The invention discloses a leakage positioning method based on ultrasonic
wave speed change. The method comprises the following steps: a leakage positioning formula based on ultrasonic wave change of an oil conveying
pipe to be detected is built; ultrasonic
wave speed sensors are mounted at head and
tail stations of the oil conveying
pipe to be detected for acquiring ultrasonic
wave speed signals;a negative-
pressure wave speed from a leakage point to the ultrasonic wave speed sensors at the head and
tail stations of the
pipe is determined; the
wavelet noise removal is performed on the wave speed signals acquired by the ultrasonic wave speed sensors; difference values between the ultrasonic wave speed signals at the head and
tail stations of the pipe after the
wavelet noise removal and theultrasonic wave speed signals at the head and tail stations of the pipe under normal working conditions are calculated; and ultrasonic wave speed
signal change quantities at the head and tail stationsof the pipe and the negative-
pressure wave speed are introduced in the leakage positioning formula based on the ultrasonic wave speed change to position the leakage point. The leakage positioning method based on the ultrasonic wave speed change prevents the problem of positioning of the leakage point by using the
time difference of leaked sound
waves reaching the head and tail stations of the pipe; and when the leakage point of the pipe is positioned, the leakage point is positioned by using the ultrasonic wave speed change quantities of the head and tail stations of the pipe, so that the nondestructive installation on the pipe is achieved, and the feasibility and the applicability of the leakage detection by using the ultrasonic sensors are improved.