Thin-wall local heat transfer coefficient measuring method based on thermal fluctuation coupling infrared imaging

Abstract

The invention discloses a thin-wall local heat transfer coefficient measuring method based on thermal fluctuation coupling infrared imaging, and the method obtains a steady local heat transfer coefficient of the other side (a to-be-measured side) of a thin wall through an analytic solution of a one-dimensional unsteady state heat conduction equation under the condition that one side (a reference side with a known heat transfer coefficient) is under the periodic heat flow boundary condition, wherein the other side is in univalent function relation with a phase different between the reference side wall temperature and an applied heat flow fluctuation signal. According to the invention, the method is not affected by the temperature measurement precision of an infrared imager, and can achieve the non-contact quick measurement of the surface local heat transfer coefficient of the features of the thin wall through the collection of the thermal fluctuation of the reference side and a surface temperature signal of the thin wall based on infrared imaging.

Description

technical field [0001] The invention relates to the measurement technology of the local heat transfer coefficient of the solid surface, in particular, it is a thin-walled local heat transfer coefficient measurement method based on thermal fluctuation coupled infrared imaging. Background technique [0002] The surface heat transfer coefficient refers to the heat transferred by convection and / or radiation on a solid surface per unit area and unit time under the condition of unit temperature difference, and the international unit is watt / (m 2 ·Kelvin). The surface heat transfer coefficient is one of the important index parameters to measure the performance of the heat exchanger. [0003] The surface heat transfer coefficient can generally be obtained by numerical calculation and experiment. Numerical calculation refers to the process of iteratively solving the constitutive equation (group) corresponding to the physical model and obtaining the surface heat transfer coefficient...

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Problems solved by technology

[0005] However, there are obvious deficiencies in the above-mentioned technical solution: because it relies on the measurement of a single temperature field change process of the surface to be measured, it is often difficult to reach the nominal condition between the infrared thermal imager lens and the surface to be measured in the actual measurement process, so the temperature measurement accuracy cannot be guaranteed

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