论文标题
对不同曲率周期性凹槽的湍流对流流特征的数值研究
A numerical investigation on turbulent convective flow characteristics over periodic grooves of different curvatures
论文作者
论文摘要
热传递增强是所有传热设备中的必要要求，例如用于生物医学应用，电子冷却，太阳能空气加热器，核反应堆核心和燃气轮机叶片冷却等的热交换器等。在过去三个传播的过程中，在较热的范围内，较少的设备中的少量肋骨是较少的，较少的肋骨或凹槽是越来越多。但是，考虑到其有用性，其在文献中的相对稀缺性以及凹槽表面的其他优势，我们认为这是一种在此处增加传热的方法。这使得由于周期性凹槽（或肋骨）对物理学的研究是必要的，这是本文的主要重要性。在这项工作中，通过在下壁的周期性凹槽通道的尖角引入曲线来进行湍流强制对流的数值模拟。底壁隔热时，底壁提供了恒定量的热源。使用K-Epsilon（RNG）模型在商用软件包ANSYS Fluent 19.2中实现的RANS公式中使用K-Epsilon（RNG）模型进行了计算。模拟对6000-36000的不同雷诺数进行进行，其中凹槽的高度和凹槽的宽度，凹槽音高比分别保持恒定为1、2和0.5。对传热系数，摩擦损失和热量增强大小的评估在凹槽上的曲率半径上进行了系统地进行。曲率的插入将整体热传递提高了12％的合理幅度，在热传递增强的幅度中，总体5％的增量为5％。此外，随着曲率半径的增加，传热幅度增加。
Heat transfer augmentation is an essential requirement in all heat transfer devices, such as heat exchangers used in biomedical applications, electronic cooling, solar air heaters, nuclear reactor cores, and gas turbine blade cooling etc. Extended surfaces, protrusions, dimples, internal ribs or, grooves are among the few which are incorporated in the last three decades with the goal of heat transfer augmentation for the better performance of the thermal device. However, considering the usefulness, its relative scarcity in literature, and other advantages of grooved surfaces, we have considered this as a method of heat transfer augmentation here. This makes its necessary to investigate the physics due to turbulence and thermal behavior over periodic grooves (or, ribs) is the prime importance of the present paper. In this work, numerical simulations of turbulent forced convection are carried out by introducing curvatures at sharp corners of a periodic grooved channel at the lower wall. A heat source of constant magnitude is supplied in the bottom wall while the upper wall is insulated. Computations were performed using k-epsilon(RNG) model in RANS formulation implemented in finite volume-based solver in the commercial package ANSYS Fluent 19.2. The simulations are performed over varying Reynolds numbers of 6000-36000 where ratio of the height of the channel and breadth of the groove, groove pitch ratio, and depth ratio kept constant as 1, 2, and 0.5 respectively. Assessment of coefficient of heat transfer, frictional losses, and magnitude of heat enhancement are systematically carried out over varying radius of curvatures on grooves. The insertion of curvatures improves the overall heat transfer by a reasonable magnitude of 12% with an overall 5% increment in the magnitude of heat transfer enhancement. Further, the magnitude of heat transfer increases with increase in curvature radius.
