METHOD OF MODELLING AT LEAST A PART OF A GAS TURBINE ENGINE

A method of modelling at least a part of a gas turbine engine, the method comprising: preparing a model of at least a part of the gas turbine engine using a data structure including: a first set of data entities representing geometrical shapes of physical features; and a second set of data entities representing geometrical shapes of aerodynamic boundaries, the second set of data entities being used to preserve aerodynamic design intent during preparation of the model.

TECHNOLOGICAL FIELD

The present disclosure concerns a method of modelling at least a part of a gas turbine engine.

BACKGROUND

Gas turbine engines may be used to power various systems. For example, gas turbine engines may be used to power aircraft, ships and electrical generators.FIG. 1illustrates a gas turbine engine10for an aircraft according to an example. The gas turbine engine10has a principal and rotational axis11and comprises, in axial flow series, an air intake12, a propulsive fan13, an intermediate pressure compressor14, a high-pressure compressor15, combustion equipment16, a high-pressure turbine17, and intermediate pressure turbine18, a low-pressure turbine19, and an exhaust nozzle20. A nacelle21generally surrounds the engine10and defines both the intake12and the exhaust nozzle20.

The compressed air exhausted from the high-pressure compressor15is directed into the combustion equipment16where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines17,18,19before being exhausted through the nozzle20to provide additional propulsive thrust. The high17, intermediate18and low19pressure turbines drive respectively the high pressure compressor15, intermediate pressure compressor14and fan13, each by a suitable interconnecting shaft.

Modelling a gas turbine engine may be a time consuming process and require significant human resources due to the complex structure of the gas turbine engine. For example, a gas turbine engine may be modelled using a traditional computer aided design (CAD) package whereby the model is generated by assembling components from the ‘bottom-up’. That is, the modelling process commences with the design of individual product parts, which is then followed by component assembly.

BRIEF SUMMARY

According to various embodiments there is provided a method of modelling at least a part of a gas turbine engine, the method comprising: preparing a model of at least a part of the gas turbine engine using a data structure including: a first set of data entities representing geometrical shapes of physical features; and a second set of data entities representing geometrical shapes of aerodynamic boundaries, the second set of data entities being used to preserve aerodynamic design intent during preparation of the model.

According to various embodiments there is provided a method of modelling at least a part of machinery, the method comprising: preparing a model of at least a part of the machinery using a data structure including: a first set of data entities representing geometrical shapes of physical features; and a second set of data entities representing geometrical shapes of aerodynamic boundaries, the second set of data entities being used to preserve aerodynamic design intent during preparation of the model.

At least some data entities of the first set of data entities may be linked to one another.

The first set of data entities may be arranged in a tree structure having parent and child relationships.

The first set of data entities may include: a first subset for at least one physical feature having no functionality; and a second subset for at least one physical feature having functionality.

The geometrical shapes of aerodynamic boundaries may include at least one of: gas turbine engine annulus lines; an aerofoil; an aperture through at least one physical feature; and a clearance between physical features.

One or more physical features may form a component of a gas turbine engine or machinery.

A single assembly of physical features may form a component of a gas turbine engine or machinery.

A plurality of assemblies of physical features may form a component of a gas turbine engine or machinery.

The geometrical shapes of physical features may be defined by geometric parameters.

Preparing a model of the gas turbine engine may include: (i) using the second set of data to define the aerodynamic design intent of the model of the gas turbine engine or machinery; (ii) using the first set of data to provide physical features to the model of the gas turbine engine or machinery to form components; and (iii) modifying the position and/or orientation and/or shape of the provided physical features to preserve the aerodynamic design intent of the model of the gas turbine engine or machinery.

Preparing a model of the gas turbine engine may include: (iv) providing a surface of a physical feature within the model with a pointer to the corresponding physical feature in the first set of data entities.

Preparing a model of the gas turbine engine or the machinery may include: (iv) providing the surface of the physical feature within the model with a tag identifying the position of the surface on the physical feature and/or identifying the function of the physical feature.

The method may further comprise producing a general arrangement drawing of the model of the gas turbine engine or the machinery.

The method may further comprise receiving user input to model a gas turbine engine or machinery; and wherein preparing the model of the gas turbine engine or the machinery may be performed in response to the user input.

According to various embodiments there is provided a computer program that, when read by a computer, causes performance of the method as described in any of the preceding paragraphs.

According to various embodiments there is provided a non-transitory computer readable storage medium comprising computer readable instructions that, when read by a computer, causes performance of the method as described in any of the preceding paragraphs.

According to various embodiments there is provided an apparatus for modelling at least a part of a gas turbine engine, the apparatus comprising: a controller to: prepare a model of at least a part of the gas turbine engine using a data structure including: a first set of data entities representing geometrical shapes of physical features; and a second set of data entities representing geometrical shapes of aerodynamic boundaries, the second set of data entities being used to preserve aerodynamic design intent during preparation of the model.

According to various embodiments there is provided an apparatus for modelling at least a part of machinery, the apparatus comprising: a controller to: prepare a model of at least a part of the machinery using a data structure including: a first set of data entities representing geometrical shapes of physical features; and a second set of data entities representing geometrical shapes of aerodynamic boundaries, the second set of data entities being used to preserve aerodynamic design intent during preparation of the model.

At least some data entities of the first set of data entities may be linked to one another.

The first set of data entities may be arranged in a tree structure having parent and child relationships.

The first set of data entities may include: a first subset for at least one physical feature having no functionality; and a second subset for at least one physical feature having functionality.

The geometrical shapes of aerodynamic boundaries may include at least one of: gas turbine engine annulus lines; an aerofoil; an aperture through at least one physical feature; and a clearance between physical features.

One or more physical features may form a component of a gas turbine engine or machinery.

A single assembly of physical features may form a component of a gas turbine engine or machinery.

A plurality of assemblies of physical features may form a component of a gas turbine engine or machinery.

The geometrical shapes of physical features may be defined by geometric parameters.

The controller may be arranged to prepare the model of the gas turbine engine by: (i) using the second set of data to define the aerodynamic design intent of the model of the gas turbine engine or the machinery; (ii) using the first set of data to provide physical features to the model to form components of the gas turbine engine or the machinery; and (iii) modifying the position and/or orientation and/or shape of the provided physical features to preserve the aerodynamic design intent of the model of the gas turbine engine or the machinery.

The controller may be arranged to prepare the model of the gas turbine engine or the machinery by: (iv) providing a surface of a physical feature within the model with a pointer to the corresponding physical feature in the first set of data entities.

The controller may be arranged to prepare the model of the gas turbine engine or the machinery by: (iv) providing the surface of the physical feature within the model with a tag identifying the position of the surface on the physical feature and/or identifying the function of the physical feature.

The controller may be arranged to produce a general arrangement drawing of the model of the gas turbine engine or the machinery.

The controller may comprise: at least one processor; at least one memory comprising computer readable instructions; the at least one processor being configured to read the computer readable instructions to cause performance of modelling a gas turbine engine.

The controller may be to receive user input to model a gas turbine engine; and to control preparation of the model of the gas turbine engine in response to the user input.

According to various embodiments there is provided a method of modelling at least a part of a gas turbine engine, the method comprising: preparing a model of at least a part of the gas turbine engine using a data structure including: a first set of data entities representing geometrical shapes of physical features, the first set of data entities including: a first subset for at least one physical feature having no functionality; and a second subset for at least one physical feature having functionality.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any of the above aspects may be applied mutatis mutandis to any other aspect.

DETAILED DESCRIPTION

FIG. 2illustrates an apparatus24for modelling at least a part of a gas turbine engine10. The apparatus24includes a controller26, a user input device28, and an output device30. The apparatus24may be any computing device and may be located in a single location (for example, the apparatus24may be a personal computer (PC) located in a single room) or may be distributed across a plurality of locations (for example, the controller26may be located remotely (in another room, building, city, or country) from the user input device28and the output device30).

The controller26may comprise any suitable circuitry to cause performance of the methods described herein and as illustrated inFIGS. 7, 8 and 13. For example, the controller26may comprise at least one application specific integrated circuit (ASIC) and/or at least one field programmable gate array (FPGA) to perform the methods. By way of another example, the controller26may comprise at least one processor32and at least one memory34. The memory34stores a computer program36comprising computer readable instructions that, when read by the processor32, causes performance of the methods described herein, and as illustrated inFIGS. 7, 8 and 13. The computer program36may be software or firmware, or may be a combination of software and firmware.

The memory34stores a data structure38that is described in greater detail in the following paragraphs. Generally, the data structure38includes a plurality of data entities from which a model of a gas turbine engine may be constructed. Additionally, the memory34may store at least one model40of a gas turbine engine generated by the apparatus24as described in the following paragraphs. In some examples, the memory34may not permanently store the model40of the gas turbine engine and instead, the model40may be built on demand and then stored (at least temporarily) by the memory34.

The processor32may be located at a single location (for example, within a housing or cover of a computer), or may be distributed across a plurality of locations (for example, the processor32may be distributed within a plurality of separate housings or covers of different computers, which may be located in the same room, or in different rooms, buildings, cities or countries). The processor32may include at least one microprocessor and may comprise a single core processor, or may comprise multiple processor cores (such as a dual core processor, a quad core processor, and so on).

The memory34may be located at a single location (for example, within a housing or cover of a computer), or may be distributed across a plurality of locations (for example, the memory34may be distributed within a plurality of separate housings or covers of different computers, which may be located in the same room, or in different rooms, buildings, cities or countries). The memory34may be any suitable non-transitory computer readable storage medium, data storage device or devices, and may comprise a hard disk and/or solid state memory (such as flash memory). The memory34may be permanent non-removable memory, or may be removable memory (such as a universal serial bus (USB) flash drive).

The computer program36, and/or the data structure38, and/or the model40, may be stored on a non-transitory computer readable storage medium42. The computer program36, and/or the data structure38, and/or the model40, may be transferred from the non-transitory computer readable storage medium42to the memory34. The non-transitory computer readable storage medium42may be, for example, a USB flash drive, a compact disc (CD), a digital versatile disc (DVD) or a Blu-ray disc. In some examples, the computer program42may be transferred to the memory34via a wireless or wired signal44.

The user input device28may include any suitable device or devices for enabling a user to control the apparatus24. For example, the user input device28may include a keyboard, a keypad, a mouse, a touch pad, or a touch screen display. The controller26is arranged to receive control signals from the user input device28.

The output device30may include any suitable device or devices for conveying information to a user. For example, the output device30may be a display (such as a liquid crystal display, or a light emitting diode display, or an active matrix organic light emitting diode display, or a thin film transistor display, or a cathode ray tube display) and/or a printing device (such as an inkjet printer or a laser printer for example). The controller26is arranged to provide a signal to the output device30to cause the output device30to convey information to the user.

FIG. 3illustrates a schematic diagram of the data structure38including a first set of data entities46and a second set of data entities48. It should be appreciated that the data structure38may be coded in any suitable programming language. For example, the data structure38may be implemented as a library of object-oriented, hierarchical C++ classes.

The first set of data entities46represents geometrical shapes of physical features of a gas turbine engine. As used herein, a ‘physical feature’ is an assembly of components, a component, or a part of a component, of a gas turbine engine. In other words, a ‘physical feature’ may not correspond to a single, recognisable component of the gas turbine engine, and each component of a gas turbine engine may be reproduced by assembling one or more physical features.

Data entities in the first set of data entities46may be referred to as ‘design-objects’, which control the geometric representation of the physical features. The data structure38comprises a library of multiple data entities, at least some of which may be dedicated to a gas turbine engine application. The data entities46may have their own taxonomy and follow an internal hierarchy for acquiring, retaining, hiding and passing on various data.

The first set of data entities46may specify the allowable position or positions of physical features within the model of the gas turbine engine. For example, the first set of data entities46may specify one or more axial positions for a bearing within a model of the gas turbine engine. Consequently, the first set of data entities46may specify starting positions of components or assemblies of components within the model of the gas turbine engine.

A single assembly of physical features may form a component of a gas turbine engine (as illustrated inFIGS. 4 and 5for an intermediate pressure compressor blade disc). Additionally, a plurality of assemblies of physical features may form a component of a gas turbine engine. For example, a seal may be formed by a rotatable assembly of physical features, and by a stationary assembly of physical features.

In some (but not all) examples, the first set of data entities46includes a first subset50and a second subset52of data entities. The first subset50includes at least one data entity for a physical feature having no functionality. That is, the one or more physical features in the first subset50may be considered building blocks that do not, in themselves, perform a function in the gas turbine engine. For example, shaft assemblies may be modelled using a plurality of such ‘building block’ physical features. The second subset52includes at least one data entity for a physical feature having functionality. That is, the one or more physical features in the second subset52may perform, in themselves, a function in the gas turbine engine. An example of a physical feature having functionality is a labyrinth seal where the parameters of the geometry may be dictated directly by the function of the feature.

As described in greater detail in the following paragraphs with reference toFIGS. 4, 5 and 6, the first set of data entities46may be arranged in a tree structure having parent and child relationships. In such a tree structure, data entities for physical features located near the root of the assembly tree carry general information and represent high level assemblies, such as spools or modules (or even the whole engine). Such physical features at the root of the tree may also be referred to as ‘top level’ physical features. Data entities for physical features located near the bottom of the assembly tree represent finer and finer geometric details. Consequently, a child physical feature is an addition to the parent physical feature and the position of the child physical feature may be determined by its position relative to the parent physical feature, and by the position of the parent physical feature. Such physical features near the bottom of the assembly tree may be referred to as ‘bottom level’ physical features. The assembly tree may be executed by a method that follows a partial sequential or procedural approach.

In other examples, the first set of data entities46may not be arranged in a tree structure and instead, at least some of the first set of data entities46may be linked to one another. Such assembled data entities may be executed by means of constraint-based declarative statements. For example, one or more of the data entities46for a physical feature may include information that allows the physical feature to be positioned (or have its position, orientation, scale or any other geometric property modified according to certain criteria) relative to another physical feature.

It should be appreciated that in the above described examples, the data in the first set of data entities46may enable the mechanical design intent of a component or an assembly of components to be generated and preserved. In more detail, where data entities are linked to other data entities or are arranged in a tree structure, the relative positioning of the physical features within the component may be preserved during assembly of the model.

In further examples, the first set of data entities46may not be linked to one another or have a tree structure.

The data structure38also includes a second set of data entities48representing geometrical shapes of aerodynamic boundaries. As used herein, an ‘aerodynamic boundary’ indicates a boundary for the flow of fluid through the gas turbine engine. An ‘aerodynamic boundary’ represents the aerodynamic design intent for the gas turbine engine and may be a desired physical boundary (for example, a desired surface of a component positioned within the flow of fluid within the gas turbine engine) or may be a boundary within free space and having no physical surface (that is, an aerodynamic boundary may indicate a desired path within free space for the flow of fluid within the gas turbine engine). The geometrical shapes of aerodynamic boundaries may include one or more of: gas turbine engine annulus lines; an aerofoil; an aperture through at least one physical feature; and a clearance between physical features.

FIG. 4illustrates a schematic diagram of data entities, illustratively organised in a tree structure, for an intermediate pressure compressor blade disc according to an example. In more detail, the diagram illustrates an intermediate pressure (IP) compressor blade disc data entity54, a disc drive arm data entity56, a disc seal arm data entity58, a disc rear arm data entity60, a disc drive arm lug data entity62, and a disc drive arm hole data entity64. It should be appreciated that the data entities54,56,58,60,62,64are a subset of the data structure38for the gas turbine engine.

The tree structure is arranged so that the IP compressor blade disc data entity54is the root of the tree structure and is the parent physical feature to the disc drive arm data entity56, the disc seal arm data entity58, and the disc rear arm data entity60. The disc drive arm data entity56is the parent physical feature to the disc drive arm lug data entity62and to the disc drive arm hole data entity64.

FIG. 5illustrates a graphical representation of the intermediate pressure (IP) compressor blade disc data entity54, the disc drive arm data entity56, the disc seal arm data entity58, the disc rear arm data entity60, the disc drive arm lug data entity62, and the disc drive arm hole data entity64.

FIG. 6illustrates a schematic diagram of a data entity66for a physical feature according to various examples. The data entity66includes geometric parameters68, parent/child relationship data70, and characterizing information72.

The geometric parameters68define the shape of the physical feature. For example, where the physical feature is a disc, the geometric parameters68define the radius and depth of the disc. The geometric parameters68enable the controller26to present the physical feature via the output device30and graphically represent the physical feature. Where the physical feature is an aperture or a cavity in a parent physical feature, the geometric parameters68may define the aperture or cavity as the removal of material from the parent physical feature.

When a data entity66is initiated and geometric parameters are defined, the controller26may advantageously perform intra-data structure validations. For example, the controller26may validate the dimensions of the geometric parameters, and for some data entities, the controller26may also check the type of parent data entity and the self-attachment location.

The parent/child relationship data70identifies the parent physical feature and/or the child physical feature(s) for that particular physical feature. The parent/child relationship data70may also define the intended positioning between the physical feature and the parent physical feature and/or the child physical feature. The final position of a physical feature may be altered by the user or by the apparatus24according to certain criteria, which are described in greater detail in the following paragraphs.

The characterising information72includes data that characterises the physical feature and/or the data entity66for the physical feature. For example, the characterising information72may include a bill of materials for the physical feature, manufacturing instructions, modification history for the data entity66, and/or the designer's notes.

The operation of the apparatus24in modelling at least a part of a gas turbine engine is described in the following paragraphs with reference toFIG. 7.

At block74, the method includes providing the data structure38including the first set of data entities46representing geometrical shapes of physical features, and the second set of data entities48representing geometrical shapes of aerodynamic boundaries. For example, the data structure38(or a part of the data structure38) may be provided by a user of the apparatus24who uses the apparatus24(or another computing device) to enter data for new data entities (either in the first or second set of data entities46,48) to generate the data structure38. By way of another example, the data structure38(or a part of the data structure38) may be provided by the controller26loading or accessing the data structure38from the memory34.

At block76, the method includes receiving user input to model a gas turbine engine. For example, the controller26may receive a control signal from the user input device28that directly initiates modelling of a gas turbine engine (for example, the user ‘presses’ a button displayed in a graphical user interface that commences modelling of the gas turbine engine). By way of another example, the controller26may receive a control signal from the user input device28that indirectly initiates modelling of a gas turbine engine (for example, the user loads the modelling software that then automatically models a gas turbine engine).

At block78, the method includes preparing a model of the gas turbine engine using the second set of data entities48to preserve the aerodynamic design intent. An example of the methodology within block78is illustrated inFIG. 8and described in the following paragraphs. Generally, in block78the method may include positioning physical features in the model so that they are not located within the aerodynamic boundaries defined by the second set of data entities48(and therefore do not restrict the desired flow of fluid through the gas turbine engine). Consequently, the aerodynamic design intent may be preserved by re-positioning physical features so that they do not occupy any space within the aerodynamic boundaries defined by the second set of data entities. In some examples, the aerodynamic design intent may be preserved by re-positioning physical features in the model so that they occupy less space within (but are still positioned within, if only to a minimal extent) within the aerodynamic boundaries defined by the second set of data entities

Upon completion of block78, the controller26may store the model40in the memory34. The model40may then be used to simulate the operation of the gas turbine engine. In some examples, the model40may be a model of a part of a gas turbine engine (for example, a compressor module of a gas turbine engine). In other examples, the model40may be a model of the whole of the gas turbine engine (that is, the model40is a model of an in-service gas turbine engine mounted on a wing of an aircraft).

At block80, the method includes producing a general arrangement drawing of the model of the gas turbine engine prepared in block78. For example, the controller26may control a display of the output device30to display a general arrangement drawing of the prepared model. By way of another example, the controller26may control a printer of the output device30to print a general arrangement drawing on a printing medium (such as paper).

FIG. 8illustrates a flow diagram of a method of preparing a model of a gas turbine engine according to various examples. The blocks illustrated inFIG. 8may form at least a part of block78illustrated inFIG. 7.

At block82, the method includes using the second set of data48to define the aerodynamic design intent of the model of the gas turbine engine. In some examples, a user may directly select one or more geometrical shapes from the second set of data48via a graphical user interface. In other examples, a user may provide a desired set of parameters (for example, a desired size for the gas turbine engine) to the controller26via the user input device28, and the controller26may then select one or more geometrical shapes from the second set of data48that most closely match the desired set of parameters.

By way of an example,FIG. 9illustrates a cross sectional side view diagram of a model including the geometrical shape84of the aerodynamic boundaries of a compressor of a gas turbine engine. The geometrical shape84comprises a plurality of dotted lines86that represent the aerodynamic boundaries of the compressor main fluid flow passage. The geometrical shape84also comprises a plurality of dotted lines88that represent the aerodynamic boundaries of leading and trailing edges of compressor blades.

At block90, the method includes using the first set of data to provide physical features to the model of the gas turbine engine to form components. The controller26may provide physical features to the model in order of their proximity to the dotted lines86,88of the geometrical shape84. For example (and with reference toFIG. 10), the controller26may provide the geometrical shape84of the compressor with physical features from the first set of data entities46to form a plurality of end walls91and compressor discs92within the model. The physical features provided to the model may include physical features (not having functionality) from the first subset50and physical features (having functionality) from the second subset52.

At block94, the method includes modifying the position and/or orientation and/or shape of at least one provided physical feature to preserve the aerodynamic design intent of the model of the gas turbine engine. For example, the controller26may determine that a compressor disc extends over one or more of the dotted lines86,88within the model, and may then re-position the compressor disc to not extend over the dotted line (or dotted lines) and thereby preserve the aerodynamic design intent of the compressor. In some examples, the controller26may determine that a physical feature extends over one or more dotted lines by comparing the locations of the perimeter of the physical feature in a coordinate system with the locations of the one or more dotted lines in the coordinate system.

Where the physical features are organised within a tree structure in the data structure38, parent and child physical features may also be re-positioned by the controller26when a physical feature is moved in order to preserve the aerodynamic design intent. In particular, once the controller26has determined that a physical feature is to be moved, the controller26uses the parent/child relationship data70to determine whether a parent or child feature should also be moved a corresponding distance to preserve the geometrical shape of the component within the model.

For example, where the controller26has determined that an intermediate pressure compressor blade disc54is to be moved within the model, the controller26may use the parent/child relationship data70of the disc data entity54to determine that the disc drive arm56, the disc seal arm58, the disc rear arm60are also to be moved. Since the disc drive arm56has the child physical features: disc drive arm lug62; and the disc drive arm hole64, the controller26may also re-position the disc arm lug62and the disc drive arm hole64within the model using the parent/child relationship data70of the disc drive arm56to preserve the geometrical shape of the compressor disc.

Where the controller26determines that no further physical features are to be provided to the model, the method moves to block96.

Where the controller26determines that further physical features are to be provided to the model (for example, child features of physical features already within the model), the method returns to block90. For example, as illustrated inFIG. 11, the controller26may provide additional physical features98to the model after block94has been performed.

At block96, the method may include providing a surface of a physical feature within the model with a pointer to the corresponding physical feature data entity in the first set of data entities46. For example, the surface of the compressor disc92in the model may be provided with a pointer to the IP compressor blade disc data entity54. The pointer may be an address that identifies the location of the corresponding data entity within the data structure38.

An advantage of block96is that it may allow surfaces to be identified automatically when an analysis needs to be performed for that component. As an example, one may consider the case of a flow analysis on a cavity in the internal volume of the core. Such an analysis may require data, such as roughness. Then, if the analysis program has access to the model built according to the present disclosure, the analysis program may be able to interrogate the surface and retrieve the bill of materials and manufacturing instructions for the corresponding component, and hence the roughness.

At block98, the method may include providing the surface of the physical feature within the model with a tag identifying the position of the surface on the physical feature and/or identifying the function of the physical feature. For example, the controller26may provide at least one surface of the compressor disc92with a tag that identifies the position of that surface on the disc and/or identifies that the function of the compressor disc is to rotate.

An advantage of block98is that it may enable the identification of surfaces of a physical feature. For the purpose of programs accessing the database, surfaces having such a tag contain a link to the physical feature data entity. The additional tag also allows a program to identify “which” surface on that physical feature has been accessed.

Once the model has been completed and stored in the memory34, the method may move to block80and the apparatus24may produce a general arrangement drawing of the model of the whole of the gas turbine engine. In some examples, the apparatus24may produce a general arrangement drawing of a model of only a part of the gas turbine engine.

The method may additionally validate inter-data entity relationships and geometric assembly relationships such as attachment pre-conditions, interaction and data transfer and geometry interference. The method may then highlight incorrect and/or impermissible types of attachments and geometric interferences.

It should be appreciated that at least some of the blocks74,76,78,80,82,90,94,96,98may be controlled or initiated by the controller26. Additionally or alternatively, at least some of the blocks74,76,78,80,82,90,94,96,98may be controlled or initiated by a human operator of the apparatus24. Additionally or alternatively, at least some of the blocks74,76,78,80,82,90,94,96,98may be controlled or initiated by another program which has access to a representation of gas turbine geometry.

FIG. 12illustrates a general arrangement drawing100produced by the method described above. The general arrangement drawing includes the compressor section illustrated inFIGS. 9 to 11, and also includes a combustor102and a turbine section104.

The apparatus24and above described method may be advantageous in that the use of the second set of data entities enables a model of a gas turbine engine to be prepared that preserves the aerodynamic design intent of the designer of the model. This may enable the gas turbine engine to be modelled from the ‘top down’. In other words, the model may be prepared by starting with a functional design (that is, the geometrical shapes of the aerodynamic boundaries), followed by a coarser to fine design process (that is, primary or core physical features at the root of the tree structure, followed by successive child physical features that fill in further geometric features).

Additionally, the apparatus24and the above described method may be advantageous in that since the data structure38may have a tree structure (or since the data entities in the data structure38are linked as described above), changes made to the position and/or orientation of a parent physical feature may carry through to successive child physical features. This may reduce the human resources required for preparing the model of the gas turbine engine.

FIG. 13illustrates a flow diagram of another method of modelling a gas turbine engine according to various examples. In these examples, the data structure38includes the first and second subset50,52of first data entities46, but may or may not include the second set of data entities48.

At block106, the method includes providing a data structure including a first set of data entities representing geometrical shapes of physical features. The first set of data entities comprises: a first subset for at least one physical feature having no functionality; and a second subset for at least one physical feature having functionality. For example, the data structure38(or a part of the data structure38) may be provided by a user of the apparatus24who uses the apparatus24(or another computing device) to enter data for new data entities in the data structure38. By way of another example, the data structure38(or a part of the data structure38) may be provided by the controller26loading or accessing the data structure38from the memory34.

At block108, the method includes receiving user input to model a gas turbine engine. For example, the controller26may receive a control signal from the user input device28that directly initiates modelling of a gas turbine engine (for example, the user ‘presses’ a button displayed in a graphical user interface that commences modelling of the gas turbine engine). By way of another example, the controller26may receive a control signal from the user input device28that indirectly initiates modelling of a gas turbine engine (for example, the user loads the modelling software that then automatically models a gas turbine engine).

At block110, the method includes preparing a model of the gas turbine engine using the first set of data entities46(and optionally the second set of data entities48). In more detail, the model of the gas turbine engine may be prepared using physical features having no functionality (that is, physical features that are building blocks (or primary or core physical features) that do not perform a function in themselves) and using physical features that have functionality (that is, the physical features in the first and second subsets50,52of the first set of data entities46).

At block112, the method includes producing a general arrangement drawing of the model of the gas turbine engine prepared in block110. For example, the controller26may control a display of the output device30to display a general arrangement drawing of the prepared model. By way of another example, the controller26may control a printer of the output device30to print a general arrangement drawing on a printing medium (such as paper).

It should be appreciated that at least some of the blocks106,108,110,112may be controlled or initiated by the controller26. Additionally or alternatively, at least some of the blocks106,108,110,112may be controlled or initiated by a human operator of the apparatus24.

It will be understood that the disclosure is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the various concepts described herein. For example, the above described methods may be used to model machinery other than gas turbine engines, and may be used to model rotating electrical machinery for example. Furthermore, the above described methods may be used to model a gas turbine engine having a different (architecture) to the one mentioned in the preceding paragraphs. For example, the above described methods may be used to model a two shaft gas turbine engine.

Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein in any form.