Splitter - Nouman090/ThermoSim GitHub Wiki

A splitter divides one inlet stream into multiple outlet streams with specified mass-flow fractions. All outlets have the same temperature, pressure, and enthalpy as the inlet (isenthalpic, isobaric split).

Physics

ṁ_out,i = fraction_i × ṁ_in
H_out,i = H_in
P_out,i = P_in
Ex_D = 0  (ideal splitter)

The fractions must sum to 1.0 (or will be normalized automatically).

Syntax

Splitter(Model, ID, In_state, Out_states, split_fractions, Calculate=False)

Parameter	Type	Default	Description
Model	ThermodynamicModel	—	The model object
ID	str	—	Unique component name
In_state	str	—	Inlet state point name
Out_states	list of str	—	List of outlet state point names
split_fractions	list of float	—	Mass-flow fractions for each outlet
Calculate	bool	False	Solve immediately if True

Output Attributes

Attribute	Type	Unit	Description
.Ex_D	float	W	Exergy destruction (always 0)
.split_fractions	list	—	Normalized fractions
.Solution_Status	bool	—	True if solved
.In	Prop	—	Inlet state point object

Cases

Case 1: Two-Way Split

Most common. Split one stream into two equal or unequal parts.

from Thermosim import ThermodynamicModel, Splitter

Model = ThermodynamicModel()
Model.set_dead_state()

# Inlet
Model.add_point('water', 'In', P=10e5, T=473.15, Mass_flowrate=1.0)

# Outlets (will be calculated)
Model.add_point('water', 'Out1', P=10e5)
Model.add_point('water', 'Out2', P=10e5)

Splitter(Model, 'Split1', In_state='In', Out_states=['Out1', 'Out2'],
         split_fractions=[0.6, 0.4], Calculate=True)

print(f"Out1 mass flow: {Model.Point['Out1'].Mass_flowrate:.2f} kg/s")
print(f"Out2 mass flow: {Model.Point['Out2'].Mass_flowrate:.2f} kg/s")
print(f"Out1 T:         {Model.Point['Out1'].T - 273.15:.2f} °C")
print(f"Out2 T:         {Model.Point['Out2'].T - 273.15:.2f} °C")

Case 2: Three-Way Split

Split into three outlets with different fractions.

Model = ThermodynamicModel()
Model.set_dead_state()

Model.add_point('air', 'Inlet', P=5e5, T=300, Mass_flowrate=10)
Model.add_point('air', 'A', P=5e5)
Model.add_point('air', 'B', P=5e5)
Model.add_point('air', 'C', P=5e5)

Splitter(Model, 'Manifold', In_state='Inlet', Out_states=['A', 'B', 'C'],
         split_fractions=[0.5, 0.3, 0.2], Calculate=True)

print(f"A: {Model.Point['A'].Mass_flowrate:.2f} kg/s")
print(f"B: {Model.Point['B'].Mass_flowrate:.2f} kg/s")
print(f"C: {Model.Point['C'].Mass_flowrate:.2f} kg/s")

Case 3: Regenerative Rankine (Steam Extraction)

Extract steam from turbine for feedwater heating.

Model = ThermodynamicModel()
Model.set_dead_state()

# Turbine mid-point extraction
Model.add_point('water', 'Turb_mid', P=5e5, T=425.15, Mass_flowrate=1.0)

# Split: 20% to feedwater heater, 80% continues to LP turbine
Model.add_point('water', 'Extraction', P=5e5)
Model.add_point('water', 'To_LP_Turb', P=5e5)

Splitter(Model, 'Extractor', In_state='Turb_mid',
         Out_states=['Extraction', 'To_LP_Turb'],
         split_fractions=[0.2, 0.8], Calculate=True)

print(f"Extraction flow: {Model.Point['Extraction'].Mass_flowrate:.2f} kg/s")
print(f"LP turbine flow: {Model.Point['To_LP_Turb'].Mass_flowrate:.2f} kg/s")

Case 4: Fractions Don't Sum to 1 (Auto-Normalization)

If fractions sum to something other than 1.0, the splitter normalizes them and issues a warning.

Model = ThermodynamicModel()
Model.set_dead_state()

Model.add_point('water', 'In', P=10e5, T=473.15, Mass_flowrate=1.0)
Model.add_point('water', 'Out1', P=10e5)
Model.add_point('water', 'Out2', P=10e5)

Splitter(Model, 'Split1', In_state='In', Out_states=['Out1', 'Out2'],
         split_fractions=[3, 2], Calculate=True)
# Warning: Split fractions for Split1 sum to 5. Normalising.
# Actual fractions: [0.6, 0.4]

print(f"Normalized fractions: {Model.Component['Split1'].split_fractions}")

Print Component Data

print(Model.Component['Split1'])

Output:

Split1 (Splitter):
  Inlet mass flow  : 1.0000 kg/s
  Split fractions  : [0.6, 0.4]
  Exergy destr.    : 0
  Solved           : True

Complete Example

from Thermosim import ThermodynamicModel, Splitter

# Create model
Model = ThermodynamicModel()
Model.set_dead_state()

# Define inlet
Model.add_point('water', 'MainFlow', P=20e5, T=500, Mass_flowrate=5.0)

# Define outlets
Model.add_point('water', 'Branch1', P=20e5)
Model.add_point('water', 'Branch2', P=20e5)
Model.add_point('water', 'Branch3', P=20e5)

# Add splitter
Splitter(Model, 'FlowDivider', In_state='MainFlow',
         Out_states=['Branch1', 'Branch2', 'Branch3'],
         split_fractions=[0.5, 0.3, 0.2], Calculate=True)

# Access results
print(f"Branch 1 flow: {Model.Point['Branch1'].Mass_flowrate:.2f} kg/s")
print(f"Branch 2 flow: {Model.Point['Branch2'].Mass_flowrate:.2f} kg/s")
print(f"Branch 3 flow: {Model.Point['Branch3'].Mass_flowrate:.2f} kg/s")
print(f"All have T = {Model.Point['Branch1'].T - 273.15:.2f} °C")

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