A Method for Measuring Fluid Velocity Using Dual Thermocouples

Abstract

The invention discloses a method of measuring the fluid velocity using double thermocouples, and belongs to the technical field of fluid thermal measurement. Measuring elements adopted in the method are two thermocouples, which are of the same size, are made of different materials and are close in space. A data acquisition card is used to collect the measured temperature values of the two thermocouples. In consideration of measurement noise interference and measurement resolution, the surface convective heat transfer coefficients of the thermocouples are fitted based on a lumped parameter method and a spline fitting method; and after the convective heat transfer coefficients are obtained, the relationship between the flow velocity and corresponding convective heat transfer coefficients is obtained based on a dimensional empirical relational expression, and thus, the flow velocity information of a flow field is obtained. Through the method, temperature information frequency response in a flow field can be measured, and fluid velocity information can be obtained according to a dimensional relational expression. As the method only involves two thermocouples, installation is easy. Qualitative velocity distribution of a complex flow field can be obtained. The method can be applied to both compressible flow and incompressible flow.

Description

technical field [0001] The invention provides a method for measuring fluid velocity based on double thermocouples, which belongs to the technical field of fluid thermal measurement. Background technique [0002] People have been concerned about mobile information for a long time. The turbulence problem is considered to be the only unsolved problem in classical physics. The main reason is that the solution of the famous N-S equation describing the flow problem is very difficult in mathematics. At present, there is no hope of a direct and complete solution. Therefore, from Fundamentally speaking, fluid mechanics is still an experimental science, and the solution of many problems and the improvement of actual flow models depend on the acquisition of high-quality experimental results. Anyone who studies fluid mechanics knows that the flow velocity of a fluid is the most basic physical quantity of the flow field, and the understanding of the flow characteristics largely depends ...

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Problems solved by technology

[0005] For some complex structures, such as the air system of an aeroengine, the traditional speed measurement method is difficult to realize due to factors such as difficult layout and cost, so a new, cost-effective and easy-to-arrange speed measurement method is required to be applied to these special structures. in complex structure

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