Validation of a Newly Developed Cross-Flow High Temperature Heat Exchanger (HT-HE) using Multiphysics Simulation

Heat-exchangers are devices used to transfer heat between two or more fluids and can be found in both heating and cooling processes. At high temperatures during operation, thermal induced stresses occur and can lead to the failure of the device. The Technische Hochschule Mittelhessen has, in cooperation with the company WK, started a research project for the development of a HT-HE, which is designed for operating temperatures up to 1100°C and the contact with aggressive chemical media. In order to develop an efficient HT-HE regarding the heat recovery, semi analytical calculations have been carried out to optimize the geometry of the heat exchanger. This study focusses on the validation of these semi-analytical calculations by using Multiphysics simulation. Due to the time costly simulation of transient fluid-structure-interactions (FSI) while taking high temperatures into account, special emphasis has been placed on the reduction of simulation time without losing accuracy. Initially, a number of simplified models were set up to control the bug-free operation of the relatively new ICFD-Solver. It has been shown that the necessary workarounds, due to some implementation errors, only had a minor effect on the heat transfer. Modifications have been added to the input data in order to significantly reduce simulation time without affecting the quality of results. The results of the simulations done with LS-DYNA show a qualitatively good correlation with the semi analytical calculations and improve the understanding of the thermo- and fluid dynamic processes inside the HT-HE during operation.