A method and device for simulating the pulsation characteristics of a rotary detonation turbine engine

Abstract

This application belongs to the field of aero-engine simulation technology, and relates to a method and apparatus for simulating the overall pulsation characteristics of a rotating detonation turbine engine. The method includes: obtaining the given total pressure pulsation characteristics of the rotating detonation combustor; calculating the total outlet pressure of the rotating detonation combustor at the current simulation moment; inputting the total outlet pressure of the rotating detonation combustor into a pre-constructed overall performance model of the turbojet engine in transition state. The overall performance model is formed by coupling various engine components through aerodynamic parameter interfaces in the order of airflow, considering rotor dynamics and volume effects during coupling; solving for independent engine variables and the characteristics of each component under the constraints of overall engine matching conditions of flow balance and power balance until the residuals converge; extracting the total inlet pressure of the rotating detonation combustor and calculating the characteristics of each engine component at the next simulation moment. This application realizes the simulation of the unsteady coupling characteristics of the rotating detonation combustor and the turbojet engine.

Description

Technical Field

[0001] This application belongs to the field of aero-engine simulation technology, and specifically relates to a method and device for simulating the overall pulsation characteristics of a rotating detonation turbine engine. Background Technology

[0002] Current aero-gas turbine engines employ combustion modes close to isobaric combustion, and the Brayton cycle, based on isobaric combustion, is becoming increasingly sophisticated. However, constraints such as material tolerance and structural complexity limit further improvements in the thermal efficiency of the Brayton cycle. Pressurized combustion approximates isochoric combustion, where the total pressure of the working fluid increases during combustion. The Humphrey cycle, based on pressurized combustion, can significantly improve cycle thermal efficiency and reduce entropy production.

[0003] Rotating detonation combustion is a typical mode of pressurized combustion, theoretically possessing advantages over traditional isobaric combustion such as self-pressurization, high thermal efficiency, rapid heat release rate, and wide operating range. Applying rotating detonation combustion technology to aero-gas turbine engines holds promise for overcoming performance bottlenecks and has broad application prospects. The high-frequency circumferential propagation of detonation waves within the rotating detonation combustion chamber causes high-frequency pulsations in the total pressure at the combustion chamber inlet and outlet, exhibiting significant unsteady characteristics. This will affect the matching operation of upstream and downstream components and the entire aero-gas turbine engine, and may even pose challenges to the reliability and safety of normal engine operation. Therefore, it is necessary to study the matching characteristics and mechanisms of rotating detonation turbine engine components or the entire engine.

[0004] Currently, there are three main research methods for the matching characteristics and mechanisms of rotating detonation turbine engines' components or the entire engine. The first is the steady-state performance simulation method, which typically constructs an equivalent steady-state model of the rotating detonation combustor and then embeds it into the turbine engine's component-level model to achieve performance simulation and scheme design. The second is the multi-component coupled numerical simulation method, which usually uses CFD to conduct dynamic simulations of the rotating detonation combustor. Furthermore, it uses the unsteady flow field parameters at the combustor's inlet and outlet as boundary conditions for upstream and downstream components such as the inlet, exhaust nozzle, and turbine to simulate the dynamic flow fields of other components and explore the unsteady co-operation characteristics and mechanisms of the rotating detonation combustor and other turbine engine components. The third is the systematic experimental method, including component integration and whole-engine simulation tests. Component integration tests typically build a combined test bench for the rotating detonation combustor and upstream and downstream engine components to explore the matching characteristics and mechanisms between components. Whole-engine simulation tests typically integrate the rotating detonation combustor onto a turbojet engine to verify the feasibility and reliability of the rotating detonation turbine engine.

[0005] Existing research methods have limitations in addressing the matching problems of rotating detonation turbine engine components or the entire engine. Simulation-based methods cannot simultaneously account for the unsteady characteristics of the rotating detonation combustion chamber and the overall matching conditions of the turbine engine. Experimental methods can only obtain a limited number of engine measurement parameters, and measuring high-frequency pulsation parameters is difficult. Modifying experimental schemes and systems requires significant time and cost, making it difficult to support in-depth analysis and iterative research on the matching characteristics and mechanisms of engine components or the entire engine. Furthermore, research conclusions cannot be directly generalized to similar engines. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a simulation method and apparatus for the overall pulsation characteristics of a rotating detonation turbine engine. Based on numerical simulation, the total pressure pulsation characteristics of the rotating detonation combustor are obtained, and a total pressure pulsation characteristic characterization method suitable for the overall performance model of a turbine engine component is established. Then, the total pressure pulsation characteristics of the rotating detonation combustor are coupled with the transition state performance simulation model of the turbojet engine component to construct a dynamic simulation model of the overall performance of the rotating detonation turbine engine.

[0007] The first aspect of this application provides a simulation method for the overall pulsation characteristics of a rotating detonation turbine engine, mainly including:

[0008] Step S1: Obtain the given total pressure pulsation characteristics of the rotating detonation combustion chamber;

[0009] Step S2: Calculate the total pressure at the outlet of the rotating detonation combustor at the current simulation moment based on the total pressure pulsation characteristics and the total pressure at the inlet of the rotating detonation combustor.

[0010] Step S3: Input the total pressure at the outlet of the rotating detonation combustion chamber into the pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustion chamber, and tail nozzle. It is formed by coupling the components in the airflow sequence through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics and volume effects are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustion chamber, which results in the acceleration of the engine rotor due to the residual power generated. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustion chamber is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustion chamber. The characteristics of each component of the engine are calculated using the excitation disk volume model.

[0011] Step S4: Under the constraints of overall engine matching conditions of flow balance and power balance, solve the engine independent variables and characteristics of each component by Newton-Rafersen iteration method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine.

[0012] Step S5: Extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics, return to step S2, and perform characteristic calculations for each engine component at the next simulation time.

[0013] Preferably, step S1 further includes:

[0014] Step S11: Using kerosene as fuel for the rotating detonation combustion chamber, the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotating detonation combustion chamber, as well as the mass percentage of each gas in the gas, are given.

[0015] Step S12: Numerical simulation of the flow process and motion shock wave propagation process in the rotating detonation combustion chamber is performed by applying the FLUENT solver to obtain the outlet airflow parameters of the rotating detonation combustion chamber at each moment.

[0016] Step S13: Determine the total pressure at the outlet of the rotating detonation combustion chamber using the cross-sectional mass flow rate weighted average method;

[0017] Step S14: The change in the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustion chamber over time is taken as the total pressure pulsation characteristic of the rotating detonation combustion chamber.

[0018] Preferably, in step S13, the total pressure at the outlet of the rotating detonation combustion chamber is calculated using the following formula. :

[0019] ;

[0020] in, cross section The local total pressure on the top For local density, This represents the local velocity component perpendicular to the interface.

[0021] Preferably, step S1 further includes constructing a total pressure pulsation characteristic for characterizing different rotating detonation combustion chambers by selecting parameter combinations in the Fourier series, wherein the total pressure pulsation characteristic is described by the following formula:

[0022] ;

[0023] in, It is the ratio of the total pressure at the outlet of the rotary detonation combustion chamber to the total pressure at the inlet; For time; For harmonic order; This is the DC component; , All are Fourier coefficients. The amplitude of the cosine term representing the nth harmonic is given. Characterizes the amplitude of the sinusoidal term of the nth harmonic; The fundamental angular frequency, , It is a periodicity.

[0024] The second aspect of this application provides a simulation device for the overall pulsation characteristics of a rotating detonation turbine engine, mainly comprising:

[0025] The total pressure pulsation characteristic acquisition module is used to acquire the given total pressure pulsation characteristics of the rotating detonation combustion chamber.

[0026] The rotating detonation combustor outlet total pressure calculation module is used to calculate the rotating detonation combustor outlet total pressure at the current simulation moment based on the total pressure pulsation characteristics and the rotating detonation combustor inlet total pressure.

[0027] The overall performance model input module is used to input the total pressure at the outlet of the rotating detonation combustor into a pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustor, and tail nozzle, which are coupled in the order of airflow through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics effect and volume effect are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustor, resulting in residual power that causes the engine rotor to accelerate. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustor is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustor. The characteristics of each component of the engine are calculated using the excitation disk volume model.

[0028] The component characteristic calculation module is used to solve the engine independent variables and the characteristics of each component under the constraints of the whole machine matching conditions of flow balance and power balance, using the Newton-Rafersen iterative method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and the tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine.

[0029] The simulation control module is used to extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics and to calculate the characteristics of each engine component at the next simulation time.

[0030] Preferably, the total pressure pulsation characteristic acquisition module includes:

[0031] The parameter acquisition unit is used to provide the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotary detonation combustion chamber, as well as the mass ratio of each gas in the gas, when kerosene is used as the fuel for the rotary detonation combustion chamber.

[0032] The rotating detonation combustor outlet airflow parameter calculation unit is used to numerically simulate the flow process and motion shock wave propagation process inside the rotating detonation combustor by applying the FLUENT solver, and obtain the rotating detonation combustor outlet airflow parameters at each moment.

[0033] The rotating detonation combustor outlet total pressure calculation unit is used to determine the rotating detonation combustor outlet total pressure using a cross-sectional mass flow rate weighted average method.

[0034] The total pressure pulsation characteristic calculation unit is used to take the change of the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustor over time as the total pressure pulsation characteristic of the rotating detonation combustor.

[0035] Preferably, in the total pressure calculation unit at the outlet of the rotating detonation combustion chamber, the total pressure at the outlet of the rotating detonation combustion chamber is calculated using the following formula. :

[0036] ;

[0037] in, cross section The local total pressure on the top For local density, This represents the local velocity component perpendicular to the interface.

[0038] Preferably, the total pressure pulsation characteristic acquisition module further includes:

[0039] The total pressure pulsation parameterized mathematical model construction unit is used to construct a total pressure pulsation characteristic for different rotating detonation combustion chambers by selecting parameter combinations from the Fourier series. The total pressure pulsation characteristic is described by the following formula:

[0040] ;

[0041] in, It is the ratio of the total pressure at the outlet of the rotary detonation combustion chamber to the total pressure at the inlet; For time; For harmonic order; This is the DC component; , All are Fourier coefficients. The amplitude of the cosine term representing the nth harmonic is given. Characterizes the amplitude of the sinusoidal term of the nth harmonic; The fundamental angular frequency, , It is a periodicity.

[0042] This application realizes the simulation of the unsteady coupling characteristics between the rotating detonation combustion chamber and the turbojet engine. Attached Figure Description

[0043] Figure 1 This is a flowchart of a preferred embodiment of the simulation method for the overall pulsation characteristics of a rotating detonation turbine engine according to this application.

[0044] Figure 2 This is a schematic diagram of a rotary detonation afterburning turbojet engine.

[0045] Figure 3 This is a schematic diagram of the pulsation characteristics of the total pressure ratio at the inlet and outlet of the rotating detonation combustion chamber.

[0046] Figure 4 This is a schematic diagram of a dynamic simulation model of a rotating detonation turbine engine. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0048] The first aspect of this application provides a simulation method for the overall pulsation characteristics of a rotating detonation turbine engine, such as... Figure 1 As shown, it mainly includes:

[0049] Step S1: Obtain the given total pressure pulsation characteristics of the rotating detonation combustion chamber;

[0050] Step S2: Calculate the total pressure at the outlet of the rotating detonation combustor at the current simulation moment based on the total pressure pulsation characteristics and the total pressure at the inlet of the rotating detonation combustor.

[0051] Step S3: Input the total pressure at the outlet of the rotating detonation combustion chamber into the pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustion chamber, and tail nozzle. It is formed by coupling the components in the airflow sequence through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics and volume effects are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustion chamber, which results in the acceleration of the engine rotor due to the residual power generated. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustion chamber is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustion chamber. The characteristics of each component of the engine are calculated using the excitation disk volume model.

[0052] Step S4: Under the constraints of overall engine matching conditions of flow balance and power balance, solve the engine independent variables and characteristics of each component by Newton-Rafersen iteration method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine.

[0053] Step S5: Extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics, return to step S2, and perform characteristic calculations for each engine component at the next simulation time.

[0054] This application first takes a rotating detonation afterburning turbojet engine as the research object. In step S1, the total pressure pulsation characteristics of the rotating detonation combustion chamber are obtained using numerical simulation, and a method for characterizing the total pressure pulsation characteristics of the turbine engine component-level model is established. Then, in step S2, the pulsating total pressure at the outlet of the rotating detonation combustion chamber at any simulation moment is calculated. Subsequently, in step S3, under the engine matching conditions (flow balance, pressure balance, power balance, etc.), the interaction mechanism between the total pressure pulsation characteristics of the detonation combustion chamber and engine dynamic factors (volume effect and rotor dynamics effect) is analyzed. Based on this mechanism, the total pressure pulsation characteristics are coupled into the turbojet engine component-level transition state performance simulation model to establish a dynamic simulation model of the overall engine performance, and simulation is performed.

[0055] In some alternative implementations, step S1 further includes:

[0056] Step S11: Using kerosene as fuel for the rotating detonation combustion chamber, the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotating detonation combustion chamber, as well as the mass percentage of each gas in the gas, are given.

[0057] Step S12: Numerical simulation of the flow process and motion shock wave propagation process in the rotating detonation combustion chamber is performed by applying the FLUENT solver to obtain the outlet airflow parameters of the rotating detonation combustion chamber at each moment.

[0058] Step S13: Determine the total pressure at the outlet of the rotating detonation combustion chamber using the cross-sectional mass flow rate weighted average method;

[0059] Step S14: The change in the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustion chamber over time is taken as the total pressure pulsation characteristic of the rotating detonation combustion chamber.

[0060] This application employs a rotating detonation combustor to replace the afterburner of a traditional single-shaft turbojet engine. The overall configuration and section numbering of this engine are defined as follows: Figure 2 As shown, 0 represents the unturbulent cross-section, 1 represents the inlet cross-section, 2 represents the inlet cross-section or compressor inlet cross-section, 3 represents the compressor outlet or main combustion chamber inlet cross-section, 4 represents the main combustion chamber outlet or turbine inlet cross-section, 5 represents the turbine outlet or rotating detonation combustion chamber inlet cross-section, 7 represents the rotating detonation combustion chamber outlet or exhaust nozzle inlet cross-section, and 9 represents the exhaust nozzle outlet cross-section. Subsequent engine component performance parameters (such as temperature T and pressure P) will use these designations as subscripts to reflect the component characteristics of the corresponding cross-section, such as... It is the total pressure at the turbine outlet. It is the total temperature at the outlet of the rotating detonation combustion chamber.

[0061] To clarify the changes in total pressure at the inlet and outlet of the rotating detonation combustion chamber, the FLUENT solver was used to numerically simulate the flow process and the propagation of the moving shock wave within the combustion chamber. The solution process is based on the ideal gas assumption, using the standard k-ε turbulence model. The Navier-Stokes equations are solved using a density-based approach. Physical fluxes are decomposed using the AUSM scheme, and the convection and viscous terms are discretized using a third-order MUSCL scheme, while the time term is discretized using a second-order implicit scheme. A single-step reaction mechanism is applied, employing a finite-rate model, and the reaction rate constant is calculated using the Arrhenius equation.

[0062] Due to the size constraints of the turbojet engine, and disregarding the radial influence of the annular cavity configuration of the rotating detonation combustor, the three-dimensional combustor is expanded into a two-dimensional rectangular computational domain along the generatrix. The detonation wavefront pressure, temperature, and composition parameters are calculated using CJ theory. The rotating detonation combustor uses kerosene as fuel and lean-air combustion gas after the turbine as the oxidizer. The total temperature, total pressure, and composition of the combustion gas after the turbine at 100% speed are shown in Table 1, where mass represents the mass percentage of a certain gas in the combustion gas. This is used as the inlet parameter of the rotating detonation combustor.

[0063] Table 1. Inlet Boundary Conditions of Rotating Detonation Combustion Chamber

[0064]

[0065] According to the combustion chamber pressure cloud diagram when the detonation wave propagates stably in the rotating detonation combustion chamber, the structure of the rotating detonation wave and the combustion product zone behind it remains basically unchanged. The pressure on the detonation wave surface is 0.72 MPa, the propagation period of the rotating detonation wave in the combustion chamber is 0.41 ms, and the corresponding propagation speed is 1391 m / s. The height of the rotating detonation wave changes under different periods, indicating that the intensity of the rotating detonation wave is constantly changing.

[0066] In some alternative implementations, in step S13, the total pressure at the outlet of the rotating detonation combustion chamber is calculated using the following formula. :

[0067] ;

[0068] in, cross section The local total pressure on the top For local density, This represents the local velocity component perpendicular to the interface.

[0069] In this embodiment, the inlet and outlet airflow parameters of the rotating detonation combustor are statistically analyzed, and the total outlet pressure of the rotating detonation combustor is calculated based on the cross-sectional mass flow rate weighted average method for a turbine engine component-level model. Finally, in step S14, the total outlet pressure p of the rotating detonation combustor is calculated. t7 Total pressure p at the inlet of the rotating detonation combustion chamber t5 ratio The pattern of change over time, such as Figure 3 As shown.

[0070] Therefore, in step S2, for any given simulation moment, the total pressure at the outlet of the rotating detonation combustor can be calculated based on the total pressure pulsation characteristics and the total pressure at the inlet of the rotating detonation combustor. The calculation results are then input into the overall performance model for simulation. In step S3 of this application, the pre-constructed overall performance model of the turbojet engine in the transient state is obtained by coupling the total pressure pulsation characteristics with the turbojet engine simulation model. Furthermore, rotor dynamics effects and volumetric effects are considered during the coupling process, which will be explained separately below.

[0071] Rotor dynamics refers to the effect of changes in the rotational speed of an engine rotor, while maintaining the rotor's inherent moment of inertia. Under this action, the rotor will consume additional residual power. The phenomenon is described below. The engine rotor dynamics equation is shown in the following equation, where the rotor's remaining power... Equal to turbine power Compressor power The difference, the remaining power during acceleration Positive value indicates remaining power during deceleration. It is negative.

[0072] ;

[0073] in, Let be the engine rotor speed. According to the formula, the engine rotor acceleration is related to the turbine's remaining power. Proportional.

[0074] Turbo power The calculation formula is:

[0075] ;

[0076] in, This refers to the turbine inlet gas flow rate. For the specific heat capacity of the gas at constant pressure, This refers to the turbine inlet temperature. The total temperature ratio between the turbine inlet and outlet (which is the turbine pressure ratio) (function) For turbine efficiency.

[0077] The operating state and overall performance of a turbojet engine dynamically respond to the total pressure pulsation in the rotating detonation combustion chamber. Its basic principle can be derived from the common operating equations of a fixed-geometry single-shaft turbojet engine. The flow balance between the turbine guide vane throat and the tailpipe throat satisfies the following equation:

[0078] ;

[0079] in, It is a constant. , , , These are the area, total pressure, total temperature, and flow rate function of the turbine guide vane throat. , , , These are functions representing the nozzle throat area, total pressure, total temperature, and flow rate, respectively. The equation... , , , The equation is obtained by characterizing the four parameters as expressions for the inlet and outlet aerodynamic parameters of the turbine and rotating detonation combustion chamber:

[0080] ;

[0081] In the formula, The total pressure recovery coefficient from the turbine inlet to the turbine guide vane throat. The ratio of the total pressure at the outlet of the rotating detonation combustion chamber to the total pressure at the inlet is the total pressure pulsation characteristic described in step S1 of this application. As described in step S1, it has the characteristic of high-frequency pulsation over time. , These are the total pressure and total temperature at the turbine inlet, respectively. It is the total pressure at the turbine outlet. It is the total temperature at the outlet of the rotating detonation combustion chamber.

[0082] Assuming the single-shaft turbojet engine with its rotating detonation combustion chamber open is in a stable operating state, then and All are constant values, that is:

[0083] ;

[0084] Substituting into the original expression, we can obtain

[0085] .

[0086] Assuming the total pressure recovery coefficient from turbine inlet to turbine guide throat The turbine pressure ratio is a constant. When the engine is under high operating conditions, the turbine guide vane and exhaust nozzle are in critical or supercritical states. satisfy:

[0087] .

[0088] This shows that the turbine pressure ratio With total pressure pulsation characteristics They are directly proportional and also fluctuate with time. If from a certain moment to the next moment... If the pulsation value is larger, then the turbine pressure ratio is higher. The power also increases accordingly. As can be seen from the aforementioned derivation process, the turbine work also increases, resulting in excess power. This will cause the engine rotor to accelerate, and the overall engine matching will be affected. The pulsations exhibit unsteady characteristics.

[0089] The volumetric effect refers to the unsteady airflow through various components of an engine during unsteady operation. This causes the mass and energy stored in the components to change over time, resulting in the inlet and outlet airflow mass flow rates and energy no longer being equal. This makes the flow rate at the turbine guide vane throat not completely consistent with the flow rate at the nozzle throat, and the original equation changes to:

[0090] ;

[0091] In the formula, Let be the flow rate change coefficient, and then the above formula simplifies to:

[0092] .

[0093] Therefore, under the high-frequency total pressure pulsation of the rotating detonation combustion chamber, the component volumetric effect of the turbojet engine will affect the turbine pressure ratio and output power, and thus couple with the rotor dynamics effect, causing the overall engine matching to exhibit unsteady characteristics. The influence of the volumetric effect on the engine's transient operation is usually considered using the conventional "excited disk-volume" model, which will not be elaborated here.

[0094] The above analysis shows that, under the constraints of overall engine matching conditions of flow balance and power balance, the total pressure pulsation characteristics of the rotating detonation combustion chamber will cause pulsation in the turbine output power, further causing the rotating detonation afterburning turbojet engine to produce a dynamic response. Based on this coupling mechanism, the specific calculation process of the dynamic simulation model of the rotating detonation afterburning turbojet engine is as follows: Figure 1 As shown. This model can be described as a four-variable nonlinear equation system, with the independent variables being the compressor percentage physical speed n, the compressor pressure ratio, and so on. Turbine flow conversion With turbine inlet temperature Based on the common working principle of turbojet engines, four residual equations are constructed, representing the turbine inlet temperature residual, which in turn represents the engine control law. Turbine converted flow residual, reflecting the flow balance between components and tail nozzle total pressure residual The power residual characterizing the power balance between the compressor and turbine ,in, Let be the turbine power. The equations are solved using the Newton-Rafersen iterative method.

[0095] refer to Figure 1 Suppose that starting from a certain time t, due to the total pressure pulsation in the rotating detonation combustor, the turbojet engine transitions from a stable operating state to a dynamic response. Based on the engine's iterative variables from the previous time step, the characteristics of the compressor, main combustion chamber, turbine, rotating detonation combustor, and exhaust nozzle are calculated sequentially. Component characteristic calculation methods are well-established; here, only the method for calculating the total pressure at the rotating detonation combustor outlet is introduced:

[0096] ;

[0097] Using the current time t as the independent variable, the ratio of the outlet total pressure to the inlet total pressure at that time is obtained by interpolation in the total pressure pulsation characteristic dataset. This is further determined by the total pressure at the turbine outlet, which is also the total pressure at the inlet of the rotating detonation combustion chamber. The total pressure at the outlet of the rotating detonation combustion chamber was calculated. ,visible The engine's flow rate changes relative to the previous steady state, disrupting the flow balance between the nozzle and the detonation combustion chamber. This imbalance causes the residual equations to no longer satisfy the engine's equilibrium conditions, triggering iterative calculations based on the Newton-Raphson method. This iterative solution works by solving for the engine's independent variables and the characteristics of each component until the residual equations again satisfy all the engine's overall equilibrium conditions, reaching a convergent solution at the current moment. By continuously calculating the engine's state at various moments over a period of time using the above steps, the unsteady characteristics of the engine during this process can be obtained.

[0098] When the dynamic simulation model of the rotating detonation afterburning turbojet engine reaches a convergent solution, its output parameters include not only experimentally measurable parameters such as speed, thrust, and key aerodynamic parameters of each section, but also component characteristic parameters such as compressor power, turbine power, and compressor surge margin. This provides sufficient data support for the analysis of the matching characteristics and mechanisms of rotating detonation afterburning turbojet engine components or the whole engine.

[0099] In some optional embodiments, step S1 further includes constructing a total pressure pulsation characteristic for characterizing different rotating detonation combustion chambers by selecting parameter combinations in the Fourier series, wherein the total pressure pulsation characteristic is described by the following formula:

[0100] ;

[0101] in, It is the ratio of the total pressure at the outlet of the rotary detonation combustion chamber to the total pressure at the inlet; For time; For harmonic order; This is the DC component; , All are Fourier coefficients. The amplitude of the cosine term representing the nth harmonic is given. Characterizes the amplitude of the sinusoidal term of the nth harmonic; The fundamental angular frequency, , It is a periodicity.

[0102] Depend on Figure 3 It can be seen that the total pressure pulsation of the rotating detonation combustor exhibits significant periodicity. The frequency, amplitude, and waveform of this pulsation are influenced by a combination of factors, including the geometry of the rotating detonation combustor, intake conditions, supply conditions, and combustion wave propagation modes, and thus show considerable variation within a certain range. Differences in the total pressure pulsation characteristics directly affect the performance and stability of the turbine engine. To systematically study the matching mechanism of rotating detonation turbine engine components or the entire engine, this application introduces Fourier series to describe the periodicity of the total pressure pulsation.

[0103] By selecting parameter combinations from the Fourier series, this application transforms the time-domain characteristics of the periodic pulsation of total pressure in the rotating detonation combustion chamber into frequency-domain characteristics. This enables parameterized mathematical modeling of the total pressure pulsation waveform, frequency, and amplitude, allowing for flexible definition and adjustment of pulsation characteristics through programmed parameter input. This facilitates the analysis of the coupling matching mechanism between different total pressure pulsation characteristics and the turbine engine.

[0104] A parameterized mathematical model of total pressure pulsation based on Fourier series is integrated and embedded into the component-level calculation model of the rotating detonation combustor, thereby constructing a combustor characteristic calculation module capable of adjusting the pulsation frequency, amplitude, and waveform characteristics. Based on this, a standardized cross-sectional aerodynamic parameter interface is further defined, clarifying the key parameters such as total pressure, total temperature, and flow rate, as well as their data formats, to achieve data interaction between this combustor module and other engine component modules such as the intake, compressor, turbine, and exhaust nozzle.

[0105] Based on the modular component model established above, this application extends the overall dynamic simulation method of rotating detonation afterburning turbojet engines to include various configurations of aero-turbo engines, such as split-row turbofans and mixed-row turbofans, and constructs a multi-configuration engine simulation model with adjustable total pressure pulsation characteristics, such as... Figure 4 As shown, the model mainly consists of three sequentially connected sub-modules. First, based on the target engine's configuration and flow path layout, modular components such as the intake, compressor, main combustion chamber, turbine, rotating detonation combustion chamber, and exhaust nozzle are coupled in the order of airflow through standardized cross-sectional aerodynamic parameter interfaces to construct a component-level model of the entire engine. Then, based on the overall engine balance conditions (flow balance, pressure balance, power balance, etc.) of this turbine engine configuration, residual equations for relevant engine parameters are established, further forming a closed-loop multivariate nonlinear equation system with the engine's independent variables. Finally, numerical methods such as the Newton-Raphson iteration method and particle swarm optimization algorithm are used to solve the nonlinear equation system, calculate, and output the engine characteristics.

[0106] This application proposes a whole-engine simulation method for a rotating detonation turbine engine that considers the total pressure pulsation characteristics. The beneficial effects of this method are as follows:

[0107] 1. This application establishes a dynamic simulation model of the overall performance of a rotating detonation afterburning turbojet engine. For the first time, under the overall balance conditions (flow balance, pressure balance, power balance) of the turbojet engine, it considers the coupling effect between the high-frequency pulsation of the total pressure of the rotating detonation combustion chamber and various components of the engine, and realizes the simulation of the unsteady coupling characteristics between the rotating detonation combustion chamber and the turbojet engine.

[0108] 2. The simulation model established in this application outputs complete parameters, including test-measurable parameters such as rotational speed, thrust, and key aerodynamic parameters of each cross section, as well as component characteristic parameters such as compressor power, turbine power, and compressor surge margin. This provides sufficient data support for the analysis of the matching characteristics and mechanisms of rotating detonation turbine engine components or the whole machine.

[0109] 3. This application allows for flexible definition and adjustment of total pressure pulsation characteristics through programmed parameter input, and, based on a modular modeling approach oriented towards system architecture, achieves broad applicability to various configurations of rotating detonation turbine engines. This method supports system comparison and analysis under different total pressure pulsation conditions and engine configurations, contributing to the revelation of the universal mechanism of rotating detonation turbine engines.

[0110] The second aspect of this application provides a simulation device for the overall pulsation characteristics of a rotating detonation turbine engine corresponding to the above method, mainly comprising:

[0111] The total pressure pulsation characteristic acquisition module is used to acquire the given total pressure pulsation characteristics of the rotating detonation combustion chamber.

[0112] The rotating detonation combustor outlet total pressure calculation module is used to calculate the rotating detonation combustor outlet total pressure at the current simulation moment based on the total pressure pulsation characteristics and the rotating detonation combustor inlet total pressure.

[0113] The overall performance model input module is used to input the total pressure at the outlet of the rotating detonation combustor into a pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustor, and tail nozzle, which are coupled in the order of airflow through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics effect and volume effect are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustor, resulting in residual power that causes the engine rotor to accelerate. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustor is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustor. The characteristics of each component of the engine are calculated using the excitation disk volume model.

[0114] The component characteristic calculation module is used to solve the engine independent variables and the characteristics of each component under the constraints of the whole machine matching conditions of flow balance and power balance, using the Newton-Rafersen iterative method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and the tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine.

[0115] The simulation control module is used to extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics and to calculate the characteristics of each engine component at the next simulation time.

[0116] In some optional embodiments, the total pressure pulsation characteristic acquisition module includes:

[0117] The parameter acquisition unit is used to provide the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotary detonation combustion chamber, as well as the mass ratio of each gas in the gas, when kerosene is used as the fuel for the rotary detonation combustion chamber.

[0118] The rotating detonation combustor outlet airflow parameter calculation unit is used to numerically simulate the flow process and motion shock wave propagation process inside the rotating detonation combustor by applying the FLUENT solver, and obtain the rotating detonation combustor outlet airflow parameters at each moment.

[0119] The rotating detonation combustor outlet total pressure calculation unit is used to determine the rotating detonation combustor outlet total pressure using a cross-sectional mass flow rate weighted average method.

[0120] The total pressure pulsation characteristic calculation unit is used to take the change of the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustor over time as the total pressure pulsation characteristic of the rotating detonation combustor.

[0121] In some optional embodiments, the total pressure at the outlet of the rotating detonation combustor is calculated in the rotating detonation combustor outlet total pressure calculation unit using the following formula. :

[0122] ;

[0123] in, cross section The local total pressure on the top For local density, This represents the local velocity component perpendicular to the interface.

[0124] In some optional embodiments, the total pressure pulsation characteristic acquisition module further includes:

[0125] The total pressure pulsation parameterized mathematical model construction unit is used to construct a total pressure pulsation characteristic for different rotating detonation combustion chambers by selecting parameter combinations from the Fourier series. The total pressure pulsation characteristic is described by the following formula:

[0126] ;

[0127] in, It is the ratio of the total pressure at the outlet of the rotary detonation combustion chamber to the total pressure at the inlet; For time; For harmonic order; This is the DC component; , All are Fourier coefficients. The amplitude of the cosine term representing the nth harmonic is given. Characterizes the amplitude of the sinusoidal term of the nth harmonic; The fundamental angular frequency, , It is a periodicity.

[0128] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A simulation method for the overall pulsation characteristics of a rotating detonation turbine engine, characterized in that, include: Step S1: Obtain the given total pressure pulsation characteristics of the rotating detonation combustion chamber; Step S2: Calculate the total pressure at the outlet of the rotating detonation combustor at the current simulation moment based on the total pressure pulsation characteristics and the total pressure at the inlet of the rotating detonation combustor. Step S3: Input the total pressure at the outlet of the rotating detonation combustion chamber into the pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustion chamber, and tail nozzle. It is formed by coupling the components in the airflow sequence through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics and volume effects are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustion chamber, which results in the acceleration of the engine rotor due to the residual power generated. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustion chamber is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustion chamber. The characteristics of each component of the engine are calculated using the excitation disk volume model. Step S4: Under the constraints of overall engine matching conditions of flow balance and power balance, solve the engine independent variables and characteristics of each component by Newton-Rafersen iteration method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine. Step S5: Extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics, return to step S2, and perform characteristic calculations for each engine component at the next simulation time.

2. The method of claim 1, wherein, Step S1 further includes: Step S11: Using kerosene as fuel for the rotating detonation combustion chamber, the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotating detonation combustion chamber, as well as the mass percentage of each gas in the gas, are given. Step S12: Numerical simulation of the flow process and motion shock wave propagation process in the rotating detonation combustion chamber is performed by applying the FLUENT solver to obtain the outlet airflow parameters of the rotating detonation combustion chamber at each moment. Step S13: Determine the total pressure at the outlet of the rotating detonation combustion chamber using the cross-sectional mass flow rate weighted average method; Step S14: The change in the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustion chamber over time is taken as the total pressure pulsation characteristic of the rotating detonation combustion chamber.

3. The simulation method for the overall pulsation characteristics of a rotating detonation turbine engine as described in claim 2, characterized in that, In step S13, the total pressure at the outlet of the rotating detonation combustion chamber is calculated by the following equation : ； where is the local total pressure on the cross section is the local total pressure on the cross section is the local density, is the local velocity component normal to the interface.

4. The method of claim 1, wherein, Step S1 further includes constructing a total pressure pulsation characteristic for characterizing different rotating detonation combustion chambers by selecting parameter combinations in the Fourier series, wherein the total pressure pulsation characteristic is described by the following formula: ； in, It is the ratio of the total pressure at the outlet of the rotary detonation combustion chamber to the total pressure at the inlet; For time; For harmonic order; This is the DC component; , All are Fourier coefficients. The amplitude of the cosine term representing the nth harmonic is given. The amplitude of the sinusoidal term of the nth harmonic is represented. The fundamental angular frequency, , It is a periodicity.

5. A device for simulating the pulsation characteristics of a rotating detonation engine, characterized in that, include: The total pressure pulsation characteristic acquisition module is used to acquire the given total pressure pulsation characteristics of the rotating detonation combustion chamber. The rotating detonation combustor outlet total pressure calculation module is used to calculate the rotating detonation combustor outlet total pressure at the current simulation moment based on the total pressure pulsation characteristics and the rotating detonation combustor inlet total pressure. The overall performance model input module is used to input the total pressure at the outlet of the rotating detonation combustor into a pre-constructed overall performance model of the turbojet engine in the transient state. The overall performance model consists of the intake, compressor, main combustion chamber, turbine, rotating detonation combustor, and tail nozzle, which are coupled in the order of airflow through the cross-sectional aerodynamic parameter interface. During the coupling process, rotor dynamics effect and volume effect are considered. The rotor dynamics effect refers to the change in turbine pressure ratio caused by the pulsating total pressure at the outlet of the rotating detonation combustor, resulting in residual power that causes the engine rotor to accelerate. The volume effect refers to the fact that the mass flow rate of the airflow at the inlet and outlet of the rotating detonation combustor is no longer equal due to the pulsating total pressure at the outlet of the rotating detonation combustor. The characteristics of each component of the engine are calculated using the excitation disk volume model. The component characteristic calculation module is used to solve the engine independent variables and the characteristics of each component under the constraints of the whole machine matching conditions of flow balance and power balance, using the Newton-Rafersen iterative method until the residuals converge. The residuals include the turbine inlet temperature residual characterizing the engine control law, the turbine converted flow residual and the tail nozzle total pressure residual reflecting the flow balance between components, and the power residual characterizing the power balance between the compressor and the turbine. The simulation control module is used to extract the total inlet pressure of the rotating detonation combustion chamber from the component characteristics and to calculate the characteristics of each engine component at the next simulation time.

6. The rotating detonation engine whole engine pulsation characteristics simulation apparatus of claim 5, wherein, The total pressure pulsation characteristic acquisition module includes: The parameter acquisition unit is used to provide the total temperature and total pressure parameters of the outlet gas of the turbine component located in front of the rotary detonation combustion chamber, as well as the mass ratio of each gas in the gas, when kerosene is used as the fuel for the rotary detonation combustion chamber. The rotating detonation combustor outlet airflow parameter calculation unit is used to numerically simulate the flow process and motion shock wave propagation process inside the rotating detonation combustor by applying the FLUENT solver, and obtain the rotating detonation combustor outlet airflow parameters at each moment. The rotating detonation combustor outlet total pressure calculation unit is used to determine the rotating detonation combustor outlet total pressure using a cross-sectional mass flow rate weighted average method. The total pressure pulsation characteristic calculation unit is used to take the change of the ratio of the total pressure at the outlet to the total pressure at the inlet of the rotating detonation combustor over time as the total pressure pulsation characteristic of the rotating detonation combustor.

7. The simulation device for the overall pulsation characteristics of a rotating detonation turbine engine as described in claim 6, characterized in that, In the rotating detonation combustion chamber outlet total pressure calculation unit, the rotating detonation combustion chamber outlet total pressure is calculated by the following formula : ； where is the local total pressure on the cross section is the local density, is the local velocity component normal to the interface.​ 8. The rotating detonation engine whole engine pulsation characteristics simulation apparatus of claim 5, wherein, The total pressure pulsation characteristic acquisition module further includes: The total pressure pulsation parameterized mathematical model construction unit is used to construct a total pressure pulsation characteristic for different rotating detonation combustion chambers by selecting parameter combinations from the Fourier series. The total pressure pulsation characteristic is described by the following formula: ； wherein is the ratio of the total pressure at the outlet of the rotating detonation combustion chamber to the total pressure at the inlet; is time; is the harmonic number; is the direct current component; , are Fourier coefficients, represents the amplitude of the nth harmonic cosine term, represents the amplitude of the nth harmonic sine term; is the fundamental angular frequency, , is the period.

Images