Karami Fatemeh, Abbasian Arani Ali Akbar, Akbari Omid Ali, Pourfattah Farzad, Toghraie Davood
Department of Mechanical Engineering, University of Kashan, Kashan, Iran.
Young Researchers and Elite Club, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Iran.
Heliyon. 2023 Mar 3;9(3):e14239. doi: 10.1016/j.heliyon.2023.e14239. eCollection 2023 Mar.
This current work expresses numerical simulation of forced turbulent flow convection in a grooved cylinder. Rectangular grooves with a spacing of A = 1, A = 1.1, and A = 1.3, and groove depth to cylinder diameter of e/D = 0.1 and 0.2 were considered. This research concentrates on the effect of groove depth, location of the grooves and CuO nanoparticles on the heat transfer for Reynolds numbers 10000, 12,500, 15,000 and 17,500 in volume fractions of 0, 1, 2, 3 and 4% of nanoparticles. Results show that grooves improve heat transfer. This behavior at a lower A ratio results in a significant Nu number increase so that the highest Nu number occurs for A ratio of 1, 1.1 and 1.3. Increasing e/D ratio, due to increasing the channel section in this area, results in loss of velocity and dissipation of flow momentum, resulting in lower convective heat transfer and lower Nu number. Changing the pitch for e/D = 0.1 results in a 1.1 to 1.6 times increase of Nu number compared with the smooth channel, and for e/D = 0.2 this value is 1.1-1.5 times the smooth channel for similar Re, φ and geometry. Changing groove pitch at e/D = 0.1 results in a 2.1-2.9 times increase in friction factor compared with the smooth channel in similar conditions. For e/D = 0.2, this increase is 1.8-2.8 times the smooth channel. In low Re, the thermal performance is higher than in higher velocities. This is because the grooved channel acts as a smooth channel at high Re, and the average Nu does not have significant growth.
这项工作展示了带槽圆柱体内强制湍流对流的数值模拟。研究考虑了间距A分别为1、1.1和1.3，槽深与圆柱直径之比e/D分别为0.1和0.2的矩形槽。本研究聚焦于槽深、槽的位置以及氧化铜纳米颗粒对雷诺数为10000、12500、15000和17500，纳米颗粒体积分数分别为0%、1%、2%、3%和4%时传热的影响。结果表明，槽能改善传热。在较低的A比时，这种情况会导致努塞尔数显著增加，使得A比为1、1.1和1.3时出现最高的努塞尔数。增加e/D比，由于该区域通道截面增大，会导致流速损失和流动动量耗散，从而导致对流换热降低和努塞尔数降低。对于e/D = 0.1，改变间距会使努塞尔数比光滑通道增加1.1至1.6倍，对于e/D = 0.2，在相似的雷诺数、纳米颗粒体积分数和几何形状下，该值是光滑通道的1.1 - 1.5倍。在e/D = 0.1时改变槽间距，与相似条件下的光滑通道相比，摩擦系数增加2.1 - 2.9倍。对于e/D = 0.2，这种增加是光滑通道的1.8 - 2.8倍。在低雷诺数下，热性能高于较高流速时。这是因为带槽通道在高雷诺数下相当于光滑通道，平均努塞尔数没有显著增长。
