--- title: Bioreactor CFD - gradients and cell lifelines | p4b description: "CFD beyond P/V and kLa: resolved oxygen and nutrient gradients, gas-liquid mixing and lifelines of individual cells in large-scale bioreactors." image: https://www.p4b.io/hubfs/raw_assets/public/p4b/images/og-default.png --- [![p4b](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/p4b-logo-white.svg) ![p4b](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/p4b-logo-navy.svg)](https://www.p4b.io/?hsLang=en) Products [**pDS inserts**Large-scale conditions in your lab bioreactor](https://www.p4b.io/pds?hsLang=en) [**Advanced CFD**Gradients, lifelines and cell experiences](https://www.p4b.io/cfd?hsLang=en) [**DREAM-bio**Find the best geometry for your bioreactor](https://www.p4b.io/dream-bio?hsLang=en) [**Ambr 250 vs. 2,000 L**Interactive CFD comparison of the mixing](https://www.p4b.io/compare?hsLang=en) [Case studies](https://www.p4b.io/case-studies?hsLang=en) [Insights](https://www.p4b.io/insights?hsLang=en) [Events](https://www.p4b.io/events?hsLang=en) [About](https://www.p4b.io/about?hsLang=en) [Contact](https://www.p4b.io/contact?hsLang=en) [Request a quote](https://www.p4b.io/contact#quote) [Home](https://www.p4b.io/?hsLang=en) / Products / Advanced CFD Advanced CFD # …where every cell tells a story Average values hide what your cells actually experience. We simulate gradients within your bioreactor and track individual cell trajectories through them - at your current scale and the scale you plan to use. [Discuss your reactor](https://www.p4b.io/contact#quote)[Explore gradients](https://www.p4b.io/cfd#explorer) ![CFD simulation: bubbles and flow field in a stirred bioreactor](https://www.p4b.io/hubfs/website/cfd-bubbles.webp) Go beyond global values ## P/V and kLa are where the analysis starts, not where it ends Two reactors with the same P/V can have very different mixing patterns. Global values describe the reactor as a whole, while your cells experience local conditions. We simulate gas–liquid flow throughout your vessel to reveal where oxygen levels, nutrient concentrations, temperature, and shear differ from the average. Instead of a single mixing time, you get a distribution of mixing times across the volume, the size and location of depleted zones, and detailed insights into power input, shear stress, and kLa. We then track cell trajectories: how often cells encounter conditions your process cannot tolerate, how long they remain there, and how severe the exposure is. This is where scale-up problems become visible and where solutions begin. Tracer with gas flow (left) and without (right) - the bubbles change how the tank mixes. Gas-liquid CFD. Microbial fermentation · 15,000 L ## Watch gradients form at scale Simulation results for a 15,000 L stirred tank. Switch between glucose and dissolved oxygen and increase the process intensity. Glucose Dissolved oxygen Carbon-limited feed in a microbial fermentation. The higher the process intensity, the larger the depleted zones far from the feed point. Low Mid High Very high Carbon-limited fed-batch · glucose concentration. Dissolved oxygen at 1.5 vvm gassing with air. With rising process intensity, oxygen-depleted zones open up between the impellers. Low Mid High 1.5 vvm gassing with air · dissolved oxygen. ![Glucose gradient, low intensity](https://www.p4b.io/hubfs/website/cfd/glc-low.webp)![Glucose gradient, mid intensity](https://www.p4b.io/hubfs/website/cfd/glc-mid.webp)![Glucose gradient, high intensity](https://www.p4b.io/hubfs/website/cfd/glc-high.webp)![Glucose gradient, very high intensity](https://www.p4b.io/hubfs/website/cfd/glc-vhigh.webp) ![Dissolved oxygen, low intensity](https://www.p4b.io/hubfs/website/cfd/o2-low.webp)![Dissolved oxygen, mid intensity](https://www.p4b.io/hubfs/website/cfd/o2-mid.webp)![Dissolved oxygen, high intensity](https://www.p4b.io/hubfs/website/cfd/o2-high.webp) 15,000 L: glucose and oxygen availability along individual cell lifelines, and bubble size. Lifeline analysis ## From particle tracks to cell experiences We track up to 100,000 virtual cells through the reactor, record what each experiences, and turn those insights into metrics that help bioprocess engineers make informed decisions. Each virtual cell records glucose concentration, dissolved oxygen, temperature, and shear along its path. Using thresholds you define for your organism - a minimum DO level, glucose limits for starvation and overflow metabolism, a temperature range, and a shear limit - we quantify how often and for how long each cell leaves the acceptable range. The area between the trajectory and the threshold captures both the magnitude and duration of each excursion. Combined across all lifelines, these metrics form a fingerprint of the reactor. You can compare designs, scales, or operating conditions based on what cells experience and identify the conditions a scale-down model needs to reproduce. Validation first ## We test our simulations against tough cases Full gas-liquid simulations using Siemens’ M-Star CFD, validated against experiments where it matters. ### [![CFD streamlines in a stirred bioreactor](https://www.p4b.io/hubfs/website/cfd-streamlines.webp) kLa validation Can CFD rank stirrer positions by kLa? A 2 L reactor at 1.5 vvm - only the impeller position changed. The simulation ranked the configurations in the same order as the experiments. Read more →](https://www.p4b.io/insights/cfd-validation-kla-stirrer-position?hsLang=en) ### [![Tracer simulation in a 2 L bioreactor](https://www.p4b.io/hubfs/website/cfd-bubbles.webp) Mixing time Same reactor, eleven mixing times Eleven tracers, the same flow conditions: mixing times from 20.3 to 23.5 s. Why a single mixing time is not enough to compare reactors. Read more →](https://www.p4b.io/insights/eleven-mixing-times-one-reactor?hsLang=en) ### [![Gas-liquid CFD of a 2,000 L single-use bioreactor at different stirrer speeds](https://www.p4b.io/hubfs/website/video/xcellerex-2000l-rpm.webp) 2,000 L Higher stirring speed, faster mixing? In a 2,000 L single-use reactor, mixing was fastest at ~80 rpm - the impeller controls how far the gas plume spreads. Read more →](https://www.p4b.io/insights/faster-stirring-not-faster-mixing?hsLang=en) What you get ## Simulation as a service ### Digital twin of your reactor Your vessel, impellers and operating conditions - at lab, pilot or production scale. ### Gradients and lifelines Mixing time distributions, depleted zones, and cell experiences instead of a single number. ### Scale-down target The basis for generating a pDS insert that recreates your production reactor’s mixing conditions in the lab. ### Consulting Support from bioprocess engineers for scaling challenges and bioreactor setup questions. Get in touch ## Accelerate your process development. Let’s discuss how p4b can help your team accelerate process development and bring your product to market faster. [Request a quote](https://www.p4b.io/contact#quote)[Book a 30-min call](https://www.p4b.io/contact#meeting) ![Lena Achleitner](https://www.p4b.io/hs-fs/hubfs/website/team/lena-avatar.webp?width=84&height=84&name=lena-avatar.webp) **Lena Achleitner**Senior Bioprocess Engineer, Key Account Manager[lena.achleitner@p4b.io](mailto:lena.achleitner@p4b.io) ### Get new insights by email CFD results, case studies and new insert systems when we publish them. Unsubscribe any time. ![p4b](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/p4b-logo-white.svg) Scale reliably. Develop faster. Digital and 3D-printed technologies for bioprocessing. [Follow us on LinkedIn](https://www.linkedin.com/company/p4b-gmbh/) #### Products - [pDS inserts](https://www.p4b.io/pds?hsLang=en) - [Advanced CFD](https://www.p4b.io/cfd?hsLang=en) - [DREAM-bio](https://www.p4b.io/dream-bio?hsLang=en) - [Request a quote](https://www.p4b.io/contact#quote) #### Company - [About us](https://www.p4b.io/about?hsLang=en) - [Case studies](https://www.p4b.io/case-studies?hsLang=en) - [Insights](https://www.p4b.io/insights?hsLang=en) - [Events](https://www.p4b.io/events?hsLang=en) - [Contact](https://www.p4b.io/contact?hsLang=en) #### Contact **Office & deliveries** p4b GmbH Leopold-Ungar-Platz 2 Spaces Square One, Stiege 2 1190 Vienna, Austria [+43 677 61062225](tel:+4367761062225) [office@p4b.io](mailto:office@p4b.io) Registered office: Gärtnersteg 4, 2120 Obersdorf, Austria Supported by ![austria wirtschaftsservice](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/logos/aws.png) ![Bundesministerium Arbeit und Wirtschaft](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/logos/bmaw.png) ![Bundesministerium Klimaschutz, Umwelt, Energie, Mobilität, Innovation und Technologie](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/logos/bmk.png) ![FFG](https://www.p4b.io/hubfs/raw_assets/public/p4b/images/logos/ffg.png) © 2026 p4b GmbH · FN 611768i · ATU79846712 [Imprint](https://www.p4b.io/imprint?hsLang=en)[Privacy policy](https://www.p4b.io/privacy-policy?hsLang=en)Cookie settings ```json { "@context" : "https://schema.org", "@type" : "Organization", "address" : { "@type" : "PostalAddress", "addressCountry" : "AT", "addressLocality" : "Obersdorf", "postalCode" : "2120", "streetAddress" : "Gärtnersteg 4" }, "description" : "Scale-down technology for bioprocess development: 3D-printed pDS inserts, bioreactor CFD and DREAM-bio design optimisation.", "email" : "office@p4b.io", "logo" : "//143831650.fs1.hubspotusercontent-eu1.net/hubfs/143831650/raw_assets/public/p4b/images/p4b-logo-navy.svg", "name" : "p4b GmbH", "sameAs" : [ "https://www.linkedin.com/company/p4b-gmbh/" ], "telephone" : "+43 677 61062225", "url" : "https://www.p4b.io" } ```