Ultrasonic flow rate measurement device for rectangular tube portion

An ultrasonic flow rate measurement device for a rectangular tube portion, the ultrasonic flow rate measurement device comprising:

• an ultrasonic wave emission unit that is installed on one side surface of the rectangular tube portion and emits an ultrasonic pulse toward a measurement target fluid in the rectangular tube portion;
• an ultrasonic wave reception unit that receives the ultrasonic pulse having passed through the measurement target fluid in the rectangular tube portion;
• an ultrasonic processing unit that executes processing of emitting the ultrasonic pulse in the ultrasonic wave emission unit and processing of receiving the ultrasonic pulse in the ultrasonic wave reception unit;
• and
• a flow rate calculation unit that calculates an average flow velocity of the measurement target fluid flowing in the rectangular tube portion based on a reception result of the ultrasonic pulse received by the ultrasonic wave reception unit, and calculates an intra-tube flow rate by multiplying the average flow velocity by a cross-sectional area of the rectangular tube portion, wherein
• a plurality of the ultrasonic wave emission units are arranged on a same straight line orthogonal to a flow direction on the one side surface and installed at a same angle with respect to the one side surface,
• a plurality of the ultrasonic wave reception units are installed at positions respectively facing the plurality of ultrasonic wave emission units on an opposing side surface facing the one side surface,
• the ultrasonic processing unit causes each of the ultrasonic wave emission units to emit ultrasonic pulses having different frequencies from each other, determines whether or not the ultrasonic pulse received by the ultrasonic wave reception unit is an ultrasonic pulse emitted from the opposing ultrasonic wave emission unit on the basis of the frequency of the ultrasonic pulse, and transmits a reception result to the flow rate calculation unit when the ultrasonic pulse is the ultrasonic pulse emitted from the opposing ultrasonic wave emission unit, and
• the flow rate calculation unit calculates a local average flow velocity for each of the ultrasonic wave emission units on the basis of the reception result of the ultrasonic pulse transmitted from the ultrasonic processing unit for each of the ultrasonic wave reception units, and calculates the intra-tube flow rate by a sum of local flow rates obtained by multiplying the local average flow velocity by a local area for each of the ultrasonic wave emission units.