The study of heat transfer and laminar flow of kerosene/multi-walled carbon nanotubes (MWCNTs) nanofluid in the microchannel heat sink with slip boundary condition

2017 ◽  
Vol 131 (2) ◽  
pp. 1553-1566 ◽  
Author(s):  
Abedin Arabpour ◽  
Arash Karimipour ◽  
Davood Toghraie
Author(s):  
Blake E. Jakaboski ◽  
Yogendra Joshi ◽  
Michael Rightley

A new type of microchannel heat sink has been developed and evaluated in this study. The device consists of silicon microchannels on whose bottom surfaces multi-walled carbon nanotubes are grown. The objective of the study is to investigate the effect of carbon nanotubes on the heat transfer characteristics. The heat sink size is 15 mm × 15 mm × 0.675 mm. It contains two microchannel designs. One consists of eight channels of cross section 682 μm × 50 μm; the other has six channels of cross section 942 μm × 50 μm. The heat sink is incorporated in an open loop flow facility, with water as the coolant. Six different configurations are compared. Two have no nanotubes, two have closely spaced nanotube, while the last two designs have widely spaced nanotubes. The tests utilize an infrared camera as well as thermocouples placed in the flow for characterization. The heat transfer characteristics are compared for the different cases.


2020 ◽  
Vol 68 ◽  
pp. 214-223 ◽  
Author(s):  
Weidong Yang ◽  
Xuehui Chen ◽  
Zeyi Jiang ◽  
Xinru Zhang ◽  
Liancun Zheng

2020 ◽  
Vol 274 ◽  
pp. 128043
Author(s):  
Shahir Hussain ◽  
Md. Mottahir Alam ◽  
Mohd Imran ◽  
Nasser Zouli ◽  
Abdul Aziz ◽  
...  

Author(s):  
Pratanu Roy ◽  
N. K. Anand ◽  
Debjyoti Banerjee

Investigation of fluid flow and heat transfer in rotating microchannels is important for centrifugal microfluidics, which has emerged as an advanced technique in biomedical applications and chemical separations. The pseudo forces namely the centrifugal force and the Coriolis force arising as a consequence of the rotating reference frame change the flow pattern significantly from the parabolic profile in a non-rotating channel. The convective heat transfer process is also influenced by the secondary flow introduced by the rotational effect. Moreover, if the microchannel wall is hydrophobic, slip flow can occur inside the channel when the conventional no slip boundary condition is no longer valid. In this work, we have numerically investigated the flow and heat transfer inside a straight rotating rectangular microchannel in the slip flow regime. A pressure based finite volume technique in a staggered grid was applied to solve the steady incompressible Navier-Stokes and energy equations. It has been observed that, depending on the rotational velocity, different slip velocities are induced at the channel walls. The average fluid temperature increases with the increase of rotation as convective heat transfer mechanism is increased due to the secondary flow. However, the slip boundary condition has a negligible effect on the temperature profiles.


Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 180 ◽  
Author(s):  
Bahaa Saleh ◽  
Lingala Syam Sundar

The heat transfer, friction factor, and collector efficiency are estimated experimentally for multi-walled carbon nanotubes+Fe3O4 hybrid nanofluid flows in a solar flat plate collector under thermosyphon circulation. The combined technique of in-situ growth and chemical coprecipitation was utilized to synthesize the multi-walled carbon nanotubes+Fe3O4 hybrid nanoparticles. The experiments were carried out at volume flow rates from 0.1 to 0.75 L/min and various concentrations from 0.05% to 0.3%. The viscosity and thermal conductivity of the hybrid nanofluids were experimentally measured at different temperatures and concentrations. Due to the improved thermophysical properties of the hybrid nanofluids, the collector achieved better thermal efficiency. Results show that the maximum thermal conductivity and viscosity enhancements are 28.46% and 50.4% at 0.3% volume concentration and 60 °C compared to water data. The Nusselt number, heat transfer coefficient, and friction factor are augmented by 18.68%, 39.22%, and 18.91% at 0.3% volume concentration and 60 °C over water data at the maximum solar radiation. The collector thermal efficiency improved by 28.09% at 0.3 vol. % at 13:00 h daytime and a Reynolds number of 1413 over water data. Empirical correlations were developed for friction factor and Nusselt number.


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