Measurement of the effective thermal conductivity of particulate materials by the steady-state heat flow method in a cuvette

To measure the thermal conductivity of particle beds, a specially designed cuvette is inserted into the chamber of an ITP-MG4 device fitted with a vertical heat flux sensor. The cuvette with a transparent wall makes it possible to reduce the amount of test material to 25 cm3, to monitor visually the uniformity of a charge, to determine the bulk density of the particle bed (and to increase it if necessary using vibrocompaction) and to apply external pressure to the bed from 2.5 to 30 kPa. Using various continuous-solid and particulate materials as references, a calibration equation is obtained for thermal conductivity in the range of 0.03–1.1 W (m K)−1. To eliminate thermal contact resistance when measuring references, the end faces of glass specimens with a departure from flatness of up to 50 μm are wetted with water. To model the calibration, a calculation is carried out by the electrical circuit analogy. The calculated curve is close to the experimental points if a value for the contact thermal resistances r# = 2 × 10−3 m2 K W−1 is taken. Values of r# calculated by the Yovanovich model, based on the known roughnesses of the contact surfaces of the cuvette and the solid specimens, are an order of magnitude lower due to the decisive influence of nonflatness and not surface roughness at the low pressures used. The conditions under which our measurements were made are compared with the instructions of Russian, American and international standards for the measurement of thermal conductivity by the steady-state heat flow method (specimen size, flatness of working surfaces, etc). The sources of measurement inaccuracy and ways to improve the technique are examined.

[1]  A. Degiovanni,et al.  Thermal properties measurement of dry bulk materials with a cylindrical three layers device. , 2013, The Review of scientific instruments.

[2]  M. Yovanovich,et al.  Four decades of research on thermal contact, gap, and joint resistance in microelectronics , 2005, IEEE Transactions on Components and Packaging Technologies.

[3]  H. Ban,et al.  Compressive pressure dependent anisotropic effective thermal conductivity of granular beds , 2011 .

[4]  S. Chudzik.  Measuring system with a dual needle probe for testing the parameters of heat-insulating materials , 2011 .

[5]  J. Blum,et al.  Outgassing of icy bodies in the Solar System – II: Heat transport in dry, porous surface dust layers , 2011, 1111.0535.

[6]  Martin Schneebeli,et al.  Thermal conductivity of snow measured by three independent methods and anisotropy considerations , 2013 .

[7]  S. Kidalov,et al.  High thermal conductivity composite of diamond particles with tungsten coating in a copper matrix for heat sink application , 2012 .

[8]  A. Degiovanni,et al.  Measurement of the thermal conductivity of thin insulating anisotropic material with a stationary hot strip method , 2011 .

[9]  A. Boccara,et al.  A common path interferometer for testing the optical thickness of possibly birefringent transparent substrates , 2001 .

[10]  H. T. Aichlmayr,et al.  The effective thermal conductivity of saturated porous media , 2006 .

[11]  W. Martienssen,et al.  Springer handbook of condensed matter and materials data , 2005 .

[12]  M. Bonetti,et al.  A simply designed cell for thermal conductivity measurements of low vapor-pressure liquids. , 2011, The Review of scientific instruments.

[13]  Akira Nagashima,et al.  Viscosity and thermal conductivity of dry air in the gaseous phase , 1985 .

[14]  Juming Tang,et al.  PH—Postharvest Technology: Determination of Thermal Conductivity, Specific Heat and Thermal Diffusivity of Borage Seeds , 2002 .

[15]  C. Madhusudana.  Gap Conductance at the Interface , 2014 .

[16]  X. Hu,et al.  Ultralow thermal conductivity of nanoparticle packed bed , 2007 .

[17]  David Salmon,et al.  REVIEW ARTICLE: Thermal conductivity of insulations using guarded hot plates, including recent developments and sources of reference materials , 2001 .

[18]  Marc J. Assael,et al.  Standard Reference Data for the Thermal Conductivity of Water , 1995 .

[19]  Scott N. Schiffres,et al.  Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber. , 2011, The Review of scientific instruments.

[20]  Xiaotang Hu,et al.  Improving the accuracy of the transient plane source method by correcting probe heat capacity and resistance influences , 2013 .

[21]  E. Litovsky,et al.  Thermal conductivity of packed beds of refractory particles: Experimental results , 2005 .

[22]  S. Kidalov,et al.  Thermal conductivity of the diamond-paraffin wax composite , 2011 .

[23]  S. Min,et al.  Thermal characterization of liquids and pastes using the flash technique , 2007 .

[24]  H. Czichos,et al.  Springer Handbook of Metrology and Testing , 2011 .

[25]  A. V. Goryunov,et al.  Effective thermal conductivity of disperse materials. I. Compliance of common models with experimental data , 2013 .

[26]  A. V. Goryunov,et al.  Effective thermal conductivity of disperse materials. II. Effect of external load , 2014 .

[27]  R. Coquard,et al.  Adaptation of the FLASH method to the measurement of the thermal conductivity of liquids or pasty materials , 2009 .

[28]  E. G. Wolff,et al.  Prediction of thermal contact resistance between polished surfaces , 1998 .

[29]  Vlastimil Bohac,et al.  A step-wise method for measuring thermophysical parameters of materials , 2000 .

[30]  G. Kargl,et al.  Determination of the effective thermal conductivity of granular materials under varying pressure conditions , 2008 .