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Convective heat transfer, often referred to simply as convection, is the transfer of heat from one place to another by the movement of fluids. Convection is usually the dominant form of heat transfer in liquids and gases. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of unknown conduction and advection.
The process of convection is the main means of heat transfer within a fluid that is exposed to a heat source. Usually, the fluid, which can be a liquid or a gas, is heated from below by a warm surface; the increase in temperature results in a decrease in density, causing the fluid to rise and cooler fluid to flow inward to replace it.