Rotating Heat Transfer Measurements on a Multi-Pass Internal Cooling Channel: I — Rig Development

Abstract

The

Gas turbine blade internal cooling: design, development, and validation of a new rig for heat transfer measurements under rotation.

“…At the University of Udine a new rig has been developed to perform rotating and transient LCT measurements. The rig components, its working principle and the experimental approach have all been subject of previous publications [12]. The present contribution aims at describing the progresses made in the development of a more accurate and efficient processing algorithm and the efforts made in the difficult task to validate the results obtained by the complex experimental methodology.…”

Rotating Heat Transfer Measurements on a Multi-Pass Internal Cooling Channel: II — Experimental Tests

“…All the details are available in the Part 1 of this contribution [23]. In the following, only the information about the installation on the rig and working conditions of this specific geometry are reported.…”

“…Heat transfer measurements on the test section are carried out by means of thermochromic liquid crystals with the well-known transient technique. The fundamentals of the technique can be found in [24][25][26], while the specific methodology used in this work is reported in [23]. A mix (50% in volume) of two narrow banded encapsulated liquid crystals supplied by Hallcrest has been used, namely R2C1W and R12C1W (in the following named LC2 and LC1, respectively).…”

“…The wide angle of view of the camera optics produces distorted images that must be de-warped in order to fit the image space onto the CAD space. A dedicated procedure has been developed for the purpose and is described in details in [23]. Flow temperature values inside the model are acquired by means of K-type thermocouples (TC).…”

“…Liquid crystal calibration has been performed ex-situ on a calibration plate [23] where the effects of the mixing of the two liquid crystals has been also checked and shown not to affect the liquid crystals optical properties. More complex in-situ calibration is not required since narrow banded liquid crystals are used (1°C of activation range) and, therefore, accuracy issues related to viewing and illumination angles are negligible.…”