# Drawing a gas turbine scheme and center the picture

this is my first time using tikz but i'm afraid i didnt really get how to properly use it (i keep making a mess getting errors everywhere), so i was hoping you guys could help me drawing this scheme with tikz and then how to center the picture i obtained with it (dont really know if its like any other picture or what since i cant even get started with tikz :/)... Thank you in advance! • at least you can give a skeleton of a document which does what you want. – Herbert Aug 10 '18 at 8:54

This is a bit messy, but it should help you as a starting point

\documentclass[tikz,margin=1mm]{standalone}
\usetikzlibrary{calc,arrows.meta}
\begin{document}

\begin{tikzpicture}[inner sep=0, outer sep=0]
% Definition of burner point for reference
\coordinate (burner) at (0,0);

% Draw the compressor
\coordinate (compressor) at (-6,-1);
\draw[blue] (compressor) --++ (150:-2) node[pos=1](C2) {}--++(0,-2) --++ (-150:2) -- node[pos =-0.4] (C1) {} cycle;
\draw[blue] ($(C1)+(0,0.7)$) -- (compressor);
\draw[blue] ($(C1)+(-0.05,1)$) --++ (0.1,0) node[pos=2]{$1$}  ;
\draw[blue,-stealth] (C1) --++ (0,0.6) node[pos=0.5,xshift=10pt]{$\dot{n}_{a}$};
\draw[blue] (C2) |- node[near start] (2) {} (burner);
\draw[blue] ($(2)+(-0.05,0)$) --++ (0.1,0) node [pos=2]{$2$};

% Draw the turbine
\coordinate (turbine) at (6,-1);
\draw[red] (turbine) --++ (30:-2) node[pos=1](T2) {}--++(0,-2) --++ (-30:2) -- node[pos =-0.4] (T1) {} cycle;
\draw[red] ($(T1)+(0,0.7)$) -- (turbine);
\draw[red] ($(T1)+(-0.05,1)$) --++ (0.1,0) node[pos=2]{$4$}  ;
\draw[red,stealth-] (T1) --++ (0,0.6) node[pos=0.5,xshift=10pt]{$?$};
\draw[red] (T2) |- node[near start] (3) {} node[pos=0.7,yshift=5pt] (note){}(burner);
\draw[red] ($(3)+(-0.05,0)$) --++ (0.1,0) node [pos=2]{$3$};
\draw[red,-stealth] (note) --++ (0.5,0) node[midway, above]{$\dot{n}_{f}=\dot{n}_{a}+\dot{n}_{b}$};

% Dra burner
\path[draw=black,-stealth] ($(burner)+(0,2cm)$) --++ (0,-0.5) node[midway, xshift=10pt]{$\dot{n}_{b}$} ;
\path[draw=black,-] (burner) --++ (0,1.4cm);
\path[draw=black,-] ($(burner)+(0.2,0)$) --++ (0,1.4cm);
\path[draw=black,-] ($(burner)+(-0.2,0)$) --++ (0,1.4cm);
\path[draw=black,fill=white] (burner) circle (1cm);
\end{tikzpicture}

\end{document} 