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.

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.

A Modular Code for Real Time Dynamic Simulation of Gas Turbines in Simulink

2002 ◽  
Vol 128 (3) ◽  
pp. 506-517 ◽  
Author(s):  
S. M. Camporeale ◽  
B. Fortunato ◽  
M. Mastrovito
Keyword(s):  
Mathematical Model ◽  
Real Time ◽  
Gas Turbine ◽  
Dynamic Behavior ◽  
Gas Turbines ◽  
Simulation Software ◽  
Computational Time ◽  
High Fidelity ◽  
Time Step ◽  
The Mathematical Model

A high-fidelity real-time simulation code based on a lumped, nonlinear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high-fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage-by-stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab-Simulink using an object-oriented approach, is flexible and can be easily adapted to any kind of plant configuration. Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero-derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.

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.

scholarly journals A New Turbine for Natural Gas Pipelines

1999 ◽  
Vol 121 (05) ◽  
pp. 72-74
Author(s):  
Jay M. Wilson ◽  
Henry Baumgartner
Keyword(s):  
High Efficiency ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Gas Generator ◽  
Natural Gas Pipelines ◽  
Modular Concept ◽  
Power Turbine ◽  
Temperature Capability ◽  
Turbine Design

The new Cooper-Bessemer power turbine is a high-efficiency, center frame-mounted, three-stage unit that can be driven by either the existing RB211-24 gas generator or the new improved version. The upgraded gas generator combined with the new power turbine offers an increase in nominal output from 28.4 MW (38,000 hp) to 31.8 MW (42,600 hp). The new coupled turbine, now being tested, is called the Coberra 6761. Besides improving core engine performance, the program's objectives included improved fuel efficiency and reliability, and easier site serviceability; extension of the modular concept from the gas generator into the power turbine with improvements in sealing, materials, and temperature capability as well as interchangeability of both upgraded turbines with existing hardware. The Rolls-Royce industrial RB211 turbine, derived from an aircraft engine, is the basis for the gas generator end of Cooper Energy Services' Coberra coupled turbines. The power turbine design capacity has a significant effect on the power at a given speed. The flow capacity was optimized to achieve the best thermal efficiency and lower IP speeds to optimize IP compressor efficiency and permit future throttle push.

scholarly journals Mathematical model of the ichtyocenose with delays

2010 ◽  
Vol 51 ◽  
Author(s):  
Donatas Švitra ◽  
Giedrius Žemaitis
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Numerical Solutions ◽  
Simulation Program ◽  
Curonian Lagoon ◽  
The Mathematical Model

This article describes the authors’ work the existing ecosystem in the Curonian Lagoon. Using the mathematical model of the ichtyocenose (1)–(2) is simulated the dynamics of the ichtyocenose in the Curonian Lagoon. It is done by using Runge–Kut IV method from this simulation program ModelMaker. The model numerical solutions of F1 - F8 are compared with the experimental data for the monitoring of fish. The dynamics is projected to the year 2016.

scholarly journals MANEUVERING PERFORMANCE OF A 30 GT FISHING VESSEL WITH ASYMMERICAL PROPELLER CONFIGURATION

2018 ◽  
Vol 9 (2) ◽  
pp. 491-498
Author(s):  
Andi Haris Muhammad ◽  
. Syarifuddin ◽  
Daeng Paroka ◽  
Sabaruddin Rahman ◽  
. Wisyono ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Simulation Program ◽  
Fishing Vessel ◽  
Matlab Simulink ◽  
Fishing Vessels ◽  
Modeling Group ◽  
Left And Right ◽  
The Mathematical Model

Fishing vessels are designed with a specific mission. That mission is to locate, catch, and preserve fish while out at sea, meanwhile the vessel needed to have good maneuverability. This research describes a study on asymmetrical propeller configuration of a fishing vessel to improve its maneuvering quality. MATLAB-simulink program was used to simulate, the turning circle and the zigzag maneuvers. The simulation program was developed based on the mathematical model for a fishing vessel maneuvering. The mathematical model involved the setting-up a 3 DOF (Degres of Freedom) mathematical model in a modular of MMG (Mathematical Modeling Group) of the hull, propeller and rudder component. The result indicated that twin propeller with asymmetrical had an advantages of turning circle ability of 8% to 14 %, meanwhile the zigzag maneuver 20°/20° had 9 to 20 % 1st overshoot different between left and right heading.                                                                                         Keywords: Configuration, propeller, assymetrical, fisheries, simulation

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%.

Dynamics of a Damping Device Based on Ishlinsky Material

2019 ◽  
Vol 20 (2) ◽  
pp. 106-113 ◽  
Author(s):  
M. E. Semenov ◽  
M. G. Matveev ◽  
P. A. Meleshenko ◽  
A. M. Solovyov
Keyword(s):  
Mathematical Model ◽  
High Efficiency ◽  
Resonance Region ◽  
External Source ◽  
Weak Efficiency ◽  
Viscous Damper ◽  
Force Transmission ◽  
Hysteretic Damper ◽  
Hysteretic Nonlinearity ◽  
The Mathematical Model

In present paper we consider the damping properties of the oscillating system with hysteretic nature. The mathematical model of considered system is based on the operator approach for the hysteretic nonlinearity on the example of Ishlinsky material. Such a converter is a continual analogue of the set of stops connected in parallel. In the frame of the paper we compare the various approaches to modeling of damping systems. Namely, together with the hysteretic damper we consider the so-called nonlinear viscous damper which is a generalization of a standard linear damper with dependence on the velocity. The mathematical model of the considered system is formulated in terms of second order ordinary differential equation with hysteretic nonlinearity (namely, the operator-type nonlinearity). In comparison with the phenomenological models of hysteresis (such as Bouc-Wen model) that are often used in the modeling, the Ishlinsky model allows to " feel" the hysteretic nature of the material on the physical level. The major result of the presented paper is the comparison both the hysteretic and viscous (including the linear and nonlinear cases) dampers. Such a comparison is made in terms of transmission functions that reflect the "efficiency" of suppression of the external perturbations by the force transmission from an external source to the load. The results of numerical simulations showed the high efficiency of hysteretic damper both in and outside the resonance region (at the same time it is well known that the linear viscous damper has a weak efficiency outside the resonance region). The disadvantage of the hysteretic damper lies in the fact that its ability to dump the relative motion of the system under external forces is insignificantly reduced outside the resonance region.

scholarly journals Development of a High Pressure Ratio Centrifugal Compressor for 300kW-Class Ceramic Gas Turbine

1997 ◽  
Author(s):  
T. Sakai ◽  
Y. Tohbe ◽  
T. Fujii ◽  
T. Tatsumi
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Flow Distribution ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Angle Distribution ◽  
Gas Generator

Research and development of ceramic gas turbines (CGT), which is promoted by the Japanese Ministry of International Trade and Industry (MITI), was started in 1988. The target of the CGT project is development of a 300kW-class ceramic gas turbine with a 42 % thermal efficiency and a turbine inlet temperature (TIT) of 1350°C. Two types of CGT engines are developed in this project. One of the CGT engines, which is called CGT302, is a recuperated two-shaft gas turbine with a compressor, a gas-generator turbine, and a power turbine for cogeneration. In this paper, we describe the research and development of a compressor for the CGT302. Specification of this compressor is 0.89 kg/sec air flow rate and 8:1 pressure ratio. The intermediary target efficiency is 78% and the final target efficiency is 82%, which is the highest level in email centrifugal compressors like this one. We measured impeller inlet and exit flow distribution using three-hole yaw probes which were traversed from the shroud to the hub. Based on the measurement of the impeller exit flow, diffusers with a leading edge angle distribution adjusted to the inflow angle were designed and manufactured. Using this diffuser, we were able to attain a high efficiency (8:1 pressure ratio and 78% adiabatic efficiency).

scholarly journals Nonlinear Digital Simulation and Minimum Fuel Control of a Jet Type Gas Turbine Power Generating Unit

1978 ◽  
Author(s):  
D. Weiner ◽  
F. S. Aschner ◽  
J. Dayan
Keyword(s):  
Mathematical Model ◽  
Mathematical Programming ◽  
Gas Turbine ◽  
Digital Simulation ◽  
Measured Data ◽  
Gas Generator ◽  
Nonlinear Simulation ◽  
Power Generating Unit ◽  
Simulation Results ◽  
The Mathematical Model

This paper discusses the digital nonlinear simulation of a twin-spool gas generator-free turbine power generating unit. The mathematical model derived is flexible and can be easily converted to suit any other gas turbine. Simulation results were verified by comparison to measured data. The model was applied to optimize a fuel control schedule by methods of Mathematical Programming, taking into account the constraints imposed by the protective control of the system.

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