turboflow.axial_turbine.geometry_model module

turboflow.axial_turbine.geometry_model.calculate_full_geometry(geometry)

Computes the complete geometry of an axial turbine based on input geometric parameters.

Parameters:

geometrydict

A dictionary containing the input geometry parameters

Returns:

dict

A dictionary with both the original and newly computed geometry parameters.

turboflow.axial_turbine.geometry_model.calculate_throat_radius(radius_in, radius_out, throat_location_fraction)

Calculate the throat radius as a weighted average of the inlet and outlet radii.

This approach to estimate the area at the throat is inspired by the method described in Eq. (3) of [Ainley and Mathieson, 1951]. The throat radius is computed as a linear combination of the inlet and outlet radii, weighted by the location of the throat expressed as a fraction of the axial length of the cascade. For instance, a throat_location_fraction of 5/6 would return the throat radius as: (1/6)*radius_in + (5/6)*radius out.

Parameters:

radius_innp.array

The radius values at the inlet sections.

radius_outnp.array

The radius values at the outlet sections.

throat_location_fractionfloat

The fraction used to weight the inlet and outlet radii in the calculation.

Returns:

np.array

The calculated throat radius values, representing the weighted average of the inlet and outlet radii based on the specified throat location.

turboflow.axial_turbine.geometry_model.check_turbine_geometry(geometry, display=True)

Checks if the geometrical parameters are within the predefined recommended ranges.

Recommended Parameter Ranges and References

Variable	Lower Limit	Upper Limit	Reference(s)
Blade chord	5.0 mm	inf	Manufacturing
Blade height	5.0 mm	inf	Manufacturing
Blade maximum thickness	1.0 mm	inf	Manufacturing
Blade trailing edge thickness	0.5 mm	inf	Manufacturing
Tip clearance	0.2 mm	inf	Manufacturing
Hub to tip radius ratio	0.50	0.95	Figure (6) of [Kacker and Okapuu, 1982]
Flaring angle	-25 deg	+25 deg	Section (7) of [Ainley and Mathieson, 1951]
Aspect ratio	0.80	5.00	Section (7.3) of [Saravanamuttoo et al., 2008] Figure (13) of [Kacker and Okapuu, 1982]
Pitch to chord ratio	0.30	1.10	Figure (4) of [Ainley and Mathieson, 1951]
Stagger angle	-10 deg	+70 deg	Figure (5) of [Kacker and Okapuu, 1982]
Leading edge metal angle	-60 deg	+25 deg	Figure (5) of [Kacker and Okapuu, 1982]
Trailing edge metal angle	+40 deg	+80 deg	Figure (4) of [Ainley and Mathieson, 1951]
Leading wedge angle	+10 deg	+60 deg	Figure (2) from [Benner et al., 1997] Figure (10) from [Pritchard, 1985]
Leading edge diameter to chord ratio	0.03	0.30	Table (1) [Moustapha et al., 1990]
Maximum thickness to chord ratio	0.05	0.30	Figure (4) of [Kacker and Okapuu, 1982]
Trailing edge thickness to opening ratio	0.00	0.40	Figure (14) of [Kacker and Okapuu, 1982]
Tip clearance to height ratio	0.00	0.05	Figure (7) of [Dunham and Came, 1970]
Throat location fraction	0.50	1.00	Equation (3) of [Ainley and Mathieson, 1951]

The ranges of metal angles and stagger angles are reversed for rotor cascades

Parameters:

geometrydict

A dictionary containing the computed geometry of the turbine.

Returns:

list

A list of messages with a summary of the checks.

turboflow.axial_turbine.geometry_model.prepare_geometry(geometry, radius_type)

Convert the geometrical design variables to parameters suitable for turbine evaluation.

For design optimization, the geometrical design variables are defined as ratios, e.g. hub-to-tip radius and aspect ratio. This function convert the set of geometrical design variables to a set which is suited for turbine evaluation. The function utilize radius_type to decide if the given radius is constant for hub, mean or tip throughout the turbine.

Parameters:

geometrydict

A dictionary with all necessary geometrical parameters.

radius_typestr

A string deciding if hub, mean or tip radius is constant throughout the turbine.

Returns:

dict

Set of geometry suited for turbine evaluation.

turboflow.axial_turbine.geometry_model.validate_turbine_geometry(geom, display=False)

Performs validation of an axial turbine’s geometry configuration.

• Ensures all required geometry parameters are specified in ‘geom’.

• Verifies that no parameters beyond the required set are included.

• Checks ‘number_of_cascades’ is an integer and correctly dictates sizes of other parameters.

• Validates that all parameter arrays match the size of ‘number_of_cascades’.

• Asserts that all geometry parameter values are numeric (integers or floats).

• Ensures non-angle parameters contain only non-negative values.

• Angle parameters (‘leading_edge_angle’, ‘stagger_angle’) can be negative.

This function is intended as a preliminary check before in-depth geometry analysis.

Parameters:

geomdict

The geometry configuration parameters for the turbine as a dictionary.

Returns:

bool

True if all validations pass, indicating a correctly structured geometry configuration.