A high initial pressure pulse detonation apparatus and method using low back pressure scavenging

Abstract

The application discloses a high-initial-pressure pulse detonation device and method using low-back-pressure scavenging, and belongs to the technical field of detonation combustion power and aerospace propulsion. The device comprises a combustion chamber, a supply unit, an air inlet valve, an ignition assembly, an air outlet valve and a nozzle, and can be additionally provided with a time sequence control unit, a low-pressure space and a vacuum pump. The method uses the time sequence control unit to complete a multi-stage cycle, fills the reaction medium into the low-pressure combustion chamber to a set initial pressure, completes detonation combustion in the sealed cavity to generate high-temperature and high-pressure gas, discharges the gas into a low-back-pressure environment through the nozzle, completes scavenging reset by relying on the exhaust, maintains the pressure difference of the low-pressure space by relying on the vacuum pump in the high-back-pressure environment, can adjust the cycle frequency and the initial filling pressure to control the thrust power, and can also adjust the opening time of the air outlet valve to adapt to the heat management demand. The application omits the independent scavenging structure to simplify the equipment composition, forms a large pressure difference between the combustion chamber and the low-back-pressure environment, and widens the efficient interval of energy conversion of the fixed profile nozzle.

Description

Technical Field

[0001] This invention belongs to the field of detonation combustion power and aerospace propulsion technology, specifically relating to the cycle control and energy conversion technology of pulse detonation power devices. Background Technology

[0002] Detonation waves are characterized by high combustion efficiency and fast propagation speed. Their combustion process is close to isochoric combustion, therefore, power systems based on detonation combustion have higher thermal efficiency and power density compared to isobaric combustion systems based on slow combustion, showing promising application prospects in aerospace propulsion. There are three main types of detonation combustion organization: pulse detonation, rotating detonation, and stationary detonation. Among these, pulse detonation technology has advantages in controllability and ease of implementation compared to the other two methods. The working cycle of a conventional pulse detonation engine typically consists of four parts: exhaust gas purging, fuel filling, ignition, and exhaust power generation.

[0003] The purging process in existing pulse detonation engines increases the complexity of the system structure, consumes additional purging gas, and occupies cycle time. Furthermore, existing pulse detonation engines almost never have exhaust valves, resulting in low initial and final combustion pressures, which are key factors limiting the thrust and efficiency of pulse detonation engines. When the unsteady pulsed gas flow passes through a fixed nozzle, if the exhaust pressure ratio is insufficient, the efficient operating range of the fixed-profile nozzle is narrow, further limiting energy conversion efficiency. A low back pressure environment can achieve thorough scavenging of the combustion chamber during the exhaust phase, and with the exhaust valve closed, the fuel can be filled to a level far exceeding the back pressure. Combined with the self-pressurization characteristics of the combustion process, this forms a highly efficient thrust generation mechanism. However, currently, there is a lack of cycle methods with detailed timing control parameters and corresponding energy conversion technologies for this operating mode. Summary of the Invention

[0004] The purpose of this invention is to provide a high initial pressure pulse detonation device and method that utilizes low back pressure scavenging gas, in order to solve the problems of complex structure of traditional pulse detonation cycle purging process, low working pressure and small thrust of burned gas, small cycle pressure ratio and low thermal efficiency, and low energy conversion efficiency of fixed profile nozzle.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a high initial pressure pulse detonation device utilizing low back pressure scavenging gas, comprising:

[0007] Combustion chamber;

[0008] A supply unit, wherein the supply unit is connected to the intake end of the combustion chamber via an intake valve;

[0009] An intake valve is assembled between the supply unit and the combustion chamber to open or close the fluid passage.

[0010] An ignition assembly, which is fixedly mounted on the cavity wall of the combustion chamber;

[0011] An exhaust valve is assembled between the exhaust end of the combustion chamber and the intake end of the nozzle, and is used to open or block the fluid passage.

[0012] The nozzle has its inlet end connected to the outlet side of the exhaust valve.

[0013] In one possible implementation, the supply unit includes a fuel supply source and an oxidant supply source;

[0014] The outlet side of the fuel supply source is connected to the inlet side of the intake valve;

[0015] The outlet side of the oxidant supply source is connected to the inlet side of the intake valve.

[0016] In one possible implementation, a timing control unit is also included;

[0017] The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively.

[0018] The timing control unit is used to regulate the timing of the intake valve, the exhaust valve and the ignition assembly.

[0019] One possible implementation also includes a low-pressure space and a vacuum pump;

[0020] The low-pressure space is connected to the outlet side of the nozzle;

[0021] The vacuum pump's pumping end is connected to the low-pressure space and is used to extract gas from the low-pressure space.

[0022] Secondly, the present invention provides a high initial pressure pulse detonation method utilizing low back pressure scavenging gas, applicable to the aforementioned device, comprising the following steps:

[0023] The exhaust valve is closed and the intake valve is opened, and the reaction medium is filled into the combustion chamber, which is in a low-pressure state, through the supply unit to the set initial pressure.

[0024] The intake valve is closed to form a sealed cavity in the combustion chamber. The ignition assembly is then activated to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature and high-pressure gas.

[0025] Open the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment;

[0026] The exhaust continues until the pressure inside the combustion chamber returns to a low back pressure level, completing a single pulse cycle. The total cycle of a single pulse cycle is composed of the filling period, ignition delay period, exhaust delay period, and exhaust reset period. The time required for the fuel to burn completely in the combustion chamber after ignition is the combustion time.

[0027] In one possible implementation, the step of filling the combustion chamber, which is in a low-pressure state, with the reaction medium via the supply unit to a set initial pressure includes:

[0028] The fuel supply source of the supply unit is turned on to deliver fuel medium into the combustion chamber;

[0029] The oxidant supply source of the supply unit is turned on to deliver the oxidant medium into the combustion chamber;

[0030] The fuel medium and the oxidant medium are mixed inside the combustion chamber to form a combustible reaction medium;

[0031] The step of activating the ignition assembly to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature, high-pressure gas includes:

[0032] The ignition component triggers a deflagration flame, which spontaneously accelerates within the combustion chamber and transitions from a deflagration state to a detonation state.

[0033] The detonation combustion reaction is completed in the sealed combustion chamber, forming a high-temperature and high-pressure gas environment.

[0034] In one possible implementation, the step of completing a single pulse cycle, wherein the total period of the single pulse cycle is composed of the sum of the filling period, the ignition delay period, the exhaust delay period, and the exhaust reset period, includes:

[0035] The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively.

[0036] The timing control unit controls the intake valve opening duration corresponding to the filling period, the ignition start timing after the intake valve closes corresponding to the ignition delay period, the exhaust valve opening timing after ignition corresponding to the exhaust delay period, and the exhaust duration corresponding to the exhaust reset period.

[0037] The total cycle length of a single pulse cycle can be changed by adjusting the duration parameters of the four time periods.

[0038] In one possible implementation, when the ambient back pressure is high, the step of discharging the high-temperature, high-pressure combustion gas in the combustion chamber through the nozzle to the low-back-pressure environment includes:

[0039] A low-pressure space is provided on the outlet side of the nozzle;

[0040] Connect the vacuum pump's pumping passage to the low-pressure space, start the vacuum pump to continuously extract the gas inside the low-pressure space, and maintain the low-back pressure condition of the low-pressure space.

[0041] The high-temperature, high-pressure gas discharged from the nozzle is first introduced into the low-pressure space, and then discharged to the external environment by the vacuum pump.

[0042] In one possible implementation, the step of opening the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment includes:

[0043] The opening time of the exhaust valve is adjusted based on the ignition start time of the ignition assembly and the combustion reaction progress in the combustion chamber.

[0044] The exhaust valve can be opened at any point: before the combustion reaction is complete, at the instant the combustion reaction is complete, or after the combustion reaction is completed and delayed.

[0045] By adjusting the exhaust delay period, the timing connection point between the combustion time and the exhaust reset period is changed.

[0046] In one possible implementation, the step of continuously exhausting gas until the internal pressure of the combustion chamber returns to a low back pressure level, completing a single pulse cycle, includes:

[0047] Repeat the entire operation process of a single pulse cycle to form a continuous pulse working condition;

[0048] The initial pressure of the reaction medium in the combustion chamber is adjusted by the filling period, thereby changing the final pressure of the gas after combustion.

[0049] By coordinating the pulse cycle operating frequency and the initial pressure of the reaction medium filling, the thrust and output power of the device can be continuously and adjustablely controlled.

[0050] Compared with existing technologies, the advantages of this invention are as follows: Existing pulse detonation cycles require an additional purging process to clean exhaust gases, which increases the number of supporting structures, consumes additional purging gas, and occupies cycle time. This invention utilizes a low back pressure environment to complete the exhaust gas removal from the combustion chamber, eliminating the need for purging structures and media consumption. Existing pulse detonation engines have relatively low initial combustion pressure and power pressure. This invention utilizes an exhaust valve to significantly increase the initial combustion pressure, widening the pressure difference between the combustion gas and the external environment, expanding the operating range of the fixed-profile nozzle for high efficiency, and effectively improving the overall energy conversion efficiency.

[0051] Most existing pulse detonation thrust devices rely on adaptive frequency output, resulting in a limited thrust adjustment range and a lack of control over the combustion chamber's heating conditions. This makes it difficult to balance output power and thermal protection requirements across different application scenarios. This invention adjusts the thrust output by changing the cycle operating frequency and initial fuel filling pressure, while simultaneously controlling the exhaust valve opening and closing time to regulate the residence time of high-temperature combustion gases within the combustion chamber. This allows for control of the wall heating, addressing both power output regulation and thermal management needs, thus better adapting to different operating conditions.

[0052] Most existing pulse detonation cycles are designed to operate under high back pressure environments, but the low final combustion pressure results in a relatively low power output pressure ratio and a narrow efficient operating range for fixed-profile nozzles. This invention selects the low back pressure environment of space as the design scenario to improve the power output pressure ratio and broaden the efficient operating range of fixed-profile nozzles. Simultaneously, a low-pressure creation system can be built on the ground to construct artificial low back pressure conditions, allowing the entire cycle process to operate normally in the vacuum environment of space and also to be tested and debugged on the ground. This lowers the threshold for practical application and verification, facilitating integration with existing ground-based power testing systems for performance verification. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram illustrating the working principle of a high initial pressure pulse detonation cycle utilizing low back pressure scavenging gas according to an embodiment of the present invention.

[0055] Figure 2 This is a schematic diagram of the working cycle stage under high back pressure environment according to an embodiment of the present invention;

[0056] Figure 3 This is a graph showing the pressure change in the combustion chamber under the delayed-opening exhaust valve condition according to an embodiment of the present invention.

[0057] Figure 4 This is a graph showing the pressure change in the combustion chamber under the condition of the exhaust valve being open in an embodiment of the present invention. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0059] Example:

[0060] It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0061] This embodiment of a high initial pressure pulse detonation device utilizing low back pressure scavenging gas includes:

[0062] Combustion chamber;

[0063] A supply unit, wherein the supply unit is connected to the intake end of the combustion chamber via an intake valve;

[0064] An intake valve is assembled between the supply unit and the combustion chamber to open or close the fluid passage.

[0065] An ignition assembly, which is fixedly mounted on the cavity wall of the combustion chamber;

[0066] An exhaust valve is assembled between the exhaust end of the combustion chamber and the intake end of the nozzle, and is used to open or block the fluid passage.

[0067] The nozzle has its inlet end connected to the outlet side of the exhaust valve.

[0068] Specifically, the combustion chamber can be a sealed cavity structure that contains fuel and oxidizer and completes detonation combustion; the supply unit can be a complete set of equipment that stores and transports the medium required for combustion; the intake valve can be a fluid valve device with controlled on / off switching; the fluid passage can be a pipeline channel for the flow of fuel and oxidizer; the ignition assembly can be a device that outputs an electric spark to ignite the mixture; the cavity wall can be the side wall structure of the combustion chamber; the exhaust end can be the port of the combustion chamber that discharges combustion products; the nozzle can be a fluid profile component that converts the internal energy of high-temperature and high-pressure gas into kinetic energy; and the outlet side can be the end of the component away from the upstream medium inflow.

[0069] For example, the combustion chamber uses a high-temperature resistant alloy sealed cavity; both the intake and exhaust valves are electromagnetically driven on / off valves; the ignition assembly can be a spark plug; the nozzle can be a fixed-profile Laval nozzle; the entire device follows... Figure 1 In terms of structural layout, the intake valve is connected to the upstream of the combustion chamber, and the exhaust valve and nozzle are installed sequentially downstream.

[0070] In one possible implementation, the supply unit includes a fuel supply source and an oxidant supply source;

[0071] The outlet side of the fuel supply source is connected to the inlet side of the intake valve;

[0072] The outlet side of the oxidant supply source is connected to the inlet side of the intake valve.

[0073] Specifically, the fuel supply source can be a pressurized storage device for storing liquid or gaseous combustion fuels; the oxidizer supply source can be a pressurized storage device for storing combustion-supporting media; the outlet side can be a port from which the media flows out; the inlet side can be a port from which the media flows in; and the connection can be a fluid connection method with sealed pipeline connections. For example, the fuel supply can be a hydrogen storage tank or a liquid hydrocarbon fuel storage tank; the oxidizer supply source can be a high-pressure oxygen storage tank; the fuel supply source and the oxidizer supply source are each connected to the inlet side of the intake valve through independent pipelines; the output supply pressure of the supply unit can be set in the range of 0 MPa to 70 MPa.

[0074] In one possible implementation, a timing control unit is also included;

[0075] The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively.

[0076] The timing control unit is used to regulate the timing of the intake valve, the exhaust valve and the ignition assembly.

[0077] Specifically, the timing control unit can be an electronic control processing module that outputs timing control signals; the signal connection can be a cable connection method for transmitting control electrical signals; the action timing can be the sequential logic of the intake valve on / off, exhaust valve on / off, and ignition assembly ignition; the regulation can be the output drive signal to control the start and stop times of each component. For example, the timing control unit has a built-in programmable timing program that can set four types of timing parameters: fill time, ignition angle, exhaust angle, and exhaust time; the timing control unit outputs electrical signals to drive the intake valve solenoid actuator, exhaust valve solenoid actuator, and spark plug ignition power supply respectively; the complete cycle is equal to the fill time plus the ignition angle plus the exhaust angle plus the exhaust time, and the cycle frequency is the reciprocal of the period.

[0078] One possible implementation also includes a low-pressure space and a vacuum pump;

[0079] The low-pressure space is connected to the outlet side of the nozzle;

[0080] The vacuum pump's pumping end is connected to the low-pressure space and is used to extract gas from the low-pressure space.

[0081] Specifically, the low-pressure space can be an independent, sealed cavity downstream of the nozzle; the vacuum pump can be a gas extraction device that continuously extracts gas to create a low-pressure environment; the extraction end can be the port where the vacuum pump draws in gas; extraction can be the process by which the vacuum pump continuously removes gas from the cavity. For example, the low-pressure space can be an annular sealed cavity structure, suitable for high back pressure applications such as ground surfaces; the vacuum pump can be a dry-type pump; the exhaust back pressure within the low-pressure space can be maintained in the range of 0 kPa to 50 kPa; the device structure is as follows. Figure 2 The layout involves connecting the nozzle outlet to a low-pressure space, with a vacuum pump continuously evacuating the low-pressure space.

[0082] This invention provides a high initial pressure pulse detonation method utilizing low back pressure scavenging gas, applicable to the aforementioned device, comprising the following steps:

[0083] The exhaust valve is closed and the intake valve is opened, and the reaction medium is filled into the combustion chamber, which is in a low-pressure state, through the supply unit to the set initial pressure.

[0084] The intake valve is closed to form a sealed cavity in the combustion chamber. The ignition assembly is then activated to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature and high-pressure gas.

[0085] Open the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment;

[0086] The exhaust continues until the pressure inside the combustion chamber returns to a low back pressure level, completing a single pulse cycle. The total cycle of a single pulse cycle is composed of the filling period, the ignition and combustion period, the exhaust pressure relief period, and the scavenging and reset period.

[0087] A high initial pressure pulse detonation method utilizing low back pressure scavenging gas, applicable to the aforementioned device, includes the following steps:

[0088] Step 1: Close the exhaust valve and open the intake valve, and fill the combustion chamber, which is in a low-pressure state, with the reaction medium through the supply unit until the set initial pressure is reached;

[0089] Step 2: Close the intake valve to form a sealed cavity in the combustion chamber, and start the ignition assembly to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature and high-pressure gas.

[0090] Step 3: Open the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment;

[0091] Step 4: Continue exhausting until the pressure inside the combustion chamber returns to a low back pressure level, completing a single pulse cycle. The total cycle of a single pulse cycle consists of the sum of the filling period, the ignition delay period, the exhaust delay period, and the exhaust reset period.

[0092] Specifically, the low-pressure state can be the pressure level inside the combustion chamber close to the back pressure after the previous exhaust cycle is completed; the reaction medium can be the combustible mixture formed by the mixing of fuel and oxidizer; the initial pressure setting can be the target pressure value inside the combustion chamber after filling is completed; the sealed cavity can be the combustion chamber cavity that is completely sealed after both the intake and exhaust valves are closed; the high-temperature and high-pressure gas can be the high-temperature and high-pressure combustion products generated after detonation combustion; the low back pressure environment can be the natural vacuum environment in space or the low-pressure space created by a vacuum pump; the filling period can be the duration for which the intake valve remains open to complete the filling of the medium; the ignition delay period can be the duration from the moment the intake valve closes to the moment the spark plug ignites; the exhaust delay period can be the duration from the moment the spark plug ignites to the moment the exhaust valve opens; the exhaust reset period can be the duration for which the exhaust valve opens, the gas is vented, and the combustion chamber pressure drops back to low pressure; the total cycle of a single pulse can be the total time consumed for one complete detonation operation.

[0093] For example, the filling time parameter ranges from 0 ms to 100 ms for the filling period; the ignition delay period includes the ignition angle from 0 ms to 10 ms; the exhaust delay period corresponds to the exhaust angle from 0 ms to 100 ms; the exhaust reset period corresponds to the exhaust time from 0 ms to 100 ms; the initial pressure can be set to be controlled within the range of 0 MPa to 70 MPa; the exhaust back pressure in the low back pressure environment is maintained from 0 kPa to 50 kPa; in space operations, vacuum is directly used as the low back pressure environment, while in ground operations, a vacuum pump is used to extract low-pressure space to create a low back pressure environment.

[0094] In one possible implementation, the step of filling the combustion chamber, which is in a low-pressure state, with the reaction medium via the supply unit to a set initial pressure includes:

[0095] The fuel supply source of the supply unit is turned on to deliver fuel medium into the combustion chamber;

[0096] The oxidant supply source of the supply unit is turned on to deliver the oxidant medium into the combustion chamber;

[0097] The fuel medium and the oxidant medium are mixed inside the combustion chamber to form a combustible reaction medium;

[0098] The step of activating the ignition assembly to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature, high-pressure gas includes:

[0099] The ignition component triggers the ignition flame, causing the reaction medium to change from a deflagration state to a detonation state;

[0100] The detonation combustion reaction is completed in the sealed combustion chamber, forming a high-temperature and high-pressure gas environment.

[0101] Specifically, the fuel supply source can be a pressurized tank storing liquid or gaseous fuel; the fuel medium can be hydrogen or hydrocarbon combustible fluid; the oxidizer supply source can be a pressurized tank storing combustion-supporting gas; the oxidizer medium can be oxygen or other combustion-supporting fluid; mixing can be the process of fully mixing two media in the cavity; the combustible reaction medium can be a mixture that meets the detonation combustion ratio; the ignition flame can be an electric spark source released by the ignition component; the detonation state can be a combustion state with low-speed flame propagation; the detonation state can be a supersonic high-speed combustion state; the detonation combustion reaction can be a near-isochoric rapid heat release combustion process; and the high-temperature and high-pressure gas environment can be the high-temperature and high-pressure working condition of the combustion cavity after combustion.

[0102] For example, gaseous hydrogen is used as the fuel medium, and high-pressure oxygen is used as the oxidant medium; the two media are introduced into the combustion chamber simultaneously to achieve uniform mixing; the ignition component is a spark plug, which releases an electric spark to trigger the initial flame; the initial deflagration flame is rapidly accelerated and transformed into a detonation wave; the final combustion pressure inside the sealed combustion chamber can reach up to 1.822 MPa; the combustion time can be controlled within the range of 0.63 ms to 0.73 ms.

[0103] In one possible implementation, the step of completing a single pulse cycle, wherein the total period of the single pulse cycle is composed of the sum of the filling period, the ignition delay period, the exhaust delay period, and the exhaust reset period, includes:

[0104] The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively.

[0105] The timing control unit controls the intake valve opening duration corresponding to the filling period, the ignition start timing after the intake valve closes corresponding to the ignition delay period, the exhaust valve opening timing after ignition corresponding to the exhaust delay period, and the exhaust duration corresponding to the exhaust reset period.

[0106] The total cycle length of a single pulse cycle can be changed by adjusting the duration parameters of the four time periods.

[0107] Specifically, the intake valve opening duration can be the filling time parameter corresponding to the filling period; the ignition start timing can be the interval from intake valve closing to ignition, i.e., the ignition angle; the exhaust valve opening timing can be the interval from ignition to valve opening, i.e., the exhaust angle; the exhaust duration can be the exhaust time after the exhaust valve opens; the duration parameter can be the time value that can be set independently for each stage; the total cycle length can be the total time consumed for a complete cycle.

[0108] For example, the timing control unit drives the intake valve, exhaust valve, and spark plugs separately through independent control lines; the fill time can be set to 10 ms, 20 ms, or 30 ms; the ignition angle is fixed at 1 ms; the exhaust angle can be matched with the combustion duration or set to 15 ms with a delay; the exhaust time can be set to 10 ms or 20 ms; the total cycle is equal to the fill time plus the ignition angle plus the exhaust angle plus the exhaust time; shortening the duration of each stage can increase the cycle frequency, while extending the duration will decrease the cycle frequency.

[0109] In one possible implementation, the step of discharging the high-temperature, high-pressure combustion gas in the combustion chamber through the nozzle into a low-back-pressure environment includes:

[0110] A low-pressure space is provided on the outlet side of the nozzle;

[0111] Connect the vacuum pump's pumping passage to the low-pressure space, start the vacuum pump to continuously extract the gas inside the low-pressure space, and maintain the low-back pressure condition of the low-pressure space.

[0112] The high-temperature, high-pressure gas discharged from the nozzle is first introduced into the low-pressure space, and then discharged to the external environment by the vacuum pump.

[0113] Specifically, the evacuation passage can be a pipeline connecting the vacuum pump to the low-pressure space; continuous evacuation can be the uninterrupted evacuation operation of the vacuum pump; stable low back pressure can be the constant low pressure inside the low-pressure space; and the external environment can be the atmospheric environment at normal ground pressure.

[0114] For example, this process is suitable for high back pressure applications such as ground-level applications; the low-pressure space is a ring-shaped sealed cavity; a dry-type vacuum pump is used; the exhaust back pressure of the low-pressure space is stably maintained at 10 kPa; high-temperature gas first enters the low-pressure space to form a huge pressure difference, and then is extracted by the vacuum pump and discharged to the atmosphere; this structure corresponds to the attached... Figure 2 Device layout.

[0115] In one possible implementation, the step of opening the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment includes:

[0116] The opening time of the exhaust valve is adjusted based on the ignition start time of the ignition assembly and the combustion reaction progress in the combustion chamber.

[0117] The exhaust valve can be opened at any point: before the combustion reaction is complete, at the instant the combustion reaction is complete, or after the combustion reaction is completed and delayed.

[0118] By adjusting the delay period of the exhaust valve, the timing connection point between the combustion time and the exhaust reset period is changed.

[0119] Specifically, the ignition start time can be the point at which the spark plug outputs an electric spark; the time reference can be the starting point for calculating the exhaust angle; the combustion reaction progress can be the degree of completion of detonation combustion; the exhaust valve opening time can be the point at which the exhaust valve is opened after ignition; before the combustion reaction is completed can be the period when the detonation wave has not completely propagated; the moment the combustion reaction is completed can be the moment when the medium is completely burned; the delay after the combustion reaction is completed can be the period of continued heat preservation after combustion ends; and the time connection point can be the boundary between the end of the ignition and combustion stage and the start of the exhaust pressure relief stage.

[0120] For example, when the time required for complete combustion is 0.63 ms, the exhaust angle for early valve opening should be less than 0.63 ms; the exhaust angle for synchronous valve opening should be equal to 0.63 ms; and the exhaust angle for delayed valve opening should be greater than 0.63 ms (e.g., 15 ms). Early valve opening will leak unburned mixture, reducing thrust; synchronous valve opening provides the best thrust and conversion efficiency; delayed valve opening increases wall heat exchange, making it suitable for cavity thermal management. The delayed valve opening and synchronous valve opening conditions correspond to the following parameters: Figure 3 Appendix Figure 4 Pressure curve.

[0121] In one possible implementation, the step of continuously exhausting gas until the internal pressure of the combustion chamber returns to a low back pressure level, completing a single pulse cycle, includes:

[0122] Repeat the entire operation process of a single pulse cycle to form a continuous pulse working condition;

[0123] The initial pressure of the reaction medium in the combustion chamber is adjusted by the filling period, thereby changing the final pressure of the gas after combustion.

[0124] By coordinating the pulse cycle operating frequency and the initial pressure of the reaction medium filling, the thrust and output power of the device can be continuously and adjustablely controlled.

[0125] Specifically, repetitive execution can mean automatically starting the next operation after a single cycle ends; continuous pulse-type operation can mean periodic, uninterrupted detonation operation; the final pressure of the gas can mean the peak pressure of the cavity after detonation combustion; coordinated control can mean simultaneously modifying two sets of parameters: frequency and initial pressure; the pulse cycle frequency can mean the number of cycles completed per unit time; and continuously adjustable control can mean a wide range of stepless adjustment of thrust and power. For example, when the initial pressure is set to 600 kPa, a filling time of 10 ms corresponds to a final pressure of 1.389 MPa, and a filling time of 30 ms corresponds to a final pressure of 1.822 MPa; increasing the cycle frequency can simultaneously increase the total thrust per unit time; increasing the initial pressure can increase the work capacity of a single cycle; and the combination of these two can continuously adjust the output thrust and mechanical power over a wide range.

[0126] To facilitate a clear understanding of this embodiment, the following description is provided in conjunction with the accompanying drawings.

[0127] Appendix Figure 1 This is a schematic diagram illustrating the working principle of a high initial pressure pulse detonation cycle utilizing low back pressure scavenging gas in an embodiment of the present invention. The device includes a combustion chamber, a supply unit, an intake valve, an ignition assembly, an exhaust valve, and a nozzle. The supply unit is divided into a fuel supply source and an oxidizer supply source. The nozzle outlet is directly connected to a low back pressure environment. The timing of the entire device's operation is uniformly controlled by a timing control unit.

[0128] The pulse detonation cycle consists of three processes and a total of five stages. Stage I is the filling process, in which the timing control unit keeps the exhaust valve closed and the intake valve open. The fuel supply source and oxidizer supply source of the supply unit synchronously output the medium to fill the combustion chamber, which is in a low-pressure state, with the reaction medium until the set supply pressure p is reached. infu The duration of the filling is denoted as the filling time t. infu After the medium filling is complete, the timing control unit closes the intake valve. Stages II and III together constitute the ignition and combustion process. Both the intake and exhaust valves remain closed. The timing control unit uses the intake valve closing time as a reference and adjusts the timing interval at ignition angle t. deig The rear-contact ignition assembly ignites the reaction medium in the combustion chamber. The medium transitions from deflagration to detonation and completes combustion. The time required for complete combustion is t. comb After combustion, high-temperature and high-pressure gas is generated inside the combustion chamber. Stages IV and V together constitute the exhaust power process. The timing control unit uses the ignition assembly start-up time as a reference, and the intervals are exhaust angle t. deex After the exhaust valve is opened, the high-temperature, high-pressure combustion gas in the combustion chamber flows through the exhaust valve and the nozzle and is ejected into the low back pressure environment, generating thrust. The duration for which the exhaust valve remains open is the exhaust time t. ex The combustion chamber scavenging is completed by relying on the pressure difference created by the outward depressurization of the combustion gas, and the combustion chamber pressure drops back to the exhaust back pressure p. baAfterwards, the timing control unit closes the exhaust valve, the single cycle ends, and the filling process restarts. Figure 1 The loop logic block diagram and corresponding control parameters are shown below. The total period of a single complete pulse cycle satisfies the relationship T=t. infu +t deig +t deex +t ex The cycle frequency satisfies the relationship f=1 / T; the timing control unit can independently adjust the fill time t. infu Supply pressure p infu Ignition angle t deig Exhaust angle t deex Exhaust time t ex Exhaust back pressure p ba This allows for changes in the duration of a single cycle and the magnitude of the output thrust of the device.

[0129] Figure 2 This is a schematic diagram of the working cycle stage under high back pressure environment according to an embodiment of the present invention. A low-pressure space is added to the nozzle outlet side of the device. The vacuum pump's extraction passage is connected to the low-pressure space. The vacuum pump continuously extracts gas from the low-pressure space to stably maintain the low back pressure condition of the low-pressure space. The timing control logic of the entire device is related to the attached... Figure 1 To maintain consistency, the operation process is also divided into three stages: Stage I (filling process), Stage II and Stage III (ignition and combustion process), and Stage IV and Stage V (exhaust and power process). During Stage I (filling process), the timing control unit keeps the exhaust valve closed while simultaneously opening the intake valve. The fuel supply source and oxidizer supply source of the supply unit synchronously deliver the reaction medium to the combustion chamber, filling the chamber to the set supply pressure p. infu Afterwards, the timing control unit closes the intake valve, while the vacuum pump continues to operate throughout the process, continuously evacuating the low-pressure space. Stages II and III together constitute the ignition and combustion process. Both the intake and exhaust valves remain closed, and the timing control unit operates according to the preset ignition angle t. deig The contact ignition assembly causes detonation combustion of the reaction medium in the combustion chamber, generating high-temperature, high-pressure gas. Stage IV and Stage V together constitute the exhaust power process, and the timing control unit operates according to the preset exhaust angle t. deex When the exhaust valve is opened, the high-temperature, high-pressure combustion gas in the combustion chamber flows through the nozzle and is discharged into the low-pressure space. As the gas flows through the low-pressure space, it can output extractable mechanical work. The vacuum pump continuously removes the combustion exhaust gas flowing into the low-pressure space, thereby stabilizing the pressure difference across the nozzle. The duration of continuous gas discharge is called the exhaust time t. ex Once the pressure inside the combustion chamber drops to the same level as the low-pressure space, the timing control unit closes the exhaust valve, and the device re-enters the stage I filling process. The calculation formulas for the entire cycle period and frequency are attached. Figure 1 Completely identical, the timing control unit can adjust the fill time t exSupply pressure p infu Ignition angle t deig Exhaust angle t deex Exhaust time t ex Simultaneously, the exhaust back pressure p inside the low-pressure space is adjusted using a vacuum pump. ba This allows the device to stably complete low backpressure scavenging cycles in high backpressure external environments such as atmospheric ground pressure. Operators can adjust the exhaust angle t... deex Matching burn time t comb Three different operating conditions are formed, with exhaust angle t deex Less than the combustion time t comb Opening the exhaust valve before combustion is complete will cause unburned gas to leak from the combustion chamber, reducing the device's thrust and combustion efficiency. The exhaust angle t... deex Equal to combustion time t comb The exhaust valve opens at the instant combustion is complete. Under this condition, energy conversion can be completed at the highest point of total gas temperature and pressure in the combustion chamber, with thrust and conversion efficiency at an optimal level, and an exhaust angle t. deex Greater than the combustion time t comb The exhaust valve is opened after combustion is completed. This condition prolongs the residence time of the high-temperature and high-pressure gas in the combustion chamber, allowing more heat to be transferred to the combustion chamber wall for wall heating and equipment thermal management. At the same time, it slightly reduces the device thrust and energy conversion efficiency.

[0130] Figure 3 This is a graph showing the combustion chamber pressure change under the delayed-opening exhaust valve condition according to an embodiment of the present invention. The exhaust angle t under this condition is... deex The value is greater than the combustion time t comb All test conditions were uniformly set with exhaust back pressure p. ba Equal to 10 kPa, exhaust time t ex Equal to 10 ms, ignition angle t deig Equal to 1 ms, supply pressure p infu The standard pressure was set to 600 kPa, and the three control conditions corresponded to filling times t. infu The values ​​are 10 ms, 20 ms, and 30 ms. Before the filling process begins, the combustion chamber pressure drops to 30 kPa after the previous exhaust process. The filling time is t. infu The initial combustion pressure in the combustion chamber at 10 ms is 0.187 MPa, and the final pressure after combustion is 1.389 MPa, corresponding to a combustion time t. comb Equals 0.63 ms, fill time t infu The initial combustion pressure in the combustion chamber at 20 ms is 0.238 MPa, and the final pressure after combustion is 1.653 MPa, corresponding to a combustion time t. comb Equals 0.70 ms, fill time tinfu The initial combustion pressure in the combustion chamber at 30 ms is 0.266 MPa, and the final pressure after combustion is 1.822 MPa, corresponding to a combustion time t. comb Equal to 0.73 ms. The delayed opening of the exhaust valve in the operating mode allows the high-temperature and high-pressure gas to remain inside the combustion chamber for a long time. The heat carried by the gas is continuously transferred to the combustion chamber wall, and the wall temperature continues to rise. The total temperature and total pressure of the gas itself decrease simultaneously, and the gas's ability to perform work weakens accordingly. After the exhaust valve opens, there is a 10 ms exhaust time, and the pressure inside the combustion chamber drops back to 30 kPa. After the entire process is completed, the device re-enters the filling process and starts a new round of pulse cycle.

[0131] Figure 4 This is a graph showing the combustion chamber pressure change under the condition of the exhaust valve being just opened, according to an embodiment of the present invention. The exhaust angle t under this condition... deex Numerical value and combustion time t comb To maintain equality, the exhaust back pressure p is set uniformly for all test conditions. ba Equal to 10 kPa, exhaust time t ex Equals 20 ms, ignition angle t deig Equal to 1 ms, supply pressure t infu The standard pressure was set to 600 kPa, and the three control conditions corresponded to filling times t. infu The values ​​are 10 ms, 20 ms, and 30 ms. The combustion chamber pressure is maintained at 30 kPa before the filling process begins, and the filling time t... infu The initial combustion pressure in the combustion chamber is 0.187 MPa at 10 ms, and the combustion time t is... comb Equals 0.63ms, corresponding to exhaust angle t deex Set to 0.63 ms, fill time t infu The initial combustion pressure in the combustion chamber is 0.238 MPa at 20 ms, and the combustion time t is... comb Equal to 0.70 ms, corresponding to exhaust angle t deex Set to 0.70 ms, fill time t infu The initial combustion pressure in the combustion chamber is 0.266 MPa at 30 ms, and the combustion time t is... comb Equals 0.73 ms, corresponding to exhaust angle t deex Set to 0.73ms. Under this condition, the exhaust valve opens the instant the combustion reaction is completed, and the peak pressure inside the combustion chamber is lower than that of the adjacent... Figure 3In the corresponding delayed valve opening condition, the exhaust process lasts for 20 ms. High-temperature, high-pressure gas flows rapidly through the nozzle into the low back pressure space. The pressure drop rate inside the combustion chamber is higher than in the delayed valve opening condition. After the exhaust process ends, the combustion chamber pressure drops back to 30 kPa, and the device immediately enters the filling process, starting a new cycle. Operators can synchronously adjust the cycle frequency and the initial filling pressure of the combustion chamber medium through the timing control unit, thereby continuously adjusting the thrust and power output of the device over a wide range. The nozzle used in the device has a fixed profile structure, creating a large pressure difference between the high initial pressure gas inside the combustion chamber and the low back pressure environment. This widens the high-efficiency energy conversion range of the fixed profile nozzle. The entire cycle eliminates the independent purging and isolation process required by conventional pulse detonation devices, relying on the low back pressure environment to complete the exhaust gas scavenging inside the combustion chamber, simplifying the overall structure of the equipment. The supply pressure p set in this invention... infu The value ranges from 0 to 70 MPa, and the fill time t infu The value ranges from 0 to 100 ms, and the ignition angle t deig The value ranges from 0 to 10 ms, and the exhaust angle t deex The value ranges from 0 to 100 ms, and the exhaust time t is... ex The value range is 0 to 100 ms, and the exhaust back pressure p ba The value range is from 0 to 50 kPa, and all parameters can be independently controlled through the timing control unit.

[0132] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0133] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high initial pressure pulse detonation device utilizing low back pressure scavenging gas, characterized in that, include: Combustion chamber; A supply unit, wherein the supply unit is connected to the intake end of the combustion chamber via an intake valve; An intake valve is assembled between the supply unit and the combustion chamber to open or close the fluid passage. An ignition assembly, which is fixedly mounted on the cavity wall of the combustion chamber; An exhaust valve is assembled between the exhaust end of the combustion chamber and the intake end of the nozzle, and is used to open or block the fluid passage. The nozzle has its inlet end connected to the outlet side of the exhaust valve.

2. The high initial pressure pulse detonation device utilizing low back pressure scavenging gas according to claim 1, characterized in that, The supply unit includes a fuel supply source and an oxidant supply source; The outlet side of the fuel supply source is connected to the inlet side of the intake valve; The outlet side of the oxidant supply source is connected to the inlet side of the intake valve.

3. The high initial pressure pulse detonation device utilizing low back pressure scavenging gas according to claim 1, characterized in that, It also includes a timing control unit; The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively. The timing control unit is used to regulate the timing of the intake valve, the exhaust valve and the ignition assembly.

4. The high initial pressure pulse detonation device utilizing low back pressure scavenging gas according to claim 1, characterized in that, It also includes low-pressure spaces and vacuum pumps; The low-pressure space is connected to the outlet side of the nozzle; The vacuum pump's pumping end is connected to the low-pressure space and is used to extract gas from the low-pressure space.

5. A method for high initial pressure pulse detonation using low back pressure scavenging gas, characterized in that, The apparatus applicable to any one of claims 1 to 4 includes the following steps: The exhaust valve is closed and the intake valve is opened, and the reaction medium is filled into the combustion chamber, which is in a low-pressure state, through the supply unit to the set initial pressure. The intake valve is closed to form a sealed cavity in the combustion chamber. The ignition assembly is then activated to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature and high-pressure gas. Open the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into a low-back-pressure environment; The exhaust continues until the pressure inside the combustion chamber returns to a low back pressure level, completing a single pulse cycle. The total cycle of a single pulse cycle is composed of the filling period, ignition delay period, exhaust delay period, and exhaust reset period. The time required for the fuel to burn completely in the combustion chamber after ignition is the combustion time.

6. The high initial pressure pulse detonation method using low back pressure scavenging gas according to claim 5, characterized in that, The step of filling the combustion chamber, which is in a low-pressure state, with the reaction medium through the supply unit to a set initial pressure includes: The fuel supply source of the supply unit is turned on to deliver fuel medium into the combustion chamber; The oxidant supply source of the supply unit is turned on to deliver the oxidant medium into the combustion chamber; The fuel medium and the oxidant medium are mixed inside the combustion chamber to form a combustible reaction medium; The step of activating the ignition assembly to ignite the reaction medium in the combustion chamber, completing combustion and generating high-temperature, high-pressure gas includes: The ignition component triggers a deflagration flame, which spontaneously accelerates within the combustion chamber and transitions from a deflagration state to a detonation state. The detonation combustion reaction is completed in the sealed combustion chamber, forming a high-temperature and high-pressure gas environment.

7. The high initial pressure pulse detonation method using low back pressure scavenging gas according to claim 5, characterized in that, The step of completing a single pulse cycle, wherein the total cycle of a single pulse cycle is composed of the sum of the filling period, the ignition delay period, the exhaust delay period, and the exhaust reset period, includes: The timing control unit is connected to the intake valve, the exhaust valve, and the ignition assembly respectively. The timing control unit controls the intake valve opening duration corresponding to the filling period, the ignition start timing after the intake valve closes corresponding to the ignition delay period, the exhaust valve opening timing after ignition corresponding to the exhaust delay period, and the exhaust duration corresponding to the exhaust reset period. The total cycle length of a single pulse cycle can be changed by adjusting the duration parameters of the four time periods.

8. The high initial pressure pulse detonation method using low back pressure scavenging gas according to claim 5, characterized in that, When the ambient back pressure is high, the step of discharging the high-temperature, high-pressure combustion gas in the combustion chamber through the nozzle to the low-back-pressure environment includes: A low-pressure space is provided on the outlet side of the nozzle; Connect the vacuum pump's pumping passage to the low-pressure space, start the vacuum pump to continuously extract the gas inside the low-pressure space, and maintain the low-back pressure condition of the low-pressure space. The high-temperature, high-pressure gas discharged from the nozzle is first introduced into the low-pressure space, and then discharged to the external environment by the vacuum pump.

9. The high initial pressure pulse detonation method using low back pressure scavenging gas according to claim 5, characterized in that, The step of opening the exhaust valve to allow the high-temperature, high-pressure combustion gas in the combustion chamber to flow through the nozzle and be discharged into the low back pressure environment includes: The opening time of the exhaust valve is adjusted based on the ignition start time of the ignition assembly and the combustion reaction progress in the combustion chamber. The exhaust valve can be opened at any point: before the combustion reaction is complete, at the instant the combustion reaction is complete, or after the combustion reaction is completed and delayed. By adjusting the exhaust delay period, the timing connection point between the combustion time and the exhaust reset period is changed.

10. The high initial pressure pulse detonation method using low back pressure scavenging gas according to claim 5, characterized in that, The step of continuously exhausting gas until the internal pressure of the combustion chamber returns to a low back pressure level, completing a single pulse cycle, includes: Repeat the entire operation process of a single pulse cycle to form a continuous pulse working condition; The initial pressure of the reaction medium in the combustion chamber is adjusted by the filling period, thereby changing the final pressure of the gas after combustion. By coordinating the pulse cycle operating frequency and the initial pressure of the reaction medium filling, the thrust and output power of the device can be continuously and adjustablely controlled.

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