High-temperature high-frequency turbine exit flow field measurements in a military engine with a cooled unsteady total pressure probe

Abstract

The measurement of unsteady pressures within the hot components of gas turbine engines still remains a true challenge for test engineers. Several high-temperature pressure sensors have been developed, but so far, their applications are restricted to unsteady wall static pressure measurements. Because of the severe flow conditions such as turbine inlet temperatures of 1700 C and pressures of 50 bar or more in the most advanced aero-engine designs, few (if any) experimental techniques exist to measure the time-resolved flow total pressure inside the gas path. This article describes the measurements performed at the turbine exit of a military engine with a cooled fast response total pressure probe. The probe concept is based on the use of a conventional miniature piezo-resistive pressure sensor, located in the probe tip to achieve a bandwidth of at least 40 kHz. Due to the extremely harsh conditions, the probe and sensor are heavily water cooled. The probe was designed to be continuously immersed into the hot gas stream to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency (BPV). The experimental results obtained with a second-generation prototype are presented. The probe was immersed into the engine through the bypass duct between turbine exit and flame-holders of the afterburner of a Volvo RM12 engine, at exhaust temperatures above 900 C. The probe was able to resolve the BPV ($17 kHz) and several harmonics up to 100 kHz.

High-Sensitivity and -Stability Thin-Film Heat Flux Sensor Based on Transverse Thermoelectric Effec

“…In addition, the engine of a hypersonic vehicle experiences a complex excitation structure, combustion pulsation, and oscillation in the supersonic combustion chamber. The local heat flux in the combustion chamber can easily reach an order of magnitude of 100 W/cm 2 , causing a significant thermal shock in the combustion chamber [12,13]. Therefore, timely, rapid and accurate information about the heat flow and its distribution on the external surface of equipment is very important when it comes to finding solutions and countermeasures.…”

Turbulent velocity and pressure fluctuations in gas turbine combustor exit flows

“…Brouckaert et al 31 and Mersinligil et al 32,33 developed water-cooled pressure probes using ultraminiature Kulite piezoresistive transducers. Whilst such probes were not used to measure turbulence, they could conceivably be calibrated to do so.…”

Structural Design of Dual-Type Thin-Film Thermopiles and Their Heat Flow Sensitivity Performance

“…With the rapid development of China’s aerospace industry, the design and development of aero-engines, as the core components of aero-aircraft, must rely on advanced and effective testing technologies to verify their design performance indicators and reliability [ 1 , 2 ]. As the most important component of an aero-engine, the turbine blades have a narrow internal space and a harsh working environment, so it is necessary to accurately measure the surface temperature distribution and heat transfer process of high-temperature components such as turbines and combustion chambers to verify the cooling efficiency and performance of the thermal barrier coating, evaluate the combustion efficiency of the gas, monitor the engine running state, and troubleshoot [ 3 , 4 , 5 ]. Therefore, rapid and accurate measurement of the heat distribution and transfer characteristics on the surface of turbine blades of aero-engines is essential for the development of the aerospace industry.…”