Research And Improvement On Uniformity Of Inflow Of Fan Coil Unit In Containment Cooling System

Containment cooling unit system is an important part of nuclear power plant.It is significant for the safety and economy of the whole nuclear power generating unit.The fan coil unit is the important part for cooling unit that affects the efficiency of the unit.The heat transfer performance of the fan coil directly affects the working efficiency of the unit.How to improve the air inlet of the fan coil unit of the containment cooling unit by improving the inlet air uniformity of the windward side is important.First of all,in this paper,the fan coil of the three generation nuclear motor group is the research object.The uniformity of inflow of fan coil unit in containment cooling system was studied quantitatively by numerical simulation and experimental measurement in this paper.The flow field in fan-coil unit was analyzed by numerical calculation.The inlet velocity data of 50 points on the windward face of the fan-coil unit were obtained by experimental measurement.Then,the quantitative research method for the uniformity of the inlet air of the fan coil is proposed.The data from the measurement and thecalculation were processed by using the definition of “ Face Velocity Uniformity” and “Relative Standard Deviation”.The processing results evaluated quantitatively the uniformity of inflow of fan coil unit.The results of “Face Velocity Uniformity” didn't meet the requirements of GB/T 14294 — 2008 for not less than 80%.The results of “ Relative Standard Deviation”exceeded the requirement that the value was usually less than 15%.Finally,the improvement scheme was to install baffle with different angle in the vertical direction.The angles in the vertical direction in different scheme were 30 degrees,45 degrees and 60 degrees.The flow of the fan coil with different improvement scheme was numerical simulated and experimental measurement.The value of “Face Velocity Uniformity” in the flow of the fan coil using the improvement scheme of installing baffle with 30 degree in the vertical direction was 86%.It met the requirements,not less than 80%,stipulated in the national standard GB/T14294-2008.The result of "Relative Standard Deviation" is11.78% and the result of the experiment is 12.03%,which satisfies the requirement of relative standard deviation.