Improved Hydro Runner Design and Performance

Background

Late 2008 Hi-Tech Metrology was approached  to measure and laser scan a runner from one of Pacific Hydro's power stations located on the Ord River, in Western Australia, through specialist New Zealand hydro contractor, Hydro Works. The project involved measuring multiple blades of a runner after it had been taken out of service at the power station during a planned outage. 

Timing was critical as the outage was for only 24-hours hours and so meticulous project planning and logistical support were paramount. The runner, as part of the hydro system, was manufactured a number of years ago and detail drawings and specifications were not available.  The power station client wanted to manufacture new runners for their operation in order to improve performance and to enhance the future serviceability of the overall hydro plant.

Project Brief

The project brief was for Hi-Tech Metrology to travel to site, some 50 kilometres south west of Kununurra in Western Australia, and along with the engineers from Hydro Works to accurately measure and scan the runner blades and measure other key geometric features after runner after it had been removed from the plant.

Due to the criticality of the project, Hi-Tech Metrology was asked to provide a full back-up system of equipment on-site - just in case anything went wrong. Fortunately with Hi-Tech Metrology's skills and experience with this type of measurement technology, the back-up equipment was not required. The client now has the confidence that with Hi-Tech Metrology involved in future projects there will be no need to insist on back-up systems - saving both time and costs on future projects.

The equipment used by Hi-Tech Metrology for the measurement and digitizing of the runner blades on site consisted of the latest generation, seven-axis 2.4 metre FaroArm with FARO's add-on laser scanning solution, the FARO Laser Line Probe (LLP).  The LLP is capable of performing both hard probing  - for geometric features on parts, as well as laser scanning - for quickly capturing spatial data on non-geometric features.  The FARO LLP collects data via eye-safe, non-contact laser scanning stripe 70mm in width, which collects data at a rate of over 19,200 points per second.

Data was collected during the scanning and measurement process using the latest release of leading point cloud engineering software PolyWorks® from Canadian software developer, Innovmetric Software Inc. Once the data collection was completed further on-site processing took place with the importing of aligned and semi-processed data into the client's own CAD system to ensure complete data compatibility before leaving site.

Deliverables

Back at the Hi-Tech Metrology office in Melbourne the bulk of the data processing took place.  The deliverables required by the client were a tightly  meshed 3D model of the runner, fully referenced to pre-defined  coordinate system for the part. Using PolyWorks software, Hi-Tech Metrology was able to provide the whole data set deliverable to the client within two days of returning to the office from site.

Conclusions

The success of the project was evident with comments from Rik Hothersall a project engineer from HydroWorks, who said.. "acquiring accurate turbine blade performance geometry using the Faro ScanArm meant our runner analysis data can now be used as a bench mark for future runner upgrade requirements."

Further data processing of the data provided by Hi-Tech Metrology including FEA and fluid flow analysis was covered under Hydroworks scope of works with the intention being to provide the necessary analysis to either design a new runner or alternatively to simply refine the existing system.

Future Plans

Hydroworks have subsequently involved Hi-Tech Metrology in another hydro project, this time in New Zealand for the measurement of another but smaller hydro runner system. The continuing success of these projects stands as a testament to the strong partnership that is developing between Hydroworks and Hi-Tech Metrology in the renewable energy sector in Australasia.