Gas Turbine Power Augmentation: Parametric Study Relating to Fog Droplet Size and Its Influence on Evaporative Efficiency

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbine ◽  
Droplet Size ◽  
Operating Conditions ◽  
Comprehensive Treatment ◽  
Ambient Temperatures ◽  
Numerical Studies ◽  
Spray Plume ◽  
Augmentation Techniques ◽  
Wet Compression ◽  
Nozzle Type

Several gas turbine power augmentation techniques are available to counter the detrimental drop in power and thermal efficiency that occur at high ambient temperatures. Inlet fogging and wet compression are two common and relatively simple techniques. This paper addresses the influence and importance of droplet size on evaporative cooling performance and efficiency. Spray nozzles used for inlet fogging and wet compression include impaction pin, swirl jet, air assisted, and swirl flash nozzle designs. The evaporation efficiency of the atomized droplets from these nozzles depends on the droplet size, size distribution, and spray plume shape. Droplets size varies with nozzle type, configuration, operating conditions, and nozzle manifold location in the gas turbine inlet duct and are affected by airflow velocity, residence time, coalescence effects, and water carryover. The proper selection of nozzle type, nozzle manifold location, and nozzle distribution are of cardinal importance to avoid large droplets and under-/oversaturated areas, which would affect compressor mechanical and aerodynamic efficiency. Analytical and numerical studies are compared with experimental results. This paper provides a comprehensive treatment of parameters affecting droplet size and will be of value to gas turbine fog system designers and users.

Gas Turbine Power Augmentation: Parametric Study Relating to Fog Droplet Size and Its Influence on Evaporative Efficiency

2008 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbine ◽  
Droplet Size ◽  
Operating Conditions ◽  
Comprehensive Treatment ◽  
Aerodynamic Efficiency ◽  
Ambient Temperatures ◽  
Numerical Studies ◽  
Spray Plume ◽  
Augmentation Techniques ◽  
Wet Compression

Several gas turbine power augmentation techniques are available to counter the detrimental drop in power and thermal efficiency that occur at high ambient temperatures. Inlet fogging and wet compression are two common and relatively simple techniques. This paper addresses the influence and importance of droplet size on evaporative cooling performance and efficiency. Common spray nozzles used for inlet fogging and wet compression are the impaction pin, swirl jet, air assisted, and swirl flash nozzles. The atomization process from these nozzles and their performance depends on the droplet size, size distribution, and spray plume shape. Droplets size varies with nozzle types, configurations, operating conditions, and nozzle manifold location in the gas turbine inlet duct as they are affected by airflow velocity, residence time coalescence effects, evaporation efficiency, and water carryover. The proper selection of nozzle type and location and nozzle distribution are of importance to avoid large droplets and under/over saturated areas which would affect compressor mechanical and aerodynamic efficiency. Analytical and numerical studies are compared to experimental results available from installed systems, and treated in the literature. This paper provides a comprehensive treatment of parameters affecting droplet size and will be of value to gas turbine fog system designers and users.

Neural Network Based Predictive Emission Monitoring Module for a GE LM2500 Gas Turbine

2010 ◽  
Author(s):  
K. K. Botros ◽  
M. Cheung
Keyword(s):  
Neural Network ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Training Data ◽  
Pipeline System ◽  
Emission Data ◽  
Ambient Temperatures ◽  
Emission Monitoring ◽  
Data Points ◽  
Monitoring Module

A Predictive Emission Monitoring (PEM) model has been developed for a non-DLE GE LM2500 gas turbine used on a natural gas compressor station on the TransCanada Pipeline System in Alberta. The PEM model is based on an optimized Neural Network (NN) architecture which takes four fundamental engine parameters as input variables. The model predicts NOx emission in ppmv-dry-O2 corrected and in kg/hr as NO2. The NN was trained using Continuous Emission Monitoring (CEM) measurements comprising two sets of actual emission data collected over two different dates in 2009, when the ambient ambient temperatures were vastly different (∼1° C and 24 °C), respectively. These training data were supplemented by other emission data generated by GE ‘Cycle-Deck’ tool to generate emission data at different ambient temperatures ranging from −30 to +30 °C. The outcome is a total of 1872 emission data of engine emissions at different operating conditions covering the range of the engine operating parameters (402 data points from CEM and 1470 data points from GE Cycle-Deck). The PEM model comprises a simple single hidden layer perceptron type NN with only two neurons in it. The performance of the NN-based model showed a correlation coefficient greater than 0.99, and error standard deviation of 4.5 ppmv of NOx and 1.4 kg/hr as NO2. Uncertainty analysis was conducted to assess the effects of uncertainties in the engine parameters on the NOx predictions by PEM. It was shown that for uncertainty in the ambient temperature of ±1 °C, the uncertainty in the NOx prediction is ± 0.9 to ±3.5%. Uncertainties of the order of ±1% in the other three input parameters results in uncertainties in NOx predictions by ±2.5 to ±6%. Finally, the PEM model was implemented in the station CEHM (Compressor Equipment Health Monitoring) system and NOx prediction were reported online on a minutely basis. These data are presented here over the first three months since implementation.

Effects of Spray Parameters and Operating Conditions on an Industrial Gas Turbine Washing System

2004 ◽  
Author(s):  
Friederike C. Mund ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Droplet Size ◽  
Mass Flow ◽  
Gas Turbines ◽  
Numerical Study ◽  
Operating Conditions ◽  
Injection Velocity ◽  
Spray Parameters ◽  
Compressor Inlet ◽  
Spray Distribution

Gas turbines for power generation are exposed to a variety of ambient conditions and are therefore bound to breathe contaminated airflow, thus degrading the engines internal gas path. In particular, accumulated debris on the compressor blades reduces engine efficiency. To recover this performance loss, online compressor washes may be performed. Cleaning fluid is injected through the nozzles upstream of the compressor to wash off the debris from the blades. This paper presents a numerical study of a generic compressor washing system based on an application case for a heavy duty gas turbine power plant. The inlet duct of the engine was modeled and droplet trajectories were calculated. Different spray patterns including single jet and full cone have been investigated for different ranges of injection velocity and droplet size. The spray angle was evaluated experimentally and was used to model the full cone spray pattern. The boundary conditions for the airflow were iterated with a performance simulation tool to match pressure loss and mass flow. To investigate the effect of different operating conditions on the airflow and spray distribution, an installation scenario of the engine at altitude on a hot summer day was modeled. The scenario was based on a review of plant installations and local meteorological conditions. Fluid concentration plots at the compressor inlet plane were evaluated for the different computational cases. Generally with lower injection momentum, the water droplets were significantly deflected by the main airflow. Higher injection velocity and droplet size reduced the effect of the main airflow. Different operating conditions and the significant change of air mass flow affected the spray distribution of the washing system at the compressor inlet. This can be compensated by adjusting the injection angles.

Evaporative Cooling of Gas Turbine Engines: Climatic Analysis and Application in High Humidity Regions

2007 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbine ◽  
Detrimental Effect ◽  
Low Cost ◽  
Evaporative Cooling ◽  
Turbine Engines ◽  
Climatic Data ◽  
High Humidity ◽  
Gas Turbine Engines ◽  
Ambient Temperatures ◽  
Augmentation Techniques

There are numerous power generation and mechanical drive gas turbine applications where the power drop caused by high ambient temperatures has a very detrimental effect on the production of power or process throughput. Media evaporative cooling and inlet fogging are common low cost power augmentation techniques applied to reduce these losses. Several misconceptions exist regarding the applicability of evaporative cooling to what are often called “high humidity” regions. There is a sizable evaporative cooling potential in most locations when climatic data is evaluated based on an analysis of coincident wet bulb and dry bulb data. This data is not readily available to plant users and designers. This paper provides a detailed treatment of available climatic data bases and presents actual climatic data from several world wide locations to show that considerable cooling potential actually exists even in high humidity regions. It is hoped that this paper will be of value to plant designers, engineering and operating companies that are considering the use of evaporative cooling for power augmentation.

Water Injection Evaporation in Frame 7EA Gas Turbine Wrapper

2017 ◽  
Author(s):  
Michele Bianchi ◽  
Andrea De Pascale ◽  
Francesco Melino ◽  
Antonio Peretto ◽  
Sasha Savic
Keyword(s):  
Gas Turbine ◽  
Droplet Size ◽  
Liquid Water ◽  
Gas Turbines ◽  
Water Injection ◽  
Steam Injection ◽  
Operating Conditions ◽  
Nox Abatement ◽  
The Impact ◽  
Calculation Code

A Southern California cogeneration plant is comprised of four GE-made Frame No 7, Model EA, heavy duty gas turbines driving Electrical Generators. Turbine exhaust gases are routed into the heat recovery steam generators (HRSG) of the split level. The HRSG are furnished with supplemental firing in order to boost the production of the steam. The produced NOX abatement is realized by the continuous steam injection and selective catalyst reduction (SCR). In order to reduce the steam consumption for NOX abatement, water injection in combustion chamber can be taken into account. Unfortunately, available gas turbine combustor cannot be used to inject water directly into the liner (and thus maximize the impact of water injection compared to steam injection); for this reason, an alternative solution was investigated which consists on water injection into the combustor wrapper. By doing this, effects on NOX abatement are similar to those of steam injection for power augmentation, namely only about 30% of water injected this way will actually quench the NOX, the rest flowing through the dilution holes. To ensure no impact of water injection on the combustor hardware’s integrity, any liquid droplets injected into the wrapper shall evaporate prior to reaching the liner. In order to estimate the behavior of liquid water droplets injected into the wrapper, a calculation code was developed by University of Bologna. This calculation code is able to estimate the evaporation rate of a spray of liquid water by calculating the droplets diameter reduction, the air temperature drop, etc. as function of boundary conditions. More in details, the aim of this study is to estimate the maximum droplet sizes to ensure the full evaporation of the water and to eliminate negative effects on the combustor life. In order to achieve this goal, a parametric study has been developed, changing the droplet size to calculate the time needed for full evaporation and compare this with the time of droplet travel from the injection point to the first dilution holes of the combustor liner. More in details, it was calculated, under various gas turbine operating conditions, what would be the maximal droplet size needed to evaporate within the available residence time into the wrapper.

scholarly journals INFLUENCE OF NOZZLE TYPE, WORKING PRESSURE, AND THEIR INTERACTION ON DROPLETS QUALITY USING KNAPSACK SPRAYER

2019 ◽  
Vol 50 (3) ◽  
Author(s):  
M. H. R. Alheidary
Keyword(s):  
Droplet Size ◽  
Spray Deposition ◽  
White Paper ◽  
Operating Conditions ◽  
Hollow Cone ◽  
Working Pressure ◽  
Nozzle Height ◽  
Median Diameter ◽  
Knapsack Sprayer ◽  
Nozzle Type

The present experiment was carried out at the Dept. of Agricultural Machines and Equipment, College of Agriculture, University of Basrah.  The aim of the study is to highlight the effect of the nozzle type, working pressure and their interaction onto droplet quality using knapsack sprayer to improve their performance. Droplet characteristics were sampled on white paper cards at different distances from the nozzle. On the samples spray deposits, spray coverage, droplet size, and volume median diameter was measured using BSF tracer with water after their deposit on the sample. The main studied parameters were: Six nozzle types hollow cone, Flat fan ceramic, flat fan ISO, CFA, AirMix and flat fan air induction nozzle. Two working pressures were 15 and 25 psi. All measurements carried out at the same nozzle height of 50cm by using CRD with three replications. The main results of this study showed the best spray deposition and spray coverage with the highest values 0.06nµl.cm-2 and 63% respectively when hollow cone nozzle was compared to other nozzles under the same operating conditions.  Whereas, the Flat fan air induction nozzle appeared the most significant droplet size and VMD 377.69 µm and 378 µm respectively when it was compared to the hollow cone and flat fan nozzles.

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.

Influence of Water Droplet Size and Temperature on Wet Compression

2007 ◽  
Author(s):  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
S. Ingistov
Keyword(s):  
Gas Turbine ◽  
Water Droplet ◽  
Droplet Diameter ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Air Cooling ◽  
Compression Process ◽  
Two Phase ◽  
Wet Compression

In the last years, among all different gas turbine inlet air cooling techniques, an increasing attention to fogging approach is dedicated. The various fogging strategies seem to be a good solution to improve gas turbine or combined cycle produced power with low initial investment cost and less installation downtime. In particular, overspray fogging and interstage injection involve two-phase flow consideration and water evaporation during compression process (also known as wet compression). According to the Author’s knowledge, the field of wet compression is not completely studied and understood. In the present paper, all the principal aspects of wet compression and in particular the influence of injected water droplet diameter and surface temperature, and their effect on gas turbine performance and on the behavior of the axial compressor (change in axial compressor performance map due to the water injection, redistribution of stage load, etc.) are analyzed by using a calculation code, named IN.FO.G.T.E. (INterstage FOgging Gas Turbine Evaluation), developed and validated by the Authors.

Chemical Reactor Network Application to Emissions Prediction for Industial DLE Gas Turbine

2006 ◽  
Author(s):  
I. V. Novosselov ◽  
P. C. Malte ◽  
S. Yuan ◽  
R. Srinivasan ◽  
J. C. Y. Lee
Keyword(s):  
Gas Turbine ◽  
Chemical Reactor ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Ongoing Research ◽  
Chemical Reactor Network ◽  
Reaction Zones ◽  
Reactor Network

A chemical reactor network (CRN) is developed and applied to a dry low emissions (DLE) industrial gas turbine combustor with the purpose of predicting exhaust emissions. The development of the CRN model is guided by reacting flow computational fluid dynamics (CFD) using the University of Washington (UW) eight-step global mechanism. The network consists of 31 chemical reactor elements representing the different flow and reaction zones of the combustor. The CRN is exercised for full load operating conditions with variable pilot flows ranging from 35% to 200% of the neutral pilot. The NOpilot. The NOx and the CO emissions are predicted using the full GRI 3.0 chemical kinetic mechanism in the CRN. The CRN results closely match the actual engine test rig emissions output. Additional work is ongoing and the results from this ongoing research will be presented in future publications.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

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