# Design of and Experimental Study on Drying Equipment for _Fritillaria ussuriensis_
## 4 Optimization of Structural and Process Parameters of Drying Device Based on Fluent Simulation
### Optimization of Drying Process Parameters
#### 4.4.2 Response Surface Analysis  
Fitting analysis of the data in Table 6 was carried out using Design Expert 11, and the quadratic polynomial regression equation for the three factors, namely inlet temperature (A), inlet air velocity (B), drying time (C), and moisture content \((R_{1})\) of _Fritillaria ussuriensis_ is as follows:  
\[ \begin{array}{l}R_{1}=12.2-3.61A-0.6750B-1.66C-0.15 AB\\ +0.675 AC-0.3 BC+1.69A^{2}-0.6375B^{2}-0.8125C^{2}\end{array}  \tag{10}\]  
The quadratic polynomial regression equation with the temperature non-uniformity coefficient \((R_{2})\) is as follows:  
\[ \begin{array}{l}R_{2}=0.736+0.0137A-0.0163B-0.0025C+0.0025 AB\\ -0.005 AC+0.005 BC+0.0358A^{2}+0.1158B^{2}-0.0018C^{2}\end{array}  \tag{11}\]  
Through calculation and analysis, it is concluded that the \(p\)-values of the models of both the moisture content change \((R_{1})\) and temperature non-uniformity coefficient (\(R_{2}\)) of _Fritillaria ussuriensis_ are less than 0.0001, indicating extreme significance. In contrast, the \(p\)-values of the lack-of-fit terms are greater than 0.05, suggesting non-significance. Therefore, the fitting models for the drying of _Fritillaria ussuriensis_ are accurate. The determination coefficients of the regression models re \(R_{1}{}^{2}\) = 0.9796 anseunting that the fitting degree between the predicted values and measured values of the models is extremely high; the adjusted determination coefficients are Adj. \(R_{1}{}^{2}\) = 0.9903 and Adj. \(R_{2}{}^{2}\) = 0.9703, indicating that the predicted values and measured values of the models have a high degree of correlation. In the regression fitting model, based on the \(R_{1}\) values, the order of influence of each factor on the moisture content of _Fritillaria ussuriensis_ is as follows: A (inlet temperature) > C (drying time) > B (inlet velocity). To more intuitively explore the relationship between the three factors--A (inlet temperature), B (inlet velocity), and C (drying time)--and both the moisture content and non-uniformity coefficient of _Fritillaria ussuriensis_, the fitting results obtained by Design Expert 11 are shown in Figures 8 and 9. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Test Number** & **A** & **B** & **C** & **Moisture Content \(R_{1}\) (\%)** & **Temperature Non-Uniformity Coefficient \(R_{2}\)** \\ \hline
1 & \(-1\) & 0 & 1 & 14.3 & 0.75 \\
2 & 0 & 0 & 0 & 11.8 & 0.74 \\
3 & 1 & 0 & 1 & 8.1 & 0.78 \\
4 & 0 & \(-1\) & 1 & 10.4 & 0.86 \\
5 & 0 & 1 & 1 & 8.2 & 0.84 \\
6 & 0 & 0 & 0 & 11.5 & 0.75 \\
7 & 1 &Figure 8: 3D response surface and contour plots of \(R_{1}\). Figure 9: 3D response surface and contour plots of \(R_{2}\). It can be seen from Figures 8 and 9 that the inlet temperature (A) exerts the most significant influence on the moisture content of _Frtillaria ussuriensis_. Specifically, the moisture content of _Frtillaria ussuriensis_ decreases significantly as the drying temperature increases. Compared with inlet temperature (A), the influences of inlet velocity (B) and drying time (C) on the drying of _Frtillaria ussuriensis_ are relatively weaker. The moisture content of _Frtillaria ussuriensis_ decreases as the drying time increases, but when the heating time reaches a certain point, the change in its moisture content becomes minimal, and the same trend applies to the inlet air velocity. However, the drying temperature has a weak influence on the temperature non-uniformity coefficient, whereas the air velocity is the primary factor affecting this coefficient. With the decrease of velocity, the temperature non-uniformity coefficient first decreases and then increases. After analysis and in combination with the actual drying requirements of _Frtillaria ussuriensis_, the optimal parameters were determined by referring to a comprehensive comparative analysis of the temperature non-uniformity coefficient, drying time, moisture content and energy consumption.