Titan IV Mesh

Damrong Guoy , Mark Brandyberry, Scot Breitenfeld, Dennis Parsons (LLNL)
Center for Simulation of Advanced Rockets (CSAR)
Computational Science and Engineering Program (CSE)
University of Illinois at Urbana-Champaign (UIUC)



The Center for Simulation of Advanced Rockets (CSAR) is working on computational modeling and simulation of the PQM-1 Titan IV Rocket Motor (PQM-1 = first prequalification motor), which exploded during a test firing in 1991. The three-dimensional simulation is intended to help explain why the accident happened. The fully coupled simulation modules consist of internal gas dynamics, propellant combustion, and structural response.

Preliminary simulation results were presented in AIAA paper:

R. A. Fiedler, M. S. Breitenfeld, X. Jiao, A. Haselbacher, P. Geubelle, D. Guoy, and M. Brandyberry,
Simulations of Slumping Propellant and Flexing Inhibitors in Solid Rocket Motors,
AIAA Paper 2002-4341, 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference,
Indianapolis, IN, July 7-10, 2002. AIAA_2002-4341_SlumpFlex.pdf 1 MB

Dennis Parsons created a CAD model of the Titan IV from specifications in published papers using Solid Edge from EDS. Damrong Guoy created a multi-block structured mesh for simulating the gas flow inside the rocket using Gridgen from Pointwise Inc. Scot Breitenfeld created an unstructured tetrahedral mesh for simulating the solid propellant using Patran from MSC and TetMesh-GHS3D from Simulog. Mark Brandyberry coordinated the overall meshing process.


Geometry

The somewhat idealized geometry consists of four pieces: star grain, center segment, aft segment, and nozzle, together with case. Currently the nozzle and case are treated as a rigid wall in the structural response module, Rocfrac, eliminating the need for solid tetrahedral meshes of the thin metal case and nozzle. The gas flow inside the nozzle and exit plume defines a part of the fluids multi-block structured mesh for the CFD module, Rocflo.





Solid Propellant

A tetrahedral mesh of 2,715,380 elements represents solid propellant in star grain, center segment, and aft segment. The mesh is partitioned into 504 zones for a parallel computer of 512 processors (504 computing nodes + 8 I/O nodes). Click on one of the three pictures below to see the mesh in more details (955x1857 pixels).

star 84 zones.
63-77(15), 86-93(8),
441-467(27), 470-503(34) 		center 229 zones.
0-62(63), 78-85(8),
94-251(158) 		aft 192 zones.
252-440(189),
468-469(2),471(1)
Note: zone 471 is shared by both star grain and aft segment.

An example showing zone 0 with some neighboring zones. They reside in center segment.
Some zones in center segment
Zone 0 (yellow) in the middle,
zone 1 (green) at the top left, and
zone 8, 11, 95, 100, 101 in clock-wise order.



Gas Flow

We create a multi-block structured mesh for hot gas inside the rocket and exit plume next to nozzle area. There are 58 structured blocks and 2,044,200 hexahedral elements. The mesh is partitioned into 504 zones for parallel simulation. The following picture shows the partitioning.



The following table presents the 58 structured blocks in the mesh. Click on icons to see larger pictures

star (16 blocks)
+ 1st joint (9 blocks) 		center (5 blocks)
+ 2nd joint (13 blocks) 		aft (5 blocks) nozzle (5 blocks) exit plume (5 blocks)




Last updated : Sun May 13, 2007