scholarly journals Non-contact heat transfer models identification for laser hyperthermia of semi-transparent materials

2021 ◽  
Vol 2119 (1) ◽  
pp. 012147
Author(s):  
D S Semenov ◽  
A V Nenarokomov
Keyword(s):  
Heat Transfer ◽  
Thermal Effects ◽  
Transfer Problem ◽  
Contact Heat ◽  
One Dimensional ◽  
Contact Heat Transfer ◽  
Inverse Heat Transfer ◽  
Inverse Heat Transfer Problem ◽  
Laser Hyperthermia ◽  
Unsteady Heating

Abstract The identification of mathematical models of heat transfer traditionally involves the installation of temperature sensors inside the sample under study and registration of the response to external thermal effects. In cases where the use of contact methods for measuring temperature is impossible, it is necessary to develop new approaches to determining the unknown thermophysical and radiation-optical characteristics. Laser hyperthermia of superficial tissues is one such case. The paper proposes a method for identifying a model of one-dimensional unsteady heating of a semitransparent sample using non-contact thermometry. A feature of the physical process under consideration is the possibility of its discretization. Due to this, a two-stage iterative procedure for solving the inverse heat transfer problem was formulated. The implementation of the proposed algorithm using software made it possible to carry out a computational experiment. The results showed the effectiveness of this approach. The presented method can be used in the development of means for monitoring and regulating the laser hyperthermia procedure.

scholarly journals Estimation of Functional Form of Time-Dependent Heat Transfer Coefficient Using an Accurate and Robust Parameter Estimation Approach: An Inverse Analysis

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5073
Author(s):  
Farzad Mohebbi ◽  
Mathieu Sellier
Keyword(s):  
Heat Transfer ◽  
Parameter Estimation ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Inverse Analysis ◽  
Functional Form ◽  
Transfer Problem ◽  
Function Estimation ◽  
Inverse Heat Transfer ◽  
Inverse Heat Transfer Problem

This paper presents a numerical method to address function estimation problems in inverse heat transfer problems using parameter estimation approach without prior information on the functional form of the variable to be estimated. Using an inverse analysis, the functional form of a time-dependent heat transfer coefficient is estimated efficiently and accurately. The functional form of the heat transfer coefficient is assumed unknown and the inverse heat transfer problem should be treated using a function estimation approach by solving sensitivity and adjoint problems during the minimization process. Based on proposing a new sensitivity matrix, however, the functional form can be estimated in an accurate and very efficient manner using a parameter estimation approach without the need for solving the sensitivity and adjoint problems and imposing extra computational cost, mathematical complexity, and implementation efforts. In the proposed sensitivity analysis scheme, all sensitivity coefficients can be computed in only one direct problem solution at each iteration. In this inverse heat transfer problem, the body shape is irregular and meshed using a body-fitted grid generation method. The direct heat conduction problem is solved using the finite-difference method. The steepest-descent method is used as a minimization algorithm to minimize the defined objective function and the termination of the minimization process is carried out based on the discrepancy principle. A test case with three different functional forms and two different measurement errors is considered to show the accuracy and efficiency of the used inverse analysis.

scholarly journals Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangers

2011 ◽  
Vol 32 (4) ◽  
pp. 17-32 ◽  
Author(s):  
Dawid Taler ◽  
Adam Sury
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Control ◽  
Heat Exchangers ◽  
Pid Controller ◽  
Transfer Problem ◽  
Heat Transfer Problem ◽  
Inverse Heat Transfer ◽  
Inverse Heat Transfer Problem ◽  
Exit Temperature

Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangersThe aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.

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