Fluctuation pressure measurement system induced by ship propeller cavitation

摘要

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a system for measuring fluctuation pressure induced by cavitation of a ship propeller which mainly acts on the hull vibration.;As is well known, if the cross section of the cavitation or flow of the ship propeller, which is the main cause of the hull vibration, changes rapidly or the direction of the flow is changed, a cavity is created near the vortex. It is a phenomenon that causes a flow, which causes noise and vibration at partial load, and a cavitation test of fluctuation pressure induced by heavy corrosion under the condition of eroding corrosion on the back of the van. As shown in Fig. 1, the cavitation is generated by a model car and a characteristic test according to the generation of cavitation is composed of a measuring device for supporting a variable pressure plate provided with a pressure transducer while moving up and down and an amplifier for amplifying a signal.;The fluctuating pressure plate of the measuring device is located above the propeller, and the fluctuation pressure measured in the pressure transducer is very weak due to the necessity of minimizing the vibration of the measuring device itself due to the propeller cavitation. The system should be able to be used simultaneously in the measurement of the fluctuation pressure of the actual ship in order to minimize the error caused by the measurement system when estimating the correlation between the model ship or the actual ship. However, this has not been done.;The present invention for improving the above problems is reproduced by the plate-type variable pressure plate in the model propeller and installed six pressure transducers at intervals of 62.5mm,;In a real ship, a pressure transducer is installed at the bottom of the hull, and the signal measured by the pressure transducer is stored in a tape recorder via an amplifier, and after the experiment, a frequency analysis can be performed using a FFT analyzer in a laboratory. In order to understand the accuracy of the measurement during the experiment, the oscilloscope can be used to perform time signal observation and rough frequency analysis, and it can be divided into 1st and 2nd amplification to facilitate zero adjustment. It is an invention that improves the problems of the prior art by making the waterproof and high-pressure shangdong at high pressure smoothly, preventing the vibration and adjusting the distance and manufactured in the shape of NACA 16-021.