# Meanline, Streamline and Throughflow Solvers

##### Introduction & Solvers

Whether the machine of interest was designed within the AxSTREAM® platform or imported (through geometric data manual entry, ATLAS or AxSLICE) a necessary step to predict its performance is the 1D/2D Streamline Calculation module. Within a single interface users have the opportunity to run meanline (1D), streamline (2D) or throughflow calculations depending on the intended goal and the degree of accuracy vs computation time desired. Subsonic, transonic and supersonic flows can be calculated while accounting for real fluid properties.

While these different types of direct calculations are licensed individually and separately for each machine type, the unified interface makes it convenient by not having to learn multiple tools for similar capabilities.

Such calculations allow getting precise and rapid power, efficiency, pressure ratio of a turbomachine as well as distribution of kinematics and thermodynamics parameters in both streamwise and spanwise directions. Losses are also calculated and broken down so that designers can clearly identify where their machine is losing efficiency and therefore have some leads on how to improve it.

##### Leakages & Secondary Flows

Moreover, leakages are estimated based on seal geometry provided, extractions, injections, recirculations, and cooling flows. Leakages can be modeled as well and heat exchangers can be added to account for inter-stage cooling or heating.

##### Types of Solver

The meanline approach is a 1D calculation at the pitch (mean) line with extrapolation of the flow properties at hub and shroud.

The streamline approach is a 2D calculation accounting to real blade angles at each spanwise location for up to 49 radial stations and is especially useful for longer blades.

The throughflow calculation is a qualitative calculation that allows investigating flow structures for optimization, including presence of shocks, vortices, etc.

##### Scope of Work

The system can perform analysis of stages with full blade rows, with only a single rotor or stator, stages with counter-rotation, with or without cooling or secondary flows, and flow paths with axial and/or radial stages. Modifications on the flow path contours can be performed to impose additional size restrictions or increase endwall continuity.

##### Loss Models

The software includes some industry-approved loss models for profile losses, secondary losses, blockage losses, leakage losses, etc. while allowing users to customize or implement their own models and tweak the magnitude of each value for maximum flexibility and tool evaluation purposes.

##### Visualization & Post-Processing

Streamwise and spanwise graphical and tabular representations of parameters such as metal and flow angles, velocities, Mach number, losses and reaction are readily available for visualization as well as Mollier diagram and velocity triangles for any calculated spanwise sections. Additionally, mass balance diagrams can be reviewed to look at the leakages and secondary flows within the machine. Finally, contours of static and total quantities (pressure, temperature, enthalpy, velocity, Mach number, etc.) can be displayed on the turbomachine in both absolute and relative frames of reference.

##### Additional Capabilities

Numerical experiments can also be created to compare multiple runs in both tabular and graphical formats; different calculation methods, settings, number of spanwise sections used in the calculation, etc.

Moreover, these direct solvers are also used in the AxMAP & AxPLAN modules (require separate licenses) to perform sensitivity studies / off-design calculations and optimization using a Design of Experiment (DoE) approach, respectively.

#### Available 1D/2D Analysis Modules by Machine Type:

##### Axial Turbine

The AxSTREAM® Axial Turbine 1D/2D Calculation module is capable of calculating cooled geometries (at blade LE, TE, tip and endwalls) for any fluid. Axial load with and without balance holes can be determined. Flow path diameter changes (between spools or cylinders) can be smoothed using plenums, and exhaust diffusers and intakes can be simulated and blades can be resized and trimmed. Modeling with drilled & reamed or milled nozzles as well as lashing wires and moisture separators can also be performed.

##### Axial Pump

The AxSTREAM® Axial Pump 1D/2D Calculation module is capable of calculating pumps for any incompressible fluid for any number of axial stages. Cavitation parameters can be determined and effect of IGVs/OGVs can be taken into account.

##### Axial Compressor

The AxSTREAM® Axial Compressor 1D/2D Calculation module is capable of calculating compressors for any compressible fluid for any number of axial stages. The effect of IGVs/OGVs can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed. Additionally, fixed values or percentages of the main mass flow rate can be extracted (bleed), for example for cooling purposes.

##### Axial Fan

The AxSTREAM® Axial Fan 1D/2D Calculation module is capable of calculating fans for any fluid for various applications; automotive, aerospace, industrial, consumer use, HVAC, etc.

##### Centrifugal Compressor

The AxSTREAM® Centrifugal Compressor 1D/2D Calculation module is capable of calculating machines for any compressible fluid and determine axial load. Machines may include radial and diagonal impellers (with or without L-bend duct), vaned or vaneless diffusors, with or without volute. The effect of IGV can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed.

##### Centrifugal Pump

The AxSTREAM® Centrifugal Pump 1D/2D Calculation module is capable of calculating machines for any incompressible fluid and determine axial load and cavitation parameters. Machines may include radial and diagonal impellers (with or without L-bend duct), vaned or vaneless diffusors, with or without volute. The effect of IGVs/OGVs can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed.

##### Centrifugal Fan

The AxSTREAM® Centrifugal Fan 1D/2D Calculation module is capable of calculating machines for any compressible fluid and determine axial load. Surge, choke and stall prediction is available.

##### Integrally Geared Compressor

The AxSTREAM® Integrally-Geared Compressor 1D/2D Calculation module is capable of calculating machines comprised of multistage and multishaft centrifugal compressors for any compressible fluid and determine axial load. Components may include radial and diagonal impellers (with or without L-bend duct), vaned or vaneless diffusors, return channels, deswirlers, heat exchangers, with or without volute. The effect of IGV can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed.

##### Mixed Flow Compressor

The AxSTREAM® Mixed-Flow Compressor 1D/2D Calculation module is capable of calculating compressors for any compressible fluid for any number of axial and centrifugal stages. The effect of IGVs/OGVs can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed. Additionally, fixed values or percentages of the main mass flow rate can be extracted (bleed), for example for cooling purposes.

##### Mixed Flow Turbine

The AxSTREAM® Radial-Axial Turbine 1D/2D Calculation module is capable of calculating axial load with and without balance holes. Flow path diameter changes (between spools or cylinders) can be smoothed using plenums, and exhaust diffusers and intakes can be simulated and blades can be resized and trimmed. Modeling of nozzle restaggering is also available.

##### Multi-Stage Centrifugal Compressor

The AxSTREAM® Multi-Stage Centrifugal Compressor 1D/2D Calculation module is capable of calculating machines comprised of multiple centrifugal compressor stages on a given shaft for any compressible fluid and determine axial load. Components may include radial and diagonal impellers (with or without L-bend duct), vaned or vaneless diffusers, return channels, heat exchangers, with or without volute. The effect of IGV can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed.

##### Multi-Stage Centrifugal Pump

The AxSTREAM® Multi-Stage Centrifugal Pump 1D/2D Calculation module is capable of calculating machines comprised of multiple centrifugal pump stages on a given shaft for any incompressible fluid and determine axial load as well as cavitation parameters. Components may include radial and diagonal impellers (with or without L-bend duct), vaned or vaneless diffusers, return channels, deswirlers, heat exchangers, with or without volute. The effect of IGV can be taken into account for surge, choke and stall predictions and restaggering can be optimized for any given rotation speed.

##### Radial Turbine

The AxSTREAM® Radial Turbine 1D/2D Calculation module is capable of calculating axial load with and without balance holes. Exhaust diffusers can be simulated and modeling of nozzle restaggering based on rotation speed is available. Machines may include impellers, vanes (stators) or vaneless passages with or without inlet volute(s) including twin-scroll configurations with independent mass flows.