Enhancement of Critical Heat Flux in Tight Rod Bundle with Wire Spacer

The experiment of CHF (critical heat flux) was conducted for water boiling two-phase flow in three-pin tight rod bundle. The effects of with and without wire spacers and the pitch to diameter ratio p/d on CHF were investigated under the conditions of mass flux range 250-430 kg/(m 2 ·s), inlet temperature from 70 °C to 92 °C and the pressure of 0.1 MPa. The CHF was enhanced by wire spacers in comparison with the results of CHF without wire spacers. The CHF was enhanced by reducing the p/d from 1.18 to 1.10 under the same flow rate condition, although it did not change appreciably with the change of p/d under the same mass flux condition.