156B Week 4

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Testing is in progress, 3 nozzles have been tested so far.

  • Attempts to improve design’s machinability while maintaining functionality in progress

  • Attempts to provide better charge reduction is in progress

Accomplishments from Previous Week

• • Two Nozzle Designs machined

  • Reference Carbon fiber needle tested on microscope

  • First prototype tested on microscope

  • Crushed tip (stainless steel needle) tested on microscope

  • New designs have been drawn in CAD

  • Carbon-reinforced PEEK arrived

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Redesign Nozzle and Manifold based on results that we get from the experiments (Kuanren & Dylan)

  • Better CFD analysis on different nozzle and manifold design under low-pressure environment (Kuanren)

  • If available, do more test on new nozzles and manifold designs (Haonan, Kuanren, Edwin, Dylan)

  • Finish the first draft of report (Haonan, Edwin, Dylan)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Tristan Shone (4.23 in person)

    • Crushed tip (like slit outlet) may be better

    • Maybe stick two tubes together (imagine double-barreled shotgun) to get better gas coverage

  • Dr. Mark Ellisman (4.23 in person)

    • Optimal choking size (Channel hole may need to be bigger)

    • Fabricate nozzle using chemical dissolving, or stretching glass method

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Use Mach number instead of meter/second for gas speed (4.18 in person)

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • N/A

Risks and Areas of Concern

• • Manipulating flow using nozzle might be ineffective because discharging effects requires concentrated flow of nitrogen molecules

  • The discharging effects shown in microscope is extremely localized, and the results don’t agree with CFD simulation

    • Flow requirements for discharging unclear

    • Flow characteristics unclear

  • Improper manipulation on scope which makes its upper chamber require long time to cooldown

Resources or Information Required but not Available

• • The specification for customized valve installed on microscope for controlling nitrogen gas

Schedule

• • Meet with Tom - Wednesday

  • Gas Test on Slot Nozzle (if microscope is available)

  • Group meeting Thursday

Budget (list amount spent and amount remaining)

• • PEEK, $200

  • Machining at CRMS, ~$400 (waiting for exact quote from Bob)

  • $4400 remaining

Progress on Report and Webpage

• • Still in progress, and everything is done before due

  • Currently working on standards section