Variable Regimes Operation of Cogenerative Gas-Turbine Engine With Overexpansion Turbine

2010 ◽  
Author(s):  
V. Matviienko ◽  
V. Ocheretianyi
Keyword(s):  
Gas Turbine ◽  
Electrical Power ◽  
Electrical Energy ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Energetic Efficiency ◽  
Turbine Engine ◽  
Power Turbine ◽  
Turbo Compressor ◽  
High Level

High energetic efficiency of cogenerative gas-turbine engine (GTE) is due to by deep utilization of exhaust gases heat and greater portion of produced electrical energy, with is achieved by complication of Brayton cycle application of overexpansion in turbine. Such method is realized in GTE with turbo-compressor utilizer (TCU) attached to exhaust of the engine. TCU consists of the overexpansion turbine, exhaust compressor and gas cooler between them. Gas cooler in TCU is used as a water boiler-utilizer. This paper presents characteristics of GTE with TCU in variable regimes of loading. It is found, that GTE with TCU at nominal and partial loadings has higher efficiency, than simple cycle GTE. Construction of GTE with TCU can be performed with free TCU and blocked TCU, which is mechanically linked to power turbine. High energy efficiency of GTE with free TCU is proved, enabling to maintain overall efficiency on high level on decrease of electrical power. It is suggested that GTE with free TCU is more efficient for energy supply of municipal objects, and its constructive scheme provides stable delivery of heat energy to consumer upon significant variation of electric loading.

Optimal State-Space Control of a Gas Turbine Engine

1992 ◽  
Vol 114 (4) ◽  
pp. 763-767 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
C. G. Brockus
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
State Space Model ◽  
Gas Turbine Engine ◽  
The State ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Analog Control ◽  
Linear State ◽  
High Level

An analog fuel control for a gas turbine engine was compared with several state-space derived fuel controls. A single-spool, simple cycle gas turbine engine was modeled using ACSL (high level simulation language based on FORTRAN). The model included an analog fuel control representative of existing commercial fuel controls. The ACSL model was stripped of nonessential states to produce an eight-state linear state-space model of the engine. The A, B, and C matrices, derived from rated operating conditions, were used to obtain feedback control gains by the following methods: (1) state feedback; (2) LQR theory; (3) Bellman method; and (4) polygonal search. An off-load transient followed by an on-load transient was run for each of these fuel controls. The transient curves obtained were used to compare the state-space fuel controls with the analog fuel control. The state-space fuel controls did better than the analog control.

An Optimal Automated Zone Allocation Approach for Risk Assessment of Gas Turbine Engine Components

2013 ◽  
Author(s):  
Jonathan P. Moody ◽  
Michael P. Enright ◽  
Wuwei Liang
Keyword(s):  
Risk Assessment ◽  
Finite Element ◽  
Finite Elements ◽  
Fracture Risk ◽  
Gas Turbine ◽  
Optimal Allocation ◽  
Federal Aviation Administration ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Turbine Engine

High-energy rotating components of gas turbine engines may contain rare material anomalies that can lead to uncontained engine failures. The Federal Aviation Administration and the aircraft engine industry have been developing enhanced life management methods to address the rare but significant threats posed by these anomalies. One of the outcomes of this effort has been a zone-based risk assessment methodology in which component fracture risk is estimated using groupings of elements called zones that are associated with 2D finite element (FE) stress and temperature models. Previous papers have presented processes for creation of zones either manually or via an automatic algorithm in which zones are assigned to each finite element in a component model. These processes may require significant human time and computer time. The focus of this paper is on the optimal allocation of multiple finite elements to zones that minimizes the total number of zones required to compute the fracture risk of a component. An algorithm is described that uses a relatively coarse response surface method to estimate the conditional risk value at each node in a finite element model. Zones are initially defined for each finite element in the model, and the algorithm identifies and merges zones based on minimizing the influence on component risk. The process continues until all of the zones have been merged into a single zone. The zone sequence is applied in reverse order to identify the minimum number of zones that satisfies component target risk or convergence threshold constraints. This solution provides the optimal allocation of finite elements to zones. The algorithm is demonstrated for a representative gas turbine engine component. The approach significantly improves the computational efficiency of the zone-based risk analysis process.

Analytical efficiency comparison between gas turbine and gas turbine hybrid engines for passenger cars

1997 ◽  
Vol 211 (2) ◽  
pp. 113-119 ◽  
Author(s):  
W Cheng ◽  
D. G. Wilson ◽  
A. C. Pfahnl
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Passenger Cars ◽  
Long Distance ◽  
Vehicle Performance ◽  
Turbine Engine ◽  
Compression Ignition Engines ◽  
Power Turbine ◽  
Performance And Emissions ◽  
Efficiency Comparison

The performance and emissions of two alternative types of gas turbine engine for a chosen family vehicle are compared. One engine is a regenerative 71 kW gas turbine; the other is a hybrid power plant composed of a 15 kW gas turbine and a 7 MJ flywheel. These engines would give generally similar vehicle performance to that produced by 71 kW spark ignition and compression ignition engines. (The turbine engines would be lighter and, with a free power turbine, would have a more favourable torque-speed curve (1), giving them some advantages.) Results predict that for long-distance trips the hybrid engine would have a considerably better fuel economy and would produce lower emissions than the piston engines, and that the ‘straight’ gas turbine would be even better. For shorter commuting trips the hybrid would be able to run entirely from energy acquired and stored from house electricity, and it could therefore be the preferred choice for automobiles used primarily for urban driving when environmental factors are taken into account. However, the degradation of remaining energy in flywheel batteries and thermal energy in the regenerator and other engine hot parts between use periods will result in more energy being used than for the straight gas turbine engine using normal liquid fuel. The higher initial cost and greater complexity of the hybrid engine will be additional disadvantages.

scholarly journals A Model and State-Space Controllers for an Intercooled, Regenerated (ICR) Gas Turbine Engine

1992 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
R. W. Garman
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
High Efficiency ◽  
Linear Quadratic Regulator ◽  
Gas Turbine Engine ◽  
Linear Quadratic ◽  
Turbine Engine ◽  
Simulation Language ◽  
Linear State ◽  
High Level

A two-and-one-half spool gas turbine engine was modeled using the Advanced Computer Simulation Language (ACSL), a high level simulation environment based on FORTRAN. A possible future high efficiency engine for powering naval ships is an intercooled, regenerated (ICR) gas turbine engine and these features were incorporated into the model. Utilizing sophisticated instructions available in ACSL linear state-space models for this engine were obtained. A high level engineering computational language, MATLAB, was employed to exercise these models to obtain optimal feedback controllers characterized by the following methods: (1) state feedback; (2) linear quadratic regulator (LQR) theory; and (3) polygonal search. The methods were compared by examining the transient curves for a fixed off-load, and on-load profile.

Application of a Miniature Telemetry System in a Small Gas Turbine Engine

2011 ◽  
Author(s):  
Stephen A. Long ◽  
Patrick A. Reiger ◽  
Michael W. Elliott ◽  
Stephen L. Edney ◽  
Frank Knabe ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
Turbine Rotor ◽  
Gas Turbine Engine ◽  
Telemetry System ◽  
Strain Gages ◽  
Turbine Engine ◽  
Power Turbine ◽  
Successful Execution ◽  
Integration Effort

For the purpose of assessing combustion effects in a small gas turbine engine, there was a requirement to evaluate the rotating temperature and dynamic characteristics of the power turbine rotor module. This assessment required measurements be taken within the engine, during operation up to maximum power, using rotor mounted thermocouples and strain gages. The acquisition of this data necessitated the use of a telemetry system that could be integrated into the existing engine architecture without affecting performance. Due to space constraints, housing of the telemetry module was limited to placement in a hot section. In order to tolerate the high temperature environment, a cooling system was developed as part of the integration effort to maintain telemetry module temperatures within the limit allowed by the electronics. Finite element thermal analysis was used to guide the design of the cooling system. This was to ensure that sufficient airflow was introduced and appropriately distributed to cool the telemetry cavity, and hence electronics, without affecting the performance of the engine. Presented herein is a discussion of the telemetry system, instrumentation design philosophy, cooling system design and verification, and sample of the results acquired through successful execution of the full engine test program.

Application of Nonparametric Methods to Rainflow Stress Density Estimation of Gas Turbine Engine Usage

2006 ◽  
Author(s):  
M. P. Enright ◽  
R. C. McClung ◽  
S. J. Hudak ◽  
H. R. Millwater
Keyword(s):  
Gas Turbine ◽  
Density Estimation ◽  
High Energy ◽  
Nonparametric Methods ◽  
Gas Turbine Engine ◽  
Estimation Methods ◽  
Turbine Engines ◽  
Density Estimator ◽  
Gas Turbine Engines ◽  
Turbine Engine

The risk of fracture associated with high energy rotating components in aircraft gas turbine engines can be sensitive to small changes in applied stress values which are often difficult to measure and predict. Although a parametric approach is often used to characterize random variables, it is difficult to apply to multimodal densities. Nonparametric methods provide a direct fit to the data, and can be used to estimate the multimodal densities often associated with rainflow stress data. In this paper, a comparison of parametric and nonparametric methods is presented for density estimation of rainflow stress profiles associated with military aircraft gas turbine engine usages. A nonparametric adaptive kernel density estimator algorithm is illustrated for standard parametric probability density functions and for rainflow stress pairs associated with F-16/F100 engine usages. The kernel estimates are compared to parametric estimates, including a hybrid approach based on separate treatment of maximum stress pairs. The results provide some insight regarding the strengths and weaknesses of parametric and nonparametric density estimation methods for gas turbine engines, and can be used to develop improved stress estimates for probabilistic life predictions.

Simulation of a Gas Turbine Engine With Performance Degradation Modeling

2011 ◽  
Author(s):  
Ugo Campora ◽  
Mauro Carretta ◽  
Carlo Cravero
Keyword(s):  
Gas Turbine ◽  
Engine Performance ◽  
Gas Turbine Engine ◽  
Performance Degradation ◽  
Matlab Simulink ◽  
Turbine Engine ◽  
Simulink Model ◽  
Blade Thickness ◽  
High Level ◽  
Throat Section

A simulation of performance degradation for an aeronautical gas turbine engine (Honeywell T55 L712) is presented. The effects of turbine (low and high pressure stages) erosion on the engine performance have been investigated in some detail. The behavior of the engine has been simulated using a dynamic model implemented in Matlab-Simulink. Using a throughflow code the LPT and HPT have been simulated and their performance maps have been obtained with a high level of accuracy. In order to understand the effects of turbine erosion nine degradation levels have been introduced and the LPT and HPT performance have been computed using the abovementioned throughflow code. The degradation levels have been based on stator erosion effects (increase of throat section and blade thickness reduction) only according to the experimental evidence from the engine tests from Piaggio Aero Industries. The introduction of the modified turbine characteristics into the Matlab-Simulink model has allowed the degradation effects on the overall engine performance to be tested and discussed. Finally, using experimental data from the industrial maintenance database, the link of each level of degradation with the number of the engine operational time (hours) has been obtained.

scholarly journals Supply of additional working fluid to the flow part of the NK-8 gas turbine engine

2020 ◽  
Vol 178 ◽  
pp. 01038
Author(s):  
George Marin ◽  
Dmitrii Mendeleev ◽  
Boris Osipov ◽  
Azat Akhmetshin
Keyword(s):  
Gas Turbine ◽  
Maximum Load ◽  
Constant Load ◽  
Gas Turbine Engine ◽  
Working Fluid ◽  
Turbine Engine ◽  
Power Turbine ◽  
Mixing Chamber ◽  
Flow Part ◽  
Turbine Installation

Modern energy development strategies of advanced countries are based on the construction of gas turbine units which is associated with sufficiently high values of thermal efficiency and a relatively short term for putting them into operation. In this paper, the NK-8 engine is considered. It is modernized with a mixing chamber and a power turbine for the purpose of its ground application. A study was conducted of the injection of an additional working fluid into the flow part of a dual-circuit gas turbine engine. Steam is used as an injectable substance. For research a mathematical model was created in the AS «GRET» software package. The studies were carried out under constant load, the maximum load during injection was determined. An additional worker can be supplied with summer power limitations when it is necessary to increase the power of a gas turbine installation. Studies have shown that the maximum power that can be obtained by supplying steam to the flow part is 32.2 MW.

Design of a State Space Controller for an Intercooled, Regenerated (ICR) Gas Turbine Engine

1994 ◽  
Author(s):  
Karl F. Prigge ◽  
Jerry W. Watts ◽  
Terrence E. Dwan
Keyword(s):  
Gas Turbine ◽  
Time Constant ◽  
Gas Turbine Engine ◽  
The Other ◽  
Pole Placement ◽  
Inlet Temperature ◽  
Fast Time ◽  
Turbine Engine ◽  
Power Turbine ◽  
Input Control

A multi-input, multi-output (MIMO) controller for an advanced gas turbine has been developed and tested using a computer simulation. The engine modeled is a two-and-one half spool gas turbine with both an intercooler and a regenerator. In addition, variable stator vanes are present in the free-power turbine. This advanced engine is proposed for future naval propulsion for both mechanical drive ships and electrical drive ships. The designed controller controls free-power turbine speed and turbine inlet temperature using fuel flow and angle of the stator vanes. The controller will also have four modes of operation to deal with over temperature and over speed conditions. An eight state reduced order controller was used with pole placement and LQR to arrive at control gains. Both these methods required considerable insight into the problem. This insight was provided by previous experience with controller design for a less complicated engine, and also by use of a polyhedral search model of the gas turbine engine. The difficulty with a MIMO controller was that both inputs affect both of the control variables. The classical resolution of this problem is to have one input control one variable at a fast time constant and the other input control the other variable at a slow time constant. The “optimal” resolution of this problem is analyzed using the transient curves and basic control theory.

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