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Crossflow hx (#1382)
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* add unit models

* edits

* changes

* Code cleaning

* Fix initialization

* Begin adding tests

* changes

* test units

* fix pressure drop unit issue

* Moving towards heater testing

* move changes from other branch

* format remaining file

* separate 1d hx changes

* Fix pylint errors

* more pylint issues

* remove elevation change

* run black

* get rid of commented code

* Fix typo

* At Andrew's insistence, make methods public

* address more of Andrew's comments

* Update initialization to new form

* documentation

* Documentation in progress

* remove debugging

* Documentation

* pitch

* polishing step

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* culling common

* Docstrings and merges

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dallan-keylogic committed Apr 22, 2024
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Heater1D
========

.. index::
pair: idaes.models_extra.power_generation.unit_models.heater_1D;Heater1D

.. module:: idaes.models_extra.power_generation.unit_models.heater_1D

This model is for a gas trim heater modeled as gas being blown perpendicularly across banks of hollow tubes,
which are heated by resistive heating. Note that the ``finite_elements`` option in the control
volume config should be set to an integer factor of ``number_passes`` in order for the
discretization equations to make sense as a cross-flow heat exchanger.

Example
-------

.. code-block:: python
import pyomo.environ as pyo
from idaes.core import FlowsheetBlock
import idaes.core.util.scaling as iscale
from idaes.models.properties.modular_properties import GenericParameterBlock
from idaes.models_extra.power_generation.properties.natural_gas_PR import (
get_prop,
EosType,
)
from idaes.models_extra.power_generation.unit_models import Heater1D
from idaes.core.util.model_statistics import degrees_of_freedom
optarg = {
"constr_viol_tol": 1e-8,
"nlp_scaling_method": "user-scaling",
"linear_solver": "ma57",
"OF_ma57_automatic_scaling": "yes",
"max_iter": 350,
"tol": 1e-8,
"halt_on_ampl_error": "no",
}
m = pyo.ConcreteModel()
m.fs = FlowsheetBlock(dynamic=False)
m.fs.h2_side_prop_params = GenericParameterBlock(
**get_prop(["H2", "H2O", "Ar", "N2"], {"Vap"}, eos=EosType.IDEAL),
doc="H2O + H2 gas property parameters",
)
m.fs.heater = Heater1D(
property_package=m.fs.h2_side_prop_params,
has_holdup=True,
dynamic=False,
has_fluid_holdup=False,
has_pressure_change=pressure_drop,
finite_elements=4,
tube_arrangement="in-line",
transformation_method="dae.finite_difference",
transformation_scheme="BACKWARD",
)
heater = m.fs.heater
heater.inlet.flow_mol.fix(5102.5)
heater.inlet.temperature.fix(938.83)
heater.inlet.pressure.fix(1.2e5)
heater.inlet.mole_frac_comp[0, "H2"].fix(0.57375)
heater.inlet.mole_frac_comp[0, "H2O"].fix(0.42517)
heater.inlet.mole_frac_comp[0, "Ar"].fix(0.00086358)
heater.inlet.mole_frac_comp[0, "N2"].fix(0.00021589)
heater.di_tube.fix(0.0525018)
heater.thickness_tube.fix(0.0039116)
heater.pitch_x.fix(0.1)
heater.pitch_y.fix(0.1)
heater.length_tube_seg.fix(10)
heater.number_passes.fix(1)
heater.rfouling = 0.0001
heater.fcorrection_htc_shell.fix(1)
heater.cp_wall = 502.4
if pressure_drop:
heater.fcorrection_dp_shell.fix(1)
heater.number_columns_per_pass.fix(40)
heater.number_rows_per_pass.fix(40)
heater.electric_heat_duty.fix(3.6504e06)
pp = m.fs.h2_side_prop_params
pp.set_default_scaling("enth_mol_phase", 1e-3)
pp.set_default_scaling("pressure", 1e-5)
pp.set_default_scaling("temperature", 1e-2)
pp.set_default_scaling("flow_mol", 1e-3)
_mf_scale = {
"H2": 1,
"H2O": 1,
"N2": 10,
"Ar": 10,
}
for comp, s in _mf_scale.items():
pp.set_default_scaling("mole_frac_comp", s, index=comp)
pp.set_default_scaling("mole_frac_phase_comp", s, index=("Vap", comp))
pp.set_default_scaling("flow_mol_phase_comp", s * 1e-3, index=("Vap", comp))
shell = heater.control_volume
iscale.set_scaling_factor(shell.area, 1e-1)
iscale.set_scaling_factor(shell.heat, 1e-6)
iscale.set_scaling_factor(shell.enthalpy_flow_dx, 1e-7)
iscale.set_scaling_factor(heater.heat_holdup, 1e-8)
iscale.calculate_scaling_factors(m)
initializer = m.fs.heat_exchanger.default_initializer(
solver="ipopt",
solver_options=optarg
)
initializer.initialize(m.fs.heat_exchanger)
Heater Geometry
---------------
=========================== =========== =============================================================================================
Variable Index Sets Doc
=========================== =========== =============================================================================================
``number_columns_per_pass`` None Number of columns of tube per pass
``number_rows_per_pass`` None Number of rows of tube per pass
``number_passes`` None Number of tube banks of ``nrow_tube * ncol_inlet`` tubes
``pitch_x`` None Distance between tubes parallel to flow, measured from center-of-tube to center-of-tube
``pitch_y`` None Distance between tubes perpendicular to flow, measured from center-of-tube to center-of-tube
``length_tube_seg`` None Length of tube segment perpendicular to flow in each pass
``area_flow_shell`` None Reference to flow area on control volume
``length_flow_shell`` None Reference to flow length on control volume
``area_flow_shell_min`` None Minimum flow area on shell side
``di_tube`` None Inner diameter of tubes
``thickness_tube`` None Thickness of tube wall.
=========================== =========== =============================================================================================

============================ =========== ===========================================================================
Expression Index Sets Doc
============================ =========== ===========================================================================
``nrow_tube`` None Total number of rows of tube
``do_tube`` None Outer diameter of tube (equal to ``di_tube+2*thickness_tube``)
``pitch_x_to_do`` None Ratio of ``pitch_x`` to ``do_tube``
``pitch_y_to_do`` None Ratio of ``pitch_y`` to ``do_tube``
``area_wall_seg`` None Total cross-sectional area of tube per pass
``total_heat_transfer_area`` None Total heat transfer area, as measured on outer surface of tubes
============================ =========== ===========================================================================

=========================== =========== =================================================================================================
Constraint Index Sets Doc
=========================== =========== =================================================================================================
``length_flow_shell_eqn`` None Constrains flow length from control volume to equal value implied by geometry
``area_flow_shell_eqn`` None Constrains flow cross-sectional area from control volume to equal value implied by geometry
``area_flow_shell_min_eqn`` None Constraints ``area_flow_shell_min`` to equal value determined by geometry
=========================== =========== =================================================================================================

Performance Equations
-----------------------

================================== ============ =================================================================================
Variable Index Sets Doc
================================== ============ =================================================================================
``electric_heat_duty`` time Electric heat duty supplied to entire heater unit
``fcorrection_htc_shell`` time, length Correction factor for convective heat transfer
``conv_heat_transfer_coeff_shell`` time, length Convective heat transfer coefficient
``temp_wall_shell`` time, length Wall temperature of tube
``temp_wall_center`` time, length Temperature at center of tube wall
``v_shell`` time, length Flow velocity through minimum area
``N_Re_shell`` time, length Reynolds number
``N_Nu_shell`` time, length Nusselt number
================================== ============ =================================================================================

=========================== =========== =================================================================================
Parameter Index Sets Doc
=========================== =========== =================================================================================
``therm_cond_wall`` None Thermal conductivity of tube wall
``density_wall`` None Mass density of tube wall metal
``cp_wall`` None Tube wall heat capacity (mass basis)
``rfouling_shell`` None Fouling resistance on shell side
``f_arrangement`` None Adjustment factor depending on ``tube_arrangement`` in config
=========================== =========== =================================================================================

====================================== ============ =================================================================================
Constraint Index Sets Doc
====================================== ============ =================================================================================
``v_shell_eqn`` time, length Calculates velocity of flow through shell using ``area_flow_shell_min``
``N_Re_shell_eqn`` time, length Calculates the Reynolds number
``conv_heat_transfer_coeff_shell_eqn`` time, length Calculates the convective heat transfer coefficient
``N_Nu_shell_eqn`` time, length Calculate the Nusselt number
``heat_shell_eqn`` time, length Calculates heat transfer per unit length
``temp_wall_shell_eqn`` time, length Calculate the wall temperature of the outer tube
``temp_wall_center_eqn`` time, length Overall energy balance on tube metal
====================================== ============ =================================================================================

====================================== ============ ===================================================================================
Expression Index Sets Doc
====================================== ============ ===================================================================================
``total_heat_transfer_coeff_shell`` time Returns ``conv_heat_transfer_coeff_shell``. Could be extended to include radiation.
====================================== ============ ===================================================================================

Pressure Change Equations
-------------------------

=========================== ============ =================================================================================
Parameter Index Sets Doc
=========================== ============ =================================================================================
``fcorrection_dp_shell`` None Correction factor for pressure drop
=========================== ============ =================================================================================

=========================== ============ =================================================================================
Variable Index Sets Doc
=========================== ============ =================================================================================
``fcorrection_dp_shell`` None Correction factor for pressure drop
``friction_factor_shell`` time, length Friction factor
=========================== ============ =================================================================================

================================== ============ =================================================================================
Constraint Index Sets Doc
================================== ============ =================================================================================
``friction_factor_shell_eqn`` time, length Calculates the friction factor
``deltaP_shell_eqn`` time, length Sets ``deltaP_shell`` based on the friction factor and physical properties
================================== ============ =================================================================================


Holdup Equations
----------------

Created when ``has_holdup=True`` in the config.

=========================== ============ =================================================================================
Variable Index Sets Doc
=========================== ============ =================================================================================
``heat_holdup`` time, length Energy holdup per unit length of flow path
=========================== ============ =================================================================================

=========================== ============ =================================================================================
Constraint Index Sets Doc
=========================== ============ =================================================================================
``heat_holdup_eqn`` time, length Defines heat holdup in terms of geometry and physical properties
=========================== ============ =================================================================================

Dynamic Equations
-----------------

Created when ``dynamic=True`` in the config.

=========================== ============ =================================================================================
Derivative Variable Index Sets Doc
=========================== ============ =================================================================================
``heat_accumulation`` time, length Energy accumulation in tube wall per unit length of shell flow path per unit time
=========================== ============ =================================================================================


Initialization
--------------

A simple initialization method that first initializes the control volume without heat transfer,
then adds heat transfer in and solves it again, then finally solves the entire model.


Heater1D Class
--------------

.. autoclass:: Heater1D
:members:

Heater1DData Class
------------------

.. autoclass:: Heater1DData
:members:

Heater1DInitializer Class
-------------------------

.. autoclass:: Heater1DInitializer
:members:
Expand Up @@ -26,3 +26,5 @@ Unit Models
waterpipe
boiler_heat_exchanger_3streams
feedwater_heater_0D_dynamic
cross_flow_heat_exchanger_1D
heater_1D
5 changes: 5 additions & 0 deletions idaes/models_extra/power_generation/unit_models/__init__.py
Expand Up @@ -15,10 +15,15 @@
from .boiler_fireside import BoilerFireside
from .boiler_heat_exchanger import BoilerHeatExchanger
from .boiler_heat_exchanger_2D import HeatExchangerCrossFlow2D_Header
from .cross_flow_heat_exchanger_1D import (
CrossFlowHeatExchanger1D,
CrossFlowHeatExchanger1DInitializer,
)
from .downcomer import Downcomer
from .drum import Drum
from .drum1D import Drum1D
from .feedwater_heater_0D_dynamic import FWH0DDynamic
from .heater_1D import Heater1D, Heater1DInitializer
from .heat_exchanger_3streams import HeatExchangerWith3Streams
from .steamheater import SteamHeater
from .waterpipe import WaterPipe
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