Design optimization using LabVIEW and modeFRONTIER

Morten Kjeldsen, Haakon H. Francke

Flow Design Bureau AS

Torbjorn K. Nielsen

Norwegian University of Science and Technology


The Norwegian University of Science and Technology (NTNU) runs a hydro turbine test facility. During a recent R&D initiative, initiated by FDB, NTNU erected a model for the investigation and optimization of a flow control (FC) system. This FC system works on the principle of injecting water at high velocity tangentially in to the outlet flow, thereby modifying the distribution of angular momentum and thus removing conditions prone to instabilities. Such instabilities cause restriction in the operation of turbine units, and a huge incentive exists to retrofit technologies into existing turbine units to avoid or reduce such instabilities.
The magnitude of these instabilities themselves depends on the operation point and the instantaneous submerge or NPSH, while the performance of the injection systems depends on a number of design parameters including total flow rate distributed over the injection nozzles. The design objective of the FC injection system is to reduce the injection flow rate, or injected power, while simultaneously minimizing pressure pulsations over a number of operation points.
The injection nozzles of the injection system in the NTNU facility rest in spherical bearings, and in effect, the set-up allows for a continuous variation of two angles; within a given range and independent of each other. Likewise, the nozzle flow rate easily adjusts through actuation of a control valve.
The optimization contain defined constraints, design objective and multi-parameter dependency as well as automatic control of most parameters. Since LabVIEW manages the data acquisition and control of the FC system, the project participants decided to use modeFRONTIER to run the LabVIEW solution and to find optimum FC solutions for a number of operation condition.
This presentation focuses on the problem set-up, the programming solution for the LabVIEW/modeFRONTIER environment as well as the initial testing of this set-up.