Studentische Arbeit: Design improvement of the inlet plenum for a plate-fin heat exchanger to optimise the inflow characteristics of CO2 close to the critical point

5. November 2021

Objective:

The main objective is to optimise the inlet and outlet plenums of the heat exchanger in order to achieve a uniform flow distribution into the channels and to minimise pressure losses, considering the working fluid CO2 in subcritical and supercritical state.

Background:

Since the accidents in the boiling water reactors in Fukushima Dia-ichi, the removal of decay heat became a main part of the reactor safety research. For this reason, a new concept has been developed over the last years for decay heat removal. This concept is a sCO2-operated decay heat removal system based on a Brayton cycle.

The sCO2-4-NPP project, intends to bring this heat removal system closer to the market. The system mainly consists of a heat exchanger at the heat source, a turbo-compressor system and a heat exchanger at the ultimate heat sink (ambient air). Since the system is a self-sufficient thermodynamic cycle that starts automatically with supplied heat the minimisation of pressure drop for each cycle component plays an important role. The company FIVES Cryo developed plate-fin heat exchangers with supercritical CO2 as a working fluid for the heat sink. To ensure maximum use of the heat transfer surface of the heat exchanger, a uniform flow distribution through the channels is required. By optimising the plenum geometry, the flow distribution in the channels should be improved while minimising pressure drop. Since the CO2 can occur in both subcritical and supercritical states within the heat exchanger, the simulations should take both states into account.

 

Approach:

  • Familiarisation with plena design and non-uniform flow distribution in heat exchangers.
  • Compilation of potential inlet plenum geometries.
  • Simulation of the flow in the inlet plenum and analysis of the flow distribution.
  • Optimisation of plena designs and comparison.
  • Elaboration and presentation of the results.

Conditions:

  • Ability to work independently and self-motivation.
  • Interest in supercritical fluids and numerical simulations .

Good English reading and writing / good German speak

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Dieses Bild zeigt Konstantinos Theologou

Konstantinos Theologou

M.Sc.

Wissenschaftlicher Mitarbeiter / Doktorand

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