each electromagnetic valve 52 of the pulse igniter 32 and the jet system 5 of the ignition system 3 is controlled by the signal trigger 61. In the present embodiment, the signal flip-flop 61 is an Arduino board and has a signal flip-flop control program installed thereon.

Based on the turbulent intensified flame acceleration system based on staggered jet flow, the realized turbulent intensified flame acceleration method based on staggered jet flow specifically comprises the following steps:

step S1: as shown in fig. 1, a turbulent enhanced flame acceleration system based on staggered jets as described above is provided;

step S2: on the premise of ensuring good air tightness of the shock tube 1, pumping the shock tube 1 to a vacuum state by using the air inlet and outlet system 2, and then injecting methane-oxygen combustible mixed gas or methane-air combustible mixed gas, so that the shock tube 1 is in a low-pressure state, and the pressure range is 20-25 kPa in the low-pressure state; keeping the signal trigger system 6 and the data acquisition system 4 in a standby state;

step S3: as shown in fig. 3, the opening time of each solenoid valve 52 of the fluidic system 5 is set in the signal triggering system 6 to be prior to the ignition time of the ignition system 3, so that the fluidic triggering is prior to the ignition triggering; therefore, a plurality of high-speed jet flows are formed firstly; and triggering the ignition system at intervals to form high-speed propagating flame waves or even detonation waves in the shock tube.

Wherein, the time interval between the opening time of the electromagnetic valve 52 and the ignition time of the ignition system 3 is controlled to be 20-40 ms; the jet operation time (i.e., the opening period of the solenoid valve 52) was set to 100ms, and the ignition operation time (i.e., the ignition period of the ignition system 3) was set to 1 s.

The step S3 further includes: the outlet pressure of the carbon dioxide storage tank 51 of the jet system 5 is adjusted so that the outlet pressure of the carbon dioxide storage tank 51 is 20-70 times of the air pressure (i.e., the pressure of the methane-oxygen combustible gas mixture) in the shock tube 1.

Step S4: triggering the system 6 according to the set trigger signal of the step S3 to start the shock tube detonation experiment. In the shock tube detonation experiment, the data acquisition system 4 is adopted to acquire and store data.

FIG. 4 shows a flame propagation velocity curve calculated from the flame signal captured by the ion probe. As shown in FIG. 4, when the turbulence-enhanced flame acceleration system based on staggered jet mentioned in the invention is not used, the flame propagation speed is relatively slow and is only 500m/s at most, and when the turbulence-enhanced flame acceleration system based on staggered jet mentioned in the invention is introduced, the flame propagation speed is as high as 2250m/s, and the flame propagation speed is obviously improved.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.