Irreversibility analysis of nanofluid flow in a vertical microchannel with the influence of particle shape

Author(s):  
S Sindhu ◽  
BJ Gireesha

Augmentation of thermal performance in heat transfer system has become research hotspot nowadays. Numerous techniques are carried out to pick up the effective heat transport mechanism for designing high efficient thermal frameworks which has extensive practical uses in industrial process. In the current study, mixture model has been implemented for better describing the characteristics of nanoparticles in a vertical microchannel. The nondimensional equations are computed by using Runge Kutta Fehlberg method. Effect of heat source, buoyancy force and convective boundary on the thermal system has been demonstrated. The role of spheroidal nanoparticles on thermal conductivity of the conventional fluid has been examined. The causes of irreversibilities in a microchannel due to nanoliquid flow has been reported in the current research work. It is obtained that Aluminum foam has higher thermal field compared to Al2 O3. Entropy generation is reduced by lowering Eckert number and Grashof number. It is explored that nanofluid containing oblate shaped nanoparticels has higher thermal conductivity ratio.

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 697 ◽  
Author(s):  
Milad Sadeghzadeh ◽  
Heydar Maddah ◽  
Mohammad Hossein Ahmadi ◽  
Amirhosein Khadang ◽  
Mahyar Ghazvini ◽  
...  

In this paper, an artificial neural network is implemented for the sake of predicting the thermal conductivity ratio of TiO2-Al2O3/water nanofluid. TiO2-Al2O3/water in the role of an innovative type of nanofluid was synthesized by the sol–gel method. The results indicated that 1.5 vol.% of nanofluids enhanced the thermal conductivity by up to 25%. It was shown that the heat transfer coefficient was linearly augmented with increasing nanoparticle concentration, but its variation with temperature was nonlinear. It should be noted that the increase in concentration may cause the particles to agglomerate, and then the thermal conductivity is reduced. The increase in temperature also increases the thermal conductivity, due to an increase in the Brownian motion and collision of particles. In this research, for the sake of predicting the thermal conductivity of TiO2-Al2O3/water nanofluid based on volumetric concentration and temperature functions, an artificial neural network is implemented. In this way, for predicting thermal conductivity, SOM (self-organizing map) and BP-LM (Back Propagation-Levenberq-Marquardt) algorithms were used. Based on the results obtained, these algorithms can be considered as an exceptional tool for predicting thermal conductivity. Additionally, the correlation coefficient values were equal to 0.938 and 0.98 when implementing the SOM and BP-LM algorithms, respectively, which is highly acceptable.


Author(s):  
C. Claire Thomson

The first book-length study in English of a national corpus of state-sponsored informational film, this book traces how Danish shorts on topics including social welfare, industry, art and architecture were commissioned, funded, produced and reviewed from the inter-war period to the 1960s. For three decades, state-sponsored short filmmaking educated Danish citizens, promoted Denmark to the world, and shaped the careers of renowned directors like Carl Th. Dreyer. Examining the life cycle of a representative selection of films, and discussing their preservation and mediation in the digital age, this book presents a detailed case study of how informational cinema is shaped by, and indeed shapes, its cultural, political and technological contexts.The book combines close textual analysis of a broad range of films with detailed accounts of their commissioning, production, distribution and reception in Denmark and abroad, drawing on Actor-Network Theory to emphasise the role of a wide range of entities in these processes. It considers a broad range of genres and sub-genres, including industrial process films, public information films, art films, the city symphony, the essay film, and many more. It also maps international networks of informational and documentary films in the post-war period, and explores the role of informational film in Danish cultural and political history.


2002 ◽  
Author(s):  
Julaporn Kaenton ◽  
Victoria Timchenko ◽  
Mohammed El Ganaoui ◽  
Graham de Vahl Davis ◽  
Eddie Leonardi ◽  
...  

2020 ◽  
Vol 10 (5) ◽  
pp. 602-609
Author(s):  
Adil H. Awad

Introduction: A new approach for expressing the lattice thermal conductivity of diatomic nanoscale materials is developed. Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries, point defects and other phonons via normal and Umklapp processes. Methods: A comparative study of the results of the present analysis and those obtained using Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering relaxation rate. The formulas derived from the correction term are also presented, and their difference from Callaway model is evident. Furthermore their percentage contribution is sufficiently small to be neglected in calculating lattice thermal conductivity. Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity with that of the experimental observation.


2020 ◽  
Vol 07 ◽  
Author(s):  
Jyotsna S. Meshram ◽  
Devendra S. Raghuvanshi

Abstract:: Now days, it is of utmost important to design synthetic methods; which can be utilized for the generation of substances that will minimize toxicity to health of human and the environment. The utilization of acid catalysts generates lots of corrosive and harmful wastes which has to be treated with appropriate alkalis. Hence, it generates lots of sludge and alarms environmental issues of its storage and disposal. Zeolites and Zeotypes; by virtue of their peculiar properties; such as specific morphology, porosity and residing acidity; attracting enormous attention as they replaces harmful acid catalysts efficiently and also reduces chemical waste in industrial process; Hence emerged as new plethora in the field of “Green Chemistry”.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 572
Author(s):  
Ching-Jenq Ho ◽  
Shih-Ming Lin ◽  
Chi-Ming Lai

This study explores the effects of pipe wall properties (thermal conductivity k and wall thickness tw) on the heat transfer performance of a rectangular thermosyphon with a phase change material (PCM) suspension and a geometric configuration (aspect ratio = 1; dimensionless heating section length = 0.8; dimensionless relative elevation between the cooling and the heating sections = 2) that ensures the optimum heat transfer efficiency in the cooling section. The following parameter ranges are studied: the dimensionless loop wall thickness (0 to 0.5), wall-to-fluid thermal conductivity ratio (0.1 to 100), modified Rayleigh number (1010 to 1011), and volumetric fraction of PCM particles (0 to 10%). The results show that appropriate selection of k and tw can lead to improved heat transfer effectiveness in the cooling section of the PCM suspension-containing rectangular thermosyphon.


2019 ◽  
Vol 52 (48) ◽  
pp. 485302 ◽  
Author(s):  
Dong-Xing Song ◽  
Yu-Feng Zhang ◽  
Wei-Gang Ma ◽  
Xing Zhang

Author(s):  
R C Segundo ◽  
P R English ◽  
G Burgess ◽  
S A Edwards ◽  
O MacPherson ◽  
...  

The role of stockmanship in relation to the wellbeing of farm animals has been emphasised in the UK Codes of Recommendations for the Welfare of Farm Livestock (MAFF, 1983). Moreover, previous research work has demonstrated important effects of good and bad stockmanship not only on welfare but also on growth, lactational and reproductive performance of pigs and other farm livestock (Hemsworth et al, 1987). There is a need, therefore, to establish the factors which motivate and demotivate stockpeople since the degree of job satisfaction is likely to have a considerable influence on the attitude and performance of stockpeople and on their empathy with the animals in their care. With this objective in mind, a questionnaire was designed to investigate the aspects which could have an influence on the job satisfaction of the stockpeople involved in pig production.


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