Eur. Phys. J. Plus (2021) 136: 1062
https://doi.org/10.1140/epjp/s13360-021-02072-w

Regular Article

Numerical investigation of mixed convection of nanofluid flow in oblique rectangular microchannels with nanofluid jet injection

¹ Department of Mechanical Engineering, Aligudarz Branch, Islamic Azad University, Aligudarz, Iran
² Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
³ Young Researchers and Elite Club, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Iran
⁴ Department of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran
⁵ Department of Chemical Engineering, University of Toledo, 43606, Toledo, OH, USA
⁶ Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Iran

^f Toghraee@iaukhsh.ac.ir

Received: 11 September 2021
Accepted: 14 October 2021
Published online: 22 October 2021

Abstract

In the present numerical study, the effect of microchannel flow with the angle of fluid jet injection is investigated. This paper aims to investigate the hydrodynamic behavior of flow and heat transfer for mixed convection in a two-dimensional rectangular microchannel with an angle of attack of 0°–180°. Water/SWCNT nanofluids are used as the cooling fluid with different volume fractions. The results of this study show that due to heat exchange between hot and cold sources, the thermal boundary layer is unavoidable. In all temperature graphs, with increasing Reynolds number, due to fluid momentum amplification, the thermal boundary layer is significantly reduced and the injection effects for the cooling fluid become important. Temperature distribution between fluid layers, especially in areas close to the hot surface, is associated with significant gradients. At Re = 25, due to the slower movement of the fluid compared to Re = 100, the growth of the thermal boundary layer is significant and even affects the central areas of the microchannel. Increasing the mass flow rate of the coolant increases the velocity and improves the mixing of the fluid by further advancing the fluid toward the microchannel outlet. Among all of the studied cases, case (3) has the highest friction factor due to gravitational effects.