Finding the optimum parabolic nozzle can be done in two ways within PRISM.

1. Call the curve fit within the Huzel routine.
2. Use the optimizer to call TDK to find the highest efficiency.

The parabolic nozzle is defined by the entrance angle and the exit angle.

This example demonstrates for a nozzle of

• area ratio = 40
• Percent Bell = 80

the curve fit result is

• entrance angle = 33.4534 deg
• exit angle = 6.30687 deg

The optimization below performs the TDK approach for comparison.

NOTICE the figure of merit in the optimization is not nozzle efficiency, it is the difference between nozzle efficiency and a reference nozzle efficiency. This is done so that the optimizer will see larger percent improvements as it explores the design space.

Aside from the sensitivity chart that shows how efficiency changes with the two design parameters, there is also a contour plot of efficiency that shows the optimizers answer at approximately the center of the optimum "island" on the plot.

PRISM System: Parabolic Nozzle
                type = analysis
======================================
      name         value        minimum   maximum
  thetaAng      36.4534           25           40 Entrance Angle  (deg)
   exitAng      9.30687            3           15 Exit Angle  (deg)
 Figure of Merit = 0.001 = Nozzle Efficiency - Ref Efficiency (eta2Ddiff)
======================================
======================================

PRISM System: Parabolic Nozzle
                type = analysis
======================================
      name         value        minimum   maximum
  thetaAng      34.3306           25           40 Entrance Angle  (deg)
   exitAng      8.41057            3           15 Exit Angle  (deg)
 Figure of Merit = 0.00119947 = Nozzle Efficiency - Ref Efficiency (eta2Ddiff)
======================================
======================================

(PRISM) PaRametrIc System Model
PRISM v1.1.7
contact: C. Taylor, cet@appliedpython.com