Impact of non-uniform heat flux conditions on convective heat transfer and energy efficiency in a corrugated tube

Abstract

Many contemporary studies often overlook the reality of non-uniform heat generation in various modern heating devices by presuming uniform heat distribution, emphasizing the need for advancements in heat transfer methods. For this purpose, convective heat transfer through a two-dimensional corrugated tube was computationally analyzed for laminar flow region under different heating conditions. Uniform Heat Flux (UHF), Linearly Increasing Heat Flux (LIHF), Linearly Decreasing Heat Flux (LDHF), and Periodic Heat Flux (PHF) were considered on the corrugation wall. For the uniform heat flux condition, a constant heat flux of 1000 kW/m2 was applied while for non-uniform heat flux (NUHF), heat flux levels ranging from 50 to 2000 W/m2 with intervals of 50 kW/m2 were applied on the corrugation wall. The results demonstrate that various non-uniform heating conditions significantly affect the temperature profile and Nusselt number (Nu). LIHF and PHF configurations demonstrated a 35.8 % and 20.8 % enhancement in the maximum local surface Nusselt number, respectively, compared to UHF. Moreover, LIHF and PHF demonstrated an average improvement of 22 % and 7 % in average Nu, respectively, while LDHF showed an average reduction of 17 % in Nu at Re = 500. The pumping power and drag force remained constant (0.004 W/m and 4.3 N at Re = 800) for all the considered heating cases. The Thermal Hydraulic Performance (THP) were 1.22, 1.08, and 0.82 for LIHF, PHF, and LDHF, respectively in comparison to UHF, reflecting thermal and energy efficiency of non-uniform heating.

Keywords

• Non-uniform heat flux
• Corrugated tube
• Nusselt number
• Thermal hydraulic performance
• Enhancement percentages