<p>Titanium alloys are widely used in aerospace and biomedical components due to their high strength-to-weight ratio and corrosion resistance. With the increasing adoption of additively manufactured titanium parts, micro-/meso-scale grinding has become essential for precision surface finishing. However, their low thermal diffusivity often causes intense local heating, resulting in tool wear and poor surface quality. To reduce excessive cutting-fluid consumption, environmentally friendly lubrication strategies such as minimum quantity lubrication (MQL) and electrospray lubrication (ESL) have gained attention. Despite this progress, most prior studies have mainly reported practical machining performance metrics (e.g., forces and surface roughness), while quantitative grinding-zone thermal metrics—such as interfacial heat flux, transient interface temperature, and energy partition—remain largely unavailable at the micro-scale where direct measurements are impractical. To address this gap, this study proposes an air-flow-assisted electrospray lubrication (AF-ESL) approach using a nanodiamond nanofluid for Ti-6Al-4V micro-grinding. An integrated experimental–CFD–inverse framework combining embedded thermocouple measurements, transient simulations, and regression-based inverse estimation was developed to reconstruct interfacial heat flux and temperature. Experiments were performed under pure AF-ESL and nanofluid-based AF-ESL with nanodiamond fractions of 0.2–1.4 wt%. The nanofluid AF-ESL reduced peak subsurface temperature by 16–20&#xa0;°C, tangential grinding force by 36–40%, and workpiece energy partition by up to 11.7% compared with pure AF-ESL. These reconstructed metrics indicate that nanodiamonds suppress interfacial heat generation and reduce the workpiece heat fraction through combined cooling–lubrication effects. The proposed workflow provides a quantitative basis for analyzing thermal behavior in microscale green grinding processes.</p> Graphical abstract <p></p>