Model Based Diagnostics of AE-T100 Micro Humid Air Turbine Cycle

2018 ◽  
Author(s):  
Mariam Mahmood ◽  
Alessio Martini ◽  
Aristide F. Massardo ◽  
Ward De Paepe
Keyword(s):  
Gas Turbines ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Injection System ◽  
Diagnostic Tools ◽  
Diagnostic Purpose ◽  
Humid Air ◽  
Power Sources ◽  
Heat Demand ◽  
Air Turbine

Micro gas turbines (mGT) are emerging power sources for distributed generation facilities with promising features like environment friendliness, high fuel flexibility, cost effectiveness and efficient cogeneration of heat and power (CHP). However, curtailed heat demand during summers reduces the plant operating hours per year and negatively affects the overall economic feasibility of a CHP project. The micro Humid Air Turbine (mHAT) cycle is one of the novel cycles to increase the electrical efficiency of the gas turbine by utilizing the exhaust gas heat in periods of low heat demand, thus avoiding the system shutdown. However, the water injection system can introduce additional pressure losses in the mGT cycle, which may lead to compressor surge and it may also affect the recuperator performance in the long run due to corrosion. Hence, numerical simulation and diagnostic tools are essential for cycle optimization of mHAT and prediction of performance degradation. This work is focused on the real time application of the AE-T100 model for the mHAT system located at the Vrije Universiteit Brussel (VUB), which is based on the T100 mGT equipped with a spray saturation tower. The AE-T100 model is a steady-state simulation tool for mGT cycles, which has been developed within a collaboration between the University of Genova (Unige) and Ansaldo Energia, and has been successfully applied at the Ansaldo Enegia test rig (AE-T100) for the diagnostic purpose. For this study, the basic AE-T100 model has been modified to simulate the humidified cycle according to the VUB plant configuration. The modified AE-T100 model has been validated against the experimental data obtained from the mHAT unit at nominal and part load. Once the model was validated using real operating conditions, it has been used for monitoring the recuperator performance over large number of tests in dry mode, conducted over the past five years, as well as initial tests in wet mode, from the VUB-mHAT system. This work has proved the modeling capability of the AE-T100 tool to simulate the mHAT cycle with reasonable accuracy and first diagnostic application of the AE-T100 tool, in dry mode. However, the lack of data available at present in wet mode does not allow to provide a complete and robust diagnostics of this novel cycle under wet operation. Hence, this preliminary analysis will provide basis for more detail diagnostics of the mHAT cycle using AE-T100 tool, over a longer time period under wet operation, in future.

Transient Simulations of a T100 Micro Gas Turbine Converted Into a Micro Humid Air Turbine

2015 ◽  
Author(s):  
Marina Montero Carrero ◽  
Mario Luigi Ferrari ◽  
Ward De Paepe ◽  
Alessandro Parente ◽  
Svend Bram ◽  
...  
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Water Injection ◽  
Humid Air ◽  
Electrical Efficiency ◽  
Exhaust Gases ◽  
Heat Demand ◽  
Air Turbine ◽  
Static Performance

Micro Gas Turbines (mGTs) have arisen as a promising technology for Combined Heat and Power (CHP) thanks to their overall energy efficiencies of 80% (30% electrical + 50% thermal) and the advantages they offer with respect to internal combustion engines. The main limitation of mGTs lies in their rather low electrical efficiency: whenever there is no heat demand, the exhaust gases are directly blown off and the efficiency of the unit is reduced to 30%. Operation in such conditions is generally not economical and can eventually lead to shutdown of the machine. To address this issue, the mGT cycle can be modified so that in moments of low heat demand the heat in the exhaust gases is used to warm up water which is then re-injected in the cycle, thereby increasing the electrical efficiency. The introduction of a saturation tower allows for water injection in mGTs: the resulting cycle is known as a micro Humid Air Turbine (mHAT). The static performance of the mGT Turbec T100 working as an mHAT has been characterised through previous numerical and experimental work at Vrije Universiteit Brussel (VUB). However, the dynamic behaviour of such a complex system is key to protect the components during transient operation. Thus, we have modelled the Turbec T100 mHAT with the TRANSEO tool in order to simulate how the cycle performs when the demanded power output fluctuates. Steady-state results showed that when operating with water injection, the electrical efficiency of the unit is incremented by 3.4% absolute. The transient analysis revealed that power increase ramps higher than 4.2 kW/s or power decrease ramps lower than 3.5 kW/s (absolute value) lead to oscillations which enter the unstable operation region of the compressor. Since power ramps in the controller of the Turbec T100 mGT are limited to 2kW/s, it should be safe to vary the power output of the T100 mHAT when operating with water injection.

Fault Detection Through Model Based Diagnostics of AE-T100 Micro Gas Turbine

2017 ◽  
Author(s):  
Mariam Mahmood ◽  
Alessio Martini ◽  
Alberto Traverso
Keyword(s):  
Sensitivity Analysis ◽  
Gas Turbines ◽  
Model Development ◽  
Operating Conditions ◽  
Diagnostic Tools ◽  
Test Rig ◽  
Power Sources ◽  
Diagnostic Capability ◽  
Actual Field ◽  
Steady State Simulation

Micro gas turbines (mGT) are emerging power sources for distributed generation facilities considering their environment friendliness, high fuel flexibility and efficient cogeneration of heat and power (CHP). Numerical simulation and diagnostic tools are essential for cycle optimization of mGT and prediction of performance degradation. This work is focused on fault diagnostics of T100 mGT through the application of AE-T100 model, a simulation tool, which has been developed within a collaboration between the University of Genoa (Unige) and Ansaldo Energia. This model has been developed for steady-state simulation of mGT in off-design conditions. Leveraging on previous efforts for model development, tuning, first phase of validation through Ansaldo Enegia test rig (AE-T100) and diagnostic application of the model, the present work deals with further utilization of the diagnostic capability of the model for mGT cycles. For this purpose, it was used in real operating conditions through the AE-T100 test rig for the diagnostic aim of some unexpected machine behavior. The model results indicated high deviation from the actual field data in terms of fuel flow and efficiency, and so justified the diagnostic capability of the AE-T100 tool. Afterwards, based on the experimental observation of some bypass leakage from the burner in the same test rig, AE-T100 model was applied to model such leakage through the variation of AS ratio, leakage from the recuperator outlet to the ambient, combustor pressure drop and turbine section modification, and carried out the sensitivity analysis of these parameters. Sensitivity analysis has verified that the accurate impact of this leakage on overall mGT performance cannot be modeled with the help of AE-T100 tool in its current capacity. Therefore, some other investigations like analysis of compressor maps must be carried out to explain such a performance deviation in case of leakage. Afterwards, the analysis of compressor maps resulted from the operating conditions of the test conducted on the same machine after leakage repair, has highlighted the change in compressor operating point and thus, more efficient compressor functioning, which results in higher net power. Hence, this analysis has provided a more comprehensible explanation of this leakage impact on the mGT performance.

Micro Humid Air Cycle: Part B — Thermoeconomic Analysis

2003 ◽  
Author(s):  
J. Parente ◽  
A. Traverso ◽  
A. F. Massardo
Keyword(s):  
Gas Turbines ◽  
Electrical Power ◽  
Specific Work ◽  
Operational Flexibility ◽  
Humid Air ◽  
Capital Costs ◽  
Large Size ◽  
Heat Demand ◽  
Short Period ◽  
Specific Capital

Part A of this paper demonstrated that the HAT cycle, when applied to small-size gas turbines, can significantly enhance the efficiency and specific work of simple and recuperated cycles without the drastic changes to plant layout necessary in medium- and large-size plants. In this part B a complete thermoeconomic analysis is performed for microturbines operating in a Humid Air cycle. The capital cost and internal rate of return for both new machines and existing microturbines working in an mHAT-optimised cycle are presented and analysed. Three different scenarios are considered. The first scenario reflects a distributed electrical power generation application where cogeneration is not taken into account. Instead, the other two scenarios deal with CHP civil applications for different heat demands. The thermoeconomic results of the integrated mHAT cycle, based on a preliminary design of the saturator, demonstrate that microturbine performance can be greatly enhanced, while specific capital costs, in some cases, can be reduced up to 14%, without significant increase in layout complexity. Moreover, thanks to its operational flexibility (able to operate in dry and wet cycles), the mHAT is financially attractive for distributed power and heat generation (micro-cogeneration), particularly when heat demand is commutated in short period.

High-Speed Operation of a Gas-Bearing Supported MEMS-Air Turbine

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
C. J. Teo ◽  
L. X. Liu ◽  
H. Q. Li ◽  
L. C. Ho ◽  
S. A. Jacobson ◽  
...  
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Feed System ◽  
Coupling Effects ◽  
Leakage Flows ◽  
Aspect Ratios ◽  
Air Turbine ◽  
Gas Bearing

Silicon based power micro-electro-mechanical system (MEMS) applications require high-speed microrotating machinery operating stably over a large range of operating conditions. The technical barriers to achieving stable high-speed operation with micro-gas-bearings are governed by (1) stringent fabrication tolerance requirements and manufacturing repeatability, (2) structural integrity of the silicon rotors, (3) rotordynamic coupling effects due to leakage flows, (4) bearing losses and power requirements, and (5) transcritical operation and whirl instability issues. To enable high-power density the micro-turbomachinery must be run at tip speeds comparable to conventional scale turbomachinery. The rotors of the micro-gas turbines are supported by hydrostatic gas journal and hydrostatic gas thrust bearings. Dictated by fabrication constraints the location of the gas journal bearings is at the outer periphery of the rotor. The high bearing surface speeds (target nearly 10×106 mm rpm), the very low bearing aspect ratios (L/D<0.1), and the laminar flow regime in the bearing gap (Re<500) place these micro-bearing designs into unexplored regimes in the parameter space. A gas-bearing supported micro-air turbine was developed with the objectives of demonstrating repeatable, stable high-speed gas-bearing operation and verifying the previously developed micro-gas-bearing analytical models. The paper synthesizes and integrates the established micro-gas-bearing theories and insight gained from extensive experimental work. The characteristics of the new micro-air turbine include a four-chamber journal bearing feed system to introduce stiffness anisotropy, labyrinth seals to avoid rotordynamic coupling effects of leakage flows, a reinforced thrust bearing structural design, a redesigned turbine rotor to increase power, a symmetric feed system to avoid flow and force nonuniformity, and a new rotor micro-fabrication methodology for reduced rotor imbalance. A large number of test devices were successfully manufactured demonstrating repeatable bearing geometry. More specifically, three sets of devices with different journal bearing clearances were produced to investigate the dynamic behavior as a function of bearing geometry. Experiments were conducted to characterize the “as-fabricated” bearing geometry, the damping ratio, and the natural frequencies. Repeatable high-speed bearing operation was demonstrated using isotropic and anisotropic bearing settings reaching whirl-ratios between 20 and 40. A rotor speed of 1.7×106 rpm (equivalent to 370 m/s blade tip speed or a bearing DN number of 7×106 mm rpm) was achieved demonstrating the feasibility of MEMS-based micro-scale rotating machinery and validating key aspects of the micro-gas-bearing theory.

Energy Analysis of Part Flow and Full Flow Humid Air Turbine Cycle (HAT)

2006 ◽  
Author(s):  
Vahid Noei Aghaei ◽  
Bahador Bakhtiari ◽  
Hiwa Khaledi ◽  
Mohammad Bagher Ghofrani
Keyword(s):  
Thermodynamic Model ◽  
Energy Analysis ◽  
Pressure Ratio ◽  
Great Influence ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Water Mixture ◽  
Humid Air ◽  
Air Turbine

Current researches on the development of gas turbine related power plants such as HAT cycle and Combined Cycle are aimed to increase the plant efficiency and output power, while reducing the cost of power generation and emission. Humid air turbine cycle (HAT) is one of innovative cycles, which are able to provide a substantial power boost of the system and an efficiency rise of several percentage points. In order to perform energy analysis of Full Flow HAT cycle and Part Flow HAT cycle an advanced thermodynamic model is developed, which is enabling evaluation of behavior of Full Flow and Part Flow Humid Air Turbines and predicting the influence of operational parameters in the performance of these cycles. Changes in level of cooling technology are introduced in the model. Results show that this parameter has great influence on the cycle efficiency, especially at high Turbine Inlet Temperature (TIT). Also to model the accurate behavior of humid air, a new thermodynamic model is used to predict thermodynamic properties of air-water mixture at elevated temperature and pressure. In The pressure, in which compressor divided into two sections (LP/HP) is considered to find the optimum performance of cycle. Finally performance of Part Flow HAT cycle at different operating conditions (compressor pressure ratio, TIT) and bypass factors is verified and compared with Full Flow HAT cycle. Results show that in Part Flow HAT cycle changes in bypass factor has little influence on performance of the cycle. Furthermore, Part Flow HAT cycle exhibits better performance (compared to Full Flow HAT cycle) at high pressure ratio region, and vice versa at low pressure ratio region.

T100 Micro Gas Turbine Converted to Full Humid Air Operation: Test Rig Evaluation

2014 ◽  
Author(s):  
Ward De Paepe ◽  
Marina Montero Carrero ◽  
Svend Bram ◽  
Francesco Contino
Keyword(s):  
Energy Transfer ◽  
Gas Turbines ◽  
Water Injection ◽  
Test Rig ◽  
Humid Air ◽  
Limited Energy ◽  
Surge Margin ◽  
Heat Demand ◽  
Compressor Surge ◽  
Efficiency Increase

Micro Gas Turbines (mGTs) are very cost effective in small-scale Combined Heat and Power (CHP) applications. By simultaneously producing electric and thermal power, a global CHP efficiency of 80 % can be reached. However the low electric efficiency of 30 % makes the mGT profitability strongly dependent on the heat demand. This makes the mGT less attractive for applications with a non-continuous heat demand like domestic applications. Turning the mGT into a micro Humid Air Turbine (mHAT) is a way to decouple the power production from the heat demand. This new approach allows the mGT to keep running with water injection and thus higher electric efficiency during periods with no or lower heat demand. Simulations of the mHAT predicted a substantial electric efficiency increase due to the introduction of water in the cycle. The mHAT concept with saturation tower was however never tested experimentally. In this paper, we present the results of our first experiments on a modified Turbec T100 mGT. As a proof of concept, the mGT has been equipped with a spray saturation tower to humidify the compressed air. The primary goal of this preliminary experiments was to evaluate the new test rig and identify its shortcomings. The secondary goal was to gain insight in the mHAT control, more precisely the start-up strategy. Two successful test runs of more than 1 hour with water injection at 60 kWe were performed, resulting in stable mGT operation at constant rotation speed and pressure ratio. Electric efficiency was only slightly increased from 24.3 % to 24.6 % and 24.9 % due to the limited amount of injected water. These changes are however in the range of the accuracy on the measurements. The major shortcomings of the test rig were compressor surge margin reduction and the limited energy transfer in the saturation tower. Surge margin was reduced due to a pressure loss over the humidification unit and piping network, resulting in possible compressor surge. Bleeding air to increase surge margin was the solution to prevent compressor surge, but it lowers the electric efficiency by approximately 4 % absolute. The limited energy transfer was a result of a low water injection temperature and mass flow rate. The low energy transfer causes the limited efficiency increase. The first experiments on the mHAT test rig indicated its shortcomings but also its potential. Stable mGT operation was obtained and electric efficiency remained stable. By increasing the amount of injected water, the electric efficiency can be increased.

Performance Analysis of a 40mw Class Advanced Humid Air Turbine Pilot Plant

2013 ◽  
Author(s):  
Yutaka Watanabe ◽  
Toru Takahashi
Keyword(s):  
Gas Turbine ◽  
Pilot Plant ◽  
Gas Turbines ◽  
Power Plants ◽  
Medium Size ◽  
Water Recovery ◽  
Humid Air ◽  
System A ◽  
Air Turbine ◽  
Operational Test

Recently, high efficiency and operational flexibility are required for thermal power plants to reduce CO2 emissions and to introduce renewable energy sources. We study the advanced humid air turbine (AHAT) system, which appears to be high suitable for practical use because its configuration is simpler than that of gas turbine combined cycle power plants (GTCCs). Moreover, the thermal efficiency of AHAT system for small and medium-size gas turbines is higher than that of GTCCs. To verify feasibility of this system and the cycle performance of AHAT system, a 3MW-class pilot plant was built in 2006 by Hitachi, Ltd., which mainly consists of a gas turbine, a water atomization cooling (WAC) system, a recuperator, a humidification tower and a water recovery tower. Through the operational test from 2006 to 2010, we confirmed the feasibility of the AHAT as a power-generation system, and various characteristics such as the effect of changes in ambient temperature, part-load characteristics, and start-up characteristics. Next step, a 40MW-class pilot plant was built in 2011 and started operational tests. This system mainly consists of a dual-shaft heavy duty gas turbine, a WAC system, a recuperator and a humidifier. As a result of the operational test, it has been confirmed that the pilot plant output achieved rated power output. In this paper, we show the 40MW-class pilot plant running test results, and evaluate thermal characteristics of this plant and the effect of WAC and humidification on performance of this gas turbine system.

scholarly journals A Comparative Study on Fault Detection Methods for Gas Turbine Combustion Systems

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 389
Author(s):  
Jinfu Liu ◽  
Zhenhua Long ◽  
Mingliang Bai ◽  
Linhai Zhu ◽  
Daren Yu
Keyword(s):  
Fault Detection ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Detection Methods ◽  
Distribution Model ◽  
Outlet Temperature ◽  
Combustion System ◽  
Comparison Results ◽  
Gas Turbine Combustion

As one of the core components of gas turbines, the combustion system operates in a high-temperature and high-pressure adverse environment, which makes it extremely prone to faults and catastrophic accidents. Therefore, it is necessary to monitor the combustion system to detect in a timely way whether its performance has deteriorated, to improve the safety and economy of gas turbine operation. However, the combustor outlet temperature is so high that conventional sensors cannot work in such a harsh environment for a long time. In practical application, temperature thermocouples distributed at the turbine outlet are used to monitor the exhaust gas temperature (EGT) to indirectly monitor the performance of the combustion system, but, the EGT is not only affected by faults but also influenced by many interference factors, such as ambient conditions, operating conditions, rotation and mixing of uneven hot gas, performance degradation of compressor, etc., which will reduce the sensitivity and reliability of fault detection. For this reason, many scholars have devoted themselves to the research of combustion system fault detection and proposed many excellent methods. However, few studies have compared these methods. This paper will introduce the main methods of combustion system fault detection and select current mainstream methods for analysis. And a circumferential temperature distribution model of gas turbine is established to simulate the EGT profile when a fault is coupled with interference factors, then use the simulation data to compare the detection results of selected methods. Besides, the comparison results are verified by the actual operation data of a gas turbine. Finally, through comparative research and mechanism analysis, the study points out a more suitable method for gas turbine combustion system fault detection and proposes possible development directions.

Reduction of NOx Emission of Heavy Duty Gas Turbines by Improving Mixing Quality Using CFD Tools

2003 ◽  
Author(s):  
Weiqun Geng ◽  
Douglas Pennell ◽  
Stefano Bernero ◽  
Peter Flohr
Keyword(s):  
Gas Turbines ◽  
Mass Fraction ◽  
Cross Flow ◽  
Nox Emission ◽  
Injection System ◽  
Water Tunnel ◽  
Injection Hole ◽  
Fuel Mass ◽  
Mixing Quality ◽  
Fuel Mass Fraction

Jets in cross flow are one of the fundamental issues for mixing studies. As a first step in this paper, a generic geometry of a jet in cross flow was simulated to validate the CFD (Computational Fluid Dynamics) tool. Instead of resolving the whole injection system, the effective cross-sectional area of the injection hole was modeled as an inlet surface directly. This significantly improved the agreement between the CFD and experimental results. In a second step, the calculated mixing in an ALSTOM EV burner is shown for varying injection hole patterns and momentum flux ratios of the jet. Evaluation of the mixing quality was facilitated by defining unmixedness as a global non-dimensional parameter. A comparison of ten cases was made at the burner exit and on the flame front. Measures increasing jet penetration improved the mixing. In the water tunnel the fuel mass fraction within the burner and in the combustor was measured across five axial planes using LIF (Laser Induced Fluorescence). The promising hole patterns chosen from the CFD computations also showed a better mixing in the water tunnel than the other. Distribution of fuel mass fraction and unmixedness were compared between the CFD and LIF results. A good agreement was achieved. In a final step the best configuration in terms of mixing was checked with combustion. In an atmospheric test rig measured NOx emissions confirmed the CFD prediction as well. The most promising case has about 40% less NOx emission than the base case.

A Multiscale NDT System for Damage Detection in Thermal Barrier Coatings

2009 ◽  
Author(s):  
A. M. G. Luz ◽  
D. Balint ◽  
K. Nikbin
Keyword(s):  
High Temperature ◽  
Damage Detection ◽  
Luminescence Spectrum ◽  
Bond Coat ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Assessment Tool ◽  
Diagnostic Tools ◽  
Spectral Parameters ◽  
Temperature Oxidation

Progress in aero-engines and land-based gas turbines is continuously linked with a rise of the operating temperature. TBCs are multilayered structures which function together to effectively lower the temperature of its load-bearing superalloy substrate while simultaneously providing oxidation protection against high temperature combustion environments during operation. They typically comprise of a ceramic top coat for thermal insulation and a metallic bond coat that provides oxidation/corrosion resistance and enhances the adhesion of the YSZ to the superalloy substrate. Due to high-temperature oxidation of the bond coat, a thermally grown oxide (TGO) scale of continuous Al2O3 is formed between the ceramic top coat and the bond coat. The formation and growth of the TGO increases the mismatch of thermal expansion coefficients among the multilayered TBC and induce high thermal stresses leading to spallation of the YSZ coat from the underlying metal. Hence, nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs are essential to take full advantage of these systems. In this contribution, a new concept of multiscale NDT system is presented. The instrument uses a combination of imaging-based methods with photoluminescence piezospectroscopy, a laser-based method. Imaging-based methods like mid-infrared reflectance, laser optical backscatter and infrared tomography were used to predict the overall lifetime of the coated component. When TBCs approach the end of life, micro-crack nucleation and propagation at the top coat/bond coat interface increases the amount of reflected light. This rise in reflectance was correlated with the lifetime of the component using a neural network that merges the mean and standard deviation value of the gray level. Photoluminescence piezospectroscopy was subsequently used to give information about the structural integrity of the hot spots identified in the image analysis. This laser-based technique measures in-situ the residual stress in the TGO at room temperature. Damage leads to a relaxation of the local stress which is in turn reflected in the luminescence spectrum shape. However, presently there is no agreement on the best spectral parameters that should be used as a measure of the damage accumulation in the coatings. Therefore, the evolution of luminescence spectrum from as-manufactured to critically damaged TBCs was determined using the finite element method. This approach helped to identify the most suitable spectral parameters for damage detection, improving the reliability of photoluminescence piezospectroscopy as a failure assessment tool for TBCs.

Sign in / Sign up

Export Citation Format

Share Document