gsphelp  Aerospace Standard 755

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gsphelp  Aerospace Standard 755

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Station number designation has been standardized to unambiguously define the station interfaces. The SAE (Society of Automotive Engineers) has developed a standard (Aerospace Standard 755) for the designation of gas turbine engine station numbers Note that this naming standardization is not obligatory for use in GSP. However, it is strongly advised to conform to this standard to prevent misunderstanding in projects where multiple people access or use the engine model or the model results. Note that GSP cannot (nor the developers of GSP can) force the modeler to comply to the aerospace standard, this is left for the modeler. GSP is programmed that standard station numbering is supported as long as the modeler complies to naming the stations correctly.


The fundamental station numbers for the core stream of an engine are based on the position in the engine and the process in which the station is located.


Station number

Process boundary


Free stream conditions


Engine intake front flange, or leading edge (vehicle/engine interface)


Mechanical compression entrance (compressor/fan front face)


Last compression stage discharge or exit face (also combustor inlet face)


Combustor discharge (also first mechanical expansion inlet face)


Last mechanical expansion discharge (last turbine exit face)


Front face of mixer, afterburner, eduction, ejection, etc.


Kinetic expansion entrance (propelling nozzle inlet)


Kinetic expansion throat (propelling nozzle throat)


Kinetic expansion discharge (propelling nozzle or exhaust diffuser exit plane)


These station numbers are based on the process they take place in.




Between station numbers


Kinetic compression

0 - 2


Mechanical compression

2 - 3


Heat addition

3 - 4


Mechanical expansion

4 - 5



5 - 7


Kinetic expansion

7 - 9


To comply to the standard, the station number should consist of at least 3 digits indicating the stream number process station number and a number that indicates the intermediate position in the process. Although all stations imply averaged flow properties, an additional A may be appended to the station numbering string if the station precedes a physical split of the flow path.


A valid exhaust nozzle station number would be 090, a high pressure compressor inlet would be e.g. 025, where the second stage of that compressor could be numbered 0252, etc. The exit of the intake could be 020A where the fan directly behind this intake would have an inlet core stream station number of 020 and an inlet duct stream station number of 120.


Through the output options, the user is able to define the 3-digit station string values, default, the option without cycle number prefix (the first number) is used. As GSP can optionally have more than a single cycle present in a model, an alternative method can to be used to identify the correct station number (prefixing with a 1 for the second cycle). Through the Output options it is possible to create 3-digit alternative station string which is used in the Output tables parameter output. The alternative station number strings can be shown between and onto the Component icon when enabled in the General Options.