refactor: rename Mixer/Splitter to Legacy, introduce single-stream ProcessUnit variants

- Rename Mixer → LegacyMixer (mixer/mixer.py → legacy_mixer/legacy_mixer.py)
- Rename Splitter → LegacySplitter (splitter/splitter.py → legacy_splitter/legacy_splitter.py)
- Introduce Mixer(ProcessUnit) in process_units/mixer.py: adds one external stream to a through-stream
- Introduce Splitter(ProcessUnit) in process_units/splitter.py: removes a fixed rate from a through-stream
- Add tests for new Mixer and Splitter

Author: olelod

src/libecalc/domain/process/compressor/core/train/stage.py

@@ -14,10 +14,12 @@
 from libecalc.domain.process.compressor.core.train.utils.numeric_methods import find_root
 from libecalc.domain.process.entities.process_units.choke import Choke
 from libecalc.domain.process.entities.process_units.legacy_compressor.legacy_compressor import LegacyCompressor
+from libecalc.domain.process.entities.process_units.legacy_mixer.legacy_mixer import LegacyMixer
+from libecalc.domain.process.entities.process_units.legacy_splitter.legacy_splitter import (
+    LegacySplitter,
+)
 from libecalc.domain.process.entities.process_units.liquid_remover import LiquidRemover
-from libecalc.domain.process.entities.process_units.mixer.mixer import Mixer
 from libecalc.domain.process.entities.process_units.rate_modifier.rate_modifier import RateModifier
-from libecalc.domain.process.entities.process_units.splitter.splitter import Splitter
 from libecalc.domain.process.entities.process_units.temperature_setter import TemperatureSetter
 from libecalc.domain.process.value_objects.chart.chart_area_flag import ChartAreaFlag
 from libecalc.domain.process.value_objects.fluid_stream import FluidService, FluidStream
@@ -29,8 +31,8 @@ class CompressorTrainStage:
 
     The stage is composed of a series of process units that modify the inlet stream before it enters the compressor.
     The process units are:
-    - Splitter: Splits the inlet stream if required. One stream goes towards the compressor, the other(s) are taken out.
-    - Mixer: Mixes the inlet stream with other streams if required.
+    - LegacySplitter: Splits the inlet stream if required. One stream goes towards the compressor, the other(s) are taken out.
+    - LegacyMixer: Mixes the inlet stream with other streams if required.
     - TemperatureSetter: Cools the inlet stream to a required temperature. Often termed an intercooler.
     - LiquidRemover: Removes liquid from the inlet stream if required. Often termed a scrubber.
     - Choke: Chokes the inlet stream if a choke valve is defined (pressure drop ahead of stage).
@@ -48,8 +50,8 @@ def __init__(
         liquid_remover: LiquidRemover | None,
         rate_modifier: RateModifier,
         fluid_service: FluidService,
-        splitter: Splitter | None = None,
-        mixer: Mixer | None = None,
+        splitter: LegacySplitter | None = None,
+        mixer: LegacyMixer | None = None,
         choke: Choke | None = None,
         interstage_pressure_control: InterstagePressureControl | None = None,
     ):
@@ -105,7 +107,7 @@ def get_compressor_inlet_stream(
         rates_out_of_splitter: list[float] | None = None,
         streams_in_to_mixer: list[FluidStream] | None = None,
     ):
-        # First the stream passes through the Splitter (if defined)
+        # First the stream passes through the LegacySplitter (if defined)
         if self.splitter is not None:
             self.splitter.rates_out_of_splitter = rates_out_of_splitter
             inlet_stream_after_splitter = self.split(
@@ -114,7 +116,7 @@ def get_compressor_inlet_stream(
         else:
             inlet_stream_after_splitter = inlet_stream_stage
 
-        # Then the stream passes through the Mixer     (if defined)
+        # Then the stream passes through the LegacyMixer     (if defined)
         if self.mixer is not None:
             if streams_in_to_mixer is None:
                 raise IllegalStateException("streams_in_to_mixer cannot be None when a mixer is defined")
@@ -157,9 +159,9 @@ def evaluate(
 
         Args:
             inlet_stream_stage (FluidStream): The conditions of the inlet fluid stream. If there are several inlet streams,
-                the first one is the stage inlet stream, the others enter the stage at the Mixer.
-            rates_out_of_splitter (list[float] | None, optional): Additional rates to the Splitter if defined.
-            streams_in_to_mixer (list[FluidStream] | None, optional): Additional streams to the Mixer if defined.
+                the first one is the stage inlet stream, the others enter the stage at the LegacyMixer.
+            rates_out_of_splitter (list[float] | None, optional): Additional rates to the LegacySplitter if defined.
+            streams_in_to_mixer (list[FluidStream] | None, optional): Additional streams to the LegacyMixer if defined.
 
         Returns:
             CompressorTrainStageResultSingleTimeStep: The result of the evaluation for the compressor stage
@@ -256,8 +258,8 @@ def mix(
         assert streams_in_to_mixer is not None
         if self.mixer.number_of_inputs != len(streams_in_to_mixer) + 1:
             raise IllegalStateException(
-                f"Number of additional rates to Mixer ({len(streams_in_to_mixer)}) "
-                f"does not match number of Mixer inputs ({self.mixer.number_of_inputs})."
+                f"Number of additional rates to LegacyMixer ({len(streams_in_to_mixer)}) "
+                f"does not match number of LegacyMixer inputs ({self.mixer.number_of_inputs})."
             )
 
         all_streams_to_mixer = [inlet_stream_stage] + streams_in_to_mixer

…entities/process_units/mixer/__init__.py …s/process_units/legacy_mixer/__init__.pysrc/libecalc/domain/process/entities/process_units/mixer/__init__.py renamed to src/libecalc/domain/process/entities/process_units/legacy_mixer/__init__.py src/libecalc/domain/process/entities/process_units/mixer/__init__.py renamed to src/libecalc/domain/process/entities/process_units/legacy_mixer/__init__.py

@@ -4,7 +4,7 @@
 from libecalc.domain.process.value_objects.fluid_stream import FluidService, FluidStream
 
 
-class Mixer:
+class LegacyMixer:
     def __init__(self, number_of_inputs: int, fluid_service: FluidService):
         self.number_of_inputs = number_of_inputs
         self._stream_mixer = SimplifiedStreamMixer(fluid_service)

…ss/entities/process_units/mixer/mixer.py …ocess_units/legacy_mixer/legacy_mixer.pysrc/libecalc/domain/process/entities/process_units/mixer/mixer.py renamed to src/libecalc/domain/process/entities/process_units/legacy_mixer/legacy_mixer.py src/libecalc/domain/process/entities/process_units/mixer/mixer.py renamed to src/libecalc/domain/process/entities/process_units/legacy_mixer/legacy_mixer.py

@@ -2,7 +2,7 @@
 from libecalc.domain.process.value_objects.fluid_stream import FluidStream
 
 
-class Splitter:
+class LegacySplitter:
     """
     A class representing a splitter that divides a fluid stream into multiple output streams.
 

…ities/process_units/splitter/__init__.py …rocess_units/legacy_splitter/__init__.pysrc/libecalc/domain/process/entities/process_units/splitter/__init__.py renamed to src/libecalc/domain/process/entities/process_units/legacy_splitter/__init__.py src/libecalc/domain/process/entities/process_units/splitter/__init__.py renamed to src/libecalc/domain/process/entities/process_units/legacy_splitter/__init__.py

@@ -0,0 +1,29 @@
+from libecalc.domain.process.entities.process_units.simplified_stream_mixer.simplified_stream_mixer import (
+    SimplifiedStreamMixer,
+)
+from libecalc.domain.process.process_system.process_unit import ProcessUnit, ProcessUnitId
+from libecalc.domain.process.value_objects.fluid_stream import FluidService, FluidStream
+
+
+class Mixer(ProcessUnit):
+    """Mixes one external stream into the through-stream.
+
+    The external stream is set via `set_stream` before propagation. This models
+    a sidestream injection point in an interstage manifold.
+    """
+
+    def __init__(self, process_unit_id: ProcessUnitId, fluid_service: FluidService):
+        self._id = process_unit_id
+        self._mixer = SimplifiedStreamMixer(fluid_service)
+        self._external_stream: FluidStream | None = None
+
+    def get_id(self) -> ProcessUnitId:
+        return self._id
+
+    def set_stream(self, stream: FluidStream) -> None:
+        self._external_stream = stream
+
+    def propagate_stream(self, inlet_stream: FluidStream) -> FluidStream:
+        if self._external_stream is None:
+            raise ValueError("Mixer has no external stream set; call set_stream() before propagating.")
+        return self._mixer.mix_streams([inlet_stream, self._external_stream])

…ities/process_units/splitter/splitter.py …units/legacy_splitter/legacy_splitter.pysrc/libecalc/domain/process/entities/process_units/splitter/splitter.py renamed to src/libecalc/domain/process/entities/process_units/legacy_splitter/legacy_splitter.py src/libecalc/domain/process/entities/process_units/splitter/splitter.py renamed to src/libecalc/domain/process/entities/process_units/legacy_splitter/legacy_splitter.py

@@ -1,8 +1,8 @@
 from collections.abc import Sequence
 
 from libecalc.domain.component_validation_error import DomainValidationException
-from libecalc.domain.process.entities.process_units.mixer.mixer import Mixer
-from libecalc.domain.process.entities.process_units.splitter.splitter import Splitter
+from libecalc.domain.process.entities.process_units.mixer import Mixer
+from libecalc.domain.process.entities.process_units.splitter import Splitter
 from libecalc.domain.process.process_system.process_system import ProcessSystem, ProcessSystemId
 from libecalc.domain.process.process_system.process_unit import ProcessUnit, ProcessUnitId, create_process_unit_id
 from libecalc.domain.process.value_objects.fluid_stream import FluidService, FluidStream
@@ -79,7 +79,7 @@ def __init__(
     def _validate_inner_process(self):
         assert isinstance(self._inner_process, ProcessSystem), "Recirculation loop should contain a ProcessSystem"
         for process_unit in self._inner_process.get_process_units():
-            if isinstance(process_unit, Splitter | Mixer):
+            if isinstance(process_unit, Mixer | Splitter):
                 raise DomainValidationException("Recirculation loop cannot contain splitters or mixers")
 
     def get_id(self) -> ProcessSystemId:

src/libecalc/domain/process/entities/process_units/mixer.py

@@ -0,0 +1,43 @@
+from libecalc.domain.process.process_system.process_unit import ProcessUnit, ProcessUnitId
+from libecalc.domain.process.value_objects.fluid_stream import FluidService, FluidStream
+
+
+class Splitter(ProcessUnit):
+    """Removes a fixed standard rate from the through-stream.
+
+    The split rate is set via `set_rate` before propagation. This models a gas
+    offtake point (e.g. fuel gas) in an interstage manifold. The remainder
+    continues downstream.
+    """
+
+    def __init__(self, process_unit_id: ProcessUnitId, fluid_service: FluidService, rate: float = 0.0):
+        self._id = process_unit_id
+        self._fluid_service = fluid_service
+        self._rate = rate
+
+    def get_id(self) -> ProcessUnitId:
+        return self._id
+
+    def set_rate(self, rate: float) -> None:
+        self._rate = rate
+
+    def get_rate(self) -> float:
+        return self._rate
+
+    def propagate_stream(self, inlet_stream: FluidStream) -> FluidStream:
+        remaining_rate = inlet_stream.standard_rate_sm3_per_day - self._rate
+        return self._fluid_service.create_stream_from_standard_rate(
+            fluid_model=inlet_stream.fluid_model,
+            pressure_bara=inlet_stream.pressure_bara,
+            temperature_kelvin=inlet_stream.temperature_kelvin,
+            standard_rate_m3_per_day=remaining_rate,
+        )
+
+    def get_split_stream(self, inlet_stream: FluidStream) -> FluidStream:
+        """Return the stream that was split off, at the same conditions as the inlet."""
+        return self._fluid_service.create_stream_from_standard_rate(
+            fluid_model=inlet_stream.fluid_model,
+            pressure_bara=inlet_stream.pressure_bara,
+            temperature_kelvin=inlet_stream.temperature_kelvin,
+            standard_rate_m3_per_day=self._rate,
+        )

src/libecalc/domain/process/entities/process_units/recirculation_loop.py

@@ -44,10 +44,12 @@
 from libecalc.domain.process.compressor.core.train.stage import CompressorTrainStage
 from libecalc.domain.process.entities.process_units.choke import Choke
 from libecalc.domain.process.entities.process_units.legacy_compressor.legacy_compressor import LegacyCompressor
+from libecalc.domain.process.entities.process_units.legacy_mixer.legacy_mixer import LegacyMixer
+from libecalc.domain.process.entities.process_units.legacy_splitter.legacy_splitter import (
+    LegacySplitter,
+)
 from libecalc.domain.process.entities.process_units.liquid_remover import LiquidRemover
-from libecalc.domain.process.entities.process_units.mixer.mixer import Mixer
 from libecalc.domain.process.entities.process_units.rate_modifier.rate_modifier import RateModifier
-from libecalc.domain.process.entities.process_units.splitter.splitter import Splitter
 from libecalc.domain.process.entities.process_units.temperature_setter import TemperatureSetter
 from libecalc.domain.process.entities.shaft import Shaft, SingleSpeedShaft, VariableSpeedShaft
 from libecalc.domain.process.evaluation_input import (
@@ -377,10 +379,12 @@ def _create_compressor_train_stage(
             ),
             interstage_pressure_control=interstage_pressure_control,
             splitter=(
-                Splitter(number_of_splitter_ports_this_stage + 1) if number_of_splitter_ports_this_stage > 0 else None
+                LegacySplitter(number_of_splitter_ports_this_stage + 1)
+                if number_of_splitter_ports_this_stage > 0
+                else None
             ),
             mixer=(
-                Mixer(number_of_mixer_ports_this_stage + 1, fluid_service=fluid_service)
+                LegacyMixer(number_of_mixer_ports_this_stage + 1, fluid_service=fluid_service)
                 if number_of_mixer_ports_this_stage > 0
                 else None
             ),

src/libecalc/domain/process/entities/process_units/splitter.py

@@ -15,11 +15,13 @@
 from libecalc.domain.process.entities.process_units.choke import Choke
 from libecalc.domain.process.entities.process_units.compressor import Compressor
 from libecalc.domain.process.entities.process_units.legacy_compressor.legacy_compressor import LegacyCompressor
+from libecalc.domain.process.entities.process_units.legacy_mixer.legacy_mixer import LegacyMixer
+from libecalc.domain.process.entities.process_units.legacy_splitter.legacy_splitter import (
+    LegacySplitter,
+)
 from libecalc.domain.process.entities.process_units.liquid_remover import LiquidRemover
-from libecalc.domain.process.entities.process_units.mixer.mixer import Mixer
 from libecalc.domain.process.entities.process_units.rate_modifier.rate_modifier import RateModifier
 from libecalc.domain.process.entities.process_units.recirculation_loop import RecirculationLoop
-from libecalc.domain.process.entities.process_units.splitter.splitter import Splitter
 from libecalc.domain.process.entities.process_units.temperature_setter import TemperatureSetter
 from libecalc.domain.process.entities.shaft import Shaft, SingleSpeedShaft, VariableSpeedShaft
 from libecalc.domain.process.process_solver.process_system_runner import ProcessSystemRunner
@@ -299,10 +301,10 @@ def create_compressor_stage(
             fluid_service=fluid_service,
             choke=choke_factory(pressure_change=pressure_drop_ahead_of_stage) if pressure_drop_ahead_of_stage else None,
             interstage_pressure_control=interstage_pressure_control,
-            splitter=Splitter(number_of_outputs=number_of_output_ports_stage + 1)
+            splitter=LegacySplitter(number_of_outputs=number_of_output_ports_stage + 1)
             if number_of_output_ports_stage > 0
             else None,
-            mixer=Mixer(number_of_inputs=number_of_input_ports_stage + 1, fluid_service=fluid_service)
+            mixer=LegacyMixer(number_of_inputs=number_of_input_ports_stage + 1, fluid_service=fluid_service)
             if number_of_input_ports_stage > 0
             else None,
         )