Jan Zanger

Experimental Investigations of Pressure Losses on the Performance of a Micro Gas Turbine System

Pressure losses between the compressor outlet and the turbine inlet are a major issue of overall efficiency and system stability for a solid oxide fuel cell/micro gas turbine (MGT) hybrid power plant system. The goal of this work is the detailed analysis of the effects of additional pressure losses on MGT performance in terms of steady-state and transient conditions. The experiments were performed using the micro gas turbine test rig at the German Aerospace Centre in Stuttgart using a butterfly control valve to apply additional pressure loss. This paper reports electric power and pressure characteristics at steady-state conditions as well as a new surge limit for this Turbec T100 micro gas turbine test rig. Furthermore, the effects of additional pressure loss on the compressor surge margin are quantified and a linear relation between the relative surge margin and additional pressure loss is shown. For transient variation of pressure loss at constant turbine speed, time delays are presented and an instability issue of the commercial gas turbine controller is discussed. Finally, bleed-air blow-off and reduction of the turbine outlet temperature are introduced as methods of increasing the surge margin. It is quantified that both methods have a substantial effect on the compressor surge margin. Furthermore, a comparison between both methods is given in terms of electric power output.

Experimental Characterization of a Micro Gas Turbine Test Rig

For the development of efficient and fuel flexible decentralized power plant concepts a test rig based on the Turbec T100 micro gas turbine is operated at the DLR Institute of Combustion Technology. This paper reports the characterization of the transient operating performance of the micro gas turbine by selected transient maneuvers like start-up, load change and shut-down. The transient maneuvers can be affected by specifying either the electrical power output or the turbine speed. The impact of the two different operation strategies on the behavior of the engine is explained. At selected stationary load points the performance of the gas turbine components is characterized by using the measured thermodynamic and fluid dynamic quantities. In addition the impact of different turbine outlet temperatures on the performance of the gas turbine is worked out. The resulting data set can be used for validation of numerical simulation and as a base for further investigations on micro gas turbines.Copyright

Experimental Investigation of the Combustion Characteristics of a Double-Staged FLOX?-Based Combustor on an Atmospheric and a Micro Gas Turbine Test Rig

To establish micro gas turbine (MGT) systems in a wide field of CHP applications, innovative combustion concepts are needed to meet the demands for low exhaust gas emissions, high efficiency and reliability as well as high fuel flexibility. A promising technology for future MGT combustion is the FLOX® concept. The goal of the presented work is to prove the feasibility of a double–staged, FLOX®–based MGT combustion system on a MGT test rig. The paper reports a reliable operating behavior of a Turbec T100 MGT in combination with the new FLOX®–based combustion chamber utilizing natural gas. The measured exhaust gas emissions are compared for different configurations of the combustion chamber and the standard Turbec system. It is shown that the carbon monoxide emissions are reduced whereas the nitrogen oxide emissions exceed the emission levels of the standard MGT burner. However, they still fall far below the German legal limits. For helping to interpret the results of the MGT combustion system, the double–staged combustor is compared to a single–staged FLOX®burner on basis of atmospheric measurements. Here, it is shown that the margin to lean blow–off is substantially increased by the fuel staging. Moreover, it is demonstrated that the exhaust gas emissions of the double–staged combustor could be kept at a similar very low level by applying the staging. Additionally, the overall reaction regions are reported by OH* chemiluminescence imaging as a function of burner air number. Based on this atmospheric study the transfer to MGT conditions is made and appropriate measures are derived to optimize the exhaust gas emissions of the MGT FLOX® combustion system.© 2015 ASME

Experimental Investigation of Cycle Properties, Noise and Air Pollutant Emissions of an APS3200 Auxiliary Power Unit

Auxiliary power unit (APU) operators face increasingly stricter airport requirements concerning exhaust gas and noise emission levels. To simultaneously reduce exhaust gas and noise emissions and to satisfy the increasing demand of electric power on board, optimization of the current technology is necessary. Prior to any possible demonstration of optimization potential, detailed data of thermodynamic properties and emissions have to be determined. Therefore, the investigations presented in this paper were conducted at a full-scale APU of an operational aircraft. A Pratt & Whitney APS3200, commonly installed in the Airbus A320 aircraft family, was used for measurements of the reference data. In order to describe the APS3200, the full spectrum of feasible power load and bleed air mass flow combinations were adjusted during the study. Their effect on different thermodynamic and performance properties, such as exhaust gas temperature, pressure as well as electric and overall efficiency is described. Furthermore, the mass flows of the inlet air, exhaust gas and fuel input were determined. Additionally, the work reports the exhaust gas emissions regarding the species CO2, CO and NOx as a function of load point. Moreover the acoustic noise emissions are presented and discussed. With the provided data the paper serves as a database for validating numerical simulations and provides a baseline for current APU technology.

Experimental characterization of a swirl stabilized MGT combustor

A swirl stabilized MGT combustor (Turbec T100) was operated with natural gas and was experimentally characterized in two test rigs, a pressurized and optically accessible MGT test rig and an atmospheric combustor test rig. For the detailed characterization of the combustion processes, planar OH-PLIF and simultaneous 3D-stereo PIV measurements were performed in the atmospheric combustor test rig. Flow fields, reaction zones and exhaust gas emissions are reported for a range of pressure scaled MGT load points. Parameter studies on combustor inlet conditions (e.g. air preheating temperature, air and fuel mass flow rates and fuel split) were conducted in the atmospheric combustor test rig. From the parameters studies the fuel split between the pilot and the main stage and the air preheating temperature were found to have the biggest impact on the flame shape, flame stabilization and exhaust gas emissions. The measurements of the ATM test rig are compared with measurements of the pressurized MGT test rig with and without an optically accessible combustion chamber. Opened and closed conical flame and flow pattern were found in both test rigs. Reasons for the two flame and flow pattern are supposed to be the interaction of pilot stage combustion and flow field and the interaction of the dilution air with the combustion and the flow field. The results are discussed and compared with repect to a transferability of combustion characteristics from the ATM test rig to the MGT test rigs.Copyright