Theory from exams - rocket

Bell nozzle:

• Positive properties:

  • axial flow at the nozzle exit, allows for eliminating divergence losses

  • up to 3-4% better efficiency than conical nozzles

  • fast, almost radial expansion in the initial part of the divergent section

  • gradual contour changes to prevent the formation of oblique shocks

• the Bell nozzle does not follow the same geometric law in all its sections, unlike some other nozzle designs that maintain a consistent shape.