Optical testing system based on thickness of distributed optical fiber annular liquid film

Abstract

The embodiment of the invention relates to an optical test system based on the thickness of a distributed optical fiber annular liquid film. The optical test system comprises a liquid film generationmodule, an acquisition module and an imaging module. The acquisition module is circumferentially arranged on the outer side of the liquid film generation module and is used for acquiring a fluorescence signal of a liquid film in the liquid film generation module, the output terminal of the acquisition module is connected with the imaging module and is used for outputting the fluorescence signal tothe imaging module, and the imaging module is used for imaging according to the fluorescence signal. Therefore, imaging of the axial thickness and the circumferential thickness can be realized, a complex time sequence synchronization system is omitted, only an output signal of the laser needs to be used for triggering the enhanced charge coupler for collection, the structure is simple, and operation is easy.

Description

technical field [0001] The embodiment of the present invention relates to the field of liquid model measurement, and in particular to an optical test system based on distributed optical fiber ring liquid film thickness. Background technique [0002] The phenomenon of liquid film formation and evaporation exists in various industrial applications, such as oil film on the piston head in the engine, oil film on the inner wall of the inlet in the gasoline engine, water film and falling film cooling in fire extinguishing applications, etc. Due to the unique advantages of liquid film flow, such as 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 engineeri...

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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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