Localized heat generation is common in high-power energy and electronic systems, yet its spatial interaction with engineered wettability remains poorly understood. Molecular dynamics simulations were conducted to examine explosive boiling of an argon liquid film over a mixed-wettability rectangular groove under four local heat-source configurations. Only the heat-source position was varied, while the groove geometry, wettability distribution, heating area, and thermal conditions were kept unchanged. A clear decoupling between bubble nucleation and liquid-film detachment was observed. Groove-bottom heating produced the earliest nucleation at approximately 108 ps but delayed detachment to about 5.5 ns. In contrast, outer-platform heating caused the latest nucleation at approximately 187 ps but triggered detachment within about 0.8 ns. Heat-source positioning altered thermal propagation, groove depletion, bubble-growth pathways, and interfacial energy transfer. Early detachment strongly limited subsequent heat input, whereas the long-term vapor-phase atom numbers remained comparable among the four cases. These results show that heat-source location governs bubble evolution and film motion more strongly than cumulative vaporization, providing guidance for coordinating localized heat sources with mixed-wettability structures in advanced thermal-management systems.

Coalescence-induced droplet jumping is a key mechanism for passive phase-change transport and energy-efficient liquid removal on superhydrophobic surfaces. While static droplet coalescence has been widely studied, the energy conversion behavior of moving droplets, especially under rolling motion, remains unclear at the nanoscale. In this work, molecular dynamics simulations are conducted to investigate the coalescence-induced jumping of translating and rolling nanodroplets over a range of Weber numbers. Results show that translational motion mainly compresses the coalescence timescale, while the dimensionless jumping velocity remains nearly constant due to the interfacial energy constraint on vertical kinetic energy. In contrast, rolling motion enhances vertical momentum establishment and modifies directional energy partitioning. Although the absolute vertical kinetic energy increases under rolling conditions, its conversion efficiency decreases with increasing initial velocity, while horizontal and total energy conversion efficiencies exhibit a rise-then-decline trend, indicating an optimal inertial regime. These findings elucidate how motion mode governs energy redistribution during droplet coalescence and provide nanoscale insight for improving energy-efficient phase-change transport.