CN113028454B - High-frequency detonation combustion scheme based on regenerative cooling - Google Patents

Abstract

The invention provides a regenerative cooling-based high-frequency detonation combustion scheme, which comprises a pulse detonation combustion chamber and a high-frequency detonation combustion control method. The detonation tube is externally provided with a cooling jacket structure in a single-layer cooling layout or a double-layer cooling layout, liquid water is used as a cooling medium or liquid water and liquid fuel are used as the cooling medium, when the liquid water is used as the cooling medium, the liquid water firstly flows through the cooling jacket, forced convection cooling is carried out on the detonation tube from the outer side by utilizing the characteristics of small volume, large specific heat capacity and convenience and easiness in obtaining of the liquid water, the cooling medium after absorbing heat is conveyed to the head of the detonation tube through a supply pipeline and is sprayed into the detonation tube through a spraying system arranged at the head to serve as an isolating medium, the purpose of isolating a previous cycle combustion product from a next cycle fresh reactant is achieved, and the detonation combustion failure caused by early ignition of the fresh reactant is prevented; when two liquid fuels are used as cooling media, in addition to the advantages, the liquid fuel can be preheated, so that atomization and evaporation are promoted, and the initiation performance is improved. The invention can not only realize the effective cooling of the detonation tube, but also ensure the high-frequency stable work of the pulse detonation combustor, and can be used in the fields of ship pulse detonation engines, thermal spraying, power generation and the like.

Description

A High Frequency Detonation Combustion Scheme Based on Regenerative Cooling

technical field

The invention relates to the technical field of detonation combustion, in particular to a high-frequency detonation combustion scheme based on regenerative cooling.

Background technique

The detonation combustion is close to the constant volume combustion, the heat release rate is fast and the self-pressurization can be realized, which has a potential important application prospect in the field of jet propulsion. When the Pulse Detonation Combustor (PDC) runs for a long time, the large amount of heat released by the detonation combustion causes the wall temperature of the detonation tube to rise sharply. On the one hand, it will exceed the heat resistance limit of the material and cause structural damage. On the one hand, this part of the heat will cause a large performance loss, thereby reducing the thermal efficiency; in addition, the hot tube wall will cause the reactants to ignite prematurely, making the detonation combustion ineffective. Therefore, it is very necessary to find effective cooling measures to ensure the stable operation of PDC. The valveless and isolated supply method can not only get rid of the limitation of the mechanical valve on the working frequency of PDC, but also avoid the occurrence of continuous combustion. It is a feasible high-frequency working method of PDC. The traditional valveless and isolated working method requires an independent isolation medium supply system, which increases the overall system weight and complexity to a certain extent.

In view of the above problems, it is particularly important to design a pulse detonation combustion chamber that can not only effectively cool the detonation tube, but also ensure high-frequency stable operation. The present invention proposes a high-frequency detonation combustion scheme based on regenerative cooling, which can meet the above requirements and has practical value in the fields of ship pulse detonation engines, thermal spraying and power generation.

SUMMARY OF THE INVENTION

technical problem to be solved

Aiming at the problems in the current PDC valveless filling method and wall thermal management, the present invention proposes a high-frequency detonation combustion scheme based on regenerative cooling. A cooling jacket structure with a single-layer cooling layout or a double-layer cooling layout is adopted outside the detonation tube, and liquid water is used as the cooling medium or two kinds of liquid water and liquid fuel are used as the cooling medium. When liquid water is used as the cooling medium, the liquid water first flows through the cooling jacket, and the detonation tube is cooled by forced convection from the outside using the characteristics of small volume, large specific heat capacity, and convenience and availability of liquid water; the cooling medium after heat absorption passes through the supply tube. It is transported to the head of the detonation tube, and injected into the detonation tube through the injection system installed on the head to act as an isolation medium, so as to achieve the purpose of isolating the combustion products of the previous cycle and the fresh reactants of the next cycle, and prevent the fresh reactants from igniting in advance. lead to the failure of knock combustion. When two kinds of liquid water and liquid fuel are used as the cooling medium, in addition to the above advantages, the liquid fuel can also be preheated to promote atomization and evaporation, and improve the detonation performance. It can not only realize the effective cooling of the detonation tube, but also ensure the high-frequency stable operation of the pulse detonation combustion chamber. The invention can be used in the fields of ship pulse detonation engine, thermal spraying and power generation.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A high frequency detonation combustion scheme based on regenerative cooling includes a pulse detonation combustion chamber and a high frequency detonation combustion control method.

The pulse detonation combustion chamber is composed of a detonation tube, a cooling system, a supply and mixing system and an ignition system.

The detonation tube is a cylindrical structure with one end closed and one end open, and the direction of the closed end is defined as upstream, and the direction of the open end is downstream.

The cooling system consists of a liquid water supply channel, a liquid fuel supply channel, a liquid water cooling jacket, a liquid fuel cooling jacket, a cooling medium-water supply channel, a cooling medium-fuel supply channel, a water vapor separation device, a pressure regulating device, and a flow regulating device. It consists of a cooler and a cooling medium discharge channel. The liquid water cooling jacket is the main device for the heat exchange between the detonation tube and the cooling water, and the liquid fuel cooling jacket is the main device for the heat exchange between the detonation tube and the liquid fuel. Cooling passage; the cooling jacket covers at least the downstream of the ignition device to the end of the detonation tube, and the inlet and outlet can be designed according to the actual situation; the axial length of the liquid water cooling jacket and the liquid fuel cooling jacket can be designed according to the actual situation; When the nozzle is used, the cooling jacket can be extended to the tail nozzle according to the specific situation. The liquid water enters the liquid water cooling jacket through the liquid water supply channel, and the liquid fuel enters the liquid fuel cooling jacket through the liquid fuel supply channel, respectively for forced convection cooling on the outer wall of the detonation tube, and then flows to the outlet of the cooling jacket; the water vapor enters the cooling jacket The medium-water supply channel is sent to the head of the detonation tube, and the outlet of the channel is equipped with a water vapor separation device, a pressure regulating device and a flow regulator. The remaining cooling water is discharged through the cooling medium discharge channel, and this part of the cooling water can be used for heating or other purposes for waste heat recovery.

The supply and blending system consists of a fuel supply channel, a fuel injector, an oxidant supply channel, and an isolation medium injector. The isolating medium injector is located at the geometric center of the closed section of the detonation tube; the fuel and oxidant enter the front end of the detonation tube respectively through independent channels, and the two are symmetrically distributed along the central axis of the detonation tube, and the included angle with the downstream direction of the axis is 30~ 90°, the specific angle should be less than or equal to the injection half cone angle of the isolation medium injector; extend the dotted line of the side wall surface of the fuel and oxidant supply channels near the head of the detonation tube to the intersection, which should coincide with the position of the isolation medium nozzle ; The inner diameter of the fuel and oxidant supply channels should be specifically designed according to the actual situation.

The ignition system is as follows: an ignition device is used to ignite and detonate to detonate; a spark plug can be used as the ignition device; and a solid obstacle or a fluid obstacle can be used as the detonation enhancement device.

The high-frequency detonation combustion control method is as follows: the fuel, the oxidant and the isolation medium all adopt a valveless filling method, that is, during the working process of the pulse detonation cycle, the valve is in a normally open state; the filling pressure of the isolation medium is controlled in the detonation tube. Between the head peak pressure and the platform pressure, the fuel and oxidant filling pressures are controlled near the platform pressure, which is lower than the filling pressure of the isolation medium; at the beginning of the detonation cycle, the fuel and oxidant pass through the fuel supply channel, the fuel injector, respectively. , The oxidant supply channel is filled into the detonation tube; after the filling process, the ignition device starts to ignite to form a detonation wave; the isolation medium enters the detonation tube through the head isolation medium injector, and the filling time should be later than the fuel and oxidant start to fill Time 0~1ms, the specific filling delay time should be determined by the vaporization effect of the isolation medium. When the vaporization effect is poor, the delay time can be appropriately shortened to make it enter the detonation tube as soon as possible to vaporize to form an isolation area; At the same time, the detonation wave forms a high-pressure area at the head of the detonation tube. The pressure in this area is higher than the filling pressure of the fuel, oxidant and isolation medium, and a pneumatic valve will be formed at the head of the detonation tube, so that the fuel, oxidant and isolation medium Can not enter the detonation tube, the filling process is suspended; the continuous exhaust process of the combustion products causes the pressure of the head of the detonation tube to drop, and when it falls below the filling pressure of the isolation medium, the filling process of the isolation medium resumes, and the first to enter the detonation tube to form A section of isolation area isolates the combustion products; the pressure at the head of the detonation tube continues to drop until the pressure drops below the filling pressure of the fuel and oxidant. At this time, the filling process of fuel and oxidant resumes and the next cycle begins.

Beneficial effects:

The invention provides a high-frequency detonation combustion scheme based on regenerative cooling. A cooling jacket structure with a single-layer cooling layout or a double-layer cooling layout is adopted outside the detonation tube, and liquid water is used as the cooling medium or liquid water and liquid fuel are used as two as a cooling medium. When liquid water is used as the cooling medium, the liquid water first flows through the cooling jacket, and the detonation tube is cooled by forced convection from the outside using the characteristics of small volume, large specific heat capacity, and convenience and availability of liquid water; the cooling medium after heat absorption passes through the supply tube. It is transported to the head of the detonation tube, and injected into the detonation tube through the injection system installed on the head to act as an isolation medium, so as to achieve the purpose of isolating the combustion products of the previous cycle and the fresh reactants of the next cycle, and prevent the fresh reactants from igniting in advance. lead to the failure of knock combustion. When two kinds of liquid water and liquid fuel are used as the cooling medium, in addition to the above advantages, the liquid fuel can also be preheated to promote atomization and evaporation, and improve the detonation performance. It can not only realize the effective cooling of the detonation tube, but also ensure the high-frequency stable operation of the pulse detonation combustion chamber. The invention can be used in the fields of ship pulse detonation engine, thermal spraying and power generation.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the pulse detonation combustion chamber of the present invention (Example 1, gaseous fuel);

Figure 2 is a schematic structural diagram of the pulse detonation combustion chamber of the present invention (Example 2, liquid fuel, single-layer cooling layout);

3 is a schematic structural diagram of the pulse detonation combustion chamber of the present invention (Embodiment 3, liquid fuel, inner and outer double-layer cooling layout);

Fig. 4 is the control sequence diagram of the pulse detonation combustion chamber of the present invention;

Fig. 5 is the change curve of the head pressure of the detonation tube of the present invention with time;

In the above figure, 1 is the detonation tube, 2 is the liquid water cooling jacket, 3 is the ignition device, 4 is the oxidant supply channel, 5 is the fuel supply channel, 6 is the isolation medium injector, 7 is the liquid water supply channel, 8 9 is the cooling medium-water supply channel, 9 is the water vapor separation device, 10 is the pressure regulating device, 11 is the flow regulator, 12 is the cooling medium discharge channel, 13 is the control system, 14 is the liquid fuel cooling jacket, 15 is the liquid fuel Supply channels, 16 are cooling medium-fuel supply channels, and 17 are fuel injectors.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific implementation processes.

1, 2 and 3, the pulse detonation combustion chamber consists of a detonation tube 1, a cooling system (such as a liquid water supply channel 7, a liquid fuel supply channel 15, a liquid water cooling jacket 2, a liquid fuel cooling jacket 14) , cooling medium-water supply channel 8, cooling medium-fuel supply channel 16, water vapor separation device 9, pressure regulating device 10, flow regulator 11 and cooling medium discharge channel 12), supply and blending system (such as fuel supply channel 5. The fuel injector 17 , the oxidant supply channel 4 , the isolation medium injector 6 ), the ignition system (such as the ignition device 3 ) and the control system 13 are composed. The detonation tube 1 is a cylindrical structure with one end closed and one end open, and the direction of the closed end is defined as upstream and the direction of the open end is downstream. The liquid water enters the liquid water cooling jacket 2 through the liquid water supply channel 7, and the water vapor after endothermic vaporization enters the cooling medium-water supply channel 8 and is sent to the head of the detonation tube, and the outlet of the channel 8 is equipped with a water vapor separation device 9, The pressure regulating device 10 and the flow regulator 11 , water vapor with a certain pressure and flow is injected into the pipe through the head isolation medium injector to serve as the isolation medium, and the remaining cooling water is discharged through the cooling medium discharge channel 12 . The isolation medium injector 6 is located at the geometric center of the closed end of the detonation tube 1, and the isolation medium enters the detonation tube 1 through the cooling system; the fuel and the oxidant enter the front end of the detonation tube 1 through the fuel supply channel 5 and the oxidant supply channel 4 respectively. , the two are symmetrically distributed about the central axis of the detonation tube 1, and the included angle with the downstream direction of the axis is 30° to 90°, and the specific angle should be less than or equal to the injection half cone angle of the isolation medium injector 6; and the oxidant supply channel 4 close to the detonation tube head side wall dashed line extends to the intersection, which should coincide with the position of the isolation medium nozzle; the inner diameter of the fuel supply channel 5 and the oxidant supply channel 4 should be specifically designed according to the actual situation. The ignition system adopts a detonation method in which the ignition device 3 is ignited and transformed from detonation to detonation. The ignition device can be a spark plug, and a solid obstacle or a fluid obstacle can be used as the detonation enhancement device.

Referring to Figure 4 and Figure 5, during operation, the fuel, oxidant and isolation medium are all filled with valveless, that is, during the working process of the pulse detonation cycle, the valve is in a normally open state; the filling pressure p _purge of the isolation medium is controlled at the detonation level. Between the peak pressure of the tube head and the plateau pressure p _plateau , the fuel p _fuel and the oxidant filling pressure p _oxidizer are controlled around the plateau pressure p _plateau , which is lower than the filling pressure p _purge of the isolation medium; at the beginning of the detonation cycle, the fuel and The oxidant is filled into the detonation tube 1 without valve through the fuel supply channel 5 and the oxidant supply channel 4 respectively; after the filling process is over, the ignition device 3 starts to ignite to form a detonation wave; the isolation medium enters the detonation through the head isolation medium injector In the shock tube, the filling time should be 0-1ms later than the filling time of fuel and oxidant. The specific filling delay time should be determined by the vaporization effect of the isolation medium. When the vaporization effect is poor, the delay time can be appropriately shortened to make it enter the knocking process as soon as possible. The vaporization in the tube forms an isolation zone; the detonation wave propagates to the open end of the detonation tube, and at the same time, the detonation wave forms a high-pressure zone at the head of the detonation tube, and the pressure in this zone is higher than the fuel p _fuel , the oxidant p _oxidizer and the isolation medium filling pressure p _purge , a pneumatic valve will be formed at the head of the detonation tube, so that the fuel, oxidant and isolation medium cannot enter the detonation tube, and the filling process will be suspended; When the medium filling pressure p _purge is lower, the filling process of the isolation medium resumes, and it first enters the detonation tube to form a section of isolation area to isolate the combustion products; the pressure at the head of the detonation tube continues to drop until the pressure drops to the level of fuel p _fuel , oxidant Under the filling pressure p _oxidizer , the filling process of fuel and oxidant is resumed at this time, and the next cycle is started.

Example 1:

1, in this example, the cooling system consists of a liquid water supply channel 7, a liquid water cooling jacket 2, a cooling medium-water supply channel 8, a water vapor separation device 9, a pressure regulating device 10, a flow regulator 11 and a cooling medium The discharge channel 12 is formed. The liquid water cooling jacket 2 is the main device for the heat exchange between the detonation tube 1 and the cooling water, and an annular, radially ribbed, tube bundle or brazed cooling channel can be used inside. The liquid water cooling jacket 2 covers at least the downstream of the ignition device 3 to the end of the detonation tube, the inlet is located at the end of the detonation tube, and the outlet is located at the downstream position of the ignition device; when a tail nozzle is installed at the rear of the combustion chamber, the liquid water can be cooled according to specific conditions. The jacket 2 is extended to the tail nozzle; when working for a long time, the liquid water cooling jacket 2 can cover the entire detonation tube 1 according to the specific situation.

Example 2:

2, in this example, the cooling system consists of a liquid water supply passage 7, a liquid fuel supply passage 15, a liquid water cooling jacket 2, a liquid fuel cooling jacket 14, a cooling medium-water supply passage 8, and a cooling medium-fuel supply passage 16. Water vapor separation device 9, pressure regulating device 10, flow regulator 11 and cooling medium discharge channel 12. The installation position of the liquid water cooling jacket 2 should be upstream of the installation position of the liquid fuel cooling jacket 14, and at least cover the transition from slow combustion to detonation; the axial length of the liquid water cooling jacket 2 and the liquid fuel cooling jacket 14 can be specifically designed according to the actual situation. When working for a long time, the liquid water cooling jacket 2 and the liquid fuel cooling jacket 14 may cover the entire detonation tube 1 according to specific conditions. The liquid water cooling jacket 2 is the main device for the heat exchange between the detonation tube 1 and the cooling water, and the liquid fuel cooling jacket 14 is the main device for the heat exchange between the detonation tube 1 and the liquid fuel. Or a brazed cooling channel; when a tail nozzle is installed at the rear of the combustion chamber, the cooling jacket 14 may be extended to the tail nozzle according to specific conditions. The liquid water enters the liquid water cooling jacket 2 via the liquid water supply passage 7, and the liquid fuel enters the liquid fuel cooling jacket 14 via the liquid fuel supply passage 15, respectively, to perform forced convection cooling on the outer wall of the detonation tube, and then flow to the cooling jacket outlet; Water vapor enters the isolation medium injector 6 as an isolation medium, and the heat-exchanged fuel enters the detonation tube 1 via the cooling medium-fuel supply passage 16 , the fuel supply passage 5 and the fuel injector 17 .

Example 3:

Referring to Fig. 3, in this example, each part of the cooling system is the same as Example 2, but the cooling jacket is a double-layer cooling layout, specifically, the liquid water cooling jacket 2 is installed on the inner layer, and the liquid fuel cooling jacket 14 is installed on the outer layer. The liquid fuel cooling jacket 14 can be installed in the inner layer and the liquid water cooling jacket 2 can be installed in the outer layer according to the actual situation; when working for a long time, the liquid water cooling jacket 2 and the liquid fuel cooling jacket 14 can cover the entire detonation tube 1 according to the specific conditions.

The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings and the specific implementation process, but the present invention is not limited to the above-mentioned embodiments. Those skilled in the art can make the above-mentioned methods without departing from the principles of the present invention. Various changes and optimizations.

Claims (4)

1. The high-frequency detonation combustion chamber based on regenerative cooling is characterized in that: a cooling jacket structure of a single-layer cooling layout or a double-layer cooling layout is adopted outside the detonation tube, and liquid water is used as a cooling medium or two liquid water and liquid fuels are used. It is used as a cooling medium; when liquid water is used as the cooling medium, the liquid water first flows through the cooling jacket, and the detonation tube is forced convection cooling from the outside by using the characteristics of small volume, large specific heat capacity, and convenience and availability of liquid water. The cooling medium is transported to the head of the detonation tube through the supply pipeline, and injected into the detonation tube through the injection system installed in the head to act as an isolation medium, so as to achieve the purpose of isolating the combustion products of the previous cycle and the fresh reactants of the next cycle, preventing The pre-ignition of the fresh reactant leads to the failure of detonation combustion; when two kinds of liquid water and liquid fuel are used as the cooling medium, in addition to the above advantages, the liquid fuel can be preheated to promote atomization and evaporation, and improve the detonation performance. To achieve effective cooling of the detonation tube, and to ensure the high-frequency stable operation of the pulse detonation combustion chamber; when liquid water is used as the cooling medium, the cooling system consists of a liquid water supply channel, a liquid water cooling jacket, a cooling medium-water supply channel, It consists of a water vapor separation device, a pressure regulating device, a flow regulator and a cooling medium discharge channel; when two kinds of liquid water and liquid fuel are used as the cooling medium, the cooling system consists of a liquid water supply channel, a liquid fuel supply channel, a liquid water cooling jacket, a liquid water cooling jacket, and a liquid water supply channel. Composed of fuel cooling jacket, cooling medium-water supply channel, cooling medium-fuel supply channel, water vapor separation device, pressure regulating device, flow regulator and cooling medium discharge channel; liquid water enters the liquid water cooling jacket through the liquid water supply channel The water vapor after endothermic vaporization enters the cooling medium-water supply channel and is sent to the head of the detonation tube. The outlet of the channel is equipped with a water vapor separation device, a pressure regulating device and a flow regulator. The water vapor of a certain pressure and flow passes through the head. The isolation medium injector is injected into the pipe to act as an isolation medium, and the remaining cooling water is discharged through the cooling medium discharge channel. This part of the cooling water can be used for waste heat recovery for heating; when a single-layer cooling layout is used, the liquid water cooling jacket should be installed at the The liquid fuel cooling jacket is installed upstream, and needs to cover the transition section from slow combustion to detonation; when a double-layer cooling layout is adopted, a liquid water cooling jacket should be installed on the inner layer, a liquid fuel cooling jacket should be installed on the outer layer, or a liquid fuel cooling jacket should be installed on the inner layer. , the outer layer is equipped with a liquid water cooling jacket, and the axial length of the liquid water cooling jacket and the liquid fuel cooling jacket is designed according to the actual situation; the inner cooling jacket adopts annular, radial ribbed, tube bundle or brazing cooling channels, and the cooling jacket covers From the downstream of the ignition device to the end of the detonation tube, the inlet is located downstream of the detonation tube, and the outlet is located upstream of the detonation tube. When a tail nozzle is installed at the rear of the combustion chamber, extend the cooling jacket to the tail nozzle. The cooling jacket covers the entire detonation tube. 2 . The high frequency detonation combustion chamber based on regenerative cooling according to claim 1 , wherein the liquid water enters the liquid water cooling jacket through the liquid water supply passage, and the liquid fuel enters the liquid fuel cooling jacket through the liquid fuel supply passage. 3 . Inside, the outer wall of the detonation tube is subjected to forced convection cooling, and then flows to the outlet of the cooling jacket. 3. The high-frequency detonation combustion chamber based on regenerative cooling according to claim 1, wherein the isolating medium injector is located at the geometric center of the closed section of the detonation tube; the fuel and the oxidant enter the detonation tube respectively through independent channels At the front end, the two are symmetrically distributed about the central axis of the detonation tube, and the included angle with the downstream direction of the axis is 30° to 90°, and is less than or equal to the injection half cone angle of the isolation medium injector; the fuel and oxidant supply channels are close to the detonator The dashed line of the side wall surface of the shock tube head is extended to the intersection, which should coincide with the position of the isolation medium nozzle. 4. The high-frequency detonation combustion chamber based on regenerative cooling according to claim 1, wherein the control method adopted by the high-frequency detonation combustion chamber is that fuel, oxidant and isolation medium all adopt valveless filling mode, that is, In the pulse detonation cycle, the valve is in a normally open state; the filling pressure of the isolation medium is controlled between the peak pressure of the detonation tube head and the pressure in the plateau area, and the filling pressure of fuel and oxidant is controlled near the pressure in the plateau area, which is lower than that of the isolation medium At the beginning of the detonation cycle, the fuel and oxidant are filled into the detonation tube without valve through the fuel supply channel and the oxidant supply channel respectively; after the filling process, the ignition device starts to ignite to form a detonation wave; the isolation medium passes through the head When the isolation medium injector enters the detonation tube, the filling time should be 0~1ms later than the filling time of the fuel and oxidant, which is determined by the vaporization effect of the isolation medium. Enter the detonation tube as soon as possible to vaporize to form an isolation area.

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