Ain Shams Engineering Journal (Dec 2021)
Irreversibility analysis in natural bio-convective flow of Eyring-Powell nanofluid subject to activation energy and gyrotactic microorganisms
Abstract
The developing interest in thermal engineering and nano-technology presented the idea of nanoparticles with enhanced thermal mechanisms and attained convinced novel applications in heat transportation systems, solar energy, micromechanics, air conditioning systems, cooling and heating facilities, bio-medical applications like cancer treatment, artificial heart surgery etc. Beside this, the phenomenon of entropy generation is another fascinating research area which used to improve the assessment of heat transportation with optimized procedure. The entropy generation in bio-convective flow of Eyring-Powell nanofluid over permeable stretched surface of cylinder is scrutinized in this research. The effects of magnetic field, thermal radiation and viscous dissipation are considered. Concentration communication is obtained in view of activation energy associated with binary chemical reaction. Furthermore, properties of Brownian diffusion and thermophoresis of nanoparticles are accounted. Suspended nanoparticles are made stable through mutual effects of bioconvection and buoyancy forces. Total entropy generation rate is modeled through second thermodynamics law. The governing flow model is obtained with the help of boundary layer approximations. Dimensional model is transformed into non-dimensional one by transformations and then tackled by Newton built-in shooting procedure. Impact of different influential variables on entropy generation, velocity, temperature, concentration, Bejan number and motile density of microorganisms are analyzed via graphs. Numerical values of skin friction coefficient, density, Sherwood and Nusselt numbers are tabulated and examined. Major findings are listed at the end. Since this analysis is based on theoretical flow assumptions, therefore the flow parameters specify the constant range like 0.0⩽Γ⩽6.0, 1.0⩽γ⩽4.0, 0.1⩽Ha⩽1.2, 0.2⩽λ⩽0.6,0.2⩽Rd⩽1.7, 0.1⩽K⩽3.0, 0.1⩽Pr⩽4.5, 0.3⩽Nb⩽1.8, 0.2⩽Nt⩽1.7, 0.0⩽E1⩽1.0, 1.0⩽Ec⩽4.0, 0.2⩽σ⩽1.4, 0.4⩽Sc⩽1.7, 1.0⩽δ⩽2.5, 0.5⩽Pe⩽2.0, 0.5⩽Ω°⩽2.0, 0.1⩽Br⩽1.0,0.1⩽Lb⩽1.5. The results show that fluid velocity decreases with curvature parameter and porosity constant. A decreasing variation in nanofluid temperature due to curvature parameter is examined. The entropy generation and Bejan number decline Brinkman number, motile density diffusion parameter and mass concentration diffusion variable. Furthermore, it is observed that skin friction coefficient increases with curvature parameter and porosity constant.
