Research on the artificial control method of the gas nuclei spectrum in the small-scale experimental pool under atmospheric pressure

Abstract

With the improvement of the accuracy of experimental devices and measuring instruments, cavitation experiments such as cross-media vehicles and propellers have been carried out in small pools. However, the water quality in the laboratory and the engineering application waters differs, especially the concentration of the gas nuclei that cause cavitation, resulting in experimental results that differ from prototype experimental results, and the scale effect occurs. In order to reduce the influence of the scale effect, according to the conditions of cavitation, gas nuclei can be mixed with water before the experiment is formally implemented. Aeration behavior will affect the size and concentration of gas nuclei (gas nuclei spectrum) in water. In order to obtain better experimental results, it is necessary to clarify the variation of the gas nuclei spectrum in small-scale experimental pools before and after aeration, so as to master aeration technology. Through research, it is found that the artificial aeration method can effectively change the gas nuclei spectrum in water and increase the concentration of gas nuclei. By using the underwater acoustic measurement method, the change in the gas nuclei spectrum can be captured sensitively. The gas nuclei spectrum in water after aeration is in good agreement with the mathematical model of gas nuclei spectrum under non-artificial intervention, which shows that the distribution of gas nuclei in water under artificial aeration is similar to that under non-artificial intervention, which is conducive to the occurrence of cavitation. At the same time, it shows that the combination of experiment and numerical method can reduce the measuring state and the measurement cost and improve the measurement efficiency.

Keywords

• cavitation
• aeration
• gas nuclei spectra
• experiment
• mathematical model