Experimental investigation on the flow CCD by analogically utilizing the CHF correlation

Abstract We simulated the critical heat flux (CHF) of flow boiling using the hydrogen evolution at a water electrolysis. Hydrogen bubbles were evolved at the cavities of the cathode surface just like the vapor bubbles in boiling. Critical current density (CCD) was reported similarly where the hydrogen film is formed on the cathode surface. The influences of mass flux and inclination on the CCD on a downward-facing surface were investigated, for which CHF data have not been sufficiently accumulated. The measured CCD increased as the mass flux increased and decreased as the inclination became more horizontal. The photographic analysis showed similar trends of the CCD and CHF conditions with respect to the test parameters. However, the superficial gas velocity at the CCD condition was lower than that at the CHF condition, and sensitivity of the mass flux on the CCD was also less than that of the CHF. A set of correlations were developed as the function of mass flux and inclination. The present work reveals the possibility of experimental simulation of the CHF condition using the CCD condition.