CN102174913A - Pulse detonation engine with ejector and method for processing main detonation tube - Google Patents

Abstract

The invention proposes a pulse detonation engine with an ejector and a main detonation tube processing method, which is characterized in that: one end of the ejector inlet is a horn-shaped expansion section, and the wall surface of the expansion section is a 1/4 arc wall surface, The relationship between the arc radius R and the inner diameter D of the cylindrical section is: 2/5≤R/D≤3/5; the ejector is installed coaxially with the main detonation tube, and the relationship between the inner diameter d and D of the main detonation tube is: 2 /5≤d/D≤3/5, the axial distance of the main detonation tube extending into the ejector is L, the relationship between L and d is: 2≤L/d≤6, the inner opening of the main detonation tube wall There is a spiral channel. The present invention designs the inlet structure of the ejector, the structural relationship between the main detonation tube and the ejector, and the spiral passage in the wall of the main detonation tube, so that the fuel for secondary ignition can be fully heated in the tube wall, which is beneficial to reduce The DDT distance of the secondary detonation reduces the temperature of the main detonation tube and improves the thermal fatigue life of the main detonation tube.

Description

A pulse detonation engine with an ejector and a processing method for a main detonation tube

technical field

The invention relates to the field of engines, in particular to a pulse detonation engine with an ejector and a processing method for a main detonation tube.

Background technique

The pulse detonation engine (PDE) is a new concept engine that uses pulse detonation waves to generate thrust. Since the pulse detonation engine is still in the initial stage of research, there are many challenges and difficulties, especially in increasing the engine thrust. aspect. At present, for a PDE with a fixed volume, there are generally two ways to improve the thrust performance: one is to increase the repetition rate, and the other is to increase the impulse per unit pulse.

For the second method, the thrust can be increased by changing the structure of the intake port, detonation section, tail nozzle, etc., but according to domestic and foreign research in recent years, the thrust has not been greatly improved only by the above means . The use of adding an ejector at the tail of the engine can significantly increase the thrust of the engine. At present, there are many studies on the structure of the ejector at home and abroad, but most of the researches focus on when the mainstream is the steady state, while there are relatively few studies when the mainstream is the unsteady state. Only sporadic reports suggest that the shape of the ejector inlet is mainly round The body is the main body. This structure has a small aerodynamic area, which is not conducive to the ejector entraining the surrounding air, thereby reducing the amount of projection and reducing the boosting effect of the ejector. In addition, if the detonation can be re-ignited (secondary ignition) inside the ejector, the thrust of the engine will also be greatly improved.

When the pulse detonation engine is working, the high-frequency detonation wave passes through the surface of the inner wall of the detonation tube, and transfers part of the heat to the tube wall, causing the temperature of the engine tube wall to rise sharply. This part of the heat has no contribution to the performance of the pulse detonation engine. It will overheat the engine tube wall and cause harm to its working life and stability. At the same time, the study found that when the temperature of the fuel used to supply the engine is high, the fuel can be easily flashed, thereby reducing the deflagration to detonation conversion (DDT) distance. At present, the use of fuel oil to cool the engine pipe wall has been studied at home and abroad, and the waste heat of the pipe wall is absorbed to increase the temperature of the fuel, and then the fuel is supplied to the engine, and the pipe wall under different knock frequencies is cooled by fuel oil. On the one hand, it can reduce the engine The temperature of the pipe wall increases the thermal fatigue life of the engine; on the other hand, the fuel that has absorbed waste heat is used as the engine fuel to improve the atomization and evaporation of the fuel, which is easy to form knocking and shorten the DDT distance. However, most of the current heat exchanger structures have uneven heat transfer, poor fluidity, and potential safety hazards.

Contents of the invention

technical problem to be solved

In order to effectively improve the thrust of the pulse detonation engine, the invention proposes a pulse detonation engine with an ejector and a processing method for the main detonation tube.

Technical solutions

Technical scheme of the present invention is:

The pulse detonation engine with an ejector includes a main detonation tube, and is characterized in that it also includes an ejector, one end of the inlet of the ejector is a horn-shaped expansion section, the rest are cylindrical sections, and the expansion section The wall surface is a 1/4 arc wall surface, and the relationship between the arc radius R and the inner diameter D of the cylindrical section is: 2/5≤R/D≤3/5; the ejector is installed coaxially with the main detonation tube, and the main detonation tube The relationship between the inner diameter d of the tube and the inner diameter D of the cylindrical section of the ejector is: 2/5≤d/D≤3/5, the end face of the main detonation tube extending into the ejector and the outer end face of the expansion section of the ejector The axial distance is L, the relationship between L and the inner diameter d of the main detonation tube is: 2≤L/d≤6, there is a spiral channel inside the tube wall of the main detonation tube, and the spiral channel is opened on the outer wall of the main detonation tube There is an inlet, and the inlet is fixedly connected with the fuel inlet nozzle, and the spiral channel is provided with a plurality of outlets on the end face of the main detonation tube extending into the ejector, and the outlet is fixedly connected with the fuel nozzle.

The preferred solution of the present invention is characterized in that: the relationship between the arc radius R and the inner diameter D of the cylindrical section is: R/D=0.5.

The preferred solution of the present invention is characterized in that the relationship between the inner diameter d of the main detonation tube and the inner diameter D of the cylindrical section of the ejector is: d/D=0.5.

The processing method of the main detonation tube with a spiral channel is characterized in that: firstly, the wall of the main detonation tube is processed, and the thickness of the tube wall is equal to the sum of the wall thickness of the conventional detonation tube and the depth of the spiral channel; A spiral groove is made on the wall of the main detonation tube; finally, a sleeve with an inner diameter of the main detonation tube and an outer diameter of the main detonation tube is processed, and the main detonation tube with a spiral groove is embedded in the sleeve and welded at both ends fixed.

Beneficial effect

The invention realizes a better ejection effect by designing the inlet structure of the ejector and the structural relationship between the main detonation tube and the ejector, and at the same time designs the spiral channel in the wall of the main detonation tube, so that the fuel for secondary ignition It can be fully heated in the tube wall, which is not only beneficial to reduce the DDT distance of the secondary detonation, but also can reduce the temperature of the main detonation tube, and improve the thermal fatigue life of the main detonation tube.

Description of drawings

Fig. 1: structural representation of the present invention;

Fig. 2: plan view of the present invention;

Figure 3: Structural diagram of ejector;

Among them: 1. Ejector; 2. Fuel nozzle; 3. Spiral channel; 4. Oil inlet nozzle; 5. Main detonation tube.

Detailed ways

The present invention is described below in conjunction with specific embodiments.

Example:

Referring to accompanying drawing 1 and accompanying drawing 2, present embodiment comprises injector 1, fuel nozzle 2, spiral channel 3, oil inlet nozzle 4 and main detonation tube 5.

Referring to accompanying drawing 3, one end of the inlet of the injector 1 is a trumpet-shaped expansion section, and the rest is a cylindrical section, and the wall surface of the expansion section is a 1/4 arc wall surface, and the relationship between the arc radius R and the inner diameter D of the cylindrical section is R/D=0.5 . Referring to accompanying drawing 2, ejector 1 is coaxially installed with main detonation tube 5; the requirements for the inner diameter D of the cylindrical section of ejector 1 must firstly provide sufficient area for ejecting the secondary flow, and secondly ensure that the ejector 1 The pressure difference between the inside and the outside, so in this embodiment, the relationship between the inner diameter d of the main detonation tube 5 and the inner diameter D of the cylindrical section of the ejector 1 is d/D=0.5; the main detonation tube 5 extends into the ejector 1. The depth inside will also have an impact on the ejection effect and the secondary ignition effect. The axial distance between the end face of the main detonation tube 5 extending into the ejector 1 and the outer end face of the expansion section of the ejector 1 is L, in this embodiment, the relationship between L and the inner diameter d of the main detonation tube is L/d=4.

Referring to accompanying drawing 2, in order to make full use of the heat generated when the main detonation tube 5 works to heat the fuel for secondary ignition and reduce the DDT distance of the secondary detonation, a spiral channel 3 is opened inside the wall of the main detonation tube 5. The channel 3 has an inlet on the outer wall of the main detonation tube 5, and the inlet is fixedly connected with the oil inlet nozzle 4. The spiral channel 3 has three outlets on the end surface of the main detonation tube 5 extending into the ejector 1, each The outlets are all fixedly connected with a fuel nozzle 2 . Fuel enters the spiral channel 3 from the fuel inlet nozzle 4, is sprayed out from the fuel nozzle 2 after being fully heated therein, and is directly sprayed into the injector 1, and is re-ignited by the tail flame of the main detonation tube 5.

The processing method of the main detonation tube with a spiral channel is as follows: firstly process the wall of the main detonation tube, and the thickness of the tube wall is equal to the sum of the wall thickness of the conventional detonation tube and the depth of the spiral channel; Spiral grooves are made on the pipe wall; finally, a casing with the inner diameter of the main detonation tube and the outer diameter of the main detonation tube is processed, and the main detonation tube with the spiral groove is embedded in the casing and fixed by welding at both ends, and the A hole is opened on the pipe corresponding to the inlet of the spiral passage as a fuel inlet, and a fuel outlet connected with the spiral passage is also opened on the end face of the pipe wall.

When the present embodiment works, the oil inlet nozzle 4 is connected with the outer oil pipe, and the oil pressure is 0.6MP-0.7MP. Start the main pulse detonation engine normally. After the engine works stably, there will be a detonation flame ejected from the tail of the main detonation tube, and at the same time, air will be ejected into the ejector. At this time, the ejector is in a fuel-lean state; Gasoline is injected into the channel, and the amount of gas injected is matched with the amount of gas contained in the ejector to ensure that the equivalence ratio in the ejector can be maintained at 1; at this time, gasoline is ejected from the fuel nozzle at the tail of the main detonation tube. temperature, so it can become a gaseous state in a short time and mix with the injected airflow, which is equivalent to the fuel filling process of the detonation engine; finally these mixtures are ignited at the flame ejected from the main detonation tube, thus forming two Knock. Due to the relatively large diameter of the injector, it is difficult to ignite it directly with the igniter, and the flame ignition at the tail of the main detonation tube can effectively solve this problem. Generally speaking, the larger the diameter of the main detonation tube, the larger the cross-section connection, which can generate greater thrust. The secondary detonation is equivalent to another detonation in the ejector, so it can Generate greater thrust, so that within a certain period of time, the overall thrust value of the engine can be effectively increased.

Claims (4)

1. pulse-knocking engine that has ejector, comprise main detonation tube, it is characterized in that: also include ejector, ejector import one end is tubaeform extending section, all the other are cylindrical section, the extending section wall is 1/4 circular arc wall, and the pass of radius of arc R and cylindrical section inside diameter D is: 2/5≤R/D≤3/5; Ejector and the coaxial installation of main detonation tube, and the pass of main detonation tube inner diameter d and ejector cylindrical section inside diameter D is: 2/5≤d/D≤3/5, main detonation tube stretches into the interior end end face of ejector and the axial distance of ejector extending section outer end end face is L, and the pass of L and main detonation tube inner diameter d is: 2≤L/d≤6; The tube wall inside of main detonation tube has helical duct, and helical duct has import on main detonation tube outer wall, and import and oil intake nozzle are connected, and helical duct has some outlets on main detonation tube stretches into an end end face in the ejector, and outlet is connected with fuel nozzle.

2. a kind of pulse-knocking engine that has ejector according to claim 1 is characterized in that: the pass of radius of arc R and cylindrical section inside diameter D is: R/D=0.5.

3. a kind of pulse-knocking engine that has ejector according to claim 1 is characterized in that: the pass of main detonation tube inner diameter d and ejector cylindrical section inside diameter D is: d/D=0.5.

4. have the main detonation tube processing method of helical duct in the claim 1, it is characterized in that: at first process main detonation tube tube wall, pipe thickness equals conventional detonation tube pipe thickness and helical duct degree of depth sum; Secondly on the main detonation tube tube wall that processes, leave spiral groove; The sleeve pipe that to process an internal diameter at last be main detonation tube external diameter, embed the main detonation tube of band spiral groove in the sleeve pipe and the two ends welding fixing.

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