Akademik Veri Yönetim Sistemi
International Journal of Heat and Mass Transfer, cilt.260, 2026 (SCI-Expanded, Scopus)
Interactions among liquid phase, vapor bubbles and geometrical structures along the flow path strongly affect thermo-fluidic mechanisms for flow boiling in micro-spaces. Therefore, in a micro-pin-finned system, layout of pin-fins has great potential for improvement of thermal performance in such systems. As a first investigation in literature, here, role of pin-fin layout on transient saturated flow boiling conditions being performed in expanding micro heat sinks under variable heating powers was conducted. Four different pin-finned heat sinks (PF1, PF2, PF3, PF4), one of which is the reference case (PF1, having uniform fin distribution), were tested for two mass velocities (159 and 256 kg m-2 s-1). For each experimental run, a variable heating power (147W, 252W, 195W, 290W, 147W) sequence was applied. Discussion was improved by flow images. Contribution of effective forces changes based on the pin-fin distribution, and this variation plays a critical role in flow boiling performance. Under both mass fluxes, at each heating power value, the highest values of htp (abbreviation of two-phase heat transfer coefficient) are obtained for PF4. For 147W and 159 kg s-1 m-2, the average htp of PF4 is approximately 85%, 41%, 45% higher than that calculated for PF1, PF2 and PF3, respectively. It is concluded that PF4 is the optimal choice. PF4 is distinctly superior in terms of heat transfer performance, provides the highest PEC value at low mass flux, and offers the second-highest PEC value at high mass flux, with a magnitude comparable to that of PF2.