Flow and thermal characteristics of power-law fluids through a rectangular-shaped orifice: Effects of aspect ratio and orifice location

• Published in: International communications in heat and mass transfer 2024-03, Vol.152, p.107303, Article 107303
• Main Authors: Maurya, Anamika, Chhabra, Rajendra P.
• Format: Article
• Language: English
• Subjects: Discharge coefficient; Nusselt number; Power-law fluids; Rectangular orifice; Separation zones; Temperature distribution
• ISSN: 0735-1933; 1879-0178
• DOI: 10.1016/j.icheatmasstransfer.2024.107303

This work numerically studies the momentum and thermal characteristics of the power-law fluids flowing through a rectangular-shaped orifice fitted in a two-dimensional channel, over wide ranges of conditions: fluid behavior index, n (0.3–1.0), Reynolds number, Re (1–50), Prandtl number, Pr (10−100), aspect ratio, β (0.3–0.7) and three different locations of the orifice, Co (0.5–0.75). Extensive results have been analyzed in terms of streamlines, separation zones, discharge coefficient, isotherm contours, temperature profiles and local Nusselt number. Multiple separation zones are formed in downstream section depending upon the combinations of parameters, which, in turn, influence the discharge coefficient and the local Nusselt number. Separated flow regions formed on the bottom wall expand with increasing Reynolds number (Re), while it decreases with n and β and shows a complex dependence on Co. The local Nusselt number, NuL, observed herein which is found to be more pronounced at high Co and low n and β for the upper wall. Further, it bears an inverse relation with n, on both walls while a strong effect of orifice location, Co and aspect ratio, β is seen over the range of conditions spanned here. •Influence of orifice location on the flow and thermal characteristics of power-law fluids.•Effect of orifice aspect ratio on the momentum and heat transfer characteristics.•Discussion on the flow visualization and isotherm contours.•Demonstration of the orifice discharge coefficient.•Effect of orifice location and aspect ratio on the local Nusselt number.