Cross-Cutting Engineering

Computational Fluid Dynamics (CFD)

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

We build validated CFD models calibrated against chamber datasets to quantify flow fields, track particle trajectories, and evaluate sensitivity to boundary conditions.

ISO 17025ASHRAE 90.1FDA CFD GuidanceICH Q9Reviewed 2026-05-16
Request a quoteTalk to a scientist

Purpose & when to use

Computational Fluid Dynamics (CFD) uses numerical simulation, supported by measured validation data, to predict airflow, mixing, pressure fields, and aerosol transport. ARE Labs combines CAD geometry, chamber decay datasets, particle size inputs, and documented boundary conditions to support design and safety decisions. Studies follow ISO 17025 quality practices, FDA CFD guidance, ASHRAE 90.1 energy context, and ICH Q9 risk framing, as applicable. 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 the full range of geometries and scenarios. The model can help rank performance drivers, narrow prototype options, 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, so its credibility depends on measured inputs, controlled geometry, mesh checks, and relevant 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

Each CFD study begins with the decision the model must support. We then define the geometry, boundary conditions, validation data, and sensitivity plan. A fit-for-purpose setup balances model fidelity against the uncertainty that can be reduced through measurement, design changes, or clearer scenario definitions. The following 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. Regulatory and engineering frameworks are selected according to the model's intended use. The anchors below define how ARE Labs documents assumptions, validation results, and sensitivity evidence.

  • 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

Each CFD study delivers decision-focused outputs, validation evidence, and a discussion of uncertainty, not just an isolated simulation image. Results may include velocity fields, pressure maps, concentration histories, deposition indicators, and sensitivity rankings formatted for design reviews, risk files, or validation packages. The deliverables below describe the standard report. Extended programs that compare multiple geometries or operating modes include additional 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 matched to the model's purpose, measured inputs, and decision risk. Controls include versioned geometry, documented solver settings, mesh checks, convergence review, and traceability from measured validation datasets to 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

Quick answers to the questions air-treatment engineers, aerosol-device teams, medical-device developers, and facility stakeholders ask when scoping a CFD study - what data is needed, how validation works, where sensitivity studies fit, and what outputs they receive. The answers below are starting points; reach out if your geometry, release condition, or regulatory frame does not match the examples here.

Q.Do you run CFD without measurements?
A.Yes, although a calibrated model is generally more defensible. When possible, we recommend providing at least one validation dataset, such as chamber decay, flow mapping, pressure, or particle concentration data. This allows ARE Labs to document model agreement and define the model's limitations.
Q.What information do you need to start?
A.We need the geometry or CAD files, operating flow rates or fan curves, source definitions, particle size inputs, and a clear description of the decision the model must support. Room-scale studies also require the ventilation layout and assumptions about obstructions.
Q.Can you predict deposition on surfaces?
A.Yes, when the model is fit for purpose. Deposition estimates depend on particle size, surface properties, the turbulence model, and the near-wall mesh. For that reason, we document the assumptions and uncertainty instead of presenting deposition results as absolute values.
Q.What determines model accuracy most?
A.Accuracy is usually most affected by boundary conditions, geometry fidelity, turbulence model selection, particle properties, and the quality of the validation data. Sensitivity runs show which assumptions could change the decision and which have little practical effect.
Q.What do I receive?
A.You receive a PDF report with scenario metrics, validation comparisons, sensitivity tables, and figures or animations for design reviews. If model transfer or reuse is required, access to the native model files can be discussed during scoping.

Standards & guidance

CFD does not have one test-method accreditation that applies across every application, so the governing framework depends on the model's intended use. ARE Labs documents which standards inform the validation data, boundary conditions, risk language, and design-control evidence. Accredited status applies only to ISO 17025 laboratory work. All other rows below identify guidance used 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 ->