Heat flux is a key concept in thermodynamics and heat transfer. It refers to the amount of heat energy passing through a unit area per unit time. Its international unit is watts per square meter (W/m²). Its physical meaning is to quantify the intensity of heat transfer, reflecting the efficiency and direction of heat flow in a system. It is a core indicator for analyzing heat transfer processes. Heat flux is directional and follows the basic law of "heat transfer from high temperature areas to low temperature areas." For example, when a high-temperature object dissipates heat to the surroundin