A METHOD TO FLUSH MOUNT REPLACEABLE PRESSURE

This paper is concerned with the set-up of a meas-urement system for onboard pressure measurements on a Kaplan runner blade of a 9.3 MW prototype situated at Porjus, Sweden. Piezo-resistive pressure transducers will be flush mounted on both the pres-sure- and suctionside of the blade. The hydraulic excitation frequencies will thus be determined and coupled with measurements of the natural frequencies of the machine and the electromagnetic excitation force acting on rotor of the generator. Instrumentation of a prototype is a delicate work. Therefore, the set-up of the measurement system must be carefully prepared in advance. The empha-sis of the paper lies on the development of a method to flush mount the sensors on the blade that allows damaged sensors to be replaced without dismantling the runner blade. In conclusion, possible drawbacks are discussed. KEYWORDS Piezo-resistive pressure transducers, flush mounting