Effect of heating surface size on critical heat flux in different-mode-interacting boiling inside narrow gaps for water

In this study, the effect of heating surface size (squares with 10–40 mm edges) on critical heat flux (CHF) when applying a novel method of different-mode-interacting boiling in narrow gaps in a water pool was investigated. Nonuniform heating plates with alternately arranged materials with high and low thermal conductances were applied under various material widths operated with different gaps. Significant enhancements in CHF were observed for the nonuniform heating surface compared to a uniform surface, along with a clear effect of the heating surface size on CHF. Furthermore, the effects of surface size, gap size, and material width on CHF were classified into two trends; decreasing the gap and increasing the surface size tended to monotonically decrease CHF, while the material width had an optimum value for maximizing CHF for each surface size and gap. Therefore, it has been shown that different-mode-interacting boiling was effective in improving CHF even when the surface size was increased.