Tap point / distribution area
-----------------------------

TAP (class)
^^^^^^^^^^^

.. figure:: ../media/image729.png
	:figwidth: 0.92708in
	:align: center
	
	Tap point or distribution area

**Supplier type**

+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+
| type label                             | description                                                                                                                                                       | active |
+========================================+===================================================================================================================================================================+========+
| Tap return flow                        | If system head drops below downstream head, tap supplies back to system.                                                                                          | No     |
+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+
| Tap non-return flow                    | If system head drops below downstream head, tap does not supply back to system.                                                                                   | No     |
+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+
| Tap non-return flow with dP for reopen | If system pressure drops below downstream pressure, tap does not supply back to system. Supply to system (re)starts when a minimum required pressure is exceeded. | No     |
+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+

.. _mathematical-model-35:

Mathematical model
""""""""""""""""""

In steady state the governing equation of this component is very simple:

.. math::

	Q=-Q_{\mathrm{D}}

in which:

=========== ============================= ===============
Q           = system discharge to the TAP [m\ :sup:`3`/s]
Q\ :sub:`D` = delivery rate               [m\ :sup:`3`/s]
=========== ============================= ===============

The negative sign appears because of the convention that a flow out of the system is defined negative. After obtaining the steady state solution the head loss coefficient is computed with:

.. math::

	C=\left(H-H_{\mathrm{D}}\right) / Q^{2}

in which:

=========== = ======================== =========================
C           = head loss coefficient    [s\ :sup:`2`/m\ :sup:`5`]
H           = system pressure head     [m]
H\ :sub:`D` = downstream pressure head [m]
=========== = ======================== =========================

The downstream head is either given by the user or for the Tap non-return flow 2 based on the downstream pressure specified by the user.

This head loss coefficient is kept constant throughout the unsteady state computation.

The governing equation then is:

.. math::

	H-H_{D}=C Q|Q|

For the **return** type of the tap component equation (3) is valid for positive as well as negative values of *Q*. For the **non-return** type equation (3) is only valid for positive values of *Q*. In case *Q* becomes negative the component changes from H-phase and closes like a check valve. The governing equation the simply is:

.. math::

	Q=0

The non-return tap opens again if *H* > *H*\ :sub:`D`. For the Tap non-return flow 2 an additional pressure drop can be set which is required to open the tap.

Tap return flow
^^^^^^^^^^^^^^^

.. _hydraulic-specifications-40:

Hydraulic specifications
""""""""""""""""""""""""

===================== ===== ================ ===== ======= =======
Description           Input unit             range default remarks
downstream head       Real  [Pa]                           
initial delivery rate Real  [m­\ :sup:`3`/s] (0-5]         
===================== ===== ================ ===== ======= =======

See also "Mathematical model" (:numref:`mathematical-model-35`).

.. _component-specific-output-38:

Component specific output
"""""""""""""""""""""""""

None

.. _h-actions-36:

H-actions
"""""""""

None

.. _component-messages-35:

Component messages
""""""""""""""""""

+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Message                                                          | Type  | Explanation                                                                                                                                                                                       |
+==================================================================+=======+===================================================================================================================================================================================================+
| System pressure head (... m) is lower than delivery head (... m) | Error | Initially the tap discharge must be out of the system. Since the computed head loss coefficient may not be nega­tive the system pressure head must be higher than the delivery (downstream) head. |
+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

See also "Mathematical model" (:numref:`mathematical-model-35`).

Tap non-return flow
^^^^^^^^^^^^^^^^^^^

.. _hydraulic-specifications-41:

Hydraulic specifications
""""""""""""""""""""""""

===================== ===== ================ ===== ======= =======
description           input unit             range default remarks
===================== ===== ================ ===== ======= =======
downstream head       Real  [m]                            
initial delivery rate Real  [m­\ :sup:`3`/s] (0-5]         
===================== ===== ================ ===== ======= =======

See also "Mathematical model" (:numref:`mathematical-model-35`).

.. _component-specific-output-39:

Component specific output
"""""""""""""""""""""""""

None

.. _h-actions-37:

H-actions
"""""""""

None

.. _component-messages-36:

Component messages
""""""""""""""""""

+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Message                                                          | Type  | Explanation                                                                                                                                                                                       |
+==================================================================+=======+===================================================================================================================================================================================================+
| System pressure head (... m) is lower than delivery head (... m) | Error | Initially the tap discharge must be out of the system. Since the computed head loss coefficient may not be nega­tive the system pressure head must be higher than the delivery (downstream) head. |
+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| opens                                                            | Info  |                                                                                                                                                                                                   |
+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| closes                                                           | Info  |                                                                                                                                                                                                   |
+------------------------------------------------------------------+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Tap non-return flow with DP reopen
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. _hydraulic-specifications-42:

Hydraulic specifications
""""""""""""""""""""""""

===================== ===== ================ ===== ======= =======
description           input unit             range default remarks
===================== ===== ================ ===== ======= =======
downstream pressure   Real  [Pa]                           
initial delivery rate Real  [m­\ :sup:`3`/s] (0-5]         
Delta P for reopen    Real  [Pa]                           
===================== ===== ================ ===== ======= =======

See also "Mathematical model" (:numref:`mathematical-model-35`).

.. _component-specific-output-40:

Component specific output
"""""""""""""""""""""""""

None

.. _h-actions-38:

H-actions
"""""""""

None

.. _component-messages-37:

Component messages
""""""""""""""""""

+----------------------------------------------------------------------+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Message                                                              | Type  | Explanation                                                                                                                                                                                          |
+======================================================================+=======+======================================================================================================================================================================================================+
| System pressure (... barg) is lower than delivery pressure (...barg) | Error | Initially the tap discharge must be out of the system. Since the computed pressure loss coefficient may not be nega­tive the system pressure must be higher than the delivery (downstream) pressure. |
+----------------------------------------------------------------------+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| opens                                                                | Info  |                                                                                                                                                                                                      |
+----------------------------------------------------------------------+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| closes                                                               | Info  |                                                                                                                                                                                                      |
+----------------------------------------------------------------------+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

.. include:: substitutions_liquid.rst