Equivalent value of non-uniform temperature field for thermocouple measurement

Authors

  • Lingling Yue
  • Qinghuang Huang
  • Luqiang Li
  • Peiyong Wang

DOI:

https://doi.org/10.56028/aetr.4.1.371.2023

Keywords:

non-uniform temperature; equivalent temperature; probability density function; thermocouple correction.

Abstract

The incoming flow is assumed to have a uniform temperature profile when the energy balance of a thermocouple bead is analyzed for the purpose of measurement corrections, which is hardly true in real applications. The incoming temperature is normally non-uniform and the temperature of the flow closer to the bead has a stronger influence on the bead temperature. Considering this, for the first time, a Gaussian probability density function is established to generate an equivalent temperature of the non-uniform temperature field, which can be used in the corrections. With the one-dimensional thermocouple heat transfer program, the bead temperatures are calculated with five non-uniform temperature profiles and compared with the bead temperatures with the uniform temperatures to find the variance correlation of the Gaussian function. The variance is correlated to the Nusselt number and the wire diameter and the bead diameter of the thermocouple. Many cases with different thermocouple sizes, velocities and temperature ranges and widths of the power function profile are simulated. For all the tested cases, the bead temperature differences between the real profiles and the equivalent profiles are less than 27K, demonstrating the good accuracy of the current method.

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Published

2023-03-22