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The heat flow can be modelled by analogy to an electrical circuit where heat flow is represented by current, temperatures are represented by voltages, heat sources are represented by constant current sources, absolute thermal resistances are represented by resistors and thermal capacitances by capacitors.
Also called chordal or DC resistance This corresponds to the usual definition of resistance; the voltage divided by the current R s t a t i c = V I. {\displaystyle R_{\mathrm {static} }={V \over I}.} It is the slope of the line (chord) from the origin through the point on the curve. Static resistance determines the power dissipation in an electrical component. Points on the current–voltage ...
The thermal conductivity of a material is a measure of its ability to conduct heat.It is commonly denoted by , , or and is measured in W·m −1 ·K −1.. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity.
Assuming the element behaves as a perfect resistor and that the power is completely converted into heat, the formula can be re-written by substituting Ohm's law, =, into the generalized power equation: = = = / where R is the resistance.
A temperature distribution chart with Bi on the x-axis. The Biot number (Bi) is a dimensionless quantity used in heat transfer calculations, named for the eighteenth-century French physicist Jean-Baptiste Biot (1774–1862).
This value is different at every interface and is an important concept in understanding heat flow at an interface. The series solution can be analyzed with a nomogram . A nomogram has a relative temperature as the y coordinate and the Fourier number, which is calculated by Fo = α t L 2 . {\displaystyle {\textit {Fo}}={\frac {\alpha t}{L^{2}}}.}
Most experimentally determined values of the thermal contact resistance fall between 0.000005 and 0.0005 m 2 K/W (the corresponding range of thermal contact conductance is 200,000 to 2000 W/m 2 K). To know whether the thermal contact resistance is significant or not, magnitudes of the thermal resistances of the layers are compared with typical ...
Therefore, many materials that produce acceptable values of include materials that have been alloyed or possess variable negative temperature coefficient (NTC), which occurs when a physical property (such as thermal conductivity or electrical resistivity) of a material lowers with increasing temperature, typically in a defined temperature range ...