Externally-attached portable electromagnetic induction flow pattern sensor and method for monitoring boiling two-phase flow pattern in heat exchange tube

Abstract

The invention relates to an externally-attached portable electromagnetic induction flow pattern sensor and a method for monitoring the boiling two-phase flow pattern in a heat exchange tube, and belongs to the technical field of digital sensors. The electromagnetic induction flow pattern sensor comprises an electromagnetic induction sensor and a host, the electromagnetic induction sensor is externally attached to the surface of a to-be-tested heat exchange tube and is parallel to the horizontal axis of the to-be-tested heat exchange tube, the electromagnetic induction sensor comprises an electrified solenoid and an induction coil, and the induction coil is arranged in the middle of the inner side of the electrified solenoid; and the electrified solenoid and the induction coil are connectedwith the host. The electromagnetic induction flow pattern sensor is low in cost and easy to install and operate, a pipeline is not damaged, a corresponding two-phase flow structure appearing in the heat exchange tube is judged through the induced electromotive force waveform generated when bubbles in the magnetic nanoparticle-containing working medium pass through the induction coil, the problemof boiling two-phase flow pattern non-contact monitoring in the tube is solved, and the electromagnetic induction flow pattern sensor is safe and reliable.

Description

technical field [0001] The invention relates to an externally attached portable electromagnetic induction flow pattern sensor and a method for monitoring boiling two-phase flow pattern in a heat exchange tube, belonging to the technical field of digital sensors. Background technique [0002] When the liquid undergoes forced convective boiling in the heat exchange tube, because the generated steam is mixed into the liquid flow, various forms of boiling two-phase flow structures appear in the tube, and different flow patterns correspond to different heat transfer types. Bubble flow, slug flow, and annular flow enhance heat transfer, but the annular liquid film continues to be heated and evaporates, gradually thinning, and finally the liquid film disappears, and the wet steam directly contacts the wall surface, deteriorating heat transfer, and causing the wall temperature to rise sharply , posing a serious threat to device security. [0003] Based on this, there is an urgent n...

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Problems solved by technology

[0004] Aiming at the difficulty of monitoring and early warning of the boiling two-phase flow pattern in the prior art, the present invention proposes an externally attached portable electromagnetic induction flow pattern sensor and a monitoring method for the boiling two-phase flow pattern in the heat exchange tube. The electromagnetic induction phenomenon caused by phase flow, that is, adding magnetic nanoparticles to the heat transfer working fluid, when the working fluid passes through the electromagnetic induction sensor, the magnetic nanoparticles are magnetized by the magnetic field generated by the energized solenoid, and the non-magnetic particles carried in the working fluid When the gas passes through the induction coil on the electromagnetic induction sensor, the magnetic flux in this area will change with time, thereby generating an induced electromotive force on the induction coil; using the induced electromotive force, the signal can be monitored through the electromagnetic induction sensor attached to the outer wall of the pipeline , inferring the different forms of two-phase flow structures appearing in the tube and whether the heat transfer deteriorates

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