Berestovitsky E., Gladilin Y.

Object of researches was a stability of characteristics of test hydraulic system with pumps for checks of samples of hydraulic devices on hydrodynamical noise (HDN). The test system has long pipelines of a complex configuration and regulating armature throttle valves. At long work of the stand as a result of heating a working environment inevitably there should be an allocation of air dissolved of it in a disperse phase. Bubbles are collecting in air bags, for example, in a cavity of the valve, change acoustic resistance of a liquid path of the pipeline. It in turn should result in change of own frequencies of fluctuations of a liquid path of the pipeline and factors of transfer on the path of acoustic energy of a source. To check up a degree of stability of acoustic characteristics of the stand, was produced a series of measurements with a long interval , on the same mode , at the same variant of a set of the equipment during a labour shift. Results of measurements show, that at long work of the stand its acoustic characteristics can spontaneously vary in rather wide limits, especially on discrete frequencies. Even in rather wide strip, in a 1/3-octave, the size of instability can leave far beyond allowable confidential probability of acoustic measurements. To provide an opportunity more or less long work on the test system on measurement HDN necessary its modernization is represented. Was offered ways of the modernization.