Liquid film temperature field and flow field simultaneous measurement method based on laser induced fluorescence

Abstract

The invention relates to the field of two-phase/multi-phase flow measurement, aims to realize the non-intrusive and high precision synchronization acquisition of the flow parameters of a liquid film in (outside) a pipeline and temperature field distribution, and is used for the deep study of a liquid film flow characteristic, a heat transfer characteristic and the like. The employed technical scheme is that according to the liquid film temperature field and flow field simultaneous measurement method based on laser induced fluorescence, when a liquid film with dissolved fluorescent dye forms a dynamic liquid film in a pipeline inner/outer wall or a flat panel, a liquid film fluorescence image is taken through a high speed camera, for a same taken fluorescence image, based on a high speed calibration parameter, the geometric feature of the liquid film fluorescence image is accurately extracted, and flow field characteristics comprising a liquid film thickness and a velocity are obtained. At the same time, based on a calibrated temperature-fluorescence intensity calibration curve, laser intensity calibration and a fluorescence intensity extraction method, a liquid film fluorescence image brightness is accurately extracted, and the instantaneous and time averaged temperature field distribution of the liquid film are obtained. The method is mainly applied to a two-phase/multi-phase flow measurement occasion.

Description

technical field [0001] The invention relates to the field of two-phase / multiphase flow measurement, in particular to a method for simultaneously measuring liquid film temperature field and flow field based on laser-induced fluorescence (PLIF) technology. Background technique [0002] Due to its high-efficiency heat and mass transfer characteristics, liquid film has a wide range of applications in chemical industry, electronic cooling, seawater desalination, etc. The temperature field and flow field information are very important for studying the heat transfer performance and flow state of liquid film. For example, falling film evaporator is a kind of efficient evaporation equipment. Its principle is to use the efficient evaporation and heat transfer properties of vertical falling film in the tube. The calculation of evaporation heat transfer is very important for the design of falling film evaporator, process improvement and equipment evaluation. plays an important role, and...

AI Technical Summary

Problems solved by technology

Among them, the conductivity probe can only detect nearby signals, and has an averaging effect. When the thickness of the liquid film is large, the signal sensitivity will be reduced. Even if a multi-conductivity electrode array is used, it is difficult to obtain a sufficiently high temporal and spatial resolution. The emission frequency and signal-to-noise ratio requirements are high, and it is more effective for the liquid film flowing on the plate, which greatly limits its application range

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