.. _TableLookupHX:

.. _section-5.4.5:

Table Look-Up for Steam Generators or Intermediate Heat Exchangers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Table look-ups for steam generators or intermediate heat exchangers are
used when the behavior of these components is known from other sources
or when the details of the temperature distributions within the
components are not important for the case at hand. The user supplies a
table of normalized temperature drops vs. time and also a table of
elevation of the thermal center vs. time. The thermal center of the
steam generator or intermediate heat exchanger is the point above which
the circulating fluid is assumed to have the density corresponding to
the inlet temperature and below which it is assumed to have the density
corresponding to the outlet temperature.

The outlet temperature of the steam generator or intermediate heat
exchanger is calculated from the inlet temperature by

.. math::
   :label: eq-5.4-81

   T_{\text{out}} \left( t \right) = T_{\text{in}} \left( t \right) + f \left( t \right) \left\lbrack T_{\text{out}} \left( t = 0 \right) - T_{\text{in}}\left( t = 0 \right)  \right\rbrack

where :math:`f \left( t \right)` is obtained by linear interpolation from the
user-supplied table of temperature drops. Also

.. math::
   :label: eq-5.4-82

   f \left( t = 0 \right) = 1.0

For the table look-up steam generator there is an option in the code for
the user to specify the steam generator outlet temperature directly
instead of specifying the temperature drop. For this option the user
supplies a table of steam generator outlet temperature vs. time.

The gravity head is calculated from

.. math::
   :label: eq-5.4-83

   \Delta p_{\text{gr}} \left( t \right) = \rho_{\text{in}} \left( t \right) g\left\lbrack z_{\text{c}} \left( t \right) - z_{\text{in}} \right\rbrack + \rho_{\text{out}} \left( t \right) g \left\lbrack z_{\text{out}} - z_{\text{c}} \left( t \right)  \right\rbrack

where

:math:`\rho_{\text{in}} \left( t \right), \rho_{\text{out}} \left( t \right)` =
the densities of the inlet and outlet fluids at the inlet and outlet
temperatures

:math:`z_{\text{c}} \left( t \right)` = the user-supplied table of the elevation of the
thermal center as a function of time

:math:`z_{\text{in}}`, :math:`z_{\text{out}}` = the inlet and outlet elevations

:math:`g` = the acceleration of gravity

.. _section-5.4.5.1:

.. include::    input-TabHX.rst