156B Week 5

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

• • The tests that we conducted last week showed that our design direction is incorrect for discharging purposes. After the nozzle test, we got real data on how discharging effects behaves. Based on that data, we realize that we’ve been using CFD the wrong way. The most important factor in the discharging effect is not how streamlines of the nitrogen gas flow behaves, it is the interaction between nitrogen molecules and the sample surface.

  • Current nozzle were designed to spread the flow over the sample surface, but covering the sample does not help with discharging. Now we are working on new tip designs that delivers controlled flow that hits the sample with optimal amount of molecules for discharging effects.

Accomplishments from Previous Week

• • Brainstorm session on next design with Tristan (Project manager and sponsor)

  • Last weekly progress update was completed on last Wednesday night

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

• • Get the machined prototype from CRMS (PEEK nozzle)

  • More Tip designs and CFD analysis (CAD files and results from ANSYS)

  • More microscope test on organic samples (if available)

    • Current sample charges crazy and renders image useless for nozzle designing

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

• • Steve (in person 4/27)

    • Try two nozzles coming from different sides of the sample

      • Various tips were designed to see the simulation results

  • Tristan (in person 4/27)

    • T splitters - extremely small

      • Online search - medical supply

    • Manufacture - make the tip in two parts and then put them together

• Tom Chalfant (in person 4/25)

  • Prototype split flow nozzle design is viable for machining

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

All comments are on 4/25 in person

• • EDM Machining - High precision but requires metal

    • Discussed with Tristan on purchasing and using Titanium

    • Ordered Grade 2 Titanium

  • Additional vacuum pump

    • Discussed with Tristan, not viable, and the metal column is going to be replaced in 3 weeks.

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

• • Machinability - Titanium

  • Our current nozzles are designed based on golden particles sample, might not be suitable for organic sample

  • Microscope availability

Resources or Information Required but not Available

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

Schedule

• • Another test (if microscope is available)

  • Tip prototype design

Budget (list amount spent and amount remaining)

• • PEEK, $200

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

  • Grade 2 Titanium,  1 inch wide, 1 ft long, 1/4 in thick, ~$43 (McMaster)

  • $4357 remaining

Progress on Report and Webpage

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