Thermal hydraulic performance of the printed circuit heat exchanger in a helium test loop

The development of an Intermediate Heat Exchanger (IHX), transferring high temperature heat to a process heat application, is primarily important for the Gen IV VHTR. The IHX requires high structural integrity and reliability, high effectiveness and compactness with low pressure drop under high temperature and high pressure. The fanning factor, Nusselt number, and effectiveness in the PCHE were investigated in the KAIST helium test loop. The experiment was done in the laminar region with 350 < Re < 1200. The hot/cold side conditions were 25degC-550degC/25degC-100degC at the pressure conditions of 15-19bar. The mass flow rate ranged over 40 kg/h- 100 kg/h. It is found out that the pressure drop and heat transfer coefficients in the PCHE were enhanced. The correlation with the physical meaning of the product of fanning factor multiplied by the Reynolds number (fPCHE.Re) was developed and the empirical correlation of Nusselt number was proposed. The proposed correlations predicted (fPCHE.Re) and Nu within the ranges of 3% and 9.23%, respectively. The effectiveness of the KAIST PCHE was more than 95%. (author)