Simulation of gasketed-plate heat exchangers using a generalized model with variable physical properties

Abstract

In this article, we present a new generalized model for the steady-state simulation of gasketed-plate exchangers handling single-phase fluids with properties varying with temperature. The model is based on differential balance equations that are discretized using a finite-difference scheme. The set of equations of the proposed model can simulate gasketed-plate heat exchangers with any configuration, encompassing any number of passes for each stream and including the variation of the streams’ physical properties with temperature. The selection of a given configuration is provided by a set of model parameters, without the need to modify the system of equations. Comparisons of the simulation results with closed-form relations valid for an infinite number of plates and with a numerical solution indicate average differences equal to 0.17 % and 0.075 %, respectively. The comparison with experimental data available in the literature indicates mean deviations smaller than 2 °C. The analysis of the simulation results of a typical heat exchanger shows that the models usually employed in the design optimization problems, based on uniform physical properties, may present large departures from the results of our detailed modeling, based on varying properties with temperature, which for its nature is considered more accurate. Moreover, when used in a design, we show that uniform physical properties may yield exchangers that are either oversized or undersized as compared to the use of our model. Therefore, the capacity of the proposed model to provide more accurate simulation results for any gasketed-plate heat exchanger configuration using a unique set of equations is an important contribution to future works involving heat exchanger design optimization.