Method and apparatus for detection of erosive cavitation in an aqueous

Abstract

Method and device for quantitatively measuring the intensity of erosive cavitation present in an aqueous solution such as, for instance, fresh water. According to the method, a set of measuring electrodes is placed in the liquid, these electrodes including a reference electrode, at least one auxiliary electrode and at least one working electrode made of a metal selected from those capable of forming highly insulating oxide films capable of becoming thicker by ionic mobility under the action of an electric field, this metal being preferably titanium. The auxiliary and working electrodes are located in the zone where it is desired to measure the cavitation and a constant anodic voltage is applied across the working electrode by means of the auxiliary and reference electrodes. The intensity of the anodic current is then measured and any variation in the intensity of this current is detected and measured. The variation thus measured is, in terms of the appropriately selected constant anodic voltage applied, directly proportional to the intensity of erosive cavitation in the measure zone. This method as well as the device for carrying it out may particularly be useful in the design of hydraulic machines; during the testing of models or prototypes such as during tests on pumps, turbines, propellers or water valves, as well as for the supervision of machines in operation in hydraulic, thermo or nuclear plants, or in pumping stations for fresh or salt water.