Effective thermal conductivity and thermal diffusivity of catalysts and their supports as functions of temperature in various gaseous media and in vacuum. II. Thermal conductivity and thermal diffusivity of granulated porous catalysts as functions of internal and external factors

1996 ◽  
Vol 69 (1) ◽  
pp. 120-127
Author(s):  
Kh. Madzhidov
Author(s):  
Masamichi Kohno ◽  
Koichi Kimura ◽  
Shogo Moroe ◽  
Yasuyuki Takata ◽  
Peter L. Woodfield ◽  
...  

Thermal conductivity and thermal diffusivity of CNT-nanofluids and Al2O3-nanofulids were measured by the transient short-hot-wire method. The uncertainty of their measurements is estimated to be within 1% for the thermal conductivity and 5% for the thermal diffusivity. Three different shapes of Al2O3 particles were prepared for Al2O3–water nanofluids. For the thermal conductivity of Al2O3-water nanofluids, there are differences in the enhancement of thermal conductivity for differences in particle shapes. Hardly any enhancement of thermal conductivity was observed for SWCNT-water nanofluids because the volume fraction of SWCNT was extremely low. However, we consider by increasing the volume fraction of SWCNTs, it will be possible to enhance the thermal conductivity.


Author(s):  
Siva Bhaskara Rao Devireddy ◽  
Sandhyarani Biswas

The utilization of natural fiber-reinforced polymer composites is rapidly increasing in many industrial applications and fundamental research. In this work, short banana-jute fiber-reinforced epoxy-based hybrid composite was prepared by varying the fiber loading (0–40 wt.%) and different weight ratios of banana and jute fiber (1:1, 1:3, and 3:1). The physical and thermal properties such as density, water absorption, thermal conductivity, specific heat and thermal diffusivity were evaluated as per ASTM standards. A new micromechanical model was developed for evaluating the effective thermal conductivity of short fiber-reinforced hybrid composites by using the law of minimal thermal resistance and equal law of specific equivalent thermal conductivity. The thermal conductivity was calculated numerically by using the steady state heat transfer simulations. The proposed model and numerical results were validated with the experimental results and analytical methods existing in the literature. The effective thermal conductivity was predicted with the proposed model, and the finite element method is in good agreement with the experimental values and observed an acceptable range of 0–6.5% and 0–11% error, respectively. The results reveal that the composite made with banana and jute in the weight ratio of 1:3 shows minimum void content, water absorption, thermal conductivity, and thermal diffusivity at all fiber loadings. The fabricated hybrid composites were suitable for building components and automobiles in order to reduce the energy consumption.


2006 ◽  
Vol 39 (12) ◽  
pp. 2592-2595 ◽  
Author(s):  
V Kishore ◽  
N S Saxena ◽  
Vibhav K Saraswat ◽  
Rakesh Sharma ◽  
Kananbala Sharma ◽  
...  

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