A simulation method for trajectory control thermal plume interference effects including temperature effects

Abstract

The application discloses a simulation method of track control thermal jet interference effect containing temperature influence, and comprises the following steps: determining the parameters of the flow Mach number, momentum and total enthalpy according to the real flight flow conditions, and determining the parameters of the real gas jet total pressure, total enthalpy, specific heat ratio and nozzle outlet momentum according to the real track control engine gas jet parameters; determining the ground research scaled model geometric size under the condition of ensuring the geometric similarity of the research configuration and the nozzle according to the ground research flow conditions, using air or gas jet to simulate the real track control engine gas, and simulating the jet and the flow momentum ratio and the total enthalpy ratio; and obtaining the force interference factor of the track control thermal jet interference and the track control deviation by using the ground wind tunnel test or numerical simulation method. The application can be used for thermal jet interference wind tunnel test or numerical simulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail control thermal jet interference ground simulation, and particularly relates to a simulation method of interference force and interference moment of rail control thermal jet interference containing temperature influence. BACKGROUND

[0002] Currently, all space powers are actively promoting the development of hypersonic attack and defense weapons, and more and more hypersonic vehicles use jet direct force control technology to adjust the flight attitude or improve the maneuverability. When the jet engine is working, complex interference flow is generated between the gas jet and the high-speed incoming flow. A series of complex flow phenomena such as shock wave / boundary layer interference, shock wave / shock wave interference, flow separation / reattachment, vortex, shear layer, etc. exist in the flow field, and effects such as high temperature of jet flow, multi-medium and secondary combustion change the aerodynamic force / thermal environment of the whole vehicle and components (wings, rudders, etc.) and generate interference force / moment. Based on different control purposes, jet control technology can be divided into two categories: (1) attitude control jet: the jet nozzle is far away from the vehicle center of mass, and the pitch, yaw and roll moments are provided to ensure or adjust the flight attitude; (2) rail control jet: the jet nozzle is near the center of mass of the projectile, and the direct force is provided to achieve large overload and high maneuvering variable orbit. Previously, the research on the additional interference of attitude control jet usually used constant temperature air jet to simulate high temperature gas jet by meeting the similar pressure ratio and momentum ratio, and the simulation results basically met the engineering application requirements. The new type of vehicle developed in the future needs to use rail control jet to provide large overload to achieve high maneuverability or high interception capability in order to enhance the maneuverability and penetration capability and improve the control precision. Compared with attitude control jet, the rail control jet usually has more than one order of magnitude in thrust and flow, and the differences in the separation range and pressure distribution of the interference flow field generated by cold / hot jet interference are obviously increased, and the error of the interference force / moment obtained by cold jet simulation is large, which is difficult to meet the engineering application requirements, so a new hot jet simulation strategy needs to be established.

[0003] At present, the research conclusions on rail control thermal jet interference effects are not uniform, different researches choose different similarity parameters, and there is a lack of simulation criteria applicable to rail control thermal jet simulation. At the same time, compared with the previous pressure ratio and momentum ratio, the similarity parameters do not contain temperature effects, which further affects the precision. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a simulation method of rail control thermal jet interference effects containing temperature influence.

[0005] The technical solution of the present application is:

[0006] A simulation method of rail control thermal jet interference effects containing temperature influence, comprising:

[0007] The flow parameters are determined according to the real flight flow, including Mach number, momentum and total enthalpy;

[0008] The real gas jet total pressure, total enthalpy, specific heat ratio and nozzle exit momentum are determined according to the real gas jet parameters of the real trajectory control engine;

[0009] The ground research scale model geometry, scale model shape and the similarity between the scale model nozzle and the real trajectory control engine are determined according to the real vehicle shape, jet nozzle geometry and ground simulation conditions;

[0010] The simulation jet parameters are determined according to the ground simulation flow conditions and the simulation of the real trajectory control engine jet and flow momentum ratio and total enthalpy ratio;

[0011] The force interference factor and trajectory control deviation caused by the trajectory control hot jet interference are obtained by ground wind tunnel test or numerical simulation method.

[0012] Preferably, the flow parameters are obtained by flow conditions and one-dimensional isentropic relation.

[0013] Preferably, the gas jet total enthalpy is obtained by gas jet temperature and medium attribute parameters, and the nozzle exit momentum is obtained by one-dimensional isentropic formula.

[0014] Preferably, the flow Mach number and flow state of the ground simulation conditions are consistent with the real flow, and the ground research scale model is scaled according to the ground simulation conditions under the condition of satisfying the geometric similarity between the model shape and the jet nozzle size.

[0015] Preferably, the ground simulation jet parameters are determined according to the ground simulation flow conditions, model size, simulation momentum ratio and total enthalpy ratio.

[0016] Preferably, the force interference factor K y satisfies

[0017]

[0018] In the formula, ΔC y is the normal additional interference force, C jet is the jet thrust coefficient, C y,jeton , C y,jetoff are the aerodynamic force coefficient components with and without jet;

[0019] The trajectory control deviation

[0020] In the formula, ΔS is the jet thrust action point deviation distance, L is the body length, C mz,jeton , C mz,jetoff are the aerodynamic moment coefficient components in the pitch direction with and without jet.

[0021] Preferably, the negative value of AS represents a forward shift, resulting in a low head torque; the positive value represents a rear shift, resulting in a high head torque.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] (1) The present application provides a simulation method for the interference effect of track control thermal jet, which ensures the momentum ratio and total enthalpy ratio of the jet and the incoming flow, obtains the parameters of the ground simulation jet, simulates the total enthalpy of the thermal jet at the same time as the momentum of the thermal jet, and further obtains the force interference factor and the track control deviation, which is closer to the real flight interference result compared with the traditional cold jet simulation method, and improves the simulation accuracy.

[0024] (2) Compared with the original cold jet simulation method, the present application can further simulate the total pressure ratio and the total enthalpy ratio, and the simulation parameters are more; the jet nozzle and the real thermal jet nozzle satisfy geometric similarity.

[0025] (3) The simulation method of the present application is applicable to but not limited to air simulation jet;

[0026] (4) The present application can be used as a supplement to the original pressure ratio and momentum ratio simulation method. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a flow chart of the present application;

[0028] Figure 2 is a schematic diagram of a typical track control thermal jet nozzle layout provided by the embodiment of the present application;

[0029] Figure 3 is a schematic diagram of the track control thermal jet interference flow field provided by the embodiment of the present application;

[0030] Figure 4 is a result diagram of the track control jet force interference factor and the track control deviation under the simulation strategy provided by the embodiment of the present application. DETAILED DESCRIPTION

[0031] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0032] The application establishes a simulation method of track control thermal jet interference flow field containing temperature parameters, and provides guidance and basis for ground thermal jet test or numerical simulation research of real flight thermal jet interference.

[0033] Figure 1 The application provides a simulation strategy flow chart of track control thermal jet interference effect containing temperature influence. As shown in the figure, Figure 1 the method comprises the following steps:

[0034] Step 1: Determine the Mach number, momentum and total enthalpy of the incoming flow according to the incoming flow conditions. The incoming flow parameters are obtained through the incoming flow conditions and one-dimensional isentropic relationship.

[0035] Step 2: Determine the total pressure, total enthalpy, specific heat ratio and nozzle exit momentum of the real gas jet according to the real track control engine gas jet parameters. The jet nozzle exit parameters are obtained according to the one-dimensional isentropic relationship.

[0036] Step 3: Determine the geometric size of the ground research scale model under the condition of meeting the geometric similarity of the model shape and the jet nozzle, simulate the momentum ratio and total enthalpy ratio of the real track control engine jet and the incoming flow, and determine the simulation jet parameters according to the ground simulation incoming flow conditions.

[0037] Momentum ratio:

[0038] Total enthalpy ratio:

[0039] Step 4: Obtain the force interference factor and track control deviation of the track control jet interference by using wind tunnel test or numerical simulation method.

[0040] The total enthalpy of the gas jet is obtained through the gas jet temperature and medium attribute parameters, and the nozzle exit momentum is obtained through the one-dimensional isentropic formula. According to the ground simulation incoming flow conditions and model size, the momentum ratio and total enthalpy ratio are determined to determine the ground simulation jet parameters.

[0041] Momentum ratio:

[0042] Total enthalpy ratio:

[0043] In the formula, ρ is the density, u is the speed, A j is the jet nozzle exit area, A ∞ is the incoming flow reference area (the cross-sectional area of the missile body at the nozzle axis position), P is the static pressure, γ is the specific heat ratio, M is the Mach number, c p is the constant pressure heat capacity, T is the static temperature, subscript j represents the jet, and subscript ∞ represents the incoming flow.

[0044] Specifically, is the jet nozzle exit momentum, is the incoming flow momentum, and Pj is jet static pressure, γ j is jet specific heat ratio, M j is jet Mach number, A j is jet nozzle exit area, P ∞ is free stream static pressure, γ ∞ is free stream specific heat ratio, M ∞ is free stream Mach number, A ∞ is free stream reference area.

[0045] h 0j is jet nozzle exit total enthalpy, h 0∞ is free stream total enthalpy, T ∞ is free stream gas static temperature, c pj is jet nozzle exit constant pressure specific heat, c p∞ is free stream constant pressure specific heat, T j is jet gas static temperature, u j is jet nozzle exit velocity, u ∞ is free stream velocity.

[0046] Force interference factor:

[0047] where, K y is jet generated force interference factor, ΔC y is additional interference, C y,jeton , C y,jetoff is aerodynamic force coefficient component with and without jet (jet force without jet thrust), C jet is jet thrust coefficient, y represents normal component, jet off represents without jet, jet on represents with jet.

[0048] Orbit control offset:

[0049] where, ΔS is jet thrust point offset distance, meaning the change of equivalent jet thrust point position caused by jet interference, negative value represents forward movement, generating pitch down moment, positive value represents backward movement, generating pitch up moment, L is the length of the missile body, ΔS / L% is the jet thrust point offset distance percentage of the total length of the missile body, C mz,jeton , C mz,jetoff is aerodynamic moment coefficient component with and without jet (jet force without jet moment), C jet is jet thrust coefficient.

[0050] Embodiment:

[0051] A typical calculation model is selected as an example for the trajectory control jet flow layout in this embodiment, and the calculation model is a typical trajectory control jet flow cone-column-skirt shape. The model has a total length L = 2250 mm, a nozzle outlet diameter d = 69.8 mm, and a nozzle axis near the center of the projectile body, x = 1177 mm. The moment reference point is the trajectory control jet flow action point (1177 mm, 0, 0). The jet flow parameters are shown in Table 1, and the incoming flow parameters are shown in Table 2.

[0052] Table 1: Jet flow parameters

[0053]

[0054] Table 2: Incoming flow parameters

[0055]

[0056] Figure 2 is a schematic diagram of a typical trajectory control hot jet nozzle layout provided by an embodiment of the present application. Figure 3 is a schematic diagram of a trajectory control hot jet flow interference flow field provided by an embodiment of the present application. Figure 4 is a result diagram of the trajectory control jet flow force interference factor and the trajectory control offset under the simulation method provided by an embodiment of the present application. The force interference factor and the trajectory control offset obtained by the simulation strategy under numerical simulation are closer to the trajectory control hot jet flow interference results under flight conditions than the cold jet simulation with similar pressure ratios and momentum ratios. The results show that, compared with the traditional cold jet simulation with similar pressure ratios and momentum ratios, the simulation strategy described in the present application can significantly improve the numerical simulation accuracy of the trajectory control jet flow force interference factor and the trajectory control offset.

[0057] The above describes the preferred embodiments of the present application, but the present application is not limited to the above embodiments. For those skilled in the art, various changes or modifications within the scope of the claims are obvious and also belong to the technical scope of the present application.

Claims

1. A simulation method for the interference effect of track control thermal jets, including temperature influence, characterized in that, include: The incoming flow parameters are determined based on the actual flight flow. The incoming flow parameters are obtained through the incoming flow conditions and the one-dimensional isentropic relationship, including Mach number, momentum, and total enthalpy. The total pressure, total enthalpy, specific heat ratio, and nozzle exit momentum of the actual gas jet are determined based on the actual gas jet parameters of the rail control engine. The total enthalpy of the gas jet is obtained from the gas jet temperature and medium property parameters, and the nozzle exit momentum is obtained from the one-dimensional isentropic formula. Based on the actual aircraft shape, jet nozzle geometry and ground simulation conditions, the geometry of the ground-based scale model is determined. The shape and nozzle of the scale model are similar to the shape and nozzle geometry of the actual aircraft. Based on the incoming flow conditions simulated on the ground, the gas jet simulation on the ground was used to simulate the ratio of the actual orbit control engine jet to the incoming flow velocity and the total enthalpy ratio, and the simulated jet parameters were determined. The force interference factor and track control offset caused by the thermal jet interference of track control were obtained by ground wind tunnel test or numerical simulation method. The Mach number and flow regime of the incoming flow under the ground simulation conditions need to be consistent with the actual incoming flow. Furthermore, based on the ground simulation conditions, the ground-based research scale-down model needs to be scaled down while ensuring that the model shape and the nozzle size are geometrically similar.

2. The simulation method for the interference effect of track control thermal jet stream including temperature influence as described in claim 1, characterized in that: Based on the inflow conditions and model dimensions from the ground simulation, the simulated momentum ratio and total enthalpy ratio are used to determine the parameters of the simulated jet flow on the ground.

3. The simulation method for the interference effect of track control thermal jet stream including temperature influence as described in claim 1, characterized in that: Force interference factor K y satisfy In the formula, ΔC y It is the normal additional disturbance force, C jet It is the jet thrust coefficient, C y,jeton C y,jetoff These are the aerodynamic coefficient components under conditions of spraying and no spraying; Track control offset In the formula, ΔS is the offset distance of the jet thrust application point, L is the projectile length, and C is the distance of the projectile body. mz,jeton C mz,jetoff It is the pitch component of the aerodynamic moment coefficient under conditions of spraying and no spraying.

4. The simulation method for the interference effect of track control thermal jet stream including temperature influence as described in claim 3, characterized in that: A negative ΔS value represents forward movement, generating a head-down torque; a positive value represents backward movement, generating a head-up torque.

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