Optimization methodology for fin geometry on Pool-dry PDHR (Passive Decay Heat Removal system) to enhance air cooling using CFD

The system is called Pool-dry PDHR (Passive Decay Heat Removal system). Firstly, the heat exchangers are submerged in a water pool to deal with the high decay heat within 3 days because heat transfer rate in a pool boiling is effective. The air cooling method is totally passive and permanent way, so the decay heat can be removed even under the station blackout with a proper design of the Pool-dry PDHR. Optimization methodology for fin geometry is established using CFD simulation. Firstly optimum spacing is obtained because it has a unique value for our Pool-dry PDHR. Then, overall effectiveness correlation considering both of natural convection and radiation has been completed comparing with CFD results. Based on the correlation, overall effectiveness for various fin geometry can be estimated and it is utilized to design the Pool-dry PDHR. Furthermore, the optimization methodology presented in this study can be applied to other large scale vertical structure using fin to evaluate the enhancement of heat transfer.