thermal diffusivity การใช้

• In a sense, thermal diffusivity is the measure of thermal inertia.
• Where \ kappa \; is the thermal diffusivity.
• The higher the thermal diffusivity of the sample, the faster the energy reaches the backside.
• The great benefit of this device is that it measures both thermal diffusivity and volumetric heat capacity.
• The thermal diffusivity of air is about K = 1.9 * 10-5 m2 / s.
• The thermal diffusivity is calculated to be 0.0105 ft 2 / h or 2.72x10  " 7 m 2 / s.
• In thermal diffusivity of a substance, k is its thermal conductivity, \ rho is its density and C _ P is its heat capacity.
• For thermal convection due to heating from below, as described in the boiling pot above, the equation is modified for thermal expansion and thermal diffusivity.
• By recording temperature vs . time response in the sensor, the thermal conductivity, thermal diffusivity and specific heat capacity of the material can be calculated.
• In a substance with high thermal diffusivity, heat moves rapidly through it because the substance conducts heat quickly relative to its volumetric heat capacity or'thermal bulk '.
• So the flash-pulse analysis does not only detect the presence of defects but also determine their depth under the surface if a thermal diffusivity of the sample is known.
• The thermal diffusivity of the base material plays a large role & mdash; if the diffusivity is high, the material cooling rate is high and the HAZ is relatively small.
• The "'laser flash analysis "'or "'laser flash method "'is used to measure thermal diffusivity of a multiplicity of different materials.
• In the energy balance this is replaced by thermal diffusivity \ alpha = { k / \ rho C _ P }, and by mass diffusivity D _ { AB } in the mass balance.
• A state-of-the-art laser flash apparatus ( "'LFA "') to measure thermal diffusivity over a broad temperature range, is shown on the right hand side.
• Needles 1 and 2 work in conjunction to measure salts in the regolith, heat the soil to measure thermal properties ( thermal conductivity, specific heat and thermal diffusivity ) of the regolith, and measure soil temperature.
• As a result the thermal diffusivity in most solids can be estimated as the speed of sound in the material ( typically a few km / s ) times the phonon mean free path ( typically several angstroms ).
• 11 . " INVESTIGATION OF THERMAL DIFFUSIVITY-MICROHARDNESS CORRELATION EXTENDED TO SURFACE-NITRURED STEEL USING BOUBAKER POLYNOMIALS EXPANSION ", Modern Physics Letters B, Volume : 22, Issue : 29 ( 2008 ) pp . 2893  2907
• Where \ alpha is the thermal diffusivity and D is the mass diffusivity, \ lambda is the thermal conductivity, D _ { im } the mixture-averaged diffusion coefficient, and c _ p the specific heat capacity at constant pressure.
• Here, h is the thickness of the oceanic mantle lithosphere, \ kappa is the thermal diffusivity ( approximately 10  " 6 m 2 / s ) for silicate rocks, and t is the age of the given part of the lithosphere.