Rotating Cavity With Axial Throughflow of Cooling Air: Heat Transfer
Rotating Cavity With Axial Throughflow of Cooling Air: Heat Transfer
复制标题
冷却空气轴向流动的旋转腔：传热
DOI：
10.1115/1.2927990
复制
发表时间：
1990
影响因子：
1.7
通讯作者：
J. R. Pincombe
中科院分区：
文献类型：
--
作者：
P. Farthing;C. Long;J. Owen;J. R. Pincombe
在两个旋转空腔试验台上进行了传热测量，其中冷却空气轴向穿过圆盘中心，测量了大范围的流速、转速和温度分布。对于对称加热腔体(其中两个圆盘具有相同的温度分布)，发现两个圆盘的局部Nusselt数分布相似，辐射的影响可以忽略不计。对于非对称加热空腔(其中一个圆盘比另一个圆盘热)，较热圆盘上的Nusselt数与对称加热圆盘上的Nusselt数相似，但比较冷圆盘上的Nusselt数大；在这种情况下，从热盘到冷盘的辐射与对流换热的量级相同。虽然两台钻机具有不同的间隙比(G=0.138和0.267)，并且其中一台钻机包含中央传动轴，但测量的努塞尔特数之间几乎没有差异。对于“温度增加分布”的情况(其中圆盘的温度是径向增加的)，局部Nusselt数是径向增加的；对于“温度下降分布”的情况，Nusselt数是径向减少的，并且在外径处变为负数。对于温度升高的情况，得到了局部Nusselt数与局部Grashof数和轴向雷诺数之间的简单关系。
Heat transfer measurements were made in two rotating cavity rigs, in which cooling air passed axially through the center of the disks, for a wide range of flow rates, rotational speeds, and temperature distributions. For the case of a symmetrically heated cavity (in which both disks have the same temperature distribution), it was found that the distributions of local Nusselt numbers were similar for both disks and the effects of radiation were negligible. For an asymmetrically heated cavity (in which one disk is hotter than the other), the Nusselt numbers on the hotter disk were similar to those in the symmetrically heated cavity but greater in magnitude than those on the colder disks; for this case, radiation from the hot to the cold disk was the same magnitude as the convective heat transfer. Although the two rigs had different gap ratios (G = 0.138 and 0.267), and one rig contained a central drive shaft, there was little difference between the measured Nusselt numbers. For the case of “increasing temperature distribution” (where the temperature of the disks increases radially), the local Nusselt numbers increase radially; for a “decreasing temperature distribution,” the Nusselt numbers decrease radially and become negative at the outer radii. For the increasing temperature case, a simple correlation was obtained between the local Nusselt numbers and the local Grashof numbers and the axial Reynolds number.