## 5 Experimental Results and Calculated Data  
In this chapter, experimental and calculated data are presented in Tables 2 and 3, for different engine working regimes, following the engine test, according to the general testing procedure from Figure 8. The measured experimental data are used into a calculation model to determine some main engine parameters and some performances of engine components. Figure 8: General testing procedure of TV2-117A free turbine turbo-shaft. Figure 9: Engine graphical user interface. The calculation model [8] is based on the equality conditions of the isentropic evolutions, and the typical gasodynamic relations from the compressor and turbine thermodynamic processes, according with the TV2-117A engine enthalpy-entropy cycle diagram, from Figure 10. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reg. nr.** & **T\({}_{\text{qs}}\) [Nm]** & **P [kW]** & **N\({}_{\text{TP}}\) [\%]** & **N\({}_{\text{GG}}\) [\%]** & **T\({}_{\text{3d}}\) [\({}^{\circ}\)C]** & **P\({}_{\text{2d}}\) [bar a]** & **T\({}_{\text{2d}}\) [\({}^{\circ}\)C]** \\ \hline Idle (a) & 100 & 55.9 & 40.59 & 64.80 & 499.5 & 2.053 & 99.0 \\
1 & \(\alpha_{TLV}=100\%\) & 184.7 & 100.0 & 83.40 & 599.5 & 3.225 & 169.1 \\
2 & 200 & 248.1 & 99.48 & 86.50 & 620.5 & 3.506 & 182.4 \\
3 & 300 & 374.6 & 99.40 & 89.40 & 660.5 & 4.044 & 201.0 \\
4 & 400 & 497.0 & 99.21 & 91.70 & 698.5 & 4.513 & 216.5 \\
5 & 500 & 622.1 & 99.00 & 93.80 & 745.9 & 4.950 & 233.1 \\
6 (b) & 600 & 745.2 & 98.86 & 95.50 & 778.8 & 5.356 & 242.8 \\
7 (c) & 700 & 868.8 & 98.39 & 97.00 & 818.5 & 5.731 & 253.8 \\
8 & 800 & 985.4 & 98.00 & 98.40 & 854.9 & 6.069 & 264.5 \\
9 (d) & 840 & 1027.5 & 98.37 & 99.11 & 866.9 & 6.200 & 267.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Measured parameters at each engine working regime part one. Figure 10: TV2-117A engine cycle diagram. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reg. nr. ** & **T\({}_{\text{qs}}\) [Nm]** & **T\({}_{\text{0}}\) [\({}^{\circ}\)C]** & **P [kW]** & **N\({}_{\text{GG}}\) [\%]** & **F\({}_{\text{f}}\) [l/min]** & **DP [mbar]** & **P\({}_{\text{45d}}\) [bar a]** \\ \hline Idle (a) & 100 & 21.3 & 55.9 & 64.80 & 1.972 & 8.750 & 1.015 \\
1 & \(\alpha_{TLV}=100\%\) & 21.5 & 184.7 & 83.40 & 3.328 & 21.125 & 1.022 \\
2 & 200 & 21.8 & 248.1 & 86.50 & 3.594 & 24.875 & 1.023 \\
3 & 300 & 22.1 & 374.6 & 89.40 & 4.419 & 31.750 & 1.030 \\
4 & 400 & 22.4 & 497.0 & 91.70 & 5.516 & 38. To achieve close realistic results, the calculation model used for air and gases enthalpy and entropy defined by polynomials, as a function on working temperature, with specific coefficients for air and gases with different values for enthalpy and entropy. The air enthalpy and entropy are presented as:  
\[h_{a}(T),s_{a}(T)=a_{1.a}+a_{2.a}.T+a_{3.a}.T^{2}+a_{4.a}.T^{3}+a_{5.a}.T^{4}+a_{ 6.a}.T^{5} \tag{3}\]  
In the case of enthalpy and entropy of the flow gases, the polynomials are presented for ideal combustion, where \(\alpha_{ex}=1\):  
\[h_{g.id}(T),s_{g.id}(T)=a_{1.g}+a_{2.g}.T+a_{3.g}.T^{2}+a_{4.g}.T^{3}+a_{5.g}.T^ {4}+a_{6.g}.T^{5} \tag{4}\]  
In the case of a real combustion scenario, the enthalpy and entropy polynomials involve mass participations, and are presented as:  
\[h_{g}(T)=x_{g.id}.h_{g.id}(T)+x_{a.ex}.h_{a}(T) \tag{5}\]  
\[s_{g}(T)^{p_{0}}=x_{g.id}.s_{g.id}(T)^{p_{0}}+x_{a.ex}.s_{a}(T)^{p_{0}} \tag{6}\]  
So, by using the model calculation [8], the next engine main parameters and performances of engine components are calculated, as are the pressures (\(P\)) and temperatures (\(T\)) in the main engine stations, the mass air flow (\(M_{af}\)), the overall pressure ratio (\(\pi_{Cl}\)), the turbine total pressure ratio (\(\pi_{Tt}\)), the gases flow (\(G_{f}\)), the compressor and turbine total adiabatic efficiency (\(\eta_{Cl}\),\(\eta_{Tt}\)) and the thermal efficiency (\(\eta_{Te}\)), defined by the next mathematical relations, presented below.