Toyoaki Yoshida

Local Cooling Effectiveness Distribution of an Integrated Impingement and Pin Fin Cooling Configuration

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.© 2007 ASME

Study on Advanced Internal Cooling Technologies for the Development of Next-Generation Small-Class Aircraft Engines

An innovative internal cooling structure named multislot cooling has been invented for high-pressure turbine (HPT) nozzles and blades. This cooling structure has been designed to be simple and inexpensive and to exhibit good cooling performance. In order to confirm the cooling performance of this structure, test pieces of dummy turbine nozzles were manufactured. Three geometric parameters (width of slots, overall height of cooling channel, and height of jet impingement) are associated with these test pieces. The cooling performance tests were conducted by using these test pieces for several Reynolds numbers of the mainstream hot gas [2.2 × 10 5 -3.4 × 10 5 ] and cooling airflow [3 × 10 3 -1 × 10 4 ]. Infrared images of the heated surfaces of the test pieces were captured for every Reynolds number in the tests, and then the distributions of the cooling effectiveness were obtained. Simultaneously the pressure losses were measured, This paper describes the hot gas flow tests performed to confirm the effects of the geometric parameters on the cooling performance and pressure loss, and to obtain data of Nusselt number and pressure loss coefficient for the design of turbine nozzles in the future by applying this new cooling structure to next-generation small-class aircraft engines. Additionally a preliminary analysis of airfoil cooling was performed to evaluate both cooling performance of conventional impingement cooling and multislot cooling when applied to a HPT nozzle. As a result it was found that the multislot cooling is well applicable to cooling of HPT airfoils.

Leading Edge Cooling Performance of an Integrated Cooling Configuration

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.© 2008 ASME

Study on Visualization of Cooling Airflow in a Turbine Blade with Multiple Slot Cooling Configuration

A new model turbo-fan engine for small aircrafts is being developed as a national project. Multiple slot cooling configuration that is a new cooling structure of a turbine blade will be adopted to the engine. Cooling performance of the configuration stays equal to those of traditional methods, but this structure is much simpler than conventional ones. So the cost to make turbine blades will decrease. The representative company in this project, Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) performed numerical simulation of flow field CFD in a turbine blade and measured cooling effectiveness of this configuration. In this study, cooling airflow in a turbine blade was visualized and flow velocity was measured with the particle image velocimetry (PIV). The purpose of the present study is to confirm usefulness of CFD and to find out some relationship between the flow field and heat transfer. Thus we made a comparison among experimental results and numerical simulation.

Spatial Arrangement Dependance of Cooling Performance of an Integrated Impingement and Pin Fin Cooling Configuration

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.© 2005 ASME