ADDED mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_desc.tex Index: mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_desc.tex ================================================================== --- /dev/null +++ mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_desc.tex @@ -0,0 +1,121 @@ +% -*-latex-*- used to set EMACS into LaTeX-mode +% Verbal description for system SimpleGasTurbine (SimpleGasTurbine_desc.tex) +% Generated by MTT on Tue Jan 13 18:01:55 GMT 1998. + +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% %% Version control history +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% %% $Id$ +% %% $Log$ +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + The acausal bond graph of system \textbf{SimpleGasTurbine} is + displayed in Figure \Ref{SimpleGasTurbine_abg} and its label + file is listed in Section \Ref{sec:SimpleGasTurbine_lbl}. + The subsystems are listed in Section \Ref{sec:SimpleGasTurbine_sub}. + + \textbf{SimpleGasTurbine} can be regarded as an single-spool gas + turbine (producing shaft power) with an ideal-gas working fluid. It + corresponds to the simple Joule Cycle as described in Chapter 12 of + Rogers and Mayhew and in Chapter 2 of Cohen, Rogers and + Saravanamutto. However, unlike those examples, the system is + written with dynamics in mind. + +The system is described using an energy Bond Graph- this ensures +that the first law is observed. In particular (for I believe the first +time) transformers are used to explicitly convert between energy +covariables. Although this is a simple model, I believe that it +provides the basis for building complex thermodynamic systems +involving gas power cycles. + + +There are five main components: +\begin{enumerate} +\item p1 -- a \textbf{Pump} component representing the compressor + stage. This converts shaft work to energy flow in the working fluid. +\item c1 -- a \textbf{Comb} component representing the combustion + chamber. This converts the heat obtained by burning fuel to energy + flow in the working fluid. +\item t1 -- a \textbf{Turb} component representing the turbine + component. This converts the energy flow in the working fluid to + shaft work +\item j\_s -- an \textbf{I} component representing the combined inertia + of the shaft and compressor and turbine rotors. +\item a \textbf{Load} component to absorb the shaft power. +\end{enumerate} +The components \textbf{In} and \textbf{Out} provide the inlet and +outlet conditions. + +Both \textbf{Pump} and \textbf{Turb} are implemented with the +\emph{polytropic} constitutive relationship with index $n$. When +$n=\gamma=\frac{c_p}{c_v}$ this corresponds to isentropic compression +and expansion and thus the \textbf{SimpleGasTurbine} achieves its +cycle efficiency. However, other values of $n$ can be used to account +for isentropic efficiency of less than unity. + +To obtain a very simple dynamic model (and to avoid the need for an +accurate combustion chamber model) there are no dynamics associated +with the combustion chamber, but rahter it is assumed that the +corresponding temperature is imposed on the component (that is $T_3$ +is the system input) the corresponding heat flow is then an output. + +Both heat input and work output are measured using the \textbf{PS} +(power sensor) component, that for work output is embedded in the +\textbf{Load} component. These can be monitored to give the efficiency +of the \textbf{SimpleGasTurbine}. + +A symbolic steady-state for the model was computed -- see Section +\ref{sec:SimpleGasTurbine_sspar.tex}. In particular, the load +resistance was chosen to absorb all the generated work at the steady +state and the shaft inertia was chosen to give a unit time constant +for the linearised system. The mass flow and shaft speeds were taken +as unity. + +For the purposed of simulation, the numerical values given in Examples +12.1 of Chapter 12 of Rogers and Mayhew, except that the isentropic +efficiencies are 100\% ($n=\gamma$) -- see Section +\ref{sec:SimpleGasTurbine_numpar.tex}. + +Simulations were performed starting at the steady state and increasing +the combustion chamber temperature by 10\% at $t=1$ and reducing by +10\% at $t=5$. Graphs of the various outputs are plotted: +\begin{itemize} +\item Figure + \Ref{fig:SimpleGasTurbine_odeso.ps-SimpleGasTurbine-p1-T,SimpleGasTurbine-c1-T,SimpleGasTurbine-t1-T} + -- the temperatures at the output of the + \begin{itemize} + \item compressor, + \item combustion chamber and + \item turbine + \end{itemize} +\item Figure + \Ref{fig:SimpleGasTurbine_odeso.ps-SimpleGasTurbine-Heat,SimpleGasTurbine-Work} + -- the heat input and work output +\item Figure + \Ref{fig:SimpleGasTurbine_odeso.ps-SimpleGasTurbine-Speed} -- the shaft speed and +\item Figure + \Ref{fig:SimpleGasTurbine_odeso.ps-SimpleGasTurbine-p1-P,SimpleGasTurbine-c1-P,SimpleGasTurbine-t1-P} + -- the pressure at the output of the + \begin{itemize} + \item compressor, + \item combustion chamber and + \item turbine + \end{itemize} +\end{itemize} + +This model can be modified extended in various ways to yield related +dynamic systems. For example: +\begin{itemize} +\item an air cooler is obtained by changing the direction of heat and + work flows +\item additional \textbf{Turb} and \textbf{Comb} components add reheat + to the cycle +\item an isentropic nozzle can be added and the work output removed + to give a jet engine. +\end{itemize} + + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: t +%%% End: ADDED mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_lbl.txt Index: mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_lbl.txt ================================================================== --- /dev/null +++ mttroot/mtt/lib/examples/Thermal/GasTurbines/SimpleGasTurbine/SimpleGasTurbine_lbl.txt @@ -0,0 +1,53 @@ +%SUMMARY SimpleGasTurbine: single-spool gas turbine producing shaft power +%DESCRIPTION SimpleGasTurbine can be regarded as an single-spool gas +%DESCRIPTION turbine (producing shaft power) with an ideal-gas working fluid. It +%DESCRIPTION corresponds to the simple Joule Cycle as described in Chapter 12 of +%DESCRIPTION Rogers and Mayhew and in Chapter 2 of Cohen, Rogers and +%DESCRIPTION Saravanamutto. However, unlike those examples, the system is +%DESCRIPTION written with dynamics in mind. + +%% Label file for system SimpleGasTurbine (SimpleGasTurbine_lbl.txt) + +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% %% Version control history +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% %% $Id$ +% %% $Log$ +% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%% Each line should be of one of the following forms: +% a comment (ie starting with %) +% Component-name CR_name arg1,arg2,..argn +% blank + +% Component type I + j_s lin flow,j_s + +% Component type Pump + p1 none c_v;ideal_gas,r;alpha;k + +% Component type SS + Work 0 external + Heat 0 external + Speed 0 external + T3 external external + + +% Component type Turb + t1 none c_v;ideal_gas,r;alpha;k + +% Component type Tank + c1 none m_c;v_c;r;c_v + +% Component type In + in + +% Component type Out + out + +% Component type Dummy -- create some global variables. + Dummy none t_2;t_3;t_4;p_2;p_3;p_4;mdot;gamma;q_0;w_0;omega_0;r_p;c_p;mom_0 + + + +