Metamorphic rock Metamorphic rock Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure ( or more), causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath
Enhanced heat transfer Enhanced heat transfer Heat exchangers were initially developed to use plain (or smooth) heat transfer surfaces. An Enhanced heat transfer surface has a special surface geometry that provides a higher thermal performance, per unit base surface area than a plain surface. This higher thermal performance, per unit base surface area A may be used to achieve one of the three objectives below: This increase in heat transfer capacity per unit volume comes at the expense of an increase in pressure drop across the heat exchanger. This pressure drop may be significant, so the heat transfer enhancement is often limited by