This is the base model for the `Pump` and
`PumpMech` pump models.

The model describes a centrifugal pump, or a group of
`Np` identical pumps in parallel. The pump model is based on
the theory of kinematic similarity: the pump characteristics are
given for nominal operating conditions (rotational speed and fluid
density), and then adapted to actual operating condition, according
to the similarity equations.

In order to avoid singularities in the computation of the outlet enthalpy at zero flowrate, the thermal capacity of the fluid inside the pump body can be taken into account.

The model can either support reverse flow conditions or include a built-in check valve to avoid flow reversal.

**Modelling options**

The nominal hydraulic characteristic (head vs. volume flow rate)
is given by the the replaceable function
`flowCharacteristic`.

The pump energy balance can be specified in two alternative ways:

`usePowerCharacteristic = false`(default option): the replaceable function`efficiencyCharacteristic`(efficiency vs. volume flow rate in nominal conditions) is used to determine the efficiency, and then the power consumption. The default is a constant efficiency of 0.8.`usePowerCharacteristic = true`: the replaceable function`powerCharacteristic`(power consumption vs. volume flow rate in nominal conditions) is used to determine the power consumption, and then the efficiency.

Several functions are provided in the package
`Functions.PumpCharacteristics` to specify the
characteristics as a function of some operating points at nominal
conditions.

Depending on the value of the `checkValve` parameter, the
model either supports reverse flow conditions, or includes a
built-in check valve to avoid flow reversal.

If the `in_Np` input connector is wired, it provides the
number of pumps in parallel; otherwise, `Np0` parallel pumps
are assumed.

It is possible to take into account the heat capacity of the
fluid inside the pump by specifying its volume `V` at
nominal conditions; this is necessary to avoid singularities in the
computation of the outlet enthalpy in case of zero flow rate. If
zero flow rate conditions are always avoided, this dynamic effect
can be neglected by leaving the default value `V = 0`, thus
avoiding a fast state variable in the model.

The `CheckValve` parameter determines whether the pump
has a built-in check valve or not.

If `computeNPSHa = true`, the available net positive
suction head is also computed; this requires a two-phase medium
model to provide the fluid saturation pressure.

Name | Description |
---|---|

Medium | |

flowCharacteristic | Head vs. q_flow characteristic at nominal speed and density |

powerCharacteristic | |

efficiencyCharacteristic |

*31 Oct 2006*by Francesco Casella:

Added initialisation parameter`wstart`.*5 Nov 2005*by Francesco Casella:

Model restructured according to kinematic similarity theory.

Characteristics now specified by replaceable functions.*6 Apr 2005*by Francesco Casella:

`CharData`substituted by`OpPoints`*16 Dec 2004*by Francesco Casella:

Standard medium definition added.*2 Aug 2004*by Francesco Casella:

Optional NPSHa computation added. Changed parameter names*5 Jul 2004*by Francesco Casella:

Model restructured by using inheritance. Adapted to Modelica.Media.*15 Jan 2004*by Francesco Schiavo:

`ThermalCapacity`and`CheckValve`added.*15 Dec 2003*by Francesco Schiavo:

First release.

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