Heat transfer coefficient

The heat transfer coefficient, in thermodynamics and in mechanical and chemical engineering, is used in calculating the heat transfer, typically by convection or phase change between a fluid and a solid: From the above equation, the heat transfer coefficient is the proportionality coefficient between the heat flux, Q/, and the thermodynamic driving force for the flow of heat. The heat transfer coefficient has SI units in watts per meter squared-kelvin. Heat transfer coefficient is the inverse of thermal insulance. There are numerous methods for calculating the heat transfer coefficient in different heat transfer modes, different fluids, flow regimes, and under different thermohydraulic conditions. Often it can be estimated by dividing the thermal conductivity of the convection fluid by a length scale. The heat transfer coefficient is often calculated from the Nusselt number.