[Demo] Knudsen Pumping: Can Heat Alone Pump Gas Through a Microtube?
Updated: 14 hours ago
Authors: SciViD Editorial* (demonstration item)
*Affiliation: SciViD, 4101 Brisbane, Queensland, Australia
DEMONSTRATION ITEM · PRELIMINARY · NOT PEER REVIEWED · NUMERICAL RESULTS ONLY
Type: Computational or modeling study · Collection: Micro- and Nanotechnology
Interactive lab: https://knudsen-lab.gainscholar.workers.dev
*Corresponding author: editor@scivid.net
Abstract
Thermal transpiration, the flow of a rarefied gas from cold to hot along a wall that carries a temperature gradient, allows gas to be pumped without moving parts. This article describes the Knudsen Tube Lab, an interactive three-dimensional virtual laboratory that replays the stored results of a numerical study asking whether a single rolled-up microtube with a nanometer-thick wall could act as a Knudsen pump. The lab presents four groups of results. The first is a set of transport coefficients from the linearized S-model kinetic equation over the rarefaction range 0 ≤ δ ≤ 100, which agrees with published discrete-ordinates solutions to within 2 × 10⁻⁶. The second is a set of steady wall-temperature fields for five candidate tube geometries and four wall cases, with calculated heating budgets of about 0.2–110 µW. The third is a validated closed-reservoir transient in which a 30 K temperature difference along a 200 µm tube establishes a pressure difference of about 50 Pa at a mean pressure of about 2.4 kPa. The fourth is a set of force estimates for the candidates, which rest on a simplified model. The finite-tube correction and the sign of the axial force remain unresolved, so the model makes no prediction about whether or how the tube might move. Every value in the lab is traceable to a source file and carries a status label, so that validated results, simplified estimates and conceptual scenarios remain clearly separated.
Article information
IDENTIFIER: SciViD-DEMO-01. This is a demonstration identifier outside the SciViD preprint sequence; it is not a DOI.
VERSION HISTORY: version 1, posted Oct 21, 2026. REVIEW STATUS: preliminary; not peer reviewed. License: CC BY 4.0
AI USE: Code, data processing and drafting were assisted by AI tools; all values were checked against the source files by the editors.
NOT FOR CITATION: this demonstration item illustrates the SciViD format and is not a research record.
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