Capacity Matching of Aeroderivative Gas Generator With Free Power Turbine—Challenges, Uncertainties, and Opportunities

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Deepak Thirumurthy ◽  
Jose Carlos Casado Coca ◽  
Kanishka Suraweera
Keyword(s):  
Gas Turbines ◽  
Systems Approach ◽  
Gas Generator ◽  
Performance Guarantees ◽  
Design Variables ◽  
Performance Trends ◽  
Power Turbine ◽  
Parameter Matching ◽  
Allowable Range ◽  
Statistical Studies

Abstract For gas turbines (GTs) with free power turbines (FPTs), the capacity or flow parameter matching is of prime importance. Accurately matched capacity enables the GT to run at its optimum condition. This ensures maximum component efficiencies and optimum shaft speeds within mechanical limits. This paper presents the challenges, uncertainties, and opportunities associated with an accurate matching of a generic two-shaft aeroderivative high pressure (HP)-low pressure (LP) gas generator with the FPT. Additionally, generic performance trends, uncertainty quantification, and results from the verification program are also discussed. These results are necessary to ensure that the final FPT capacity is within the allowable range, and hence, the product meets the performance guarantees. The sensitivity of FPT capacity to various design variables such as the vane throat area, vane trailing edge size, and manufacturing tolerance is presented. In addition, issues that may arise due to not meeting the target capacity are also discussed. To conclude, in addition to design, analysis, and statistical studies, a system-of-systems approach is mandatory to meet the allowed variation in the FPT capacity and hence the desired GT performance.

Capacity Matching of Aeroderivative Gas Generator With Free Power Turbine: Challenges, Uncertainties, and Opportunities

2019 ◽  
Author(s):  
Deepak Thirumurthy ◽  
Jose Carlos Casado Coca ◽  
Kanishka Suraweera
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Systems Approach ◽  
Gas Generator ◽  
Performance Guarantees ◽  
Design Variables ◽  
Performance Trends ◽  
Power Turbine ◽  
Parameter Matching ◽  
Turbine Capacity

Abstract For gas turbines with free power turbines, the capacity or flow parameter matching is of prime importance. Accurately matched capacity enables the gas turbine to run at its optimum conditions. This ensures maximum component efficiencies, and optimum shaft speeds within mechanical limits. This paper presents the challenges, uncertainties, and opportunities associated with an accurate matching of a generic two-shaft aeroderivative HP-LP gas generator with the free power turbine. Additionally, generic performance trends, uncertainty quantification, and results from the verification program are also discussed. These results are necessary to ensure that the final free power turbine capacity is within the allowable range and hence the product meets the performance guarantees. The sensitivity of free power turbine capacity to various design variables such as the vane throat area, vane trailing edge size, and manufacturing tolerance is presented. In addition, issues that may arise due to not meeting the target capacity are also discussed. To conclude, in addition to design, analysis, and statistical studies, a system-of-systems approach is mandatory to meet the allowed variation in the free power turbine capacity and hence the desired gas turbine performance.

Advanced Control System Considerations for Small Shaft-Type Aircraft Gas Turbines

1970 ◽  
Author(s):  
D. A. Prue ◽  
T. L. Soule
Keyword(s):  
Control System ◽  
Gas Turbines ◽  
Evaluation Criteria ◽  
Open Loop ◽  
Engine Control ◽  
Gas Generator ◽  
Engine Control System ◽  
Power Turbine ◽  
Advanced Control ◽  
Temperature Load

The next generation of free-turbine engines in the 2 to 5-lb/sec airflow class will undergo vast improvements in performance and efficiency. The improvements will be achieved concurrent with overall reductions in size and weight. Effort is required at optimization and miniaturization of the engine control system to keep pace with these improvements. This paper describes a conceptual design of an advanced engine control system for this class of engine. It provides gas generator and power turbine control with torque, temperature, load sharing and overspeed limiting functions. The control system was concepted to accommodate, with minimum hardware changes, such variants as regenerative cycle and/or variable power turbine geometry. In addition, considerations for closed and open loop modes of control and fluidic, electronic and hydromechanical technologies were studied to best meet a defined specification and a weighted set of evaluation criteria.

Regenerative Gas Turbines With Divided Expansion

2004 ◽  
Author(s):  
Brian Elmegaard ◽  
Bjo̸rn Qvale
Keyword(s):  
Mathematical Model ◽  
Gas Turbines ◽  
High Efficiency ◽  
Limited Range ◽  
Simulation Program ◽  
Operating Parameters ◽  
Gas Generator ◽  
Extensive Simulation ◽  
Power Turbine ◽  
The Mathematical Model

Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas generator part for recuperation ahead of the expansion in the power turbine. The present study is more complete than the predecessors in that the ranges of the parameters have been extended and the mathematical model is more realistic using an extensive simulation program. It is confirmed that the proposed divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high. The advantages of the divided expansion manifest themselves over a rather limited range of the operating parameters, that lies outside the range required to make modern micro turbines economically competitive.

Modelling and Performance Analysis of Stationary Gas Turbines Operating Under Rotational Speed Transients

2021 ◽  
Author(s):  
André L. S. Andade ◽  
Osvaldo J. Venturini ◽  
Vladimir R. M. Cobas ◽  
Vinicius Zimmerman Silva
Keyword(s):  
Gas Turbines ◽  
Engine Performance ◽  
Heat Rate ◽  
Gas Generator ◽  
Transient Regimes ◽  
Power Turbine ◽  
Nominal Capacity ◽  
Prime Movers ◽  
And Performance ◽  
Operational Envelope

Abstract In order to increase the flexibility and performance of gas turbines, generally their manufacturers and research centers involved in their development are constantly seeking the expansion of their operational envelope as well as their efficiency, making the engine more dynamic, less polluting and able to respond promptly to variations in load demands. An important aspect that should be considered when analyzing these prime movers is the assessment of its behavior under transients due to load changes, which can be accomplished through the development of a detailed, accurate and effective computational model. Considering this scenario, the present work aims to develop a model for the simulation and analysis of the dynamic behavior of stationary gas turbines. The engine considered in this analysis has a nominal capacity of 30.7 MW (ISO conditions) and is composed by a two-spool gas generator and a free power turbine. The model was developed using T-MATS, an integrated Simulink/Matlab toolbox, develop by NASA. The gas turbine was evaluated under both permanent and transient regimes and each one of its component was analyzed individually. The assessment made it possible to determine the engine performance parameters such as efficiency, heat rate and specific fuel consumption and its operational limits (surge limits, stall, turbine inlet temperatures, etc.) under different load conditions and regimes. The results obtained were compared with available field data, and the relative deviations for the considered parameters were all lower than 1%.

Service Exchange or Major Overhaul. Which Philosophy to Implement for Gas Turbine

2021 ◽  
Author(s):  
Karim Mamdouh Youssef
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Generator ◽  
Major Overhaul ◽  
Maintenance Program ◽  
Direct Benefits ◽  
Equipment Availability ◽  
Power Turbine ◽  
Service Exchange ◽  
Correct Implementation

Abstract Maintenance costs and machine availability are two of the most important concerns to gas turbine equipment owner. Therefore, a well thought out maintenance program that reduces costs while increasing equipment availability should be instituted. The correct implementation of planned maintenance relying on preventive maintenance optimization through perfect inspection frequency and scope provides direct benefits in the avoidance of forced outages, unscheduled repairs, and downtime. Major overhaul is carried out for each gas turbine every 48,000 firing hours which costs around 1 M USD for each engine and with more than 8 months unavailability for the unit. To increase equipment availability and enhance cost and time efficiency, alternatives approaches were evaluated including Service Exchange of gas turbines. It is found that service exchange is the best option for optimizing time and cost of overhaul of such engines. This paper is written to improve Major Overhaul practice for existing Gas Turbines from ongoing practice of routine major overhaul including engine strip down, inspection and repair to Service Exchange of Gas Generator and Power Turbine every 48,000 firing hours.

Investigation of the Part-Load Performance of Two 1.12 MW Regenerative Marine Gas Turbines

1994 ◽  
Vol 116 (2) ◽  
pp. 418-423 ◽  
Author(s):  
T. Korakianitis ◽  
K. J. Beier
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Thermodynamic Cycle ◽  
Operating Regime ◽  
Operational Flexibility ◽  
Gas Generator ◽  
Electric Bus ◽  
Marine Propulsion ◽  
Power Turbine ◽  
Commercial Applications

Regenerative and intercooled-regenerative gas turbine engines with low pressure ratio have significant efficiency advantages over traditional aero-derivative engines of higher pressure ratios, and can compete with modern diesel engines for marine propulsion. Their performance is extremely sensitive to thermodynamic-cycle parameter choices and the type of components. The performances of two 1.12 MW (1500 hp) regenerative gas turbines are predicted with computer simulations. One engine has a single-shaft configuration, and the other has a gas-generator/power-turbine combination. The latter arrangement is essential for wide off-design operating regime. The performance of each engine driving fixed-pitch and controllable-pitch propellers, or an AC electric bus (for electric-motor-driven propellers) is investigated. For commercial applications the controllable-pitch propeller may have efficiency advantages (depending on engine type and shaft arrangements). For military applications the electric drive provides better operational flexibility.

Real-Time Variable Geometry Triaxial Gas Turbine Model for Hardware-in-the-Loop Simulation Experiments

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Tao Wang ◽  
Yong-Sheng Tian ◽  
Zhao Yin ◽  
Da-Yue Zhang ◽  
Ming-Ze Ma ◽  
...  
Keyword(s):  
Real Time ◽  
Gas Turbine ◽  
Working Conditions ◽  
Gas Turbines ◽  
Neural Net ◽  
Hardware In The Loop ◽  
Gas Generator ◽  
Component Level ◽  
Simulation Experiments ◽  
Power Turbine

This paper proposes a hybrid method (HMRC) comprised of a radial basis function (RBF) neural net algorithm and component-level modeling method (CMM) as a real-time simulation model for triaxial gas turbines with variable power turbine guide vanes in matlab/simulink. The sample size is decreased substantially after analyzing the relationship between high and low pressure shaft rotational speeds under dynamic working conditions, which reduces the computational burden of the simulation. The effects of the power turbine rotational speed on overall performance are also properly accounted for in the model. The RBF neural net algorithm and CMM are used to simulate the gas generator and power turbine working conditions, respectively, in the HMRC. The reliability and accuracy of both the traditional single CMM model (SCMM) and HMRC model are verified using gas turbine experiment data. The simulation models serve as a controlled object to replace the real gas turbine in a hardware-in-the-loop simulation experiment. The HMRC model shows better real-time performance than the traditional SCMM model, suggesting that it can be readily applied to hardware-in-the-loop simulation experiments.

scholarly journals Development and Field Experience of a 27,400 HP Aeroderivative Gas Turbine

1983 ◽  
Author(s):  
J. K. Hubbard ◽  
R. Tillinger
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Field Experience ◽  
Performance Test ◽  
Gas Generator ◽  
Successful Operation ◽  
Field Development ◽  
Design Concepts ◽  
Power Turbine ◽  
Field Unit

The paper describes the development and field experience of the model DJ270G Gas Turbine, the second of the manufacturer’s “second generation” gas turbines. By combining the merits of a proven aero-derivative gas generator with an advanced power turbine, the DJ270G has been developed to provide a reliable and efficient dual shaft gas turbine. Previously established power turbine design concepts were uniquely modified to maximize the overall efficiency of the unit. The introduction rate was advanced by running the development and manufacturing programs simultaneously. Field development was minimized by completing a full load performance test program in the factory prior to start-up of the first field unit. The completed machine has achieved an output of 27,400 horsepower with a thermal efficiency of 36.3%. Four units are now in operation and have logged over 33,000 hours of successful operation.

VECTRA™ Power Turbine Development Program

2001 ◽  
Author(s):  
Bruce R. deBeer ◽  
David A. Nye
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Mechanical Design ◽  
Development Program ◽  
Dynamic Strain ◽  
Load Testing ◽  
Operating Characteristics ◽  
Gas Generator ◽  
Full Load ◽  
Power Turbine

Dresser-Rand developed the VECTRA-40 power turbine specifically for the LM2500+ gas generator. This “clean sheet of paper” design uses some of the best features from both aeroderivative and heavy duty gas turbines. After the design phase was complete, an extensive development program was undertaken to confirm that both the mechanical and aerodynamic design objectives were met. Two units were built, instrumented, and tested to full load. In addition, several components were rig tested to verify stiffness, natural frequency, or operating characteristics. Finally, some events that could not be physically tested, such as blade out response, were tested virtually. During development testing, the power turbine was extensively instrumented with state-of-the-art sensors to verify the mechanical design and aerodynamic performance of the VECTRA. A PC based data acquisition system (DAQ) was constructed to simultaneously acquire and record over 1000 individual channels of data. Instrumentation was installed to record the mechanical responses and operating temperatures of all rotating components, as well as critical stationary components. Other groups of instrumentation were used to verify flowpath performance, cooling air distribution, and lubrication system operation. The physical devices connected to the DAQ system ranged from industrial transducers and signal conditioners to an innovative external telemetry system for rotating thermocouples and dynamic strain gages. The VECTRA is a high speed power turbine that was initially designed for mechanical drive applications. However recent component testing and full load testing of two units in generator drive packages have demonstrated that it is also well suited for power generation applications.

Investigation of the Part-Load Performance of Two 1.12 MW Regenerative Marine Gas Turbines

1992 ◽  
Author(s):  
Theodosios Korakianitis ◽  
Kurt Beier
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Thermodynamic Cycle ◽  
Operating Regime ◽  
Gas Generator ◽  
Turbine Engine ◽  
Design Point ◽  
Electric Bus ◽  
Power Turbine ◽  
Commercial Applications

Regenerative and intercooled-regenerative shaft-power gas turbine engines of low pressure ratio have significant efficiency advantages over traditional aero-derivative engines of higher pressure ratios, and can compete with modern diesel engines for marine propulsion. The design-point performance is extremely sensitive to thermodynamic-cycle parameter choices. The type of components chosen affects power and efficiency significantly. The design-point and off-design-point performance of two 1.12 MW (1500 hp) regenerative gas turbines are predicted with computer simulations. One engine has single-shaft configuration, and the other has a gas-generator / power-turbine combination. The gas-generator / power-turbine engine arrangement is essential for wide off-design operating regime. The performance of each engine driving fixed-pitch and controllable-pitch propellers, or an AC electric bus (for electric-motor-driven propellers) is investigated. For commercial applications the controllable-pitch propeller may have efficiency advantages (depending on engine type and shaft arrangements). For military applications the electric drive provides better operational flexibility.

Sign in / Sign up

Export Citation Format

Share Document