A fuel flow control method and system for annular combustion chamber

Abstract

The present invention discloses a method and system for controlling the fuel flow rate of an annular combustion chamber, including: converting the fuel mass of the fuel pipeline to the rated working condition according to the ideal gas state equation and the rated working condition parameters of the fuel pipeline of the fuel engine to obtain the volume inertia time of the fuel pipeline; designing the flow instruction according to the fuel flow state based on the volume inertia time of the fuel pipeline, calculating the upstream and downstream pressures of the fuel valve / combustion chamber through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner; calculating the fuel valve flow coefficient according to the upstream and downstream pressures of the fuel valve / combustion chamber, and limiting the flow setting instruction according to the maximum flow coefficient of the fuel valve. The present invention can accurately control the on-duty fuel amount and premixed fuel amount of the fuel engine under different working conditions, directly deduce the required pressure from the combustion chamber step by step according to the set flow instruction, and the fuel control is more accurate and fast.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel flow control, and in particular to a fuel flow control method and system for an annular combustion chamber. Background Art

[0002] Fuel flow control is an important component of gas turbines and a key part to ensure the reliable operation of gas turbines. It plays a very important role in key performances such as combustion stability, combustion emissions, regulation performance, and thermal component life.

[0003] The fuel flow control methods for mainstream gas turbines in the existing market include: installing a pressure regulating valve in front of the fuel valve to ensure stable pressure in front of the fuel valve. Based on the pressure and temperature before and after the total fuel valve, the flow field is judged according to the design Reynolds number, or the combustion chamber as a whole is used as a turbulent flow field, and the fuel valve opening benchmark is designed based on the compressible fluid mass flow calculation formula, and the relationship between the flow coefficient of each fuel valve and the fuel flow is calculated, and the actual opening of the fuel valve is converted from the fuel valve design flow curve. This method has three defects: 1. Only the fuel flow field of the fuel valve part or the combustion chamber part is taken to calculate the flow. After the flow setting instruction is given during the adjustment process, only part of the fuel flow field flow is adjusted, the adjustment accuracy is poor and is greatly affected by changes in external working conditions. 2. Installing a pressure control valve increases costs, and it is necessary to first adjust the pressure and then adjust the flow, which increases the complexity of control. 3. The volume inertia of the fuel when passing through the fuel pipeline is not considered, and the dynamic change characteristics cannot be reflected when the valve changes. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a method and system for controlling fuel flow in an annular combustion chamber, which can solve the problems mentioned in the background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution, a method for controlling fuel flow in an annular combustion chamber, comprising:

[0008] According to the ideal gas state equation and the rated operating parameters of the fuel pipeline of the gas turbine, the fuel mass of the fuel pipeline is converted to the rated operating conditions to obtain the volume inertia time of the fuel pipeline;

[0009] Based on the volume inertia time of the fuel pipeline, a flow instruction is designed according to the fuel flow state, and the upstream and downstream pressures of the fuel valve / combustion chamber are calculated through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner;

[0010] The fuel valve flow coefficient is calculated according to the upstream and downstream pressures of the fuel valve / combustion chamber, and the flow setting instruction is limited according to the maximum flow coefficient of the fuel valve.

[0011] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, wherein: the obtaining of the fuel pipeline volume inertia time includes:

[0012]

[0013]

[0014] Among them, P e is the pressure of the fuel pipeline of the gas turbine under rated working conditions, P l refers to the absolute pressure of the ideal gas, V2 is the volume of the ideal gas, T e Indicates the temperature of the fuel pipeline of the gas turbine under rated operating conditions, T l represents the absolute temperature of the ideal gas, ρ1 is the natural gas density, m2 is the mass of natural gas converted to the rated working condition standard, V s is the design flow rate of natural gas under rated operating conditions, and t is the volume inertia time of the fuel pipeline.

[0015] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, wherein: the upstream and downstream pressures of the fuel valve / combustion chamber include:

[0016]

[0017] Where W is the mass flow rate, i.e. the flow setting instruction, C is the overall flow coefficient of the annular combustion chamber, N8 is a constant, depending on the unit used in the calculation formula and the type of flow coefficient Kv or Cv, F P is the pipe geometry coefficient, Y is the expansion coefficient, M is the fluid molecular weight, Z1 is the natural gas compressibility coefficient, T1 is the fuel valve / combustion chamber inlet absolute temperature, P s is the pressure upstream of the fuel valve / combustion chamber, X sizing It is the minimum value of the ratio of the actual differential pressure to the absolute pressure at the fuel valve / combustion chamber inlet and the product of the differential pressure ratio coefficient and the specific heat ratio coefficient of the control valve with attached fittings under choked flow conditions.

[0018] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, wherein: the upstream and downstream pressures of the fuel valve / combustion chamber also include:

[0019]

[0020] X choked =F γ *X tp

[0021]

[0022] Where X is the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet, X choked is the blocking pressure difference ratio, F γ is the specific heat ratio coefficient, X tp is the pressure difference ratio coefficient of the control valve with attached pipe fittings under choked flow conditions.

[0023] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, wherein: the upstream and downstream pressures of the fuel valve / combustion chamber also include:

[0024] Non-blocking flow pressure calculation formula:

[0025]

[0026]

[0027] Among them, P x is the pressure downstream of the fuel valve / combustion chamber.

[0028] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, it also includes:

[0029] Obtain the flow setting instruction, and calculate the required combustion chamber upstream pressure under the flow setting instruction by combining the volume inertia time, the non-blocked flow pressure calculation formula and the actual combustion chamber downstream pressure;

[0030] Calculate the pressure downstream of the fuel valve according to the pressure upstream of the combustion chamber and the non-blocked flow pressure calculation formula;

[0031] According to the upstream and downstream pressures of the fuel valve, the required flow coefficient under the flow setting instruction is calculated;

[0032] Combined with the maximum coefficient of the fuel valve design, the required flow coefficient is cyclically restricted until the required flow coefficient is less than the maximum coefficient of the fuel valve design, and the fuel valve characteristic flow curve is obtained;

[0033] The opening of the combustion valve is controlled according to the characteristic flow curve of the fuel valve.

[0034] As a preferred solution of the annular combustion chamber fuel flow control method of the present invention, it also includes: the annular combustion engine flow setting instruction is used to limit the maximum flow rate, and when the required flow coefficient of the fuel valve calculated according to the flow setting instruction is greater than the maximum flow coefficient of the valve design, the flow setting instruction is reduced until the corresponding required flow coefficient is less than or equal to the maximum flow coefficient of the valve design;

[0035] The formulas for solving the pressures upstream and downstream of the fuel valve and the combustion chamber are the same;

[0036] The annular combustion chamber comprises a duty valve, a premixing valve, a fuel main pipe, a fuel branch pipe, and a combustion chamber, and the fuel is natural gas.

[0037] A fuel flow control system for an annular combustion chamber, characterized in that it includes a volume inertia time acquisition module, a calculation module and a control module.

[0038] A volume inertia time acquisition module, which is used to convert the fuel mass of the fuel pipeline to the rated working condition according to the ideal gas state equation and the rated working condition parameters of the fuel pipeline of the combustion engine, and obtain the volume inertia time of the fuel pipeline;

[0039] A calculation module, the calculation module is used to design a flow instruction according to the fuel flow state based on the volume inertia time of the fuel pipeline, and calculate the upstream and downstream pressures of the fuel valve / combustion chamber through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner;

[0040] A control module is used to calculate a fuel valve flow coefficient according to upstream and downstream pressures of the fuel valve, and to limit a flow setting instruction according to a maximum flow coefficient of the fuel valve.

[0041] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and wherein the processor implements the steps of the above method when executing the computer program.

[0042] A computer-readable storage medium stores a computer program thereon, wherein the computer program implements the steps of the method described above when executed by a processor.

[0043] Beneficial effects of the present invention: The fuel flow control method of the present invention can accurately control the on-duty fuel amount and premixed fuel amount of the gas engine under different working conditions, and set the flow command to directly calculate the required pressure from the combustion chamber step by step, so that the fuel control is more accurate and fast; the maximum value of the flow setting command is limited to ensure that the fuel adjustment does not enter the idle stroke, thereby increasing safety. Furthermore, by increasing the volume inertia time of the fuel pipeline, the dynamic change characteristics of the fuel are reflected, making the present invention more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0045] Figure 1 A method flow chart of a method and system for controlling fuel flow in an annular combustion chamber provided by one embodiment of the present invention;

[0046] Figure 2 A fuel system diagram of an annular combustion chamber combustion engine, which is a fuel flow control method and system for an annular combustion chamber provided by one embodiment of the present invention;

[0047] Figure 3 A fuel flow control flow chart of a fuel flow control method and system for an annular combustion chamber provided by one embodiment of the present invention;

[0048] Figure 4 An internal structural diagram of a computer device of a fuel flow control method and system for an annular combustion chamber provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0050] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0051] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0052] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0053] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] Example 1

[0056] Reference Figure 1-4 , which is the first embodiment of the present invention, provides a method and system for controlling fuel flow in an annular combustion chamber, comprising:

[0057] S1: According to the ideal gas state equation and the rated operating parameters of the fuel pipeline of the gas turbine, the fuel mass of the fuel pipeline is converted to the rated operating conditions to obtain the volume inertia time of the fuel pipeline;

[0058] Among them, obtaining the fuel pipeline volume inertia time includes:

[0059]

[0060]

[0061] Among them, P e is the pressure of the fuel pipeline of the gas turbine under rated working conditions, P l refers to the absolute pressure of the ideal gas, V2 is the volume of the ideal gas, T e Indicates the temperature of the fuel pipeline of the gas turbine under rated operating conditions, T l represents the absolute temperature of the ideal gas, ρ1 is the natural gas density, m2 is the mass of natural gas converted to the rated working condition standard, V sis the design flow rate of natural gas under rated operating conditions, and t is the volume inertia time of the fuel pipeline.

[0062] It should be noted that, based on the designed natural gas flow rate under rated operating conditions and the rated operating parameters of the gas turbine fuel pipeline, the fuel mass of the fuel pipeline is converted to the rated operating conditions, and the volume inertia time of the fuel pipeline is accurately calculated; by increasing the volume inertia time of the fuel pipeline, the dynamic adjustment of the fuel flow is made more stable.

[0063] It should also be noted that by directly calculating the required pressure from the combustion chamber step by step according to the set flow command, fuel control can be performed more accurately and quickly; wherein limiting the maximum value of the flow setting command can ensure that the fuel regulation does not enter the idle stroke, thereby increasing safety.

[0064] S2: Based on the volume inertia time of the fuel pipeline, the flow command is designed according to the fuel flow state, and the upstream and downstream pressures of the fuel valve / combustion chamber are calculated through the flow setting command, the fuel main pipe and the overall flow coefficient of the burner;

[0065] Among them, the upstream and downstream pressures of the fuel valve / combustion chamber include:

[0066]

[0067] Where W is the mass flow rate, i.e. the flow setting instruction, C is the overall flow coefficient of the annular combustion chamber, N8 is a constant, depending on the unit used in the calculation formula and the type of flow coefficient Kv or Cv, F P is the pipe geometry coefficient, Y is the expansion coefficient, M is the fluid molecular weight, Z1 is the natural gas compressibility coefficient, T1 is the fuel valve / combustion chamber inlet absolute temperature, P s is the pressure upstream of the fuel valve / combustion chamber, X sizing It is the minimum value of the ratio of the actual differential pressure to the absolute pressure at the fuel valve / combustion chamber inlet and the product of the differential pressure ratio coefficient and the specific heat ratio coefficient of the control valve with attached fittings under choked flow conditions.

[0068] Furthermore, the pressure upstream and downstream of the fuel valve / combustion chamber also includes,

[0069]

[0070] X choked =F γ *X tp

[0071]

[0072] Where X is the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet, X choked is the blocking pressure difference ratio, F γ is the specific heat ratio coefficient, X tpis the pressure difference ratio coefficient of the control valve with attached pipe fittings under choked flow conditions.

[0073] Furthermore, the pressure upstream and downstream of the fuel valve / combustion chamber also includes the non-blocked flow pressure calculation formula:

[0074]

[0075]

[0076] Among them, P x is the pressure downstream of the fuel valve / combustion chamber.

[0077] S3: Calculate the fuel valve flow coefficient according to the upstream and downstream pressures of the fuel valve / combustion chamber, and limit the flow setting instruction according to the maximum flow coefficient of the fuel valve.

[0078] Furthermore, the flow setting instruction is obtained, and the required combustion chamber upstream pressure under the flow setting instruction is calculated by combining the volume inertia time, the non-blocked flow pressure calculation formula and the actual combustion chamber downstream pressure;

[0079] Furthermore, the pressure downstream of the fuel valve is calculated based on the pressure upstream of the combustion chamber and in combination with the non-blocked flow pressure calculation formula;

[0080] Furthermore, the required flow coefficient under the flow setting instruction is calculated based on the upstream and downstream pressures of the fuel valve;

[0081] Furthermore, in combination with the maximum coefficient of the fuel valve design, the required flow coefficient is cyclically restricted until the required flow coefficient is less than the maximum coefficient of the fuel valve design, and a fuel valve characteristic flow curve is obtained;

[0082] Furthermore, the opening of the combustion valve is controlled according to the characteristic flow curve of the fuel valve.

[0083] It should be noted that the annular combustion sets a maximum flow limit on the flow setting instruction of the combustion engine. When the required flow coefficient of the fuel valve calculated according to the flow setting instruction is greater than the maximum flow coefficient designed for the valve, the flow setting instruction is reduced until the corresponding required flow coefficient is less than or equal to the maximum flow coefficient designed for the valve;

[0084] It should be noted that the formulas for solving the pressures upstream and downstream of the fuel valve and combustion chamber are the same;

[0085] It should be noted that the annular combustion chamber includes a duty valve, a premixing valve, a fuel main pipe, a fuel branch pipe, and a combustion chamber, and the fuel is natural gas.

[0086] In an optional embodiment, the fuel system includes a fuel valve, a fuel pipeline, a fuel branch pipe, and a combustion chamber. The measuring points include the pressure P1 and temperature T1 before the fuel valve, the pressure P2 after the fuel valve, the pressure P3 of the main pipe before the combustion chamber, and the pressure P4 after the combustion chamber.

[0087] Furthermore, according to the flow calculation formula of compressible fluid under turbulent conditions in GB / T17213 "Industrial Process Control Valve":

[0088]

[0089] X sizing =X,(X<X choked ),X sizing =X choked ,(X>=X choked ),;

[0090] X choked =F γ *X tp ;

[0091]

[0092] It should be noted that W is the mass flow rate; X is the ratio of the actual pressure difference to the inlet absolute pressure (ΔP / P1) (pressure difference ratio); X choked is the blocking pressure difference ratio; F γ is the specific heat ratio coefficient; X tp is the pressure difference ratio coefficient of the control valve with attached pipe fittings under blocked flow conditions; C is the flow coefficient; N8 is a constant, depending on the unit used in the calculation formula and the type of flow coefficient Kv or Cv; F P is the pipeline geometry coefficient; Y is the expansion coefficient; M is the fluid molecular weight; Z1 is the natural gas compression coefficient; T1 is the inlet absolute temperature; P1 is the inlet absolute pressure.

[0093] Furthermore, according to whether the actual pressure difference reaches the blocking pressure difference, the pressure calculation formulas for non-blocking flow and blocking flow are derived:

[0094]

[0095]

[0096] Furthermore, Figure 2 The engine gives a flow setting instruction W, the pressure after the combustion chamber is measured to be P4, the inlet temperature is taken as T1, the overall flow coefficient C of the annular combustion chamber is equal to the flow coefficient of a single burner multiplied by the number of burners, and then according to the pressure calculation formula, the main pipe pressure P3 before the combustion chamber is calculated.

[0097] Furthermore, based on the calculated P3 and the total pipeline flow coefficient C, the fuel valve post-pressure P2 is calculated.

[0098] Furthermore, given the pressures P1 and P2 before and after the fuel valve, the fuel temperature T1, and the flow setting instruction W, the required flow coefficient C (Kv) of the valve can be calculated according to the flow calculation formula, and the fuel valve opening instruction can be obtained corresponding to the valve design flow curve.

[0099] Furthermore, if the required flow coefficient Kv of the valve calculated by the setting instruction W is greater than the maximum flow coefficient Kv designed for the valve, the flow setting instruction W is reduced until the required flow coefficient Kv is less than or equal to the maximum Kv value designed for the valve.

[0100] Furthermore, according to the ideal gas state equation: PV = mRT, and the density formula:

[0101] It should be noted that P refers to the absolute pressure of the ideal gas, V is the volume of the ideal gas, m represents the mass of the gas, T represents the absolute temperature of the ideal gas, R is the ideal gas constant, and ρ is the density of the natural gas.

[0102] It should be noted that the natural gas constant R will not change under different operating conditions, so the following formula can be derived:

[0103]

[0104] Furthermore, based on the pressure, temperature and density of the designed gas turbine fuel pipeline under rated operating conditions, the mass m2 of natural gas converted according to the rated operating conditions standard can be calculated.

[0105] Furthermore, based on the designed natural gas flow rate under rated operating conditions, the volume inertia time t of the natural gas pipeline under real-time operating conditions can be calculated.

[0106] It should be noted that a first-order inertia link with a time of t is added after the engine flow setting instruction W in the logic.

[0107] In an optional embodiment, a fuel flow control system for an annular combustion chamber is characterized by comprising a volume inertia time acquisition module, a calculation module and a control module,

[0108] The volume inertia time acquisition module is used to convert the fuel quality of the fuel pipeline to the rated working condition according to the ideal gas state equation and the rated working condition parameters of the fuel pipeline of the gas turbine, and obtain the volume inertia time of the fuel pipeline;

[0109] A calculation module, which is used to design a flow instruction based on the volume inertia time of the fuel pipeline and the fuel flow state, and calculate the upstream and downstream pressures of the fuel valve / combustion chamber through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner;

[0110] The control module is used to calculate the flow coefficient of the fuel valve according to the upstream and downstream pressures of the fuel valve, and to limit the flow setting instruction according to the maximum flow coefficient of the fuel valve.

[0111] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0112] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 4 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for controlling the fuel flow rate of an annular combustion chamber is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0113] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0114] According to the ideal gas state equation and the rated operating parameters of the fuel pipeline of the gas turbine, the fuel mass of the fuel pipeline is converted to the rated operating conditions to obtain the volume inertia time of the fuel pipeline;

[0115] Calculate the upstream and downstream pressures of the fuel valve / combustion chamber based on the volume inertia time of the fuel pipeline, combined with the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner;

[0116] The fuel valve flow coefficient is calculated according to the upstream and downstream pressures of the fuel valve / combustion chamber, and the flow setting instruction is limited according to the maximum flow coefficient of the fuel valve.

[0117] Example 2

[0118] Reference Figure 1-4 , which is an embodiment of the present invention, provides a fuel flow control method and system for an annular combustion chamber. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through comparative experiments.

[0119] like Figure 2 For a heavy-duty gas turbine fuel system, the fuel valve is divided into a duty fuel valve and a premix fuel valve. The fuel flow control method is analyzed by taking the duty fuel valve as an example. The control method of the premix valve is the same as that of the duty valve.

[0120] The measured combustion chamber outlet pressure is P4, in MPa; the natural gas temperature is T1, in K; the natural gas density ρ = 0.765 kg / m3. Since the fuel will not be throttled in the pipeline, the pressure calculation formula does not need to consider the blocked flow formula. According to the non-blocked flow pressure calculation formula, the combustion chamber inlet pressure P3 can be obtained:

[0121]

[0122]

[0123] Where W is the flow setting instruction given by the engine, in kg / s; 1.73 is the flow coefficient Kv value of a single burner, in m 3 / h; there are 24 burners in the combustion chamber; 1437.9 is the digital constant N. From Table 1 of GB / T 17213 "Industrial Process Control Valves" Part 2-1: Calculation formula for fluid flow under flow capacity installation conditions (GB / T17213.2), it can be found that the digital constant N8 is equal to 1.1, and the constant N can be calculated based on the flow setting instruction W, the pressure P3, P4 dimensions and the natural gas density ρ. 0.8622 is the pipeline geometry coefficient FP, which is dimensionless; 1 is the expansion coefficient Y, which is dimensionless. It should be noted that: due to the low pressure drop of the burner and fuel pipe, the influence of pressure drop on the expansion coefficient is generally not considered in the pressure calculation formula; 0.997 is the compression coefficient Z1, which is dimensionless; 17.1 is the natural gas molecular weight M, and the unit is kg / kmol.

[0124] like Figure 2 After calculating the combustion chamber inlet pressure P3, the fuel valve main pipe pressure P2 can be calculated according to the pressure calculation formula:

[0125]

[0126] Among them, 32 is the duty valve fuel main flow coefficient Kv, and the other parameters have been described in the previous paragraph.

[0127] After calculating the pressure P2 after the fuel valve, according to the measured pressure P1 before the fuel valve, the flow calculation formula of the compressible fluid can be obtained:

[0128]

[0129] Among them, 1.298 is the specific heat ratio of natural gas; 1.4 is the specific heat ratio of air; 1.298 / 1.4 is the specific heat ratio coefficient F γ ; 0.66 is the pressure difference ratio coefficient X of the control valve tp ;X sizing is the pressure difference ratio ΔP / P1 and X tp *F γ The minimum value, when the pressure difference ratio ΔP / P1 reaches X tp *F γ When the flow enters the blocked flow, the pressure difference ratio increases but the fluid flow rate no longer increases. At this time, the expansion coefficient Y is equal to 2 / 3. According to the above flow formula, the required flow coefficient C (Kv) of the fuel valve corresponding to the real-time flow setting instruction W can be calculated. The required flow coefficient C (Kv) corresponds to the fuel valve design flow curve to obtain the actual valve opening instruction.

[0130] When the required flow coefficient C (Kv) of the valve is greater than the maximum design flow coefficient of the gas turbine valve 40m 3 / h, reduce the flow setting command W until the valve required flow coefficient C (Kv) is less than or equal to 40m 3 / h.

[0131] According to the ideal gas state conversion formula, we can get:

[0132]

[0133] Among them, 1.80314 is the total pipeline pressure of the on-duty fuel under rated conditions, in MPa; 0.765 is the density of natural gas under rated conditions, in kg / m 3 ; (273.15+15.14) is the natural gas temperature under standard working conditions, in K; 1 is the design volume of the natural gas pipeline, in m 3 ; P2 and T2 are the pipeline natural gas pressure and temperature under real-time working conditions. The above formula can be used to calculate the natural gas mass m2 converted according to rated working conditions, and the unit of m2 is kg.

[0134] The design flow rate of natural gas under rated working conditions is 14.53 kg / s, and the inertia time t (unit: s) of the natural gas main pipeline of the duty valve under real-time working conditions can be calculated;

[0135]

[0136] In the logic, a first-order inertia link with a time of t is added after the gas engine flow setting instruction W.

[0137] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0138] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0139] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0140] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0141] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0142] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0143] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for controlling fuel flow in an annular combustion chamber, characterized in that: include, According to the ideal gas state equation and the rated operating parameters of the fuel pipeline of the gas turbine, the fuel mass of the fuel pipeline is converted to the rated operating conditions to obtain the volume inertia time of the fuel pipeline; the obtaining of the volume inertia time of the fuel pipeline includes: Among them, P e is the pressure of the fuel pipeline of the gas turbine under rated working conditions, P l refers to the absolute pressure of the ideal gas, V2 is the volume of the ideal gas, T e Indicates the temperature of the fuel pipeline of the gas turbine under rated operating conditions, T l represents the absolute temperature of the ideal gas, ρ1 is the natural gas density, m2 is the mass of natural gas converted to the rated working condition standard, V s is the design flow rate of natural gas under rated conditions, and t is the volume inertia time of the fuel pipeline; Based on the volume inertia time of the fuel pipeline, the flow instruction is designed according to the fuel flow state, and the upstream and downstream pressures of the fuel valve / combustion chamber are calculated through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner; the upstream and downstream pressures of the fuel valve / combustion chamber include, Where W is the mass flow rate, i.e. the flow setting instruction, C is the overall flow coefficient of the annular combustion chamber, N8 is a constant, depending on the unit used in the calculation formula and the type of flow coefficient Kv or Cv, F p is the pipe geometry coefficient, Y is the expansion coefficient, M is the fluid molecular weight, Z1 is the natural gas compressibility coefficient, T1 is the fuel valve / combustion chamber inlet absolute temperature, P s is the pressure upstream of the fuel valve / combustion chamber, X sizing It is the minimum value of the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet and the product of the pressure difference ratio coefficient and the specific heat ratio coefficient of the control valve with attached fittings under choked flow conditions; The upstream and downstream pressures of the fuel valve / combustion chamber also include: X choked =F γ *X tp Where X is the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet, X choked is the blocking pressure difference ratio, F γ is the specific heat ratio coefficient, X tp is the pressure difference ratio coefficient of the control valve with attached pipe fittings under choked flow conditions; The upstream and downstream pressures of the fuel valve / combustion chamber also include: Non-blocking flow pressure calculation formula: Among them, P x is the pressure downstream of the fuel valve / combustion chamber; Choked flow pressure calculation formula: Calculate the fuel valve flow coefficient according to the upstream and downstream pressures of the fuel valve / combustion chamber, and limit the flow setting instruction according to the maximum flow coefficient of the fuel valve; obtain the flow setting instruction, and calculate the required combustion chamber upstream pressure under the flow setting instruction in combination with the volume inertia time, the non-blocking flow pressure calculation formula and the actual combustion chamber downstream pressure; Calculate the pressure downstream of the fuel valve according to the pressure upstream of the combustion chamber and the non-blocked flow pressure calculation formula; According to the upstream and downstream pressures of the fuel valve, the required flow coefficient under the flow setting instruction is calculated; Combined with the maximum coefficient of the fuel valve design, the required flow coefficient is cyclically restricted until the required flow coefficient is less than the maximum coefficient of the fuel valve design, and the fuel valve characteristic flow curve is obtained; According to the characteristic flow curve of the fuel valve, the opening of the combustion valve is controlled; It also includes that the annular combustion chamber limits the maximum flow rate of the flow setting instruction of the combustion engine, and when the required flow coefficient of the fuel valve calculated according to the flow setting instruction is greater than the maximum flow coefficient designed for the valve, the flow setting instruction is reduced until the corresponding required flow coefficient is less than or equal to the designed maximum flow coefficient of the valve; The formulas for solving the pressures upstream and downstream of the fuel valve and the combustion chamber are the same; The annular combustion chamber comprises a duty valve, a premixing valve, a fuel main pipe, a fuel branch pipe, and a combustion chamber, and the fuel is natural gas.

2. A fuel flow control system for an annular combustion chamber, characterized in that: It includes volume inertia time acquisition module, calculation module and control module. The volume inertia time acquisition module is used to convert the fuel quality of the fuel pipeline to the rated working condition according to the ideal gas state equation and the rated working condition parameters of the fuel pipeline of the combustion engine, and obtain the volume inertia time of the fuel pipeline; the obtaining of the volume inertia time of the fuel pipeline includes: Among them, P e is the pressure of the fuel pipeline of the gas turbine under rated working conditions, P l refers to the absolute pressure of the ideal gas, V2 is the volume of the ideal gas, T e Indicates the temperature of the fuel pipeline of the gas turbine under rated operating conditions, T l represents the absolute temperature of the ideal gas, ρ1 is the natural gas density, m2 is the mass of natural gas converted to the rated working condition standard, V s is the design flow rate of natural gas at rated working conditions, t is the volume inertia time of the fuel pipeline; a calculation module, the calculation module is used to design a flow instruction according to the fuel flow state based on the volume inertia time of the fuel pipeline, and calculate the upstream and downstream pressures of the fuel valve / combustion chamber through the flow setting instruction, the fuel main pipe and the overall flow coefficient of the burner; the upstream and downstream pressures of the fuel valve / combustion chamber include, Where W is the mass flow rate, i.e. the flow setting instruction, C is the overall flow coefficient of the annular combustion chamber, N8 is a constant, depending on the unit used in the calculation formula and the type of flow coefficient Kv or Cv, F p is the pipe geometry coefficient, Y is the expansion coefficient, M is the fluid molecular weight, Z1 is the natural gas compressibility coefficient, T1 is the fuel valve / combustion chamber inlet absolute temperature, P s is the pressure upstream of the fuel valve / combustion chamber, X sizing It is the minimum value of the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet and the product of the pressure difference ratio coefficient and the specific heat ratio coefficient of the control valve with attached fittings under choked flow conditions; The upstream and downstream pressures of the fuel valve / combustion chamber also include: X choked =F γ *X tp Where X is the ratio of the actual pressure difference to the absolute pressure at the fuel valve / combustion chamber inlet, X choked is the blocking pressure difference ratio, F γ is the specific heat ratio coefficient, X tp is the pressure difference ratio coefficient of the control valve with attached pipe fittings under choked flow conditions; the upstream and downstream pressures of the fuel valve / combustion chamber also include, Non-blocking flow pressure calculation formula: Among them, P x is the pressure downstream of the fuel valve / combustion chamber; Choked flow pressure calculation formula: A control module, the control module is used to calculate the fuel valve flow coefficient according to the upstream and downstream pressures of the fuel valve, and to limit the flow setting instruction according to the maximum flow coefficient of the fuel valve; obtain the flow setting instruction, and calculate the required combustion chamber upstream pressure under the flow setting instruction in combination with the volume inertia time, the non-blocking flow pressure calculation formula and the actual combustion chamber downstream pressure; Calculate the pressure downstream of the fuel valve according to the pressure upstream of the combustion chamber and the non-blocked flow pressure calculation formula; According to the upstream and downstream pressures of the fuel valve, the required flow coefficient under the flow setting instruction is calculated; Combined with the maximum coefficient of the fuel valve design, the required flow coefficient is cyclically restricted until the required flow coefficient is less than the maximum coefficient of the fuel valve design, and the fuel valve characteristic flow curve is obtained; According to the characteristic flow curve of the fuel valve, the opening of the combustion valve is controlled; It also includes that the annular combustion chamber limits the maximum flow rate of the flow setting instruction of the combustion engine, and when the required flow coefficient of the fuel valve calculated according to the flow setting instruction is greater than the maximum flow coefficient designed for the valve, the flow setting instruction is reduced until the corresponding required flow coefficient is less than or equal to the designed maximum flow coefficient of the valve; The formulas for solving the pressures upstream and downstream of the fuel valve and the combustion chamber are the same; The annular combustion chamber comprises a duty valve, a premixing valve, a fuel main pipe, a fuel branch pipe, and a combustion chamber, and the fuel is natural gas.

3. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to claim 1 are implemented.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 are implemented.

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