The RVR is being tracked in the LTU test rig

The LTU test rig is now up and running, and the initial effort has been spent on performing efficiency measurements along with RVR characterization.

“We are still working on the control system of the test rig together with FDB, but we are using a preliminary in-house control system at the moment so we can control and operate the test rig”, says Joel Sundström from LTU.

Initial pressure measurements in the draft tube cone at part-load operation have indicated the presence of an RVR, comprising both rotating and plunging components. The next step to characterize the RVR is to perform particle image velocimetry (PIV) measurements, which are planned to take place during early December.

“We have rented a stereoscopic PIV system, and with that we hope that we will be able to perform measurements of all three velocity components in the draft tube cone”, Joel Sundström continues.

After performing the PIV measurements, the goal is to start the work on mitigating the RVR; both ICM and IPM systems are under design and construction.

Fig 1 - LTU Test Rig