A New Experimental Facility to Investigate Combustor–Turbine Interactions in Gas Turbines With Multiple Can Combustors

Abstract

This paper describes a new modular experimental facility that was purpose-built to investigate flow interactions between the combustor and first stage nozzle guide vanes (NGVs) of heavy duty power generation gas turbines with multiple can combustors. The first stage turbine NGV is subjected to the highest thermal loads of all turbine components and therefore consumes a proportionally large amount of cooling air that contributes detrimentally to the stage and cycle efficiency. It has become necessary to devise novel cooling concepts that can substantially reduce the coolant air requirement but still allow the turbine to maintain its aerothermal performance. The present work aims to aid this objective by the design and commissioning of a high-speed linear cascade, which consists of two can combustor transition ducts and four first stage NGVs. This is a modular nonreactive air test platform with engine realistic geometries (gas path and near gas path), cooling system, and boundary conditions (inlet swirl, turbulence level, and boundary layer). The paper presents the various design aspects of the high pressure (HP) blow down type facility, and the initial results from a wide range of aerodynamic and heat transfer measurements under highly engine realistic conditions.

Unsteady Phenomena at the Combustor-Turbine Interface

“…This is a cold rig, with inlet temperature of 310K. Details of the facility are given by Luque et al [28] and Aslanidou [29]. The vane geometry used for these experiments is based on a linearised version of an Mitsubishi Heavy Industries F-class NGV, reduced to 60% of actual size.…”

Development and Aerothermal Investigation of Integrated Combustor Vane Concept

“…to guide the flow. The resulting flow periodicity can be seen in the isentropic Mach number measurements (Luque, Kanjirakkad, Aslanidou, Lubbock, & Rosic, 2015) performed at the midspan of three conventional vanes as seen in Figure 3…”

“…and subsequently looking up the corresponding flow angles in the probe calibration. The estimated uncertainty to within 95% confidence is ± 0.35° (Luque, Kanjirakkad, Aslanidou, Lubbock, & Rosic, 2015). A vertical hole diameter of 1.6mm was chosen to simplify the instrumentation using 1.6mm Scanivalve tubing, and to reduce velocity and thus losses inside of the holes.…”

“…Figure 2-2: Lean premixed combustor geometry (Mandai, Matsuura, Saitoh, Tanaka, & Akizuki, 2004) (a) and NOx generation due to combustion : Flowfield downstream of swirl generator (Huang & Yang, 2009) ......................... Figure 2-4: Horse-shoe vortex development in first turbine vane (Sharma & Butler, 1987) .. ................................................................................................................................ ................................................................................................................................. Measured isentropic Mach number around conventional vanes, adapted from (Luque, Kanjirakkad, Aslanidou, Lubbock, & Rosic, 2015) .................................................. ....................................................................................................................... ................................................................................................................... x Figure 3-12: Schematic of vortex tube used in cooling system of the experimental facility (Airtx, 2016) ........................................................................................................................ Figure 3-13: Schematic overview (top) and photo (bottom) of the cooling system for the and integrated Total pressure at outlet of combustor transition duct obtained from experimental traverse measurements with upstream turbulence grid (no-swirl case) ............................... .................................................................................................…”

Aero-thermal flow characterization downstream of an NGV cascade by five-hole probe and filtered Rayleigh scattering measurements

“…The experimental characterization of aero-thermal flow properties in such configurations typically relies on well-proven probe based technology such as pneumatic multi-hole devices, hot-wire probes or thermocouples (see e. g. Heinke et al (2004); Qureshi et al (2012); Luque et al (2015)). Due to their robustness and reliability, pneumatic multi-hole probes are widely used in applications related to turbomachinery.…”