N2 - This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole), divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.
L1 - http://journals.pan.pl/Content/94511/PDF/04_paper.pdf
L2 - http://journals.pan.pl/Content/94511
PY - 2014
IS - No 1 March
EP - 61-76
KW - temperature measurement
KW - Transient conditions
KW - uncertainty analysis
A1 - Jaremkiewicz, Magdalena
PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences
SP - 61-76
T1 - Determination of transient fluid temperature using the inverse method
DA - 2014
UR - http://journals.pan.pl/dlibra/publication/edition/94511
T2 - Archives of Thermodynamics
DOI - 10.2478/aoter-2014-0004