1 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

What?

  • The module is drawn from MAE 4700/5700 FEA for Mechanical Aerospace Design at Cornell University
  • This project analyzes the bolted flange joint that connected the mid and lower parts of the F1engine nozzle by building a non-linear FEA model
  • The pressure due to the exhaust gas in the nozzle is calculated using 1D gas dynamics. It is assumed to vary linearly along the nozzle axis.

2 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

Geometry & Mesh

  • For the geometry, only 1/400 model will be simulated to save computing time, and the symmetry BC is used
  • The hex-dominant mesh was used for this model
  • The mesh was refined later when the grid refinement study was implemented
  • The quality of the mesh is good for the purpose of this study

Mid nozzle

Lower nozzle

Bolt

Nut

3 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

Model

  • After choosing Steel to be the material, the Thermal Condition Load was selected to adjust for the thermal strain
  • The bolt preload was also added by the bolt pretention model
  • Beside the symmetry BCs on both sides, the top face of the model is fixed
  • The pressure from the gas was applied along the axial direction linearly with tabular data as shown in the picture
  • The force from the regeneration channels was applied as shown

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4 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

Results

  • Total deformation at each of three-time steps as follows:

-First Step: the bolt preload

- Second step: pressure load

- Third step: temperature load

  • The Gap between the two nozzles is an interest to avoid any gas leakage

Total Deformation at the first step

Total Deformation at the second step

You can see the generated gaps due to pressure between the two nozzles

5 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

Results

  • Show are the results for the equivalent stresses for the first step and the third step.
  • The second step is similar to the first step, so it is neglected

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Equivalent stress for step 1

6 of 6

Ziad Alaswad

MASc. Mechanical Engineer, EIT

BOLTED NOZZLE FLANGE

Results

  • The red region shows the gaping, blue is the good region
  • Our goal is to reduce gaping to avoid leakage
  • The gaping didn’t change between step 2 and 3, as thermal load didn’t affect the gaping

Gaping for Step 1

Gaping for Step 2&3