Determination Of Thermal Conductivity Of Local Insulating Materials

Jurnal Teknologi ◽

10.11113/jt.v2.668 ◽

1981 ◽

pp. 31-40

Author(s):

K.S. Kannan

Keyword(s):

Thermal Conductivity ◽

Experimental Methods ◽

Hot Plate ◽

Insulating Materials ◽

Guarded Hot Plate ◽

Experimental Rig ◽

Actual Test

Tujuan pengajian ini adalah untuk menentukan nilai kealiran haba bagi bahan-bahan penebat tempatan. Olih kerana kealiran haba hanya boleh diperolehi dengan cara ujikaji, satu radas ujikaji yang dikenali sebagai 'guarded hot plate' telah direkakan di dalam makmal. Kealiran haba bagi empat bahan-bahan penebat tempatan ditentukan dengan menggunakan radas tersebut. Keputusan yang didapati adalah agak memuaskan. Bagaimanapun, ada terdapat sedikit kekurangan dalam radas dan pada ujian yang telah dilaksanakan. The aim of this study is to determine the thermal conductivity of locally available insulating materials. Since the thermal conductivity can only be obtained by experimental methods, an experimental rig known as the guarded hot plate was fabricated in the laboratory. The thermal conductivity of four locally available insulating materials was determined using this apparatus. The results obtained were acceptable. However the apparatus and the actual test had a few short comings.

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AAC 11.2 Determination of the thermal conductivity of AAC using guarded hot-plate apparatus

RILEM Technical Recommendations for the testing and use of construction materials ◽

10.1201/9781482271362-103 ◽

1994 ◽

pp. 430-430

Keyword(s):

Thermal Conductivity ◽

Hot Plate ◽

Guarded Hot Plate ◽

Plate Apparatus

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Determination of Radiative Thermal Conductivity in Needlepunched Nonwovens

Journal of Engineered Fibers and Fabrics ◽

10.1177/155892500800300406 ◽

2008 ◽

Vol 3 (4) ◽

pp. 155892500800300 ◽

Cited By ~ 4

Author(s):

Rahul Vallabh ◽

Pamela Banks-Lee ◽

Massoud Mohammadi

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Extinction Coefficient ◽

Dominant Mode ◽

Hot Plate ◽

Guarded Hot Plate ◽

Ftir Spectrometer ◽

Radiative Thermal Conductivity

Radiation heat transfer is found to be the dominant mode of heat transfer at temperatures higher than 400–500K [11]. Convection heat transfer being negligible in nonwovens, effective thermal conductivity is given by the sum of its conduction and radiation components. In this research two methods were identified to determine radiative thermal conductivity of needlepunched samples made from Nomex fibers. The first method involved the determination of radiative thermal conductivity using effective (total) thermal conductivity determined using a Guarded Hot Plate (GHP) instrument. In the second method radiative thermal conductivity was estimated using the extinction coefficient of samples. The extinction coefficient was determined by using direct transmission measurements made using a Fourier Transform InfraRed (FTIR) spectrometer. Results confirmed that radiation was the dominant mode of heat transfer at temperatures higher than 535 K. The conduction component of effective thermal conductivity did not change much in the range of densities tested. Empirical models for predicting the temperature difference across thickness of the fabric and the radiative thermal conductivity with R-square values of 0.94 and 0.88 respectively showed that fabric density, fabric thickness, fiber fineness, fiber length, mean pore size and applied temperature were found to have significant effect on the effective thermal conductivity and its radiation component. Though a high correlation between the results of Method 1 (Guarded Hot Plate) and Method 2 (FTIR) was not seen, the absorbance measurements made using the FTIR spectrometer were found to have significant effect on the radiative thermal conductivity.

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