Patent ID: 7363174
Filing Date: 2008-04-22
Classification: G01F,G01P

Abstract:
1. An apparatus for measuring a flow velocity profile of fluid flowing in a tubular member made of material that allows an acoustic wave to propagate therethrough, based on the frequency of ultrasonic wave reflected off reflectors existing in the fluid changing depending on the fluid flow velocity due to Doppler effect, comprising: a wedge that externally mounts to the tubular member, the wedge being made of material that allows an acoustic wave to propagate therethrough; and an ultrasonic wave transducer that emits ultrasonic wave mounted to the wedge at an inclination relative to the direction in which the fluid travels through the tubular member, wherein the frequency of the transmitted ultrasonic wave emitted by the ultrasonic wave transducer is set at a frequency other than the frequency at which an angle of refraction of a wave in each mode of Lamb wave in the tubular member becomes 90° relative to an axis extending perpendicular to the direction in which the fluid travels through the tubular member, and wherein the frequency at which the wave angle of refraction in each mode of lamb wave in the tubular member becomes 90° relative to the axis extending perpendicular to the direction in which the fluid travels through the tubular member is calculated from an angle of incidence of the ultrasonic wave made incident onto the tubular member from the wedge, a sound velocity in the wedge, sound velocities of a shear wave and a longitudinal wave in the tubular member, and a wall thickness of the tubular member.