scholarly journals A Highly Flexible Approach on the Steady-State Analysis of Innovative Micro Gas Turbine Cycles

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Thomas Krummrein ◽  
Martin Henke ◽  
Peter Kutne
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Solution Process ◽  
Simulation Tool ◽  
Fast Computation ◽  
Micro Gas Turbine ◽  
Simulation Tools ◽  
Complexity Result ◽  
Combustion Technology ◽  
Steady State Simulation

Steady-state simulation is an important method to investigate thermodynamic processes. This is especially true for innovative micro gas turbine (MGT)-based cycles as the complexity of such systems grows. Therefore, steady-state simulation tools are required that ensure large flexibility and computation robustness. As the increased system complexity result often in more extensive parameter studies also a fast computation speed is required. While a number of steady-state simulation tools for MGT-based systems are described and applied in literature, the solving process of such tools is rarely explained. However, this solving process is crucial to achieve a robust and fast computation within a physically meaningful range. Therefore, a new solver routine for a steady-state simulation tool developed at the DLR Institute of Combustion Technology is presented in detail in this paper. The solver routine is based on Broyden's method. It considers boundaries during the solving process to maintain a physically and technically meaningful solution process. Supplementary methods are implemented and described which improve the computation robustness and speed. Furthermore, some features of the resulting steady-state simulation tool are presented. Exemplary applications of a hybrid power plant (HyPP), an inverted Brayton cycle (IBC), and an aircraft auxiliary power unit (APU) show the capabilities of the presented solver routine and the steady-state simulation tool. It is shown that the new solver routine is superior to the standard Simulink algebraic solver in terms of system evaluation and robustness for the given applications.

scholarly journals A Highly Flexible Approach on the Steady-State Analysis of Innovative Micro Gas Turbine Cycles

2018 ◽  
Author(s):  
Thomas Krummrein ◽  
Martin Henke ◽  
Peter Kutne
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Solution Process ◽  
Simulation Tool ◽  
Fast Computation ◽  
Micro Gas Turbine ◽  
Simulation Tools ◽  
Complexity Result ◽  
Combustion Technology ◽  
Steady State Simulation

Steady state simulations are an important method to investigate thermodynamic processes. This is especially true for innovative micro gas turbine (MGT) based cycles as the complexity of such systems grows. Therefore, steady state simulation tools are required which ensure large flexibility and computation robustness. As the increased system complexity result often in more extensive parameter studies also a fast computation speed is required. While a number of steady state simulation tools for micro gas turbine based systems are described and applied in literature, the solving process of such tools is rarely explained. However, this solving process is crucial to achieve a robust and fast computation within a physically meaningful range. Therefore, a new solver routine for a steady state simulation tool developed at the DLR Institute of Combustion Technology is presented in detail in this paper. The solver routine is based on Broyden’s method. It considers boundaries during the solving process to maintain a physically and technically meaningful solution process. Supplementary methods are implemented and described which improve the computation robustness and speed. Furthermore, some features of the resulting steady state simulation tool are presented. Exemplary applications of a hybrid power plant, an inverted Brayton cycle and an aircraft auxiliary power unit show the capabilities of the presented solver routine and the steady state simulation tool. It is shown that the new solver routine is superior to the standard Simulink algebraic solver in terms of system evaluation and robustness for the given applications.

scholarly journals Design and Experimental Validation of a Supersonic Concentric Micro Gas Turbine

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Gabriel Vézina ◽  
Hugo Fortier-Topping ◽  
François Bolduc-Teasdale ◽  
David Rancourt ◽  
Mathieu Picard ◽  
...  
Keyword(s):  
Steady State ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Structural Model ◽  
Structural Integrity ◽  
Turbine Blades ◽  
External Diameter ◽  
Impulse Turbine ◽  
Micro Gas Turbine ◽  
Steady State Operation

This paper presents the design and experimental results of a new micro gas turbine architecture exploiting counterflow within a single supersonic rotor. This new architecture, called the supersonic rim-rotor gas turbine (SRGT), uses a single rotating assembly incorporating a central hub, a supersonic turbine rotor, a supersonic compressor rotor, and a rim-rotor. This SRGT architecture can potentially increase engine power density while significantly reducing manufacturing costs. The paper presents the preliminary design of a 5 kW SRGT prototype having an external diameter of 72.5 mm and rotational speed of 125,000 rpm. The proposed aerodynamic design comprises a single stage supersonic axial compressor, with a normal shock in the stator, and a supersonic impulse turbine. A pressure ratio of 2.75 with a mass flow rate of 130 g/s is predicted using a 1D aerodynamic model in steady state. The proposed combustion chamber uses an annular reverse-flow configuration, using hydrogen as fuel. The analytical design of the combustion chamber is based on a 0D model with three zones (primary, secondary, and dilution), and computational fluid dynamics (CFD) simulations are used to validate the analytical model. The proposed structural design incorporates a unidirectional carbon-fiber-reinforced polymer rim-rotor, and titanium alloy is used for the other rotating components. An analytical structural model and numerical validation predict structural integrity of the engine at steady-state operation up to 1000 K for the turbine blades. Experimentation has resulted in the overall engine performance evaluation. Experimentation also demonstrated a stable hydrogen flame in the combustion chamber and structural integrity of the engine for at least 30 s of steady-state operation at 1000 K.

scholarly journals Introduction of a New Numerical Simulation Tool to Analyze Micro Gas Turbine Cycle Dynamics

2016 ◽  
Author(s):  
Martin Henke ◽  
Thomas Monz ◽  
Manfred Aigner
Keyword(s):  
Fuel Cell ◽  
System Dynamics ◽  
Automatic Control ◽  
Gas Turbine ◽  
Cell Hybrid ◽  
Simulation Tool ◽  
Micro Gas Turbine ◽  
Novel Applications ◽  
Component Models ◽  
Fuel Cell Hybrid

Micro gas turbine (MGT) technology is evolving towards a large variety of novel applications, like weak gas electrification, inverted Brayton cycles and fuel cell hybrid cycles; however, many of these systems show very different dynamic behaviors compared to conventional MGTs. In addition, some applications impose more stringent requirements on transient maneuvers, e.g. to limit temperature and pressure gradients in a fuel cell hybrid cycle. Besides providing operational safety, optimizing system dynamics to meet the variable power demand of modern energy markets is also of increasing significance. Numerical cycle simulation programs are crucial tools to analyze these dynamics without endangering the machines, and to meet the challenges of automatic control design. For these tasks, complete cycle simulations of transient maneuvers lasting several minutes need to be calculated. Moreover, sensitivity analysis and optimization of dynamic properties like automatic control systems require many simulation runs. To perform these calculations in an acceptable timeframe, simplified component models based on lumped volume or one-dimensional discretization schemes are necessary. The accuracy of these models can be further improved by parameter identification, as most novel applications are modifications of well-known MGT systems and rely on proven, characterized components. This paper introduces a modular in-house simulation tool written in Fortran to simulate the dynamic behavior of conventional and novel gas turbine cycles with real-time calculation speed. Thermodynamics, gas composition, heat transfer to the casing and surroundings, shaft rotation and control system dynamics as well as mass and heat storage are simulated together to account for their interactions. The simulation tool is explained in detail, including a description of all component models, coupling of the elements and the ODE-solver. Finally, validation results of the simulator based on measurement data from the DLR Turbec T100 recuperated MGT test rig are presented, including cold start-up and shutdown maneuvers.

A New Sensor Diagnostic Technique Applied to a Micro Gas Turbine Rig

2012 ◽  
Author(s):  
Andrea Tipa ◽  
Alessandro Sorce ◽  
Matteo Pascenti ◽  
Alberto Traverso
Keyword(s):  
Steady State ◽  
Statistical Model ◽  
Gas Turbine ◽  
Measurement Errors ◽  
Combined Cycle ◽  
Model Approximation ◽  
Operating Life ◽  
Steady State Condition ◽  
Micro Gas Turbine ◽  
The Impact

This paper describes the development and testing of a new algorithm to identify faulty sensors, based on a statistical model using quantitative statistical process history. Two different mathematical models were used and the results were analyzed to highlight the impact of model approximation and random error. Furthermore, a case study was developed based on a real micro gas turbine facility, located at the University of Genoa. The diagnostic sensor algorithm aims at early detection of measurement errors such as drift, bias, and accuracy degradation (increase of noise). The process description is assured by a database containing the measurements selected under steady state condition and without faults during the operating life of the plant. Using an invertible statistical model and a combinatorial approach, the algorithm is able to identify sensor fault. This algorithm could be applied to plants in which historical data are available and quasi steady state conditions are common (e.g. Nuclear, Coal Fired, Combined Cycle).

scholarly journals Introduction of a New Numerical Simulation Tool to Analyze Micro Gas Turbine Cycle Dynamics

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Martin Henke ◽  
Thomas Monz ◽  
Manfred Aigner
Keyword(s):  
Fuel Cell ◽  
System Dynamics ◽  
Automatic Control ◽  
Gas Turbine ◽  
Cell Hybrid ◽  
Simulation Tool ◽  
Micro Gas Turbine ◽  
Novel Applications ◽  
Component Models ◽  
Fuel Cell Hybrid

Micro gas turbine (MGT) technology is evolving toward a large variety of novel applications, such as weak gas electrification, inverted Brayton cycles, and fuel cell hybrid cycles; however, many of these systems show very different dynamic behaviors compared to conventional MGTs. In addition, some applications impose more stringent requirements on transient maneuvers, e.g., to limit temperature and pressure gradients in a fuel cell hybrid cycle. Besides providing operational safety, optimizing system dynamics to meet the variable power demand of modern energy markets is also of increasing significance. Numerical cycle simulation programs are crucial tools to analyze these dynamics without endangering the machines, and to meet the challenges of automatic control design. For these tasks, complete cycle simulations of transient maneuvers lasting several minutes need to be calculated. Moreover, sensitivity analysis and optimization of dynamic properties like automatic control systems require many simulation runs. To perform these calculations in an acceptable timeframe, simplified component models based on lumped volume or one-dimensional discretization schemes are necessary. The accuracy of these models can be further improved by parameter identification, as most novel applications are modifications of well-known MGT systems and rely on proven, characterized components. This paper introduces a modular in-house simulation tool written in fortran to simulate the dynamic behavior of conventional and novel gas turbine cycles. Thermodynamics, gas composition, heat transfer to the casing and surroundings, shaft rotation and control system dynamics as well as mass and heat storage are simulated together to account for their interactions. While the presented models preserve a high level of detail, they also enable calculation speeds up to five times faster than real-time. The simulation tool is explained in detail, including a description of all component models, coupling of the elements and the ODE solver. Finally, validation results of the simulator based on measurement data from the DLR Turbec T100 recuperated MGT test rig are presented, including cold start-up and shutdown maneuvers.

Effects of Equivalence Ratio on the Off-Design Combustion Performance of Adjustable Fuel Feeding Combustor for a Micro-Gas Turbine

2017 ◽  
Author(s):  
Chang Xing ◽  
Penghua Qiu ◽  
Li Liu ◽  
Wenkai Shen ◽  
Yajin Lyu ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Characteristic Number ◽  
Outlet Temperature ◽  
Operation Performance ◽  
Feeding Method ◽  
Micro Gas Turbine ◽  
Combustion Performance ◽  
Fuel Flow ◽  
Combustion Technology ◽  
Fuel Tube

To improve off-design operation performance of micro-gas turbine, we proposed an adjustable fuel feeding combustor (AFFC), and it employed the lean premixed swirling combustion technology and the adjustable fuel feeding method (AFFM). The AFFM was achieved by switching the various working groups of main fuel tube, and represented by its unique characteristic number (U). To verify the availability of adopted models, the AFFC combustion performance was investigated numerically at different equivalence ratios (ϕ) in ANSYS CFX. The results indicate that NO emission has various trends with the rising U under different ϕ due to the coupling influence of fuel flow and jet velocity in each working main fuel tube. Although the AFFM has almost no effect on the distribution of outlet temperature and the length of primary recirculation zone, the maximum and non-uniform coefficient of outlet temperature increase with the rising U.

Experimental Investigations of Pressure Losses on the Performance of a Micro Gas Turbine System

2010 ◽  
Author(s):  
Jan Zanger ◽  
Axel Widenhorn ◽  
Manfred Aigner
Keyword(s):  
Steady State ◽  
Electric Power ◽  
Gas Turbine ◽  
Pressure Loss ◽  
System Stability ◽  
Pressure Losses ◽  
Micro Gas Turbine ◽  
Additional Pressure ◽  
Surge Margin ◽  
Compressor Surge

Pressure losses between compressor outlet and turbine inlet are a major issue of overall efficiency and system stability for a SOFC/MGT hybrid power plant system. The goal of this work is the detailed analysis of the effects of additional pressure losses on MGT performance in terms of steady-state and transient conditions. The experiments were performed at the micro gas turbine test rig at the German Aerospace Centre in Stuttgart using a butterfly control valve to apply additional pressure loss. The paper reports electric power and pressure characteristics at steady-state conditions, as well as, a new surge limit, which was found for the Turbec T100 micro gas turbine. Furthermore, the effects of additional pressure loss on compressor surge margin are quantified and a linear relation between relative surge margin and additional pressure loss is shown. For transient variation of pressure loss at constant turbine speed time delays are presented and a compensation issue of the commercial gas turbine controller is discussed. Finally, bleed-air blow-off and reduction of turbine outlet temperature are introduced as methods of increasing surge margin. It is quantified that both methods have a substantial effect on compressor surge margin. Furthermore, a comparison between both methods is given in terms of electric power output.

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