Accurate low-order dynamic model of a compact plate heat exchanger

摘要

This paper deals with the derivation of a low-dimensional mathematical model of a compact plate heat exchanger capturing the significant nonlinearities and the essential dynamic behavior in an accurate way. Thereby, the model is based on the basic laws of thermodynamics and the similitude theory of Nußelt. It is shown that reasonable simplifications according to the specific design and the typical operating conditions of compact plate heat exchangers together with a semi-discretization of the spatial domain by means of the finite volume method provides a compact finite-dimensional approximation of the underlying partial differential equations (pdes). In this context, two different interpolation schemes of the finite volume method are compared, i.e. a classical upwind scheme and a new concept based on an approximate stationary solution of the underlying pdes. The latter ensures high accuracy even for very low-order discretizations, which is shown by means of simulation and measurement results.