Study and verification of the superposition method used for determining the pressure losses of the heat exchangers

¹ Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec 1, Czech Republic
² Faculty of Mechanical Engineering, Technical University of Liberec, Studentská 2, 461 17, Liberec 1, Czech Republic
³ Faculty of Mechanical Systems Engineering, Conestoga College, 299 Doon Valley Drive, Kitchener Ontario, Canada.

^a Corresponding author: michal.petru@tul.cz

Published online: 6 May 2015

Abstract

This paper deals with study of the pressure losses of the new heat convectors product line. For all devices connected to the heating circuit of the building, it‘s required to declare a tabulated values of pressure drops. The heat exchangers are manufactured in a lot of different dimensions and atypical shapes. An individual assessment of the pressure losses for each type is very time consuming. Therefore based on the resulting data of the experiments and numerical models, an electronic database was created that can be used for calculating the total values of the pressure losses in the optionally assembled exchanger. The measurements are standardly performed by the manufacturer Licon heat hydrodynamic laboratory and the numerical models are carried out in COMSOL Multiphysics. Different variations of the convectors geometry cause non-linear process of energy losses, which is proportionately about 30% larger for the smaller exchanger than for the larger types. The results of the experiments and the numerical simulations were in a very good conjuncture. Considerable influence of the water temperature onto the total size of incurred energy losses has been proven. This is mainly caused by the different ranges of the Reynolds number depending on the viscosity of the used liquid. Concerning to the tested method of superposition, it is not possible to easily find the characteristic values appropriate for the each individual components of the heat exchanger. Every of the components behaves differently, depend on the complexity of the exchanger. However, the correction coefficient, depended on the matrix of the exchanger, that is suitable for the entire range of the developed product line has been found.