Impact of Air Quality and Site Selection on Gas Turbine Engine Performance

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
David W. MacPhee ◽  
Asfaw Beyene

Air pollution can have detrimental effects on gas turbine performance leading to blade fouling, which reduces power output and requires frequent cleanings. This issue is a fairly well-known phenomenon in the power industry. However, site selection for gas turbine installation on the basis of air quality is rarely part of the decision-making process, mainly due to lack of geographical options especially in an urban environment or perhaps due to a simple assumption that air quality at a local micro-level has no impact on the performance of the engine. In this paper, we perform a computational fluid dynamics (CFD) study on an area surrounding a combined heat and power (CHP) facility to assess the impact of local wind distribution on air quality and the performance of a gas turbine engine. Several aerodynamic properties are suggested as possible indicators of air quality and/or high airborne particulate concentration. These indicators are then compared to data collected at various points in and around the site. The results suggest that through post-processing of a simplified CFD simulation analyzing the adjacent terrain, a continuous map of field variables can be obtained and help designers locate future CHP or gas turbine power plants in regions of lower particulate concentrations. This, in turn, would greatly increase efficiency and cost-effectiveness of the proposed power plant.

Author(s):  
J. A. Saintsbury ◽  
P. Sampath

The impact of potential aviation gas turbine fuels available in the near to midterm, is reviewed with particular reference to the small aviation gas turbine engine. The future course of gas turbine combustion R&D, and the probable need for compromise in fuels and engine technology, is also discussed. Operating experience to date on Pratt & Whitney Aircraft of Canada PT6 engines, with fuels not currently considered of aviation quality, is reported.


2016 ◽  
Vol 66 (2) ◽  
pp. 193 ◽  
Author(s):  
Anuradha Nayak Majila ◽  
Rajeev Jain ◽  
Chandru Fernando D. ◽  
S. Ramachandra

<p>Studies the impact response of flat Titanium alloy plate against spherical projectile for damage analysis of aero engine components using experimental and finite element techniques. Compressed gas gun has been used to impart speed to spherical projectile at various impact velocities for damage studies. Crater dimensions (diameter and depth) obtained due to impact have been compared with finite element results using commercially available explicit finite element method code LS-DYNA. Strain hardening, high strain rate and thermal softening effect along with damage parameters have been considered using modified Johnson-Cook material model of LS-DYNA. Metallographic analysis has been performed on the indented specimen. This analysis is useful to study failure analysis of gas turbine engine components subjected to domestic object damage of gas turbine engine. </p><p> </p>


Author(s):  
E. A. Ogiriki ◽  
Y. G. Li ◽  
Th. Nikolaidis

Thermal barrier coatings (TBCs) have been widely used in the power generation industry to protect turbine blades from damage in hostile operating environment. This allows either a high turbine entry temperature (TET) to be employed or a low percentage of cooling air to be used, both of which will improve the performance and efficiency of gas turbine engines. However, with continuous increases in TET aimed at improving the performance and efficiency of gas turbines, TBCs have become more susceptible to oxidation. Such oxidation has been largely responsible for the premature failure of most TBCs. Nevertheless, existing creep life prediction models that give adequate considerations to the effects of TBC oxidation on creep life are rare. The implication is that the creep life of gas turbines may be estimated more accurately if TBC oxidation is considered. In this paper, a performance-based integrated creep life model has been introduced with the capability of assessing the impact of TBC oxidation on the creep life and performance of gas turbines. The model comprises of a thermal, stress, oxidation, performance, and life estimation models. High pressure turbine (HPT) blades are selected as the life limiting component of gas turbines. Therefore, the integrated model was employed to investigate the effect of several operating conditions on the HPT blades of a model gas turbine engine using a creep factor (CF) approach. The results show that different operating conditions can significantly affect the oxidation rates of TBCs which in turn affect the creep life of HPT blades. For instance, TBC oxidation can speed up the overall life usage of a gas turbine engine from 4.22% to 6.35% within a one-year operation. It is the objective of this research that the developed method may assist gas turbine users in selecting the best mission profile that will minimize maintenance and operating costs while giving the best engine availability.


Author(s):  
Asfaw Beyene ◽  
Terry Fredlund

Electric, pneumatic, combustion, and hydraulic systems are commonly used as gas turbine engine starters. All such starters must allow full-load engine operation to be reached within few or several minutes, depending on the size and type of the engine. This contrast in the power source of these starters imposes a variation in their operations including control procedures and safety measures such as blow-downs and on/off sequences. Driving characteristics such as dynamic and static behaviors of these starters also vary significantly, depending on the type of starter and the size or configuration (single or multiple shafts) of the engine to be started. This paper provides an overall comparative background of the commonly available gas turbine engine starters. It also presents numerical results comparing hot start characteristics of single, two, and three shaft engines with cold and hot ends. The possibility of a safe engine hot starting is a valid asset in some service areas, mainly military applications. The comparisons include starter power and gas producer speed (NGP) as the function of engine acceleration, and also starter torque as a function of the % NGP. Fuel consumption of the engine during the hot start is simulated and presented as a function of the load. The impact of an engine configuration on engine starting characteristics is implicated.


Author(s):  
E. Poursaeidi ◽  
A. A. Pirmohammadi ◽  
M. R. Mohammadi Arhani

This paper presents the outcomes of computational mechanics applied in the root-cause investigation on hot section failure of a 25 MW gas turbo generator in the domestic power plant after 2228 start-stops and 52,586 h operation. The failure includes the complete damage of the first and the second stage of nozzles, blades, seals, shroud segments, and also a peripheral damage on the disk of first stage. Several reported cases from the different power plants with similar events evidenced that the failure is a serious common type in the mentioned gas turbine engine. A previous study on complete metallurgical analysis of disk, moving blades, and lock-pins, was done by Poursaeidi and Mohammadi (2008, “Failure Analysis of Lock-Pin in a Gas Turbine Engine,” Eng. Fail. Anal., 15(7), pp. 847–855), which concluded that the mechanical specification of applied materials had been satisfied. Nevertheless, some problems were found in the fractographic results of lock-pins: the typical fatigue fracture surfaces in the neck of failed lock-pins and frankly localized pitting signs near the head of lock-pin. The lock-pins are kinds of small devices that lock the buckets after inserting them into disk grooves. In this work, a 3D finite element model (FEM) of a blade, a disk, and a lock-pin are made and analyzed by the ANSYS software. The results of the FEM showed a reasonable agreement between the analysis and position of fracture on lock-pins. Also, the results showed that the second vibrational mode of the bucket is a possible cause of failure because in this mode the peak stress occurs on the head of the lock-pin. However, inadequate design and long time service reduced the performance of lock-pins for sustaining a severe hot condition in the first stage of the turbine section.


Author(s):  
Rube´n A. Miranda Carrillo ◽  
Marco A. R. Nascimento ◽  
Elkin I. Gutie´rrez Vela´squez ◽  
Newton R. Moura

Microturbines have been developed as an important power unit for distributed generation (DG) or distributed energy resource (DER) options [1]. They have been established and are widely used in aircraft and power applications, due to their easy installation, reliability, high performance, multi-fuel capabilities and low emission [2]. However, the aerothermodynamic design of a radial turbine still poses a challenge due to its high rotational speed and high inlet temperature, which influence the centrifugal stress and the rotor structural integrity. This paper presents the numerical investigations on the aerothermodynamic design of the nozzle and the radial inflow rotor for a 600 kW simple cycle gas turbine engine using a One-dimensional Computer FORTRAN Code (OFC) [3], on the grounds of non-dimensional parameters aimed at computational and work time reduction. This program utilizes a one-dimensional solution of flow conditions through the turbine along the meanline. The referred computer program is an effective performance prediction tool mostly in the initial stage of the preliminary design and can be used to quickly investigate and calculate the number of design options prior to any details of the vane and blade geometry. In order to find the most promising design option, a computational fluid dynamics (CFD) simulation has been used to study the performance, the aerothermodynamic design and the flow characteristics of the turbine components. The OFC results were compared with the CFD simulation, a computer program for the design analysis of radial inflow turbines, and analytical results taken from specialized literature showed the results were in agreement.


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