Waveguides for non-invasive measurement of flow in a high temperature pipe and apparatuses, systems, and methods of use thereof

A method, comprising:

• connecting first and second transducers to first and second waveguides, respectively;
• connecting the first and second waveguides to a pipe;
• and
• exchanging ultrasonic wave signals between the first and second transducers, said ultrasonic wave signals passing through the first and second waveguides, the pipe, and a fluid flowing in the pipe;
• wherein a temperature of the fluid flowing in the pipe exceeds 600° C.;
• and
• wherein the first and second waveguides are configured to, and each have a shape to:
• (i) insulate the first and second transducers from the pipe, and (ii) permit propagation of the ultrasonic wave signals between the pipe and the first and second transducers, respectively, while maintaining an acoustic attenuation through the first and second waveguides at an acceptable level that is small enough to permit ultrasonic wave signals from one of the transducers to pass through the waveguides and be detected by the other of the transducers, so that the ability of the first and second transducers to exchange the ultrasonic wave signals is not adversely affected by the temperature of the fluid flowing in the pipe;
• insulating, using the first and second waveguides, the first and second transducers from the pipe;
• and
• maintaining, using the first and second waveguides, an acoustic attenuation of the ultrasonic wave signals.