# Measurement of Instantaneous Mass Flow Rate of Polypropylene Gasification Products in Airflow
## 5 Results and Discussion
### Yield of Gasification Products with Pyro-Charge-Assisted Ignition  
Figures 13 and 14 show the time histories of gas mass flow rates at GG inlet, \(G_{\text{in}}(t)\), and outlet, \(G_{\text{out}}(t)\), as well as the mass flow rates of gasification products, \(G_{\text{out}}(t)-G_{\text{in}}(t)\), calculated based on experimental data for test fires #4 and #5 with pyro-charge assisted ignition. For calculating \(G_{\text{in}}(t)\), \(G_{\text{out}}(t)\), and \(G_{\text{out}}(t)-G_{\text{in}}(t)\), the procedure described in Section 3 was used. In test fire #4, ignition is not activated. As a result, the mass flow rates of gas (air) at GG inlet and outlet are nearly the same. The difference in mass flow rates does not exceed 1 g/s. In test fire #5, despite the activation of pyro-charge ignition, a PP sample is not ignited. The total yield of gasification products is virtually zero, except for a small amount generated during pyro-charge ignition. In this test fire, a decrease in sample mass by about 10 g is detected.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Test Fire** & **2** & **3** \\ \hline Start of ignition, s & 1.53 & 1.53 \\ End of ignition, s & 2.05 & 2.05 \\ Air mass flow rate, g/s & 232.7 & 232.1 \\ Mass of air, g & 121.0 & 120.7 \\ Mass flow rate of gasification & 120.8 & 106.9 \\ products, g/s & 62.8 & 55.6 \\ Ratio of mass flow rates of air and & 1.93 & 2.17 \\ gasification products & 2.05 & 2.05 \\ Part of combustion, s & 5.40 & 5.20 \\ Air mass flow rate, g/s & 211.3 & 219.9 \\ Mass of air, g & 708.0 & 692.8 \\ Mass flow rate of gasification & 82.1 & 72.2 \\ products, g/s & 274.9 & 227.4 \\ Yield of gasification products, g & 2.58 & 3.05 \\ Ratio of mass flow rates of air and & 2.46 & 2.87 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Operation parameters of GG at hydrogen-assisted ignition.  
Figure 14: Calculated mass flow rates \(G_{\rm in}(t)\), \(G_{\rm out}(t)\), and \(G_{\rm out}(t)-G_{\rm in}(t)\) in test fires #6 to #9.  
Figure 13: Calculated mass flow rates \(G_{\rm in}(t)\), \(G_{\rm out}(t)\), and \(G_{\rm out}(t)-G_{\rm in}(t)\) in test fires #4 and #5.  
0.15 s. The temperature of ignition pulse is relatively low (less than 1100 K). Therefore, the contribution of the ignition stage to the total yield of gasification products can be neglected.  
Table 2 shows the operation parameters of gasification process in test fires with pyro-charge-assisted ignition. The mass flow rate of gasification products varies from 43 to 71 g/s. The measurements of PP sample mass before and after test fires confirms a significant decrease in sample mass (by 180-276 g) due to PP gasification. The time-averaged ratio of the total mass of air to the total yield of PP gasification products varies from 2.34 to 2.90.  
Thus, for the GGs with hydrogen ignition and with pyro-charge ignition, the time-averaged ratio of the total mass of air to the total yields of PP gasification products appeared to be quite close: 2.46 to 2.87 and 2.34 to 2.90, respectively. This can be related to the universality of the proposed method. Additionally, the method can be readily applied to LMSs other than polypropylene if they are gasified without the formation of the liquid phase (condensate), since the method is based on gas dynamic relationships not generally applicable to the two-phase flows containing liquid or solid particles. One of the subjects of further research is the uncertainty analysis of the proposed method.