Use of CFD Characterization of Discretized Heat Exchanger for Full-System Thermo-Hydraulic Analysis in Lumped-Parameters Simulation Environment

Functional analysis of hydraulic systems and thermal analysis of heat exchangers cooling power are usually carried out by means of separate numerical simulation techniques, viz. lumped-parameters "1-D" modelling for the former, CFD for the latter, and the interaction between the two is limited to system-wide parameters (e.g. global oil flow outputted by the 1-D analysis and used as input for CFD; global cooling power used the opposite way). In a previous research work a discretization technique was used to decompose heat exchangers in sub-domains, which were then characterized, in terms of pressure drop and WHTC, by means of CFD; these elements became the elementary blocks to be used by a custom-made algorithm to characterize exchangers of any size. The same decomposition is now reproduced in the AMESim simulation environment as a grid-connection of sub-domains, whose lumped parameters are those given by CFD, joining a detailed model of the hydraulic system. This way the heat exchanger thermal performances can be tested in simulation, both in steady-state and dynamically, against suitable system operation scenarios, providing at the same time information on the corresponding impact on system functionalities.