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functionality building, in particular, cooled gas turbines calculation did not call any principle difficulties. Axial compressors design and analysis problems introduction was decided to realize on the methodical base proposed for axial turbines with the best use of already existing invariant subsystems scopes.
In the first section of the article the architecture of axial turbomachines conceptual design integrated system is briefly described so as to pick out elements the most subjected to changes through the new functionality connection. Then an attempt of outlining axial turbomachine flowpath 1D aerodynamic calculation theory basis that describe process in turbine as well as in compressor is made. Next as an example of a uniform approach turbine and compressor multistage flowpaths preliminary design procedures are described that have received little attention in literature in contrast to verification calculations. In concluding section axial turbine and compressor flowpath design examples are given for software scopes demonstration.
For convenience of the main material perception there are some computations in the appendix.
NOMENCLATURE
| Variables |
|
| F |
area |
| G |
mass flow rate |
| H |
rothalpy |
| Ht |
load factor |
| Lu |
specific work |
| N |
capacity |
| R |
reaction |
| c |
absolute velocity |
| d |
diameter |
| i |
specific enthalpy |
| l |
blade length |
| p |
pressure |
| s |
specific entropy |
| u |
tangential velocity |
| w |
relative velocity |
| α |
flow angle in absolute frame |
| β |
flow angle in relative frame |
| δ |
flow deviation angle |
| ε |
accuracy |
| ζ | relative loss |
| η | efficiency |
| π | pressure ratio |
| ρ | density |
| φ,ψ | stator/rotor velocity coefficients |
| ω | rotation speed |
| ω | total pressure loss coefficient |
| Functions | |
| I (p, s) | specific enthalpy |
| P (i, s) | pressure |
| S (p, i) | specific entropy |
| i*(
) | cascade design incidence |
| δ(
) | flow deviation angle |
| η (G, p0*, i0*, p2n
) | turbine estimated efficiency |
|
| ρ (p, i) |
density |
| φ (
), ψ (
) |
stator/rotor velocity coefficients |
| ω(...) |
total pressure loss coefficient |
| Subscripts |
|
| 0 |
at the stage inlet, at the beginning of the process |
| |
in section 1 |
| 2 |
in section 2 |
| 3 |
in section 3 |
| N |
related to the nozzle |
| R |
related to working wheel |
| I |
internal (efficiency) as assigned |
| h |
hub |
| t |
in the isentropic process |
| u |
peripheral |
| w |
in the relative frame |
| z |
axial Superscripts |
| * |
stagnation parameters,
cascade design incidence |
SYSTEM ARCHITECTURE
Architecture of the modern system of turbomachinery flowpath conceptual design has to match a number of requirements:
- involve a set of design modules necessary for design procedures performing in 1D and 2D formulation with the blade crown 3D geometric models availability for final refinement by means of 3D aerodynamic and stress calculations;
- make it possible to automate multivariate and optimization calculations using putted in system models;
- ensure an interactive design scenario realizing adaptability with the opportunity of return at the early stages, versions support, project integrity, etc;
- to give user convenient mechanisms for input, change, reflection data, accounting forming and data export into the other systems;
- ensure expansibility, scalability, and maintainability.
Conceptual design system subsystems are divided into application (meant for subject problems for design object of the specified type) and invariant (independent of the design object and the problem being solved). As may be seen on the Fig.1 a major subsystems part is related to invariant and does not require essential alteration at addition in the system new applied models and methods. Components gain an access to projects data and reference book through the associated mechanisms with data base only and never exchange data with each other. Thats why there is no need to rewrite already existed software components at introduction into the system new models or procedures and it is requires extending data nomenclature.
Inclusion in the system axial compressor calculation and design has required
new procedures development of the multistage flowpath preliminary design and
inverse stage calculation, flowpath meanline verification calculation and
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