Cross-Cutting Engineering

Computational Fluid Dynamics (CFD)

Simulate airflow and aerosol transport to inform device design, placement, and performance estimates at room and component scales.

We build CFD models from controlled geometry and boundary conditions, then calibrate and validate them against chamber datasets to quantify flow fields, particle trajectories, and model sensitivity.

ISO 17025ASHRAE 90.1FDA CFD GuidanceICH Q9Reviewed 2026-05-16
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Purpose & when to use

Computational Fluid Dynamics (CFD) uses numerical simulation to predict airflow, mixing, pressure fields, and aerosol transport, with measured data used for validation. ARE Labs builds these models from CAD geometry, chamber decay datasets, particle size inputs, and documented boundary conditions. The work supports design and safety decisions under ISO 17025 quality practices, with FDA CFD guidance, ASHRAE 90.1 energy context, and ICH Q9 risk framing selected for the intended use. Use CFD when:

  1. Room air-cleaner placement and ventilation comparisons where ASHRAE 90.1 boundary conditions shape whole-room mixing, bypass risk, and occupant exposure estimates.
  2. Spray or inhalation device plume studies where FDA CFD guidance supports geometry-specific predictions before focused bench validation under ISO 17025 controls.
  3. Medical-device inlet, outlet, fan, or baffle revisions where 21 CFR Part 820 design controls require traceable scenario comparisons and sensitivity rationale.
  4. Chamber-test translation where ISO 17025 decay measurements calibrate CFD predictions for real rooms, ducts, or enclosures under ICH Q9 risk framing.
  5. Aerosol deposition and residence-time mapping where NIST sensitivity-analysis methods and ISO 17025 validation data identify which particle size, surface, or turbulence assumptions drive conclusions.

Use CFD when physical testing answers only part of the question or cannot cover every geometry and scenario. A fit-for-purpose model can rank the main drivers, narrow prototype choices, and document uncertainty before final validation testing.

Built for air, aerosol, device, and chamber programs

CFD supports product and facility questions where airflow geometry changes the outcome, from air-treatment systems and aerosol devices to medical-device housings and exposure chambers under ISO 17025 and FDA-aligned validation plans.

  • Air treatmentRoom and duct airflow systems
  • Spray aerosolPlumes, jets, and deposition
  • Medical deviceHousings, fans, and outlets
  • Inhalation productAerosol transport and delivery
  • RoomsChambers, enclosures, and ventilation

Instrumentation & measurement ranges

CFD is model-driven; credibility comes from measured inputs, geometry control, mesh checks, and validation datasets.

1 - 10000 sdecay-time

Chamber validation datasets

Measured concentration decay, flow rate, pressure, and particle size data calibrate the model and bound agreement against physical chamber results.

0.01 - 100 mgeometry-scale

Geometry and boundary-condition capture

CAD, measured openings, fan curves, inlet profiles, heat loads, and leakage assumptions define the simulation domain and documented applicability limits.

0.001 - 1000 m/svelocity

Micro-to-room CFD models

Component-scale jets, outlet plumes, ducts, rooms, and open configurations are modeled with turbulence and particle approaches matched to the decision.

Test method options

MethodStrengthsTradeoffAligned with
Room-scale dispersion and mixing model
  • Ranks placement and ventilation choices using ASHRAE 90.1 boundary-condition context.
  • Maps concentration, residence time, and bypass zones for room or chamber scenarios.
Furniture, leakage, and supply profiles can dominate results if poorly defined.
ASHRAE 90.1NIST Sensitivity Methods
Device internal flow and outlet jet model
  • Compares fans, baffles, inlets, seals, and housings before prototype builds.
  • Supports FDA CFD guidance and 21 CFR Part 820 design-control files.
Fan curves, porous media, and mesh resolution usually set the schedule.
FDA CFD Guidance21 CFR Part 820
Aerosol transport and deposition modeling
  • Predicts hot spots, surface deposition, and particle residence time by size band.
  • Pairs ISO 17025 chamber data with geometry-specific aerosol transport predictions.
Deposition is sensitive to particle properties, wall functions, and near-wall mesh.
ISO 17025NIST Sensitivity Methods
Model calibration with chamber data
  • Uses measured decay curves and flow records to reduce unsupported model assumptions.
  • Frames validation acceptance and residual uncertainty under ICH Q9 risk logic.
Requires a defined validation dataset before claims can be bounded.
ISO 17025ICH Q9

Setup configurations

Every CFD study begins by defining the decision the model needs to support. We then control the geometry, boundary conditions, validation data, and sensitivity plan. A fit-for-purpose setup balances model fidelity against sources of uncertainty the client can reduce through measurement, design changes, or clearer scenario definitions. These dimensions shape the modeling plan:

Device interfaces

CAD geometry, measured openings, internal passages, seals, filters, and source locations define the simulation domain and what simplifications are allowed.

Flow & actuation profiles

Ventilation rates, fan curves, inlet profiles, release rates, heat loads, duty cycles, and leakage assumptions are documented before solver setup.

Calibration & verification

Measured decay curves, flow checks, particle size distributions, pressure data, and acceptance criteria establish how the model will be judged.

Environmental controls

Temperature, humidity, background mixing, surface conditions, and chamber or room operating state are captured when they affect transport or deposition.

Sample numbers

Scenario counts and sensitivity runs are planned around the design choices, uncertainty drivers, and risk decisions the model must compare.

Modeling anchored to measured validation evidence

CFD studies are conducted within a documented quality system, using regulatory and engineering frameworks that match the model's intended use. The anchors below explain how ARE Labs reports assumptions, validation results, sensitivity evidence, and model limitations.

  • ISO 17025AccreditedLaboratory competence - documented methods, traceable measurements, and uncertainty contributors.
  • ASHRAE 90.1AlignedBuilding energy context - ventilation and boundary conditions for room models.
  • FDA CFD GuidanceAlignedMedical-device modeling expectations - verification, validation, and applicability limits.
  • ICH Q9AlignedQuality-risk framing - assumptions ranked by decision impact.

Key data outputs & reporting

A CFD study should deliver more than an isolated simulation image. The standard report includes decision-relevant model outputs, validation evidence, and a clear discussion of uncertainty. Results may include velocity fields, pressure maps, concentration histories, deposition indicators, and sensitivity rankings, formatted for design reviews, risk files, or validation packages. Extended programs that compare multiple geometries or operating modes also receive the corresponding scenario artifacts.

Primary outputs

  • Velocity fields, pressure maps, streamlines, and recirculation regions for the modeled geometry and operating conditions.
  • Aerosol concentration maps versus time and location, including residence-time and clearance indicators where applicable.
  • Deposition and hot-spot summaries tied to particle size, surface assumptions, and near-wall model choices.
  • Validation plots comparing simulated results with measured decay, concentration, flow, or pressure data.

Deliverables

#FormatContents
01PDF reportAssumptions, model setup, validation evidence, findings, and uncertainty limits.
02CSV / XLSX datasetsScenario metrics, sensitivity tables, and validation comparison data.
03Figures and animationsStreamlines, contours, concentration maps, and review-ready visual exports.
Extended deliverables · multi-arm comparability · stability · predicate studies
  • Scenario comparison pack — Ranked performance deltas across placements, geometries, flow rates, or operating modes.
  • Sensitivity appendix — Mesh, boundary-condition, turbulence, and particle-size assumptions ranked by effect on conclusions.

QA / QC & data integrity

Each CFD study includes a documented QA / QC framework scaled to the model's purpose, measured inputs, and decision risk. Controls cover versioned geometry, recorded solver settings, mesh checks, and convergence review. Traceability is maintained from the measured validation datasets through the final scenario metrics under the ISO 17025 quality system.

Version control for geometry, mesh, solver settings, source terms, boundary conditions, and analysis exports.

Mesh independence checks sized to the decision, with convergence criteria and residual behavior documented.

Traceability from chamber or device measurements to model inputs, calibration targets, and validation plots.

Sensitivity studies for ventilation, leakage, particle size, placement, turbulence model, and release assumptions.

Applicability limits stated in the report, including where physical testing remains required for final validation.

Why ARE Labs

ARE Labs connects technical topics to practical study design, method selection, controlled aerosol work, and reportable evidence without turning technical pages into sales pages.

Reviewed byJamie Balarashti (25 yrs - cascade & inhalation methods) - Weston Schaper (7 yrs - real-time sizing & nanoparticle work)
17025Accredited testing
900+Studies Performed
17+Years in operation
300+Clients supported

Common questions

Air-treatment engineers, aerosol-device teams, medical-device developers, and facility stakeholders often ask the same questions when scoping a CFD study: What data does the model need? How is it validated? Where do sensitivity studies fit? What will the final deliverables contain? The answers below provide a starting point. Contact us if your geometry, release condition, or regulatory framework falls outside these examples.

Q.Do you run CFD without measurements?
A.Yes, although a calibrated model is easier to defend. When possible, we recommend at least one validation dataset, such as chamber decay, flow mapping, pressure, or particle concentration data. The report can then document agreement between the model and measurements, along with the model's limits.
Q.What information do you need to start?
A.We need the geometry or CAD, operating flow rates or fan curves, source definitions, particle size inputs, and a clear statement of the decision the model must support. Room-scale studies also need the ventilation layout and assumptions about obstructions.
Q.Can you predict deposition on surfaces?
A.Yes, if the model is fit for purpose. Deposition estimates depend on particle size, surface properties, the turbulence model, and near-wall mesh quality. We document those assumptions and the associated uncertainty instead of treating deposition predictions as absolute.
Q.What determines model accuracy most?
A.Accuracy usually depends most on boundary conditions, geometry fidelity, turbulence model selection, particle properties, and the quality of the validation data. Sensitivity runs show which assumptions affect the decision and which make little practical difference.
Q.What do I receive?
A.You receive a PDF report, scenario metrics, model-to-measurement validation comparisons, sensitivity tables, and figures or animations for design reviews. If you need the native model files for transfer or later reuse, we can address that during scoping.

Standards & guidance

CFD does not have a single test-method accreditation across all applications, so the governing frame depends on the intended use. ARE Labs documents which standards shape validation data, boundary conditions, risk language, and design-control evidence. Accredited status is limited to ISO 17025 laboratory work; all other rows below are aligned guidance for model development, review, or decision support.

QA & Regulatory - Accredited

ISO 17025

Testing-laboratory competence - measured validation datasets, traceability, and uncertainty contributorsView standard ->Building Systems - Aligned

ASHRAE 90.1

Building energy and ventilation context - boundary-condition framing for room and HVAC modelsView standard ->QA & Regulatory - Aligned

ICH Q9

Quality risk management - assumption ranking, sensitivity framing, and decision documentationView standard ->Medical Devices - Aligned

FDA CFD Guidance

Medical-device CFD modeling - verification, validation, uncertainty, and applicability limitsView standard ->Modeling & Simulation - Aligned

NIST Sensitivity Methods

Sensitivity-analysis practices - ranking dominant model inputs and uncertainty driversView standard ->Medical Devices - Aligned

21 CFR Part 820

FDA quality system regulation - design controls and validation framing for device programsView standard ->

Related services & devices

Service

Clean Air Delivery Rate (CADR) Testing

Chamber decay data can calibrate room-scale CFD models before placement, mixing, or clearance scenarios are compared.Read more ->Devices

Air Treatment

Air cleaners, ducts, UVGI, filtration, and gas-phase systems often need flow-field modeling to explain performance differences.Read more ->Service

High-Speed Imaging & Velocimetry

Measured plume and velocity data help validate local jets, outlet flows, and transient source terms used in CFD models.Read more ->Devices

Spray Aerosol

Spray and mist products use CFD when plume transport, deposition, or enclosure mixing affects the design decision.Read more ->