Ms. Elana Helou Profile

Elana Helou

at The Univ. of Southern California

SPIE Involvement:

Author

Publications (1)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 3 October 2022 Presentation + Paper

Experimental investigation of QCM-derived sticking coefficients for use in molecular transport simulations

Lubos Brieda, Elana Helou, Tianxiang Zhao, Joseph Wang, Denisse Aranda, Vince Green, Syed Iqbal

Proceedings Volume 12224, 122240O (2022) https://doi.org/10.1117/12.2632195

KEYWORDS: Contamination, Numerical simulations, Monte Carlo methods, Visualization, Space operations, Particles, Computer simulations, Chemical species

Read Abstract +

This paper presents data from an experimental characterization of molecular transport in vacuum chambers. Specifically, our goal was to determine the applicability of a Quartz Crystal Microbalance (QCM)-derived sticking coefficients for modeling gray-body view factors. The testing was performed at Blue Origin and at USC, and consisted of performing a QCM thermogravimetric analysis (QTGA) to derive the sticking coefficient from a QCM with a direct line of sight to an outgassing sample. This sticking coefficient was then used in a numerical simulation of the chamber, which was used to compute deposition on a secondary QCM with no direct line of sight to the sample. The simulations were found to greatly under-predict the collection on the second QCM. This under-prediction is attributed to the sticking-coefficient based adhesion model reducing flux on each wall impact. In reality, the contaminant population is composed of a heterogeneous mixture of multiple chemical species. Lower vapor pressure gases collect on the first wall impact, while the remaining molecules continue to bounce around without additional sticking. A temperature-based sticking coefficient applies the reduction on each impacting, leading to an artificially low prediction for gray body deposition onto the final cold surface. For the two considered configurations, we found the model to underestimate the experimental measurements by a factor ranging from 7.2 to 1764.3.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years