Microchannels are extremely small flow passages, typically referring to channel structures within the micrometer-scale range. These microchannels can be straight, curved, or have various shapes and geometries, but their defining characteristic is their very small size, typically ranging from micrometers (millionths of a meter) to millimeters (thousandths of a meter).

Microchannel technology finds extensive applications in the fields of science, engineering, and technology, particularly in areas such as microfluidics, heat transfer, biomedicine, and chemical reactions. Due to their high surface area-to-volume ratio, microchannels increase the contact area between fluid and solid surfaces, enabling higher efficiency in processes involving heat transfer, mass transfer, and reactions.