Gas Turbine Test Research Articles

A software package for modeling power systems of arbitrary configurations

This paper presents a software package for mathematical modeling of power systems of any configuration for power system model tests in the normal and emergency modes, including tests of control algorithms for the whole power system and its individual elements. One of the specific tasks of this package is automation of gas-turbine tests, including automatic pretesting and tuning of automatic control systems (ACSs) for gas turbines in all operating modes of power plants (independently, in parallel, and with a powerful network). The paper describes the architecture of the developed software package and its optimization module as a platform for various tasks: automatic ACS tuning, selection of the optimal arrangement and types of generating units, load distribution in a power system, optimization of electric-power quality, tuning of automatic- and relay-protection systems, etc.

Application of Computational Tools to Analyze and Test Mini Gas Turbine

Abstract Performance analysis and testing of the Mini Gas Turbine was carried out in Wentworth Institute of Technology’s Thermodynamics Laboratory. The computational tool allows students to focus on more design-oriented problems. Furthermore, students had the ability to see immediate results to variations of the design conditions as well as different parameters that would affect the mini turbine. This project was carried out as a senior design project (Capstone), the students updated the existing data acquisition system, writing a new data acquisition program in LabVIEW, installing new pressure and temperature sensors, and performing a first and second law of thermodynamics analysis on the engine in Engineering Equation Solver. In order to update the existing data acquisition system, new NI SCB-68 connector blocks were implemented along with NI USB-6251 terminals. The new hardware is operated through a LabVIEW program running on a new laptop designated and mounted to the mini jet turbine housing. Instrumentation, testing, and calibration are the three main milestones for this project As a result, The Inlet Mass Flow Rate numeric indicator value is calculated, not measured. The calculated value is dependent on the measured values of Compressor Inlet Temperature (T1), Compressor Inlet Static Pressure (Ps), and Compressor Inlet Dynamic Pressure (Pt-Ps). However, the pressure, temperature and thrust were tested as a function of RPM. The mini turbine engine is ready to be used in student experimental settings. Feedback from students proves that the use of different tools significantly enhances the student learning experience and encourages the students to use different theory from different courses, make the course more dynamic, and motivate the students to learn the material.

Cleaning System with Large Consumption of Gas Emissions

High-temperature system of cleaning harmful emissions is proposed by tests high power turbine engines. It includes a new nozzle design, installed on the exhaust pipe containing a sprayers for spraying a mixture of water with ozone. Maximum decrease of temperature of gases emissions is achieved by full evaporation of the liquid drops within pipe nozzle. Provides a methodology for calculating diameter channels of pneumatic injectors by hydraulic spraying to drops, which provide their complete evaporation. To demonstrate with an example of calculating the duct diameter, the diameter of the droplets, the evaporation time within a multipurpose exhaust nozzle stand testing of gas turbine engines with a capacity of 40 MW with consumption of gas emissions 365 m 3 /c, and temperature 560 °C.

Characterization of gas turbine burner instabilities by wavelet analysis of infrared images

In this paper, an optical approach is tested to spatially characterize combustion fluctuations in a single burner atmospheric gas turbine test rig. The target of present investigation was to test the optical technique during combustion tests campaign, in order to couple it to an acoustic one in a future activity to be developed on the same experimental setup. The analysis based on fast infrared imaging of flames, coupled with photomultiplier and microphones measurements, has been elaborated on a 3MW gas turbine test rig equipped with full scale burner tested in atmospheric conditions. The rig has been purposely designed to be tuned on acoustic frequencies detected in the real gas turbine machine equipped with 24 burners and operating at 20 bars. The tests evidenced main oscillations at low frequencies around 82Hz and 146Hz. These frequencies have been recorded in real machine too. The IR technique allowed to identify these frequencies in the 2D dimensions under humming conditions. The results obtained by IR presented a good agreement with microphones and optical measurements. Moreover, further investigation based on wavelet analysis came out as an interesting tool to develop a methodology for fingerprinting different burners operating in different conditions from thermoacoustic point of view.

Statistical Analysis and Verification of Performance for CSP Subsystems

Abstract The long term success of the concentrating solar power (CSP) industry depends on having accurate and reliable measurements and predictions of performance. Agreed-upon standards for performance characterization are still lacking. This contrasts with more mature technologies such as gas turbine combined cycle power plants, where performance and testing specifications are well established in spite of system complexities. Lack of standardization inevitably results in extra cost and risk to market participants and the spread of misinformation through hidden “apples-to-oranges” comparisons. To cite just one example, there are multiple distinct metrics for characterizing heliostat tracking accuracy, and the differences can easily go unnoticed. Here we propose rigorous and accurate statistical approaches to two key performance analysis problems for tower CSP. We highlight their advantages over previous approaches, and analyze detailed operational data. Further, we demonstrate why they are sufficiently straightforward and general enough for adoption as industry standards.

Development and analysis of screw restrictor hydraulic characteristics in the air bleed valve control unit of a gas turbine engine

There is a need to change the air bypass control unit performance to estimate its influence on the compressor gas-dynamic steadiness and the combustion process in the combustion chamber during the testing and operation of gas turbine engines with low-emission combustion chamber. Setting up the required air bypass valve closed (open) time by means of standard hydraulic actuator in the process of testing requires stopping the engine, removing the air bypass control unit, changing the orifice and testing the unit’s performance on the test stand that are associated with significant time and material costs. To adjust the time of restating the air bypass control unit it is proposed a screw throttle, the parameters of which are calculated on the basis of research performance of the unit. The custom screw throttle is designed and its hydraulic characteristics are researched, its effectiveness is experimentally verified within the unit at the test stand conditions. The possibility of changing the air bypass control unit performance in a wide range at different air bypass valve reaction forces is shown.

Research of the validity of forecasting low cycle durability of gas turbine engine parts based on Manson’s equation

The article presents the prediction of low-cycle durability of gas turbine discs and test samples by the method of universal tilt on the basis of the Manson equation and its various modifications. Manson equation obtained by testing of standard specimens in stretching-compression, i.e. an uniaxial stress state and the symmetric cycle of loading. Under complex stress-strain state in the modification of the equations embeded the mean stress of the cycle, but clear guidance for determining it are missing. In this paper we proposed different ways to imagine the average stress. On the basis of verification of various modifications were adopted, the results of tests of standard specimens with circular cross-sections, samples of the lock "swallow's tail" cut from the disks of the compressor, as well as full-scale drive of new and used. The test was carried out from zero cycle of loading close to the real operating conditions of main parts of the gas turbine engine. By comparison of calculation results with the experimental data revealed the most effective ways to refine the Manson equations. It was found a significant effect on low cycle durability of not only the magnitude of deformation of the parts, but the type of stress-strain state. Therefore, the most effective was the using of the stress intensities. It was also established that the refinement equation, introduced by Manson and Muralidharan applicable only for stress states that are close to flat.

Thermal Testing of 255-MW Gas Turbine of a Single-Shaft Combined-Cycle Power Plant

Thermal tests of a single-shaft CCPP are conducted. A procedure for processing the test data is developed. Characteristics of turbomachinery at load N GT ≥ 0.4N r are determined. The high temperature of the exhaust gases (650°C) is provided by adjusting the inlet guide vanes.

China prepares to spend billions on science and technology

With its strong economy, the country wants to play a bigger role on the world science stage.

Development of an optimized artificial neural network model for combined heat and power micro gas turbines

Micro gas turbines are considered an efficient alternative to costly generation and transmission of electricity, especially in remote areas and in combined heat and power (CHP) applications. Tools for remote monitoring and diagnostics, which are easy to apply, would be needed for the realization of distributed CHP. This paper reports the development of a validated artificial neural network (ANN) model for efficient and appropriate monitoring of a micro gas turbine. This study is based on experimental data obtained from a Turbec T100 micro gas turbine. The gas turbine test rig used in this study consists of a modified engine with extended measurement points providing extensive data suitable for data-driven modeling. ANNs, in contrast to mathematical models, do not require detailed and exact component characteristics, making them applicable for monitoring in many cases. The developed ANN model was based on a multi-layer feed forward network with back-propagation algorithm. Relations between the inputs and outputs of an ANN model are not implemented by physical equations but are built up during the training process. Thus, a systematic sensitivity analysis, conducted in several steps, was performed to investigate the dependency between initially selected input and output parameters. Based on sensitivity analysis results, the “optimized” set of input parameters and final outputs were concluded, taking into account prediction accuracy. The procedure of the ANN model development and sensitivity analysis are discussed in detail. The mean relative error (MRE) was used to evaluate the prediction accuracy of the developed networks with respect to experimental data which were not used during the training. The prediction results showed that the final optimum ANN model can serve as an accurate baseline model for monitoring applications.

Large-aperture, tapered fiber–coupled, 10-kHz particle-image velocimetry

We demonstrate the design and implementation of a fiber-optic beam-delivery system using a large-aperture, tapered step-index fiber for high-speed particle-image velocimetry (PIV) in turbulent combustion flows. The tapered fiber in conjunction with a diffractive-optical-element (DOE) fiber-optic coupler significantly increases the damage threshold of the fiber, enabling fiber-optic beam delivery of sufficient nanosecond, 532-nm, laser pulse energy for high-speed PIV measurements. The fiber successfully transmits 1-kHz and 10-kHz laser pulses with energies of 5.3 mJ and 2 mJ, respectively, for more than 25 min without any indication of damage. It is experimentally demonstrated that the tapered fiber possesses the high coupling efficiency (~80%) and moderate beam quality for PIV. Additionally, the nearly uniform output-beam profile exiting the fiber is ideal for PIV applications. Comparative PIV measurements are made using a conventionally (bulk-optic) delivered light sheet, and a similar order of measurement accuracy is obtained with and without fiber coupling. Effective use of fiber-coupled, 10-kHz PIV is demonstrated for instantaneous 2D velocity-field measurements in turbulent reacting flows. Proof-of-concept measurements show significant promise for the performance of fiber-coupled, high-speed PIV using a tapered optical fiber in harsh laser-diagnostic environments such as those encountered in gas-turbine test beds and the cylinder of a combustion engine.

Experimental investigation on the off-design performance of a small-sized humid air turbine cycle

This research aimed to study the improvement of the gas turbine performance of a humid air turbine (HAT) cycle at low pressure ratio and at low turbine inlet temperature (TIT). To achieve this goal, an off-design performance test investigation was conducted on a small-sized, two-shaft gas turbine test rig. The test rig consisted of a centrifugal compressor, a centripetal turbine, an individual direct flow flame tube, a free power turbine, a dynamometer, and a saturator with structured packing. Two different conditions were considered for the test investigation: in Case I, the control system kept the fuel flow constant at 57 kg/h, and in Case II, the turbine inlet temperature was kept constant at 665 °C. In Case I, when the air humidity ratio increased from 30 g/kg dry air (DA) to 43 g/kg DA, the power output increased by 3 kW. At the same time, the turbine inlet temperature decreased by 19 °C, and the NOx emissions were reduced from 25 ppm to 16 ppm. In Case II, when the air humidity ratio increased from 48 g/kg DA to 57 g/kg DA, the power output increased by 9.5 kW.Based on the actual gas turbine parts, characteristics, and test conditions, the off-design performance of the HAT cycle was calculated. Upon comparing the measured and calculated results, the HAT cycle was found to perform better than the two-shaft cycle in terms of specific work, efficiency, and specific fuel consumption. The effect of performance improvement became more obvious as the air humidity ratio increased. Under the same inlet air flow, turbine inlet temperature, and power output, the surge margin on compressor curves became enlarged as the humidity ratio increased. The off-design performance of a HAT cycle with regenerator was also investigated. The results show that the highest efficiency can be increased by 3.1%, which will greatly improve the gas turbine performance.

Investigation of optical fibers for gas-phase, ultraviolet laser-induced-fluorescence (UV-LIF) spectroscopy

We investigate the feasibility of transmitting high-power, ultraviolet (UV) laser pulses through long optical fibers for laser-induced-fluorescence (LIF) spectroscopy of the hydroxyl radical (OH) and nitric oxide (NO) in reacting and non-reacting flows. The fundamental transmission characteristics of nanosecond (ns)-duration laser pulses are studied at wavelengths of 283 nm (OH excitation) and 226 nm (NO excitation) for state-of-the-art, commercial UV-grade fibers. It is verified experimentally that selected fibers are capable of transmitting sufficient UV pulse energy for single-laser-shot LIF measurements. The homogeneous output-beam profile resulting from propagation through a long multimode fiber is ideal for two-dimensional planar-LIF (PLIF) imaging. A fiber-coupled UV-LIF system employing a 6 m long launch fiber is developed for probing OH and NO. Single-laser-shot OH- and NO-PLIF images are obtained in a premixed flame and in a room-temperature NO-seeded N(2) jet, respectively. Effects on LIF excitation lineshapes resulting from delivering intense UV laser pulses through long fibers are also investigated. Proof-of-concept measurements demonstrated in the current work show significant promise for fiber-coupled UV-LIF spectroscopy in harsh diagnostic environments such as gas-turbine test beds.

0204 EFガスタービン試験装置の検討(GS01-1 熱工学・流体工学,オーガナイズドセッション 14:「ロボット・メカトロ」)

0204 EFガスタービン試験装置の検討(GS01-1 熱工学・流体工学,オーガナイズドセッション 14:「ロボット・メカトロ」)

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.

Micro Gas Turbine Recuperator: Steady-State and Transient Experimental Investigation

The aim of this work is the experimental analysis of a primary-surface recuperator, operating in a 100 kW micro gas turbine, as in a standard recuperated cycle. These tests, performed in both steady-state and transient conditions, have been carried out using the micro gas turbine test rig, developed by the Thermochemical Power Group at the University of Genova, Italy. Even if this facility has mainly been designed for hybrid system emulations, it is possible to exploit the plant for component tests, such as experimental studies on recuperators. The valves installed in the rig make it possible to operate the plant in the standard recuperated configuration, and the facility has been equipped with new probes essential for this kind of tests. A wide-ranging analysis of the recuperator performance has been carried out with the machine, operating in stand-alone configuration, or connected to the electrical grid, to test different control strategy influences. Particular attention has been given to tests performed at different electrical load values and with different mass flow rates through the recuperator ducts. The final section of this paper reports the transient analysis carried out on this recuperator. The attention is mainly focused on thermal transient performance of the component, showing the effects of both temperature and flow steps.

Dynamic stability experiments of compliant foil thrust bearing with viscoelastic support

In order to reduce the complexity of machine construction and improve the mechanical efficiency, high speed rotation machineries usually implement self-acting gas bearings to substitute the traditional oil-lubricated bearings. This paper presents test results of a gas thrust bearing with viscoelastic support which is designed for high speed turbo-machinery. The gas bearing, which belongs to compliant foil bearings, consists of a top thin metal foil and a bottom thin rubber foil. Static and stability experiments are conducted on a high speed gas turbine test rig. The static results indicate that the structural stiffness of test bearing generally increases with the increase in axial load and the decrease in thickness of bottom foil. In the rotation tests, rotor runs stably with small vibration amplitude, which is dominant in waterfall plot during whole speed up procedure. It shows that test bearing has preferable stability characteristics for high speed gas turbines.

Combustion Chamber Steam Injection for Gas Turbine Performance Improvement During High Ambient Temperature Operations

The gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency, which decreases in the hard climatic conditions of operation, so the cycles with thermodynamic improvement is found to be necessary. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists of introducing a high amount of steam at various points in the cycle. The main purpose of the present work is to improve the principal characteristics of gas turbine used under hard condition of temperature in Algerian Sahara by injecting steam in the combustion chamber. The suggested method has been studied and compared to a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from ISO conditions to 50°C. Computer program has been developed for various gas turbine processes including the effects of ambient temperature, pressure ratio, injection parameters, standard temperature, and combustion chamber temperature with and without steam injection. Data from the performance testing of an industrial gas turbine, computer model, and theoretical study are used to check the validity of the proposed model. The comparison of the predicted results to the test data is in good agreement. Starting from the advantages, we recommend the use of this method in the industry of hydrocarbons. This study can be contributed for experimental tests.

Gas Turbine Performances Improvement using Steam Injection in the Combustion Chamber under Sahara Conditions

Gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency which decreases in the hard climatic conditions of operation, so it is important to look for improved gas turbine based cycles. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists to introduce a high amount of steam at various points in the cycle. The objective of the present work is to improve the performances of gas turbine used under Sahara conditions by injecting suitable quantities of steam in the upstream of combustion chamber. The suggested method has been studied and compared with a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from iso conditions to 50C. Computer program has been developed for various gas turbine processes including the effect of ambient temperature. This is achieved by studying the effect of steam injection on the gas turbine performances. Data from the performance testing of an industrial gas turbine, computer model and theoretical study are used to check the validity of the proposed model. The comparison of the prediction results to the test data is in good agreement.

Performance characteristics and modelling of a micro gas turbine for their integration with thermally activated cooling technologies

We have developed a simple model of a micro gas turbine system operating at high ambient temperatures and characterized its performance with a view to integrating this system with thermally activated cooling technologies. To develop and validate this model, we used experimental data from the micro gas turbine test facility of the CREVER research centre. The microturbine components were modelled and the thermodynamic properties of air and combustion gases were estimated using a commercial process simulator. Important information such as net output power, microturbine fuel consumption and exhaust gas mass flow rate can be obtained with the empirical correlations we have developed in this study. This information can be useful for design exhaust gas fired absorption chillers. Copyright © 2006 John Wiley & Sons, Ltd.