– Transferred from de.wikipedia to Commons. “Convection-snapshot” – original uploader was Harroschmeling at German Wikipedia. “Heat Flux.” Science Direct, Available here. The key difference between heat flow and heat flux is that heat flow refers to the generation, use, conversion and exchange of thermal energy between physical systems, whereas heat flux refers to the flow of energy per unit of area per unit of time. Since nuclear fuel consists of fuel rods, the heat flux is defined in units of W/cm (local linear heat flux) or kW/rod (power per fuel rod). In nuclear reactors, limitations of the local heat flux are of the highest importance for reactor safety. Note that heat flux may vary with time and position on a surface.

The unit of heat flux in English units is Btu/hft 2. Heat flow and heat flux are related terms in physical chemistry. The average heat flux is expressed as: where A is the heat transfer area. The key difference between heat flow and heat flux is that heat flow refers to the mass flow of the fluid, whereas heat flux refers to the flow of energy per unit of area per unit of time.īelow is a summary of the difference between heat flow and heat flux in tabular form. The terms heat flow and heat flux are important concepts in physical chemistry regarding the behaviour and interchange of thermal energy between physical systems. What is the Difference Between Heat Flow and Heat Flux? Sometimes, the flow of the fluid occurs due to an external process or due to buoyancy forces that are caused due to the thermal energy expansion of the fluid. Heat convection is the other common type of heat flow where a bulk flow of a fluid carries heat along with the mass flow of the fluid. In this type of heat flow, when a body is in a different temperature from another body or from the surrounding, heat flows from high temperature to low temperature until a thermal equilibrium occurs. Heat conduction is the most common type of heat flow that involves a direct microscopic interchange of the kinetic energy of particles via the boundary between two systems. Let us understand some of these mechanisms in detail.

These mechanisms have different characteristic features, and they often occur simultaneously in the same system. We can classify this concept into various mechanisms as thermal conduction, thermal convection, thermal radiation and heat flow through phase changes. Heat flow or heat transfer is the generation, use, conversion, and exchange of thermal energy between physical systems. Side by Side Comparison – Heat Flow vs Heat Flux in Tabular Form The key difference between heat flow and heat flux is that heat flow refers to the exchange of thermal energy between physical systems, whereas heat flux refers to energy flow between physical systems per unit of area per unit of time.

Heat flux equation