کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
658473 1458084 2013 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A new guarded parallel-plate instrument for the measurement of the thermal conductivity of fluids and solids
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
A new guarded parallel-plate instrument for the measurement of the thermal conductivity of fluids and solids
چکیده انگلیسی

A versatile guarded parallel-plate instrument for the measurement of the thermal conductivity in steady state is presented. The instrument stands out due to its applicability for fluids as well as solid bodies, bulk solids, and compressible solids. Besides flexibility regarding sample material and thickness, the instrument design is aimed at the minimization of parasitic heat flows due to convection, radiation, or heat leakages. Remaining effects of radiative heat transfer can be taken into account by appropriate calculation methods. A precise and automated measurement and control system for temperature and heat flow including objective criteria for identifying steady-state conditions allows convenient and accurate measurements. A comparison of results obtained for water, toluene, air, and a PTFE disk at temperatures between 308.15 K and 368.15 K with reference data confirms that uncertainties of less than 3% can be achieved by choosing adequate sample thicknesses and temperature differences between the plates. For compressible materials, the accessibility of the equivalent quantities overall heat transfer coefficient, overall thermal resistance, and apparent thermal conductivity in dependence on the degree of compression is demonstrated.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 58, Issues 1–2, March 2013, Pages 610–618
نویسندگان
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