ABSTRACT

An experimental study was performed to determine the effect of angle of attack on the thermal-hydraulic performance of a cam-shaped tube with constant heat flux in crossflow. The Reynolds number based on an equivalent diameter was in the range of 15500 < $\mathrm{R}{\mathrm{e}}_{{\mathrm{D}}_{\mathrm{e}\mathrm{q}}}$< 42000, and the angle of attack (α) varied from 0° to 180°. For the heat transfer experiments, five different heat fluxes were considered, and the results showed that in all Reynolds numbers by increasing the angle of attack, the mean Nusselt number increases about 1–6% at α = 30°, 3–9% at α = 60° and 5–11% at α = 90° compared to the Nusselt number at $\alpha =0^{\circ }.$ Besides, the drag coefficient for these angles increased 40–53%, 105–109% and 114–122%, respectively compared to $\alpha =0^{\circ }$. In all Reynolds numbers, α = 0° and 150° had the lowest drag coefficient, which was 29–55% and 27–56% lower than other angles of attack. Also, the best thermal-hydraulic performance was achieved at α = 0° and 150°.

摘要

进行了一项实验研究，以确定迎角对横流中具有恒定热通量的凸轮形管的热工水力性能的影响。基于当量直径的雷诺数在 15500 <$\mathrm{R}{\mathrm{电子}}_{{\mathrm{丁}}_{\mathrm{电子}\mathrm{q}}}$< 42000，攻角 (α) 在 0° 到 180° 之间变化。对于传热实验，考虑了五种不同的热通量，结果表明，在所有雷诺数中，通过增加迎角，平均努塞尔数在 α = 30° 时增加约 1-6%，在 α = 30° 时增加 3-9% α = 60° 和 5–11% 在 α = 90° 与 Nusselt 数相比$\alpha =0^{\circ }.$此外，这些角度的阻力系数分别增加了 40-53%、105-109% 和 114-122%，与$\alpha =0^{\circ }$. 在所有雷诺数中，α=0°和150°的阻力系数最低，分别比其他攻角低29-55%和27-56%。此外，在 α = 0° 和 150° 时实现了最佳热工水力性能。