Response compensation of fine‐wire thermocouples and its application to multidimensional measurement of a fluctuating temperature field

Abstract

AbstractA novel sensor technique is proposed to visualize readily the spatiotemporal behavior of a fluctuating temperature field of air flow. Two temperature probes were fabricated: a rod‐type probe consisting of 24 two‐thermocouple sensors set in line, and a plane‐type probe with 64 two‐thermocouple sensors arrayed on a two‐dimensional grid (8 × 8 points). Each two‐thermocouple sensor used in these probes was composed of two fine‐wire thermocouples (type K) of unequal diameters of 25 and 51 μm, respectively. An adaptive response‐compensation scheme was applied to accurately reconstruct rapidly‐changing airflow temperatures. The plane‐type probe enables visualization of fluctuating temperature fields of an artificially disturbed hot‐air jet and of the adequate capture of spatiotemporal behavior of a rapid circular motion of a hot‐air jet blown out from a hair dryer. A time‐constant estimation scheme was proposed to estimate instantaneous time‐constants which serve as a basis for a real‐time response compensation technique for multidimensional temperature measurement. In addition, by scanning a temperature field with the rod‐type probe, the temperature distribution can be reconstructed in one‐dimensional space and time. This quasi two‐dimensional visualization can become a prototype of a “scanner” for fluid temperature fields. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20355