Experimental and numerical studies were conducted for the development of the integrated impingement and pin-fin cooling configuration. In the development, the spatial arrangements of impingement hole, pin-fin and film cooling (discharge) hole were the main concern. The temperature measurement was performed for different test pieces with various spatial arrangements to clarify the cooling effectiveness variation with the arrangement and the other cooling parameters. Experiments were conducted with 673K hot gas flow and room temperature cooling air. The Reynolds number of gas side flow was 380000 and cooling air Reynolds number was 5000–30000. Test plate surface temperatures were measured using an infrared camera. The cooling effectiveness obtained from the experiment for one specimen was different from that for a specimen that had the same pin density but a different spatial arrangement. So it was confirmed that an arrangement of hole and pin, as well as pin density, was an important parameter. CFD analysis was also conducted to make clear how spatial arrangement affected internal heat transfer characteristics. Pressure losses were also evaluated for each specimen, and total thermal performance was compared. A basic configuration with one pin at the center of a unit area showed the most superior total thermal performance.
The cooling configuration adopted in this study integrates impingement cooling and pin fin cooling devices into one body, the aim being enhancement of the effective heat transfer area. The purpose of the study is to confirm improvement of cooling effectiveness for two different pin density configurations by experimental verification. Experiments were conducted in similar conditions to actual engines using large-scaled flat-plate specimens manufactured by a new rapid prototype casting technique. The results were compared with predictions by one-dimensional analysis adopting the fin efficiency theory. Although the coarse pin density, one pin in a unit area, shows good agreement with the prediction, the fine pin density, four pins in the unit area, was overpredicted. It was found by numerical analysis that heat transfer of the new pin geometry did not increase, so that its surface area increased. CFD-aided prediction was proposed and validated with two specimen’s data.
Detailed unsteady flow surveys were conducted before, within and after the second-stage stator passage of a 1.5-stage axial flow turbine by using a single slanted hot-wire anemometry. Among the results reported in the present paper, of particular interest are the behavior of the rotor wakes and the rotor free-streams within the stator passage, and the spacially three-dimensional and time-dependent convection or mixing process between lower- and higher- energy fluids. Effects of the rotor-stator interaction causing unsteady secondary flows and tip-leakage flow are also discussed.
This paper presents the experimental work on the leading edge cooling performance of an integrated impingement and pin-fin cooling configuration. Experiments are conducted for seven different spatial geometries under the simulated condition of 1400 degree Celsius-class actual turbine vane leading edge with the temperature ratio of 2.1. The Reynolds number of the hot gas side was 91000 and the cooling air Reynolds number was varied in the range of 5900–47000. The test piece surface temperature distributions were measured using an infrared camera with the correction by a thermocouple embedded on the test piece surface. The cooling effectiveness obtained from the experiments showed the superior cooling performance by the pin-fin integration. The effect of the cooling effectiveness enhancement was more than the cooling surface area increment. The detailed analyses of the cooling performance and the pressure loss characteristics are discussed.
An integrated impingement and pin-fin cooling configuration is investigated experimentally. Temperature measurements have been performed for several test pieces with various pin/hole arrangements to clarify an influence of pin/hole arrangements on cooling effectiveness. The experiment has been conducted with 673K combustion gas flow and room temperature cooling air. Reynolds number of combustion gas flow is 380000 and Reynolds number of cooling air flow is in the range from 5000 to 30000. An infrared camera is used to measure a temperature distribution on a specimen surface. The area-averaged cooling effectiveness and the local cooling effectiveness are evaluated for each specimen and compared each other. There are evidences of the existence of pins on the local cooling effectiveness at the exact location of those. But the local cooling effectiveness are independent of the hole arrangement.
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