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BiRD: BioReactorDesign Gas-Liquid Flows for Biofuel Production

BioReactorDesign (BiRD) uses high-fidelity multiphase fluid dynamics simulations coupled with microbial bioreaction models for aerobic/anaerobic and gas fermentation pathways that generate fuels/chemicals from biomass-derived sugars and mixtures of energy-rich gas streams.

Gas and liquid phase transport, mass-transfer, and mixing physics at large length scales can significantly affect microbial conversion rates, particularly when the microbial reaction requires a narrow set of conditions. These phenomena are difficult to study in small-scale benchtop reactors that are typically well mixed. Predictive computational-fluid-dynamics-based simulations can therefore aid in the scale-up, design, and optimization of these reactors.

Three columns representing gas fraction, carbon dioxide, hydrogen gas in a bubble column reactor.

Simulations of 3,000-liter CO2/syngas bubble column reactor with a cylindrical sparger. (a) shows gas fraction, (b) CO2 concentration in the liquid, and (c) H2 concentration on liquid streamlines that indicate fluid mixing effects.

This model treats the gas and liquid as interpenetrating phases, which reduces the computational complexity of tracking individual gas bubbles that are several orders of magnitude smaller than reactor dimensions. This model also solves the Reynolds Averaged Navier-Stokes multiphase equations that account for phase and chemical species transport, interphase mass and momentum transfer, and bubble size distributions and uses a phenomenological model for gas uptake by microbes.

BiRD includes a library of cases of typical bioreactors ready to be used with a variety of multiphysics and reaction models. The geometry and operating conditions of the reactors can be easily modified to allow for rapidly running multiple simulations, such as for optimizing the design of the reactor or for rapid prototyping to obtain proof of concept for a new reactor design.

Download BioReactorDesign Codes

The BiRD software suite can be accessed via a GitHub repository.

Hariswaran Sitaraman

Researcher, Mechanical Engineering

[email protected]
303-275-3171


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Last Updated Feb. 3, 2026