Heat Flow

heat flow

[′hēt ‚flō]
(thermodynamics)
Heat thought of as energy flowing from one substance to another; quantitatively, the amount of heat transferred in a unit time. Also known as heat transmission.

Heat Flow

 

the amount of heat transferred across an isothermal surface in a unit time. Heat flow has the same dimensions as power and is measured in watts (W) or kilocalories per hour (kcal/hr); 1 W = 0.86 kcal/hr.

The amount of heat transferred across an isothermal surface of unit area in a unit time is called the heat flux. It is usually designated

Figure 1. Designs of recuperative heat exchangers: (a) coiled tubular heat exchanger, (b) double-pipe heat exchanger, (c) shell-and-tube heat exchanger, (d) tubular air heater, (e) plate-fin heat exchanger

by q and is measured in W/m2 or kcal/(m2·hr). Heat flux is a vector. The magnitude of any component of this vector is equal to the amount of heat transferred in a unit time across a surface of unit area perpendicular to the direction of the component. In English, the term “heat flux” is sometimes used in the sense of “heat flow.”

heat transfer

The flow of heat from one body at higher temperature to another body at a lower temperature, until the two temperatures are equal.
References in periodicals archive ?
The newly-developed double heat flow packaging technology can suppress the temperature increase of laser chip that accompanies laser beam output.
A large enough heat flow through Earth's interior can generate convection even when conductivity is high, he says.
Thermally insulated surfaces, that is surfaces with heat flow rate equaling to zero (fig.
epsilon]]--Effect of edge heat transfer: In general terms, the edge heat flow error is the distortion of one-dimensional heat flow through the specimen meter area due to heat flows at the periphery of the specimen.
The Modulated Differential Calorimeter enables one to distinguish between nonreversing heat flow curve (which corresponds to the heat extraction during curing) and reversing heat flow curve (which corresponds to the heat capacity of the sample).
The small gap between the glass layers creates a barrier to heat flow by conduction.
This allows for a larger diameter, narrower clutch, which improves heat flow from the friction surfaces to the atmosphere.
The product is primarily used to retard heat gain and control condensation drip from chilled water and refrigeration systems, in addition to reducing heat flow on hot systems.
Users are said to get more information out of a single measurement with combined TGA/DSC heat flow measurements.
Heat flow calculations in sedimentary basins are of prime importance.
This is not always true, of course, especially for multiple heat sources (as found on almost every PCB) where heat flow topologies for widely separated components can be quite independent of each other.