期刊名称：Bulletin of the Institute of Heat Engineering
印刷版ISSN：2083-4187
出版年度：2016
语种：English
出版社：Warsaw University of Technology
摘要：The aim of this paper is to develop a method of determining transient fluid temperature. The method is based on the solution to the inverse heat conduction problem for a cylindrical thermometer and wall of the pipeline. To determine the fluid temperature, the heat transfer coefficients on the outer surface of the thermometer and inner surface of the pipeline are estimated first. Based on the temperatures measured at the axis of the thermometer and on the temperature of the pipeline measured at the interior point, the surface temperature and heat flux on the thermometer surface and the inner surface of the pipeline are determined. The correlations for the Nusselt numbers used to determine heat transfer coefficients on the outer surface of the thermometer and the inner surface of the pipeline contain unknown coefficients that are found using the least squares method. The unknown coefficients are selected so that the sum of the squares of differences between the fluid temperature determined based on the measurement of the temperature of the pipeline wall and the fluid temperature obtained from measurements inside the thermometer is as small as possible. An application of the method is illustrated by determining the temperature of saturated steam flowing in a pipeline with the outer surface radius of 177.5 mm and the wall thickness 50 mm. The pipeline wall temperature is measured either inside the wall at the distance of 12.5 mm from the inner surface, or at the outer surface. Inside the pipeline, a steel cylinder (thermometer) is placed with the outer surface radius of 3.5 mm and an axial hole containing a thin thermocouple. First, the “exact” measurement data are generated solving the direct problem and then the unknown coefficients in correlations for the Nusselt numbers are found from the solution of the inverse problem. The determined coefficients show a good agreement with the coefficients used for solving the direct problem.
