Meetings of the Advisory Technical Committees of the International Electrotechnical Commission were held in Brussels March 27th to April 1st. The meetings were attended by delegates from eight national committees — Belgium, France, Great Britain, Holland, Italy, Spain, Switzerland, and the United States. There were about 40 delegates in all.

https://ieeexplore.ieee.org/iel5/5308791/5321388/05321395.pdf

The International Electrotechnical Commission

Effect of temperature, suction head and flow velocity on cavitation in a Francis turbine of small hydro power plant

A review on fluid structure interaction in hydraulic turbines: A focus on hydrodynamic damping

Transient cavitating flow structure and acoustic analysis of a hydrofoil with whalelike wavy leading edge

Visual observations and acoustic measurements of cavitation in an experimental model of a high-pressure homogenizer

The goal of the study was to explain the relationship between different acoustic signals and visual appearance of cavitation. Measurements of acoustic emission, vibration, and noise were performed on a Kaplan turbine model, with only two blades, in a cavitating condition. Since a model with only two blades was used, most of the side effects were eliminated, and it was concluded that the cavitation itself is the source of the recorded signal. Results showed an interesting relationship between the extent of the cavitation and the recorded data from sensors. At a decreasing cavitation number, the recorded amplitudes from all measurements first rose, experienced a local maximum, then fell to a local minimum, and finally rose again. The cavitation was also visually observed. It was concluded from the measurements that there are distinct correlations between acoustic emission, vibration, and noise on one side and the topology, extent, and type of cavitation structures on the other side. A physical explanation for the phenomenon was introduced and included in a semi-empirical model that links the visual appearance of cavitation on the blade of the turbine to the generated noise and vibration.

An investigation of the relationship between acoustic emission, vibration, noise and cavitation structures on a Kaplan turbine

The influence of pressure pulsations on the cavitation-vortex dynamics in a Francis-turbine draft tube is presented. The experiment was performed on a model Francis turbine in which pressure pulsations on the draft-tube wall and the cavitation-vortex dynamics were acquired simultaneously. The cavitation-vortex dynamics was recorded using a visualization method. An experimental model was proposed in which the cavitation-vortex dynamics was predicted based on recorded pressure information at one point on the draft-tube wall. The performance of the model is, on average, very good. The prediction of the cavitation-vortex dynamics shows better results when the distance between the pressure sensor and the cavitation vortex is short.

Tomaž Rus

Papers

An investigation of the relationship between acoustic emission, vibration, noise and cavitation structures on a Kaplan turbine

Vpliv tlačnih utripanj v sesalni cevi na dinamiko kavitacijskega vrtinca v francisovi turbini