flowtube Package

A Python package for transport and diffusion calculations in cylindrical flow reactors using the KPS method published in Knopf et al., Anal. Chem., 2015. The package is currently designed for coated wall reactor (CWR) and boat reactor analysis with plans to support aerosol flow reactors in future versions.

Author: Corey Pedersen

Documentation: https://flowtube.readthedocs.io/

Features

• Flow Calculations: Flow rates, velocities, residence times, and Reynolds numbers.
• Transport Properties: Dynamic viscosity and density
• Diffusion Analysis: Binary diffusion coefficients, Péclet numbers, and mixing parameters
• Uptake Modeling: Diffusion correction factors and uptake coefficient calculations
• Support for Inserts: Handles coated cylindrical inserts within flow tubes
• Support for Boats: Handles boat reactors which are placed inside of a flow tube and filled with an analyte solution.

Scientific Applications

This package is designed for atmospheric chemistry and aerosol research, particularly for:

• Heterogeneous reaction kinetics studies
• Uptake coefficient measurements
• Flow reactor design and optimization
• Transport phenomena analysis in laminar flow systems

Installation

pip install flowtube

Acronyms

• sccm = standard cubic centimeter per minute
• FT = flow tube
• FR = flow rate
• MR = mixing ratio
• CWR = coated wall reactor

Assumptions

KPS method assumptions (Knopf et al., 2015):

1. The interacting gas species is a trace gas in the bulk flow
2. Laminar flow is established in the flow reactor
3. The gas temperature and viscosity are homogeneous
4. The axial diffusion velocity is negligible compared to bulk flow velocity
5. The amount of gas species taken up is small compared to its reservoir
6. There is an absence of gas-phase reactions impacting gas species concentration

Bibliography (more citations within package files)

Knopf, D.A., Pöschl, U., Shiraiwa, M., 2015. Radial Diffusion and Penetration of Gas Molecules and Aerosol Particles through Laminar Flow Reactors, Denuders, and Sampling Tubes. Anal. Chem. 87, 3746–3754. https://doi.org/10.1021/ac5042395