Hgdt

Hall Consulting's Hybrid Gun Design Tool is a simulation program to aid the design of combustion cannons and hybrid cannons. It is available here.

Common problems for first time users

Read, and follow, the installation instructions for HGDT before installing.

Physics model

As of version .5.04, in modeled the following features:

1. Finite flame propagation rates and flame front acceleration and turbulence.
2. Pressure drop across the disc orifice.
3. Temperature increase in the unburned gases found within the chamber as pressure increases during propellant burning.
4. Temperature/pressure decrease due to heat lost to the walls of the gun chamber and barrel.
5. Performance differences due to different fuels (not complete as of this writing).
6. Temperature effects on gas properties (and thus, performance).
7. Performance limitations due to flow choking in the disc orifice or the barrel.
8. Disc effective orifice increases due to lowered valve throat Mach number.
9. Temperature (and thus pressure) drop in the barrel due to work performed by the gas accelerating the projectile.
10. Gas leakage around the projectile in the barrel.
11. Compressibility (Mach) effects on air pressure both in front of and behind the projectile to include the creation of shocks.

However, it does not consider:

1. Energy losses associated with turbulence or frictional forces between the gas and the gun's chamber/barrel walls. In other words, pressure drops due to bends or rough edges in the gun's plumbing.
2. Realistic combustion modeling.

As of right now, HGDT's accuracy when simulating hybrid cannons has not yet been thoroughly tested. Combustion simulations using atmospheric pressures have been matched with Burnt Latke's testing; Page 1 Page 2

Use

See Hall's page on use.

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