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

Abstract

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.

Numerical analysis of operating range and SOFC-off-gas combustor requirements of a biogas powered SOFC-MGT hybrid power plant

“…al. [8] implemented an improved solver routine which enables the detailed simulation of complex systems like HyPP.…”

On Verification of Designed Energy Systems Using Distributed Co-Simulations

“…With an electrical output of 100 kW and a thermal output of about 180 kW the CHP is integrated with a flexible burner, so that the machine can be operated with various fuels such as natural gas, biogas and synthesis gas with a calorific value of 7 to 49 MJ/kg. The cogeneration unit is modelled in a stationary 0-D simulation tool that is suitable for fast and robust analysis of complex cycles [31]. The model is implemented in MATLAB®/SIMULINK® and allows the modelling of various CHP subcomponents such as turbomachinery, burner, recuperator, heat exchanger, electric generator and intermediate circuit.…”

Characterization of an Aircraft Auxiliary Power Unit Test Rig for Cycle Optimization Studies

“…This is a steady state simulation tool for micro gas turbine based processes which is developed at the Institute of Combustion Technology of the DLR. The tool is described in detail in [11][12][13][14]. It has a modular structure and contains 0Dmodels of all system components considering heat and pressure losses.…”

“…2 are represented in the model. Additionally, the described behavior of 'bleed mode' and 'no-bleed mode' is implemented (see [14]). The pressure loss parameters of components are determined by the experimental data, as well as the parameters of valves and the centrifugal governor.…”