Entropy production and mixed convection within trapezoidal cavity having nanofluids and localised solid cylinder

Abstract

The entropy production and mixed convection within a trapezoidal nanofluid-filled cavity having a localised solid cylinder is numerically examined using the finite element technique. The top horizontal surface moving at a uniform velocity is kept at a cold temperature, while the bottom horizontal surface is thermally activated. The remaining surfaces are maintained adiabatic. Water-based nanofluids ($$\text {Al}_2\text {O}_3$$ Al 2 O 3 nanoparticles) are used in this study, and the Boussinesq approximation applies. The influence of the Reynolds number, Richardson number, nanoparticles volume fraction, dimensionless radius and location of the solid cylinder on the streamlines, isotherms and isentropic are examined. The results show that the solid cylinder’s size and location are significant control parameters for optimising the heat transfer and the Bejan number inside the trapezoidal cavity. Furthermore, the maximum average Nusselt numbers are obtained for high R values, where the average Nusselt number is increased by 30% when R is raised from 0 to 0.25.

Natural Convection Heat Transfer and Entropy Generation Analysis in Saltbox Roof under Summer Conditions

“…Alnaqi et al (2020) studied the natural convection and entropy generation in a cubical cavity and observed that total entropy fairly increased with an increase in Rayleigh number until a certain value, when it then rose significantly. Similar studies have also been carried out (Bondareva et al, 2017;Hussein et al, 2016;Yang et al, 2021;Zhang et al, 2021;Ishak et al, 2021;Oztop et al, 2017). Natural convection in Saltbox roof is analysed for a hot climate region, with the aim of helping designers improve the thermal comfort in such conditions.…”

Entropy generation and characteristics of mixed convection in lid-driven trapezoidal tilted enclosure filled with nanofluid

“…Similarly, the related dimensional quantities are expressed by u , v , T and p respectively. Reynolds number, Grashof number, Richardson number, and Prandtl number ( Pr ) are the non-dimensional governing parameters appeared respectively, which are defined by the following relations (6) as: The following relationships (7) – (10) can be used to determine the thermos-physical properties of the nanofluid (Al 2 O 3 -water) using mixing law theory [29] ,…”

“…Hence, extensive investigation on trapezoidal enclosure is required to build more effective heating and cooling systems in future. Only a few investigations in past focused on mixed convective flow in a lid-driven trapezoidal chamber [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] . All those studies along with geometric conditions (e.g., sidewall inclination angle, γ and tilt angle, θ ), working fluids, governing parameters (e.g., Ri , Re and Grashof number, Gr ) and numerical methods are summarized in Table 1 .…”

MHD Flow of a Hybrid Nano-Fluid in a Triangular Enclosure with Zigzags and an Elliptic Obstacle

“…Ravnik et al [37] studied natural convection in a cubic enclosure with a heated elliptical cylinder. Ishak et al [38] numerically analyzed entropy generation in a classic trapezoid filled with alumina/water nano-fluid and an implemented immobile circular cylinder using the finite element method. Mebarek-Oudina et al [39] studied the characteristics of a hybrid nano-fluid MHD flow in an annulus between a trapezoid and a rotating cylinder with a zigzagged wall.…”