Naučno-tehničeskij Vestnik Informacionnyh Tehnologij, Mehaniki i Optiki (Jun 2024)
Restoration of unsteady heat flow from a thermal energy accumulator by solving the inverse heat conduction problem
Abstract
This paper considers the problem restoring a non-stationary heat flow from a coolant to a heat-storing substance of a separate element of a thermal accumulator. Solving the problem allows avoiding errors associated with averaging the heat flow over all battery cells, and provides the opportunity to find the optimal sizes and composition of the filler for each battery cell. The problem is especially relevant for cascade batteries where cells with different fillers are simultaneously used. A comparison is made of two methods for solving the problem. The first method is based on numerical simulation of the thermal energy storage discharge process using the Computational Fluid Dynamics software package. The second approach proposed by the authors is based on the parametric identification of a differential-difference model of heat transfer with the solution of the inverse problem of heat conduction together with coefficient smoothing calculation. The proposed method makes it possible to smooth out abruptly changing thermophysical characteristics and take into account the moving phase boundary of a substance. The method for solving the inverse heat conduction problem can significantly reduce the recovery time of non-stationary boundary conditions of heat transfer for the entire battery and, thus, reduce the requirements for computing resources when designing and optimizing the battery by facilitating experimental search. For the first time, the use of the method of parametric identification and calculation of smoothing coefficients for solving the Stefan problem was considered and proposed. The results obtained can be used to calculate the heat flow from an individual element of a thermal energy accumulator.
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