Figure 6
The image features two graphs. On the left, a contour plot displays inlet velocity on the Y-axis, measured in metres per second, and log of temperature on the X-axis, with contour lines representing values of log of D slash U p. The optimal point is marked with a red dot. On the right, a 3 D surface plot shows inlet velocity on the X-axis and log of temperature on the Y-axis, while the Z-axis represents log of d N slash d U p. The surface depicts values corresponding to the relationship between these variables, with a point marked at the same optimal location as in the contour plot. A colour gradient in both plots transitions from blue to red, indicating varying values.(a) contour plot and (b) 3D surface plot of objective function log(D/Up). The overlaid red marker indicates the optimal operating point determined through constrained optimization