A liquid rocket engine dynamic simulation model library system based on Modelica language

Abstract

The present invention belongs to the field of liquid rocket engine system simulation, and mainly relates to a liquid rocket engine dynamic simulation model library architecture based on the Modelica language. Its purpose is to solve the technical problem that the existing liquid rocket engine dynamic simulation model library construction has great difficulty in system model construction because the rocket engine contains many components, the working fluid has complex physical properties, and the number of models required at each level is huge. The dynamic simulation model library architecture adheres to the concept of Modelica language model reuse, with the support of the medium library, interface library, and general function library. The component library is expanded layer by layer and reused in the form of base class with clear hierarchy, taking into account universality and simplicity. It is based on the principles of practicality, universality, and scalability. Through a reasonable model library architecture, various component models are grouped together, solving the problem that the liquid rocket engine contains multiple components and media, resulting in the need for simulation models of different granularity and dimensions for dynamic process simulation, which makes system model construction difficult.

Description

Technical Field

[0001] The present invention belongs to the field of liquid rocket engine system simulation, and mainly relates to a dynamic simulation model library, specifically a liquid rocket engine dynamic simulation model library architecture based on the Modelica language, which is suitable for simulating the dynamic characteristics of liquid rocket engines. Background Art

[0002] The startup and shutdown processes of liquid rocket engines involve complex physical and chemical processes, including mechanics, combustion, and heat transfer. Using modular modeling, we construct a dynamic simulation model library for liquid rocket engines. This approach, coupled with a drag-and-drop modeling approach, allows for system model building and full-system simulation, making it a key tool for improving engine design and developing new engine models. However, rocket engines contain numerous components, employ complex working fluids, and require a large number of models at all levels, making system model building challenging. Summary of the Invention

[0003] The purpose of the present invention is to solve the technical problem that in the construction of the existing liquid rocket engine dynamic simulation model library, there are great difficulties in building the system model because the rocket engine contains many components, the working fluid has complex physical properties, and the number of models required at each level is huge. The present invention provides a liquid rocket engine dynamic simulation model library architecture based on the Modelica language.

[0004] To solve the above technical problems, the present invention provides the following technical solutions:

[0005] A liquid rocket engine dynamic simulation model library architecture based on the Modelica language is special in that:

[0006] It includes five parts: media library, interface library, general function library, component library and model library. Among them, the media library, interface library and general function library serve as the support layer of the model library.

[0007] The medium library stores physical property data of liquid medium, gas medium, fuel gas medium and solid medium used in the rocket engine system;

[0008] The interface library defines a liquid interface, a gas interface and a fuel gas interface;

[0009] The general function library extracts the commonly used functions in the component model and provides them for the component model to call in the form of general functions;

[0010] The component library, as a core component, includes six types of component model packages, namely, throttling element component model package, cavity component model package, pipeline component model package, valve component model package, turbo pump component model package and thermal component model package; each component model package is expanded layer by layer and further subdivided after expansion;

[0011] By selecting a medium on the parameter panel, the component model can directly call the corresponding data of the selected medium in the medium library, realizing one-click injection of component model physical property data; when encapsulating the component model, the interface library must be called, and data is transferred between component models through the interface to realize modular modeling; the component model calls the commonly used functions extracted from the general function library to realize the simplification of the component model;

[0012] The model library is divided according to the engine model to form a model simulation example package, and each model simulation example package is expanded layer by layer;

[0013] The model simulation example package, after being expanded layer by layer, contains three categories: general subsystem test, general system model, and model simulation data; a component model test example is constructed in the general subsystem test; the component model that has been tested can be dragged to form a subsystem model to form a subsystem test example; in the general system model, a typical full-system simulation example of the model is constructed based on the verified component model and subsystem model; the test data of each engine test is stored in the model simulation data, and the characteristic parameters of the system in each test are added on the basis of the general system model to construct an actual simulation model of the model, forming a test simulation comparison and analysis example.

[0014] Furthermore, the commonly used functions include a gas flow calculation function and a pipeline Reynolds number calculation function.

[0015] Furthermore, the pipeline component model package comprises a liquid pipeline component model, a gas pipeline component model and a two-phase pipeline component model after being expanded layer by layer.

[0016] Furthermore, the liquid pipeline component model is further subdivided as follows:

[0017] The general models of pipeline interface parameter definitions, inertia equations, and flow equations in different types of liquid pipeline models are configured as base classes. By calling the base classes and adding features, centralized pipeline component models, discrete pipeline component models, and filling pipeline component models are formed.

[0018] Furthermore, the gas interface is used for the component model of pure gas medium flowing through, and transmits three variables in total, including mass flow m_flow, absolute pressure p and temperature T;

[0019] The liquid interface is used for component models that flow through single-phase liquid media, and transmits two variables, including mass flow m_flow and absolute pressure p;

[0020] The gas interface is used for the thermal component model and transmits a total of seven variables, including the mixing ratio Km, liquid fuel flow m_flowlf, liquid oxidant flow m_flowlo, liquid relative volume fraction Vlbar, and the same gas mass flow m_flowg, absolute pressure p and temperature T as the gas interface.

[0021] Furthermore, the throttling element assembly model package includes four categories: liquid throttling elements, gas throttling elements, fuel gas throttling elements and two-phase throttling elements;

[0022] The cavity component model package includes two types of models: tank component model and gas cylinder component model;

[0023] The valve component model package includes a liquid valve component model, a gas valve component model and a two-phase valve component model;

[0024] The turbo pump assembly model package includes a pump assembly model and a turbine assembly model; wherein the pump is subdivided into a centrifugal pump assembly model and a jet pump assembly model; the turbine assembly model is subdivided into an impulse turbine assembly model, a reaction turbine assembly model and a liquid turbine assembly model;

[0025] The thermal component model package includes a head cavity component model, a generator component model, a thrust chamber component model and a nozzle component model; the head cavity is subdivided into a simple head cavity component model, an emulsification blow-off head cavity component model and a low-temperature head cavity component model.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The liquid rocket engine dynamic simulation model library architecture based on the Modelica language provided by the present invention adheres to the concept of Modelica language model reuse, is supported by a medium library, an interface library, and a general function library, and the component library is expanded layer by layer and reused in the form of base classes. The hierarchy is clear, and both universality and simplicity are taken into account. Based on the principles of practicality, universality, and extensibility, various component models are grouped together through a reasonable model library architecture, thereby solving the technical problem that the liquid rocket engine contains multiple components and involves multiple media, and its dynamic process simulation requires simulation models of different granularities and dimensions, which makes it difficult to build a system model. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the liquid rocket engine dynamic simulation model library architecture based on the Modelica language of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the embodiments.

[0030] A liquid rocket engine dynamic simulation model library architecture based on Modelica language, such as Figure 1 As shown in the figure, it contains five parts: medium library, interface library, general function library, component library, and model library. Among them, the medium library, interface library, and general function library serve as the supporting layer of the model library. The medium library stores the physical property data of liquid media, gas media, fuel gas media, and solid media used in rocket engine systems. By selecting a medium on the parameter panel, the corresponding data of the selected medium in the medium library can be directly called, realizing one-click injection of component model physical property data.

[0031] The interface library defines liquid interfaces, gas interfaces, and fuel gas interfaces. These interfaces are called when encapsulating corresponding component models, and data is transferred between component models through these interfaces to achieve modular modeling. The gas interface is used for component models flowing through pure gas media, transferring three variables: mass flow rate m_flow, absolute pressure p, and temperature T. The liquid interface is used for component models flowing through single-phase liquid media, transferring two variables: mass flow rate m_flow and absolute pressure p. The fuel gas interface is used for thermal component models, transferring seven variables: the mixing ratio Km, liquid fuel flow rate m_flowlf, liquid oxidant flow rate m_flowlo, liquid relative volume fraction Vlbar, and the same fuel gas mass flow rate m_flowg, absolute pressure p, and temperature T as the gas interface.

[0032] The general function library extracts commonly used functions from the component model, such as the gas flow calculation function and the Reynolds number calculation function in the pipeline, and provides them for the component model to call in the form of general functions, avoiding the component model from repeatedly writing functions, thereby simplifying the model and improving versatility.

[0033] The component library, as a core component, includes six types of component model packages, covering various components of liquid rocket engines, namely, throttling element (Orifices) component model package, cavity (Vessels) component model package, pipeline (Pipes) component model package, valve (Valves) component model package, turbopump (Turbopumps) component model package and thermal component (Combustor) component model package; the throttling element component model package includes four categories: liquid throttling element component model, gas throttling element component model, fuel gas throttling element component model and two-phase throttling element component model; the cavity component model package includes It includes two categories: tank component model and gas cylinder; the valve component model package includes liquid valve component model, gas valve component model and two-phase valve component model; the turbine pump component model package includes pump component model and turbine component model; among them, the pump component model is subdivided into centrifugal pump component model and jet pump component model; the turbine component model is subdivided into impact turbine component model, reaction turbine component model and liquid turbine component model; the thermal component model package includes head cavity component model, generator component model, thrust chamber component model and nozzle component model; the head cavity component model is subdivided into simple head cavity component model, emulsification blowing head cavity component model and low-temperature head cavity component model. Each component model package is expanded layer by layer and further subdivided after expansion. Taking the pipeline component model package as an example, it includes three categories: liquid pipeline component model, gas pipeline component model, and two-phase pipeline component model. Each type of pipeline component model is further subdivided. Taking the liquid pipeline component model as an example, the pipeline interface parameter definition, inertia equation, flow equation, etc. (BaseClasses) in different types of liquid pipeline models are configured as base classes. By calling the base class and adding features, the centralized pipeline component model, discrete pipeline component model and filling pipeline component model are formed.

[0034] The component model calls the medium library to inject physical parameters, calls the interface library to transfer variables between component models, and calls the general function library to reduce the workload of repetitive code writing (for example, the gas flow formula is used in gas throttle holes, gas valves, nozzles, gas turbines and other components, and can be called by different component models in the form of functions).

[0035] After being expanded layer by layer, the model simulation example package contains three categories: general subsystem test, general system model, and model simulation data; in the general subsystem test, component model test examples are constructed, such as turbine pump test, generator test, thrust chamber test, valve test, etc., to verify the validity of the component model; the component model that has been tested can be dragged to form a subsystem model, such as the supply subsystem, turbine pump subsystem, generator turbine subsystem, etc., to form a subsystem test example; in the general system model, based on the verified component model and subsystem model, a typical full-system simulation example of the model is constructed; the test data of each engine test (such as the actual pump head and power characteristic curve of different batches of products) are stored in the model simulation data, and the characteristic parameters of the system in each test are added on the basis of the general system model to construct the actual simulation model of the model and form a test simulation comparison analysis example.

[0036] The present invention is supported by a media library, an interface library, and a general function library. The component library is expanded layer by layer and reused in the form of a base class. The hierarchy is clear and both universality and simplicity are taken into consideration.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. For ordinary professional and technical personnel in this field, the specific technical solutions recorded in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A liquid rocket engine dynamic simulation model library system based on Modelica language, characterized by: It includes five parts: medium library, interface library, general function library, component library and model library. Among them, the medium library, interface library and general function library serve as the support layer of the model library. The medium library stores physical property data of liquid medium, gas medium, fuel gas medium and solid medium used in the rocket engine system; The interface library defines a liquid interface, a gas interface and a fuel gas interface; The general function library extracts the commonly used functions in the component model and provides the component model with the form of general functions for calling; The component library, as a core component, includes six types of component model packages, namely, a throttling element component model package, a cavity component model package, a pipeline component model package, a valve component model package, a turbine pump component model package and a thermal component model package; each component model package is expanded layer by layer and further subdivided after expansion; The component model selects the medium on the parameter panel and directly calls the corresponding data of the selected medium in the medium library, realizing one-click injection of the physical property data of the component model; the interface library needs to be called when encapsulating the component model, and data is transferred between component models through the interface to realize modular modeling; the component model calls the commonly used functions extracted from the general function library to simplify the component model; The model library is divided according to the engine model to form a model simulation example package, and each model simulation example package is expanded layer by layer; The model simulation example package, after being expanded layer by layer, contains three categories: general subsystem test, general system model, and model simulation data; a component model test example is constructed in the general subsystem test; the component model that has been tested can be dragged to form a subsystem model to form a subsystem test example; in the general system model, a typical full-system simulation example of the model is constructed based on the verified component model and subsystem model; the test data of each engine test is stored in the model simulation data, and the characteristic parameters of the system in each test are added on the basis of the general system model to construct an actual simulation model of the model and form a test simulation comparison and analysis example.

2. The liquid rocket engine dynamic simulation model library system based on Modelica language according to claim 1, characterized in that: The commonly used functions include a gas flow calculation function and a pipeline Reynolds number calculation function.

3. The liquid rocket engine dynamic simulation model library system based on Modelica language according to claim 2 is characterized in that: The pipeline component model package comprises a liquid pipeline component model, a gas pipeline component model and a two-phase pipeline component model after being expanded layer by layer.

4. The liquid rocket engine dynamic simulation model library system based on Modelica language according to claim 3 is characterized by: The liquid pipeline component model is further subdivided as follows: The general models of pipeline interface parameter definitions, inertia equations, and flow equations in different types of liquid pipeline models are configured as base classes. The concentrated pipeline component model, discrete pipeline component model, and filling pipeline component model are formed by calling the base class and adding features.

5. The liquid rocket engine dynamic simulation model library system based on Modelica language according to claim 4 is characterized in that: The gas interface is used for the component model flowing through pure gas medium, and transmits three variables, including mass flow m_flow, absolute pressure p and temperature T; The liquid interface is used for the component model of a single-phase liquid medium, and transmits two variables, including mass flow m_flow and absolute pressure p; The gas interface is used for the thermal component model and transmits a total of seven variables, including the mixing ratio Km, liquid fuel flow m_flowlf, liquid oxidant flow m_flowlo, liquid relative volume fraction Vlbar, and the same gas mass flow m_flowg, absolute pressure p and temperature T as the gas interface.

6. The liquid rocket engine dynamic simulation model library system based on Modelica language according to any one of claims 1 to 5, characterized in that: The throttling element assembly model package includes four categories: liquid throttling elements, gas throttling elements, fuel gas throttling elements and two-phase throttling elements; The chamber component model package includes two types of tank component models and gas cylinder component models; The valve component model package includes a liquid valve component model, a gas valve component model and a two-phase valve component model; The turbine pump assembly model package includes a pump assembly model and a turbine assembly model; wherein the pump is subdivided into a centrifugal pump assembly model and a jet pump assembly model; the turbine assembly model is subdivided into an impulse turbine assembly model, a reaction turbine assembly model and a liquid turbine assembly model; The thermal component model package includes a head cavity component model, a generator component model, a thrust chamber component model and a nozzle component model; the head cavity is subdivided into a simple head cavity component model, an emulsified blow-off head cavity component model and a low-temperature head cavity component model.

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