EfficiencyCurves_Q1

Created Mittwoch 06 Dezember 2017

Calculates loss power and loss torque based on a parameter-based efficiency function.

1. Purpose of Model

The model represent losses and the power consumption curves of typical centrifugal pumps in a wide range of normal pump operation points. It gives reasonable results in dissipation mode and in reverse turbine mode. Reverse rotation is not supported

2. Level of Detail, Physical Effects Considered and Physical Insight

2.1 Level of Detail

Referring to Brunnemann et al. [1], this model can be applied in models of level of detail L1 and L2.

2.2 Physical Effects Considered

The model is purely phenomenological.

3. Limits of Validity

reverse rotation is not supported.
reverse turbining is assumed to start when the pressure difference gets negative
reverse turbining is not supported for very low negative pressure differences.

The complete characteristics are discussed in detail in [2] and the limits of applicability of the model can be marked in the four quadrant diagram of a turbine as below:

4. Interfaces

A internal communication record iCom is used for communication with the applying pump model. This is not discussed in detail.

5. Nomenclature

6. Governing Equations

Losses

The losses are defined via the efficiency and the isentropic power (defined in the respective pump model):

To allow a smooth transition between the three operation modes the Basics:Functions:Stepsmoother is used.
The efficiency model is a simple phenomenological approach based on a nominal efficiency, an affinity exponent for the rotational speed and volume flow and a relative volume flow rate in p.u. for locating the optimal point on the flow rate axis. The efficiency is defined as:

with the maximum flow rate at current speed defined as:

In the three figures below the effect of the three tuning parameters can be seen.

7. Remarks for Usage

The behaviour of a pump, especially in non-design operation, is governed by the applying pump model. Consider the respective documentation for details
The reverse turbine mode is supported only in a qualitative manner and only for moderate (negative) pressure differences Δp. The used efficiency equation becomes negative for high values of negative Δp.

8. Validation

See Components:TurboMachines:Pumps:PumpVLE L1 affinity for validation plots.

9. References

[1] Johannes Brunnemann and Friedrich Gottelt, Kai Wellner, Ala Renz, André Thüring, Volker Röder, Christoph Hasenbein, Christian Schulze, Gerhard Schmitz, Jörg Eiden: "Status of ClaRaCCS: Modelling and Simulation of Coal-Fired Power Plants with CO2 capture", 9th Modelica Conference, Munich, Germany, 2012
[2] R.T. Knapp: "Complete Characteristics of Centrifugal Pumps and Their Use in the Prediction of Transient Behaviour", Transactions of the A.S.M.E. . pp. 683-689, 1937

10. Authorship and Copyright Statement for original (initial) Contribution

Author:
DYNCAP/DYNSTART development team, Copyright 2011 - 2022.
Remarks:
This component was developed during DYNCAP/DYNSTART projects.
Acknowledgements:
ClaRa originated from the collaborative research projects DYNCAP and DYNSTART. Both research projects were supported by the German Federal Ministry for Economic Affairs and Energy (FKZ 03ET2009 and FKZ 03ET7060).
CLA:
The author(s) have agreed to ClaRa CLA, version 1.0. See https://claralib.com/pdf/CLA.pdf
By agreeing to ClaRa CLA, version 1.0 the author has granted the ClaRa development team a permanent right to use and modify his initial contribution as well as to publish it or its modified versions under the 3-clause BSD License.

11. Version History

2017-12-07 - v1 - initial implementation derived from the equation previously implemented in the model PumpVLE_L1_affinity - F.Gottelt, XRG Simulation GmbH

Backlinks: ClaRa:Components:TurboMachines:Pumps:PumpVLE L1 affinity