Main Oxygen Valve

Overview

This project started when our propulsion team realized we needed a new main oxidizer valve, something lightweight, high-flow, and safe to operate under high pressure. Off-the-shelf solutions were too heavy or complex, so another team member and I led the design of a custom pneumatically actuated sleeve valve. The goal was to create a reliable valve that could withstand 1000+ psi while integrating cleanly into the existing plumbing and control system.

Objectives

• Achieve a 2.5 kg/s flow rate of nitrous oxide at 850 psi (rated to 1050 psi, tested to 2200 psi).
• Limit valve mass to 3 lb and achieve full opening within 0.65 s.
• Ensure fail-closed behavior on pneumatic or electrical loss.
• Design for manufacturability using lathe-based machining.

Design and Process

We compared ball, gate, and pyrotechnic valves before selecting a sleeve valve for its simplicity and low mass. Mechanical design was done in SolidWorks and validation in ANSYS Workbench.

The most important part of this valve design was the force balance between pneumatic pressure, flow forces, the spring, and O-ring friction which guided the design. The body and sleeve were 6061-T6 aluminum for it’s price and machinability with Viton O-rings for nitrous oxide compatibility.

Testing and Outcomes

The design was finalized in November 2025 and released for manufacturing. Testing is happening first week of Febuary 2025, including:

• Hydrostatic pressure test (1500 psi)
• Dry actuation with N₂
• Cold-flow tests with CO₂ to measure flow performance and actuation time

Reflection

This project taught me to design for performance and manufacturability under real constraints. I deepened skills in force balancing, pneumatic control design, and O-ring seal behavior, including gland geometry and friction effects. With the highest count of critical dimensions I have designed, I managed tight tolerance stack-ups and to ensure everything fit and functioned correctly.