AxSTREAM v1.7.02 IS AVAILABLE!

FOR IMMEDIATE RELEASE
BURLINGTON, Massachusetts, November 1, 2005

SoftInWay, Inc., one of the leading providers of turbomachinery design software, releases a new version 1.7.02 of AxSTREAM™ - a professional powerful software suite that encompasses the complete engineering process of turbomachinery flow path conceptual design and multidisciplinary optimization.

AxSTREAM version 1.7.02 inherits all advantages of the preceded version appending some important features to amend and enrich the software capabilities in turbomachinery design and optimization.

The major new and weighty addition is a set of solvers that allows performing rapid preliminary design of a Multistage Axial Compressor flow path together with meanline analysis, cascades profiling, creation of airfoil 3D models, and generation of compressors maps.

New version provides the following additional key functional benefits to the turbomachinery designers that make the design and optimization process more sophisticated and convenient:

" Specialty profiling modes " AxMAP - Performance Maps Generator " New fluid types " Working Fluid Designer (WFD) " Extended Camberline Profiling " Direct Data Extraction from Charts " 3D Presentation of DoE Study Results " AxSTREAM Session Recorder " Custom DLL for leakage and loss calculations

The new functionalities streamline the process of turbine / compressor analysis, shrink time required for the project performance, and facilitate end-user operation.

Some details of a new update are as follows:

Specialty profiling modes
Beginning with v.1.7.02, AxSTREAM delivers special capabilities to perform within its own environment a flow path generation from the stages and the blades already designed.

New capabilities provide:

AxMAP - Performance Maps Generator
Additionally to the AxPLAN DoE study, an optimization module already embedded in AxSTREAM, the system is replenished with a new AxMAP module. While AxPLAN requires minimum number of runs , at that, forces to compute all points formed by a design of numerical experiment, AxMAP permits to compute any randomly chosen region in the domain of two variables.

AxMAP provides supplementary capabilities for specifying a set of miscellaneous parameters. This is very convenient in the course of compressor map generation. As miscellaneous, there may be taken the parameters such as angle of blade rotation (separately for each blade row), inlet gas temperature, etc. The map can be presented as 2D and 3D topogram.

High speed solver in combination with individual controlling of each operation point makes it possible to generate maps involving minimal computing resources.

AxMAP gives an opportunity to build various turbine/compressor characteristics useful for evaluating off-design performance, overall power plant design, control system etc.

New fluid types (gas mix usage)
Meeting increasing demand in turbo machines operating on gas mixtures, wet steam included, a line of fluid types used in AxSTREAM is added now with several gas mixtures most frequently utilized in modern turbomachinery.

Now, the fluid types in AxSTREAM are presented as:

Working Fluid Designer (WFD)
WFD utility generates unified tables that describe thermodynamical properties of the fluid (both pure gas and mixture).

WFD generates the fluids as:

Extended Camberline Profiling
An alternative Camberline Profiling method was added to the existing Pressure/Suction side profiling. Camberline Profiling mode can be used for improving a cascade channel shape. It is very useful in the case when profiles are heavily distorted. The camberline profiling preserves inlet and outlet metal angles, wedge angles and edges radii already defined and allows interactive editing the camberline curvature and the thickness of spline curvature.

Direct Data Extraction/Input from/to Charts
The new feature makes data extraction/addition from/to the charts easy and convenient. The grid with charts' data supports Copy/ Paste operations for a whole table and for a column selected, this way accelerating Import /Export of the chart data from/to external sources (MS Excel, Word, etc.). This function permits fast updating of the data utilizing traditional operations.

3D Presentation of DoE Study Results
In AxSTREAM, DoE study simplifies and speeds up a search for turbomachine performance optimal solution in a process of multidisciplinary optimization. Versus previous versions of the software when DoE results were delivered as a flat topogram, this one provides 3D presentation of F(x, y) response functions. 3D window supports interactive zoom and pad options.

AxSTREAM Session Recorder
To facilitate the process of inverted monitoring in the course of performance, a Session Recorder was built in the software structure. Enabling Session Record/Play options, a user can record and then perform a retrospective review of the session, escorting the procedure with own commentaries via Insert_UserNote function.

Custom DLL for leakage and loss calculations
Starting with release 1.7.02, AxSTREAM provides a capability to insert user custom loss models into computation. Such models have to be developed as Dynamic Link Libraries (DLL). SoftInWay provides DLL template for each model type.

New capabilities position AxSTREAM as one of industry's best price-to-performance solutions for axial turbomachinery design and optimization. AxSTREAM v1.7.02 release covers a complete engineering process of gas/steam axial turbine and compressor flow path conceptual design and multidisciplinary optimization, and delivers an advanced engineering desktop solution for use in turbomachinery industry. This software empowers designers to apply a concurrent development approach, while solving coupled problems of performance, reliability, operating life, and low-cost design process.

Please address info@softinway.com for more information and sales@softinway.com for order

 

10MW STEAM TURBINE DESIGN WITH AxSTREAM

Abstract A 12-stage steam turbine was designed with output capacity 11.23MW and internal efficiency 90.6%. At this, the airfoils of 1 to 11 stages were unified. Design process has been performed in 8 hours 30 min. on a standard commercial PC 1GHz. 1. OBJECTIVE A flow path of low power steam turbine with output capacity 10MW was to be designed from the ground with AxSTREAM™ software. One of the goals posed was the flow path components unification to simplify further manufacturing, this way reducing the cost. 2. INITIAL DATA Table 1 summarizes initial data set for the flow path design. Table 1   Flow path property Unit Value 1 Inlet total pressure kPa 2100 2 Inlet total temperature Celsius degree 370 3 Outlet static pressure kPa 300 4 Mass flow rate kg/s 27.63 5 Rotation speed rpm 3000 6 Hub diameter mm 400-800 7 1st stage blade height mm 15-50 3. PROCESS OF DESIGN In the course of processing, the following tasks have been solved: i. Preliminary design with outcomes as follows: - flow path overall capacity - total-to-static efficiency - blade height by stages - sketch of the flow path - Mollier diagram ii. Unidimensional (1D) direct analysis of the flow path pre-designed aimed to improve the flow path geometry and characteristics ii-1. 1D analysis ii-.2. DoE study in 1D formulation and 1D optimization ii-3. Stator and rotor cascades profiling of 1 to 11 stages iii. Axisymmetric (2D) analysis of 12th stage iii-1. 2D analysis iii-2. DoE study in 2D formulation and 2D optimization iii-3. 12th stages station-by-station profiling and airfoil construction

Figure 1. General layout of main Project window

4. FLOW PATH PRELIMINARY DESIGN
Outcomes:
" heat balance over flow path
" number of stages
" flow path overall characteristics (capacity, total-to-static efficiency)
" blade height by stages
" sketch of the flow path
" Mollier diagram
Processing time: 30 min (Data input included).

Preliminary design procedure uses the initial data given in Table 1, see Sec. 2.
In the course of design, the following parameters were taken as design variables:

Figure 2. Preliminary design dialog layout

Table 2 shows the flow path characteristics delivered by preliminary design.

Table 2

Flow path property	Value
Capacity, MW	11.25
Internal total-to-static efficiency, %	90.54
Blade airfoil height at LE, mm (1st stage)	27.5
Blade airfoil height at LE, mm (last stage)	93.6

 

Figure 3. Mollier diagram and sketch of the flow path after preliminary design

5. 1D DIRECT ANALYSIS
Outcomes:
Determined flow path overall characteristics at the following parameters given:
" Â1=const for 1-11 stages;
" À0=const for 1-12 stages..
Processing time: 30 min

1D direct analysis was conducted after the flow path preliminary design procedure has been completed.
The analysis was performed in a formulation "Adjustment of meanline A1 angles with fixed flow rate".

Aiming blades unification, the following trial values of inlet metal angles B1m and A0m were assumed:
for blades:
" 1-11 stage = 32deg ;
" 12 stage = 36deg ;
for nozzles:
" 1-12 stages = 90deg.

Figure 4. 1D computation final window
1 - tabled data; 2 - angles' distribution; 3 - journal of computation.

The outcomes of preliminary design and 1D analysis for two target characteristics are presented in table 3.

Table 3

Flow path property	Preliminary design	1D analysis
Capacity, MW	11.25	11.19
Internal total-to-static efficiency, %	90.40	90.08

6. DoE STUDY IN 1D FORMULATION
Outcomes: Optimization of blade gauging angles with the aim of airfoil unification
Processing time: 1 h

A study was carried out with specialty AxPLAN DoE module of AxSTREAM in the frame of 1D direct analysis solver targeting a subsequent multiparametric optimization.

Figure 4. Fragment of the results of turbine performance DoE study in AxSTREAM

Table 4 demonstrates results of pre-design, 1D analysis, and optimization with 1D DoE performed for two response functions.

Table 4

Flow path property	Preliminary design	1D analysis	Optimization with 1D DoE study
Capacity, MW	11.25	11.19	11.22
Internal total-to-static efficiency, %	90.40	90.08	90.3

Optimization of gauging angles A1eff and B2eff distribution was performed with results as shown in table 5.

Table 5

Station	1	2	3	4	5	6	7	8	9	10	11	12
Angle
B2eff	25.39	25.36	25.33	25.30	25.27	25.24	25.21	25.18	25.15	25.13	25.10	25.08
A1eff	14.21	14.41	14.51	14.61	14.73	14.85	14.98	15.12	15.28	15.46	15.66	15.82

We assume B2eff for 1-12 stages equal 25.4deg=const.

Thus, airfoil unification of 1 to 11 stages is possible now with the inlet (B1) and outlet (B2eff) angles defined as constant.

7. ANALYSIS AFTER BLADING UNIFICATION
Outcomes: Overall parameters verification
Processing time: 30 min

As described in Sec. 5, to provide the turbine airfoil unification, the inlet metal angles were changed and assumed equal for all blades except L-0 stage with vortex blades. Unidimensional analysis and optimization of the flow path with the problem formulated as "Adjustment of meanline A1 angles with fixed flow rate" resulted in computation of the blade outlet metal angles distribution.

A gauging angle of the blades B2eff over the flow path was also changed for all stages and formed 25.4deg.

1D direct reanalysis based on new data showed that the change in gauging angle wasn't followed by any noticeable changes of the flow path design points and practically coincides with the data shown in table 5.

Figure 5 Results of 1D analysis for equal inlet and outlet angles of the 1-11 stages

8. BLADE PROFILING OF 1-11 STAGES
Outcomes: Profiles for 1-11 stages
Processing time: 1.5 h

Profiling procedure is performed by "Profile" module of AxSTREAM. The blades of 1-11 stages are prismatic with aspect ratio D/l>10 and a profile once built fits a whole blading.
The process can be carried out both in interactive and automatic modes.

First stage stator cascade built with macromodel	First stage stator cascade built with other methods embedded in AxSTREAM
First stage rotor cascade built with macromodel	First stage rotor cascade built with other methods embedded in AxSTREAM

Figure 6 Stator and rotor cascades profiled with different methods embedded in AxSTREAM

9. FLOW PATH AXISYMMETRIC ( 2D ) ANALYSIS
Outcomes:
" 12th stage angles distribution spanwise;
" flow path overall characteristics with regard to parameters variation along 12th stage height.
Processing time: 30 min

In AxSTREAM axisymmetric analysis is carried out in a "stage-by-stage" manner. In the project presented, it was performed for the stage with aspect ratio D/l <10, i.e. for 12th stage.

The parameters extracted from 1D and 2D analyses of each stage preceded a current one (pressure drop distribution and parameters variation spanwise, respectively) and inlet / outlet metal angle assigned for stator and rotor are taken as the boundary conditions for axisymmetric analysis. The angles were defined parametrically. The latter particularly meets the problem of blade vortex law optimization.

D/l ratio for 12th stage is 9.49.

11 stations were assumed for computation.

Figure 7 Results of 2D calculation

10. DOE STUDY IN 2D FORMULATION
Outcomes:
" geometrical parameters distribution over 12th stage height; and
" optimized geometrical parameters distribution spanwise.
Processing time: 2 h

DoE study in 2D formulation is purposed for building the response functions chosen with regard to a set of independent variables defined. Here, the blade vortex law exponents m1 and m2 at meanline were adopted as the independent variables.

As such, the axisymmetric analysis and determination of the vortex law for 12th stage were performed in the formulation "Determination of meanline A1 angle, the angles defined as r^m ctgB=const. at B1m=B1" accounting for positive hub reaction.

Figure 6. 2D DoE study and results of 2D optimization of 12th stage
(vortex law formulation with subsequent optimization)

12th stage: angles' distribution spanwise before 2D analysis	12th stage: angles' distribution spanwise after 2D analysis

Figure 7. Angles' distribution along blade height for 12th stage

Table 6 presents final data comparison.

Table 6

Flow path property	1D DoE and 1D optimization	Blade angles unification for 1-11th stages	2D calculation	2D DoE and 2D optimization
Capacity, MW	11.19	11.22	11.22	11.23
Internal total-to-static efficiency, %	90.08	90.30	90.48	90.60

11. CASCADE PROFILING AND AIRFOIL CONSTRUCTION
Outcomes: Final cascade configuration
Processing time: 2 h

Now, when 2D analysis and optimization were executed, the geometry and gasdynamic data at the blade inlet and outlet obtained were used in cascade profiling and airfoil construction procedures.

Profiling procedure was divided in 2 steps:
" hub and tip stations profiling;
" intermediate stations profiling.

10.1. Hub and tip stations profiling

Profile built with surrogate model	Profile obtained after profiling procedure
Figure 8a. 12th stage hub station profiling
Profile built with surrogate model	Profile obtained after profiling procedure
Figure 8b. 12th stage tip station profiling

10.2. Intermediate stations profiling
Intermediate stations profiling was carried out in an automated mode with consequent interactive correction.

Figure 9a. Cascade and airfoil computed

Figure 9b. Cascade and airfoil corrected in an interactive mode

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