## 3 Properties of the Mixture of Jet A-1 Aviation Kerosene and FAME Biofuel
#### 4.1.5 The Course of Changes in SJE-20 Parameters When Using a Mixture of 60% Jet A-1 and 40% FAME
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Fuel Mixture Composition** & **20 th Second** & **25 th Second** & **30 th Second** & **35 th Second** & **40 th Second** \\ \hline
**100\% Jet A-1 + 0\% FAME** & 192,083.9 & 189,794.3 & 190,688.5 & 188,982.5 & 188,005.8 \\
**90\% Jet A-1 + 10\% FAME** & 191,195.1 & 189,728.7 & 188,207.3 & 187,871.6 & 186,511.2 \\
**80\% Jet A-1 + 20\% FAME** & 181,221.0 & 192,419.9 & 187,818.4 & 185,895.0 & 186,290.9 \\
**70\% Jet A-1 + 30\% FAME** & 196,894.4 & 188,397.5 & 190,323.3 & 183,627.4 & 184,788.6 \\
**60\% Jet A-1 + 40\% FAME** & 182,763.0 & 179,873.6 & 178,255.3 & 177,663.3 & 176,325.0 \\ \hline \end{tabular}
\end{table} 
Table 13: Change in total gas pressure in front of gas turbine p3t [Pa] SJE-20 with different concentrations of jet A-1 aviation kerosene and FAME biofuel. Figure 11: The graphical course of changes in the total air pressure in front of the gas turbine SJE-20 p3t when using different mixtures of Jet A-1 aviation kerosene and FAME biofuel. In the stable mode of operation of the SJE-20 experimental engine, there is a gradual increase in the total gas temperature in front of the gas turbine t\({}_{3t}\). The slight increase in gas temperature in front of the t\({}_{3t}\) gas turbine is caused by the gradual overheating of the SJE-20 gas turbine. The course of increasing the total gas temperature in front of the gas turbine t\({}_{3t}\) is the same for all mixtures. The average change in the total gas temperature in front of the gas turbine t\({}_{3t}\) between the 20 th and 40 th second is 65 \({}^{\circ}\)C.  
2.5 The Effect of Different Concentrations of Jet A-1 Aviation Kerosene and FAME Biofuel Mixture on the Total Gas Temperature behind the Gas Turbine t\({}_{4t}\)  
The course of changes in the total gas temperature behind the gas turbine t\({}_{4t}\) (Figure 13) depending on the composition of the mixtures of Jet A-1 aviation kerosene and FAME biofuel (Table 16) copies the course of change in the total gas temperature in front of the gas turbine t\({}_{3t}\), but with lower values of the total gas temperature behind the gas turbine t\({}_{4t}\). During the expansion of the gas on the gas turbine of the SJE-20 experimental engine, \begin{table}
\begin{tabular}{c c c c c} \hline
**Fuel Mixture Composition** & **t\({}_{3t,max.}\)** [\({}^{\circ}\)C]** & **Time to Reach** & **Note** \\ \hline
**100\% Jet A-1 + 0\% FAME** & 114.55 & 12.8 & \\
**90\% Jet A-1 + 10\% FAME** & 1130.49 & 12.2 & \\
**80\% Jet A-1 + 20\% FAME** & 1110.60 & 19.6 & Delayed ignition of the fuel mixture \\
**70\% Jet A-1 + 30\% FAME** & 1127.90 & 13.9 & \\
**60\% Jet A-1 + 40\% FAME** & 1118.97 & 13.7 & \\ \hline \end{tabular}
\end{table} 
Table 15: Change in the maximum total gas temperature in front of the gas turbine t\({}_{3t, max. }\) [\({}^{\circ}\)C] SJE-20 with different concentrations of Jet A-1 aviation kerosene and FAME biofuel. Figure 12: The graphical course of the change in the total gas temperature in front of the gas turbine SJE-20 t\({}_{3t}\) [\({}^{\circ}\)C] when using different mixtures of jet A-1 aviation kerosene and FAME biofuel. the total gas temperature \(\Delta\)t\({}_{\rm PT}\) changed with different compositions of Jet A-1 aviation kerosene and FAME biofuel in the range of total temperatures from \(\Delta\)t\({}_{\rm PT}\) = 315.1 \({}^{\circ}\)C to \(\Delta\)t\({}_{\rm PT}\) = 370.7 \({}^{\circ}\)C (Table 17). The maximum total gas temperature behind the gas turbine t\({}_{\rm tt,max. }\) is dependent on the maximum total gas temperature in front of the gas turbine t\({}_{\rm 3t,max. }\), which is set by the initial fuel pressure control valve, which regulates the fuel supply during start-up Q\({}_{\rm fuel,sp}\). The value of the maximum total gas temperature behind the gas turbine t\({}_{\rm tt,max}\) differs relatively little \(\Delta\)t\({}_{\rm tt,max. }\)\(\approx\) 17.8 \({}^{\circ}\)C. The moment of reaching the maximum total gas temperature behind the gas turbine t\({}_{\rm tt,max.