This thesis discusses experimental results of measurement of heat transfer and velocity flow in a heated multiple cavity test rig with axial throughflow. Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air. Tests were carried out for a range of non-dimensional parameters representative of gas-turbine high pressure compressor internal air system flows (ReΦ up to 5x106 and Rez up to 2x105). One configuration of the test rig was tested in the course of the reported study (Build 3) and test data from a previous rig configuration (Build 2) were processed, analysed and compared with the tested data. The most significant difference between the two builds of test rig was the size of the annular gap between the (non-rotating) shaft and the disc bores. Build 3 had a wider annular gap ratio, dh/b=0.164, while Build 2 featured a gap ratio of dh/b=0.092. Heat transfer data were obtained from thermocouples and a conduction analysis. Heat transfer results show differences between the versions of the rig, with the higher Nusselt number values in Build 3 attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity compared to Build 2. An attempt is made to correlate the average disc Nusselt numbers and this indicates the existence of different regimes. A two-component Laser Doppler Anemometry system was used on both rigs to measure cavity axial and tangential velocity components. Optical access in Build 3 also allowed for measurement of radial velocities. The axial and radial velocities inside the cavities are virtually zero. The size of the annular gap between disc bore and shaft has a significant effect on the radial distribution of tangential velocity. An analysis of the frequency spectrum obtained from the tangential velocity measurements shows evidence of periodicity in the flow consistent with the current understanding of the flow structure in a heated rotating cavity with axial throughflow.
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机译：本文讨论了在带有轴向通量的加热多腔试验台中测量传热和速度流的实验结果。特别令人感兴趣的是由相邻圆盘形成的内部圆柱形腔以及它们与冷却空气的中心轴向通流的相互作用。对代表燃气轮机高压压缩机内部空气系统流量的一系列无量纲参数进行了测试（ReΦ高达5x106，Rez高达2x105）。在报告的研究过程中对测试台的一种配置进行了测试（版本3），并处理，分析了先前测试台配置（版本2）中的测试数据，并与测试数据进行了比较。两种型号的试验台之间最显着的区别是（非旋转）轴和圆盘孔之间的环形间隙的大小。版本3具有较宽的环形间隙比dh / b = 0.164，而版本2具有dh / b = 0.092的间隙比。传热数据是从热电偶和传导分析获得的。传热结果显示了钻机版本之间的差异，与Build 2相比，Build 3中较高的Nusselt值归因于较宽的环形间隙，允许更多的通流渗透到型腔中。尝试进行平均圆盘Nusselt数字，这表明存在不同的体制。两台钻机都使用了一种由两部分组成的激光多普勒风速测定系统来测量腔体轴向和切向速度分量。 Build 3中的光学通道还允许测量径向速度。腔体内的轴向和径向速度实际上为零。圆盘孔和轴之间的环形间隙的大小对切向速度的径向分布有很大影响。从切线速度测量获得的频谱分析表明，流动的周期性证据与当前对带有轴向通流的加热旋转腔中流动结构的当前理解一致。
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