Steady state comparative-longitudinal heat flow method using specimen of different thicknesses for measuring thermal conductivity of lotus-type porous metals

Abstract

Articles you may be interested inA simple differential steady-state method to measure the thermal conductivity of solid bulk materials with high accuracy Rev. Sci. Instrum. 85, 025108 (2014); 10.1063/1.4865111 Simultaneous measurements of the specific heat and thermal conductivity of suspended thin samples by transient electrothermal method Rev. Sci. Instrum. 80, 064901 (2009);Lotus-type porous metal with many straight pores is attractive as a heat sink, because larger heat transfer capacity is obtained, owing to the small diameter of the pores. In order to use lotus-type porous metal effectively as a heat sink, it is important to clarify the effective conductivity and to consider the pore effect on heat conduction in the lotus-type porous metal. Because lotus-type porous metal is an anisotropic material, a steady state comparative-longitudinal heat flow ͑SCHF͒ method for thermal conductivity, referring to the ASTM standard, is thought to be better than a nonsteady method such as a laser flash method. This paper investigated the variable of the steady state comparative-longitudinal heat flow method by using specimens of different thicknesses ͑SCHF-DT͒ method for measuring the effective thermal conductivity. As a result, the uncertainty of effective thermal conductivity of a specimen was found to be smaller, as the diameter of a rod became larger and the length of a rod became shorter. In addition, it was found by error analysis that a dominant factor in the uncertainty of this method was the contact thermal difference between the rod and specimen.

International Round Robin Test of Thermoelectric Generator Modules

“…The most widespread technique is the so-called reference principle [ 61 , 62 , 63 ], which uses reference blocks as heat flow meters (HFM). Technical details and uncertainty sources of this measurement principle have been described extensively, but only for thermal conductivity measurements on material samples by the standard test method ASTM-E1225 [ 64 ] and within scientific publications [ 65 , 66 , 67 , 68 ]. Analogous to thermal conductivity measurement, used reference blocks are made from materials with known thermal conductivity and placed thermally in series to the TEM under test.…”

Cross-plane thermal conductivity and thermal diffusivity measurement in thin-films by one-dimensional thermal wave method

“…Assuming specimens with different thicknesses are measured and c is constant under the variety of L, s can be expressed as the gradient of total phase difference to L as: (10) In SCHF method [6][7][8][9] , a steady heat flux produces linear temperature change along the cylinder, so heat flux densities of the upper cylinder (q 1 )and that of lower cylinder (q 2 ) may be computed with known values of thermal conductivity ( Cu =401 Wm -1 K -1 at 300K [13] ) and temperature gradient (dT/dx) 1,2 detected by thermocouples as:…”

“…Several specimens (Such as Kapton [7] , Nafion [8] , porous metal [9] , et al) have been investigated by this technique. This method is also called steady state comparative-longitudinal heat flow method (SCHF), and the typical equipment mainly consists of two cylinders that are made of a standard material with known thermal conductivity.…”

Heat Transfer Performance of Lotus-Type Porous Copper Micro-Channel Heat Sink

“…The lotus-type porous copper [5,6] prepared by the metal-gas eutectic directional solidification method is a special kind of micro-channel structure with a higher thermal transfer ability, larger specific surface, smaller pore size. Compared with the traditional micro-channel structure, the lotus-type porous heat sinks have the following advantages: a) cylindrical straight pore with smooth wall; b) lower flow resistance; c) lower production costing.…”