Sustainer nozzle cross section. Sustainer nozzle exploded view
Overview
The sustainer nozzle assembly is intended to be used on Phoenix 1, attached to the sustainer stage. It is made of two components, the nozzle carrier and graphite nozzle, which are joined together with high-temp RTV sealant. The assembly is then joined to the motor case using twelve 10-32 thread, 7/16" long countersunk bolts. The nozzle is sealed into the case using three o-rings, two on the graphite nozzle, and one on the nozzle carrier. The purpose of these O-rings is to keep the hot gases from combustion inside the chamber and prevent exhaust leakage and therefore an inefficient and possibly dangerous burn. To calculate the o-ring gland size, we used this website: https://www.applerubber.com/oring-gland-calculator/
Design:
Nozzle Basic dimensions:
Throat Diameter: 0.8 in
Exit Diameter: 3 in
Throat Length: 0.1 in
Convergent Angle: 60 degrees
Divergent Angle: 15 degrees
Parts:
Part Name | Material | Purpose | Manufacturing Equipment | Team member | Progress |
|---|---|---|---|---|---|
3 in Nozzle | Graphite | The graphite has a high melting point, and is able to absorb most of the heat from combustion, and forms the throat of the nozzle. | Lathe | ||
| 3 in Nozzle Carrier | Aluminum 6061 | Houses the other three parts, and is the bolt connection point to the motor case and the rest of the rocket. It also forms the back half of the divergent section, bringing the expansion ratio up to make sure the exit pressure matches ambient pressure | Lathe; Radial Indexer on Mill |
Drawings:
Graphite Sustainer Nozzle Nozzle Carrier
Manufacturing tips
General Tips:
- Before anything else is turned, face your piece of stock so that the front face is directly perpendicular to the rotational axis on the lathe.
- Turn the stock piece down to the largest diameter present on the part first before making other features on the part.
- Make sure to set your tool settings to "fine control when contacting part, unless only taking off a small amount of material
- When turning on the lathe, the best results will come from turning at a constant rate, not a slow rate.
- Be aware of the surfaces that will interface with other parts, these will require the most precision.
- when all parts are complete, make sure to fit check them before gluing them together.
Graphite Insert:
- Critical Feature: throat ID (double-check this measurement when manufacturing)
- Graphite is easy to turn, but horrible to clean up. Make sure to use the vacuum to avoid breathing in particles (may want to wear a mask)
- When cutting out the center, use the boring tool to create the hole and then use the finishing tool to expand the hole to the correct size.
Nozzle Carrier:
- Aluminum must be cut slow.
- turn all the features of the nozzle carrier before using the radial indexer on the mill
- Use the square-shaped tool bit to cut the O-ring grooves.