Infrared Thermography Investigation of Heat Transfer on Outlet Guide Vanes in a Turbine Rear Structure

Isak Jonsson,Radheesh Dhanasegaran,Valery Chernoray

doi:10.3390/ijtpp5030023

Abstract

Aerothermal heat transfer measurements in fluid dynamics have a relatively high acceptance of uncertainty due to the intricate nature of the experiments. The large velocity and pressure gradients present in turbomachinery application add further complexity to the measurement procedure. Recent method and manufacturing development has addressed some of the primary sources of uncertainty in these heat transfer measurements. However, new methods have so far not been applied in a holistic approach for heat transfer studies. This gap is bridged in the present study where a cost-effective and highly accurate method for heat transfer measurements is implemented, utilising infrared thermography technique (IRT) for surface temperature measurement. Novel heat transfer results are obtained for the turbine rear sturcture (TRS), at engine representative conditions for three different outlet guide vane (OGV) blade loading and at Reynolds Number of 235000. In addition to that, an extensive description of the implementation and error mitigation is presented.

Highlights

Higher performance and noise requirements in modern aero-engines lead to increased by-pass ratio and slower rotating fan
The higher pressure ratio expected in the new engines introduces thermal challenges, especially at off-design conditions
The confidence interval varies between 4% and 6% along mid-span as the contribution from different independent variable changes

Summary

Introduction

Higher performance and noise requirements in modern aero-engines lead to increased by-pass ratio and slower rotating fan. Both geared and un-geared turbofans provide a solution to the challenges of higher by-pass ratios but with a very different effect on the low-pressure expansion system. The un-geared fan will, on the other hand, have a slower rotating LPT, causing a higher stage loading or stage count to extract the same amount of work. The RMA method first presented by Kirollos in [7] provides a method to account for the background radiation using Equation (9). The perceived difference in temperature of the gold markers and the surrounding area is used to isolate the background radiation since it provides two unknowns in a two-equation system.

Results

Discussion

Conclusion