## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### A novel coupling discretization method for modeling multi-phase heat exchangers

**ABSTRACT**

This paper presents a novel coupling discretization method for modeling multi-phase heat exchangers. In the method, the MBM (Moving Boundary Method) is adopted as the solver to solve each of the FVCVs (Finite Volume Control Volume) divided by the method of FVM (Finite Volume Method). When all FVCVs are solved, the FVCV boundary values are updated based on the relationships of FVCVs. The solving procedure is initiated when the starting values of HSF (Hot Source Fluid) and CSF (Cold Source Fluid) outlet of the heat exchanger are given by the user and terminated when these values no longer change anymore. The experimental results of a plate heat exchanger with R245fa and Therminol 66 as CSF and HSF are adopted to validate the proposed model. Simulation results of 11 operating conditions show that the maximum deviation is within ±4% compared to the measured values. The model presented in this paper is appropriate for heat exchangers under operating conditions either with or without fluid phase change, such as the evaporator and condenser in the ORC (Organic Rankine Cycle) system.

**KEYWORDS**

PAPER SUBMITTED: 2022-09-09

PAPER REVISED: 2023-01-09

PAPER ACCEPTED: 2023-01-13

PUBLISHED ONLINE: 2023-03-11

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