<p>Tapered conical pores are widely applied in thermal management materials owing to their superior flow and heat transfer performance. 3D printing enables the precise fabrication of complex porous structures and supports quantitative research on the relationship between structural features and heat transfer properties. Previous studies have confirmed that heat transfer performance can be regulated by porous architectures with uniform cross sections. This work quantitatively investigates the tunable heat convection of 3D-printed polylactic acid containing non-uniform tapered conical pores by adjusting pore diameter and pore density. Combustion-related parameters are acquired through experiments and further verified via the fire dynamics simulator (FDS). A Nusselt (Nu) number model considering mixed forced and natural convection is established by integrating cone calorimeter and FDS data to evaluate convection efficiency. The results show that when the pore diameter increases from 2 to 10&#xa0;mm, the fire growth index (FGI) rises from 0.013 to 0.043&#xa0;kW&#xa0;m⁻²&#xa0;s⁻¹, and the corresponding Nu increases from 92.41 to 455.73. Similarly, reducing the pore density from 6 pores per inch (PPI) to 2 PPI causes the FGI to grow from 0.02 to 0.041&#xa0;kW&#xa0;m⁻²&#xa0;s⁻¹, with the <i>Nu</i> increasing from 101.76 to 475.21. Tapered conical pores generate internal vortex flow and boost convection efficiency within the boundary layer; higher structural non-uniformity leads to a larger temperature gradient. This study quantifies the tunability of heat convection by correlating pore structural parameters with the Nu, which can be precisely regulated from 92.41 to 455.73 via tuning pore diameters of 2–10&#xa0;mm, and from 101.76 to 475.21 via adjusting pore density of 2–6 PPI. This work provides a reliable strategy for conical pore structural optimization and active heat convection regulation and offers quantitative references for designing high-performance thermal management materials.</p>