An Optical Measurement System Based on Distributed Optical Fiber Annular Liquid Film Thickness

Abstract

The embodiment of the present invention relates to an optical testing system based on distributed optical fiber annular liquid film thickness, comprising: a liquid film generation module, an acquisition module and an imaging module; the acquisition module is arranged circumferentially outside the liquid film generation module, To collect the fluorescence signal of the liquid film in the liquid film generation module, the output end of the collection module is connected to the imaging module for outputting the fluorescence signal to the imaging module, and the imaging module according to the Fluorescent signals are imaged. Thus, the imaging of the axial thickness and the circumferential thickness can be realized, and the complicated timing synchronization system is omitted, and only the output signal of the laser needs to be used to trigger the enhanced charge coupler to collect. The structure is simple and easy to operate.

Description

technical field [0001] Embodiments of the present invention relate to the field of liquid mode measurement, and in particular, to an optical testing system based on distributed optical fiber annular liquid film thickness. Background technique [0002] The formation and evaporation of liquid films is widespread in various industrial applications, such as oil films on piston heads in engines, oil films on the inner wall of the inlet in gasoline engines, water films in fire-extinguishing applications, and falling film cooling. Because the liquid film flow has the unique advantages of small flow rate, small temperature difference, high heat and mass transfer coefficient, high heat flux density, simple structure and low power consumption, its heat transfer intensity and mass transfer intensity are several times that of laminar flow under the same flow conditions. , has become a very active research field in the international heat and mass transfer science and engineering communit...

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Problems solved by technology

Among them, the first two are contact measurements, which are affected by the surface tension of the liquid film and the interference to the flow. The measurement accuracy is easily affected by the surface liquid film coverage and the structural parameters of the probe, and has interference on the flow field, which is limited. Larger, so although the conductivity method is one of the most commonly used annular flow test methods at present, its intrusive measurement method will inevitably affect the liquid film flow, and has an averaging effect in the measurement area

The ultrasonic method is a non-contact interference-free measurement method. Its measurement principle is that ultrasonic waves have different propagation characteristics and attenuation characteristics in different media, but as a non-electromagnetic wave, ultrasonic waves have relatively small propagation speeds and complex configurations. It will cause multiple reflections in the test piece, which will affect the accuracy of data measurement

And in actual use, the measurement frequency is limited by the ultrasonic attenuation cycle, and the real-time performance of the measurement is not strong

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