# Development of a Predictive Tool for the Parametric Analysis of a Turbofan Engine
## 3 Results
### Engine Parametric Analysis  
A parametric cycle analysis was conducted to investigate the effects of various flight conditions and engine parameters, like the Mach number, altitude, turbine entry temperature, BPR, and FPR, on the F100-PW229 engine. In GasTurb 14, the parametric analysis module was selected, as shown in Figure 2. For each design variable, a range was specified, and the performance parameter was plotted against this range. The results of the parametric analysis are shown in Figures 3-7. Two parameters may also be simultaneously varied like in Figure 3, where the altitude and Mach number have been selected. In contrast, in Figures 5-8 only one parameter was varied, with the other parameters being constant with the design point values, as listed in Table 2. These resulting trends conform with those typical for a turbofan, as published in the literature.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Published** & **Calculated** & **Error** \\ \hline Dry thrust (kN) & 79.45 & 83.88 & 5.3\% \\ Dry thrust’s fuel consumption rate (g/(kN \(\times\) s)) & 21.53 & 22.45 & 4.1\% \\ Wet thrust (kN) & 129.29 & 133.94 & 3.5\% \\ Wet thrust’s fuel consumption rate (g/(kN \(\times\) s)) & 54.94 & 60.51 & 9.2\% \\ Fuel mass flow rate (with afterburner) & 8.064 & 8.105 & 0.5\% \\ (kg/s) & \multicolumn{1}{c}{} & & \\ \end{tabular}
\end{table}
Table 4: Design point analysis results.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Altitude (m) & 0 \\ Mach number & 0 \\ W (kg s\({}^{-1}\)) & 113.5 \\ FPR & 3.65 \\ BPR & 0.36 \\ TET (K) & 1700 \\ Tab (K) & 2250 \\ \(\eta_{fan}\) & 0.83 \\ \(\eta_{ab}\) & 0.90 \\ \hline \hline \end{tabular}
\end{table}
Table 3: F100-PW-229 engine input parameters.  
Figures 3 and 4 show the impacts of the Mach number and flight altitude on the specific thrust and SFC. The specific thrust decreases with the Mach number and increases with the altitude. Meanwhile, the SFC increases with the Mach number and slightly decreases with the altitude.  
Figure 4: (**a**) Effect of the altitude on the specific thrust. (**b**) Effect of the altitude on the specific fuel consumption.  
Figure 3: (**a**) Effect of the Mach number on the specific thrust at different altitudes. (**b**) Effect of the Mach number on the specific fuel consumption at different altitudes.  
Figure 2: (**a**) Parametric analysis in GasTurb 14. (**b**) Parameter selection for analysis.  
Figure 5 shows that increasing the bypass ratio decreased the specific thrust and specific fuel consumption.  
The effect of the fan pressure ratio on the specific thrust and specific fuel consumption is shown in Figure 6. It can be seen that the highest specific thrust and lowest specific fuel consumption correspond to the same fan pressure ratio.  
Figure 7 depicts that increasing the turbine entry temperature (burner exit temperature) increases the specific thrust with little increase in the specific fuel consumption.  
Figure 5: (**a**) Effect of the bypass ratio on the specific thrust. (**b**) Effect of the bypass ratio on the specific fuel consumption.  
Figure 6: (**a**) Effect of the fan pressure ratio on the specific thrust. (**b**) Effect of the fan pressure ratio on the specific fuel consumption.