{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.diffuser-q905299","code":"thing-q905299","url":"https://ver.cy/models/thing/q905299/","name":"diffuser","alternateNames":[],"kind":"thing","status":"research-draft","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.OBJ"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A diffuser is a physical component or device that spreads or redistributes a flow, light, sound, or dispersed substance, with its operating principle determined by the application.","purpose":"Enable an agent to recognise a fluid-flow diffuser, assess its pressure recovery or air-distribution performance, and determine suitable installation, adjustment and maintenance actions.","scope":{"in":["Intended fluid deceleration, pressure recovery and application-specific discharge distribution","Flow-passage geometry, vanes, effective areas and connection boundaries","Fluid properties, inlet conditions and downstream constraints","Measured recovery, losses, flow stability and applicable air-distribution performance","Diffuser-specific adjustment, deterioration, inspection and operating limits"],"out":["Optical and acoustic diffusers, fragrance dispensers and gas-dispersion aerators","Complete fans, pumps, compressors and their drive systems","Whole HVAC networks, room thermal models and building ventilation strategies","Complete vehicle aerodynamics and separately registered automotive diffuser specialisations","Product-line administration and individual asset lifecycle records"],"boundaries":[]},"distinguishingFeatures":["Identify the intended flow transformation: a pressure-recovery diffuser decelerates fluid and raises static pressure at its design conditions, while a nozzle principally accelerates discharge.","Check the operating flow regime before interpreting shape; an increasing passage area alone is insufficient to identify a diffuser.","Distinguish a stationary pressure-recovery passage from the rotating impeller or compressor stage supplying energy upstream.","For an HVAC terminal, require evidence of a designed discharge pattern or mixing function rather than classifying every grille or duct opening as a diffuser.","Confirm that the working medium is a flowing fluid rather than light, sound or a fragrance consumable."],"structure":{"bundles":[{"id":"diffusion-duty","name":"Diffusion duty","description":"Establish the flow transformation that makes the component a diffuser.","layers":[{"id":"functional-identity","name":"Functional identity","description":"Identify the intended fluid behaviour and distinguish adjacent component kinds.","findings":[{"id":"intended-flow-transformation","name":"Intended flow transformation","description":"Record the design objective and distinguish it from observed performance at a particular operating point.","questions":[{"text":"Is the intended duty static-pressure recovery, terminal air distribution or a documented combination?","id":"intended-flow-transformation-q01","kind":"definition"},{"text":"What evidence distinguishes this component from a nozzle, grille or ordinary duct transition?","id":"intended-flow-transformation-q02","kind":"boundary"}]}]},{"id":"component-boundaries","name":"Component boundaries","description":"Locate the diffuser within the host flow system.","findings":[{"id":"owned-flow-path","name":"Owned flow path","description":"Identify inlet and outlet stations, integral elements and external equipment responsible for driving the fluid.","questions":[{"text":"Where do the diffuser's inlet and outlet boundaries lie, and which vanes or terminal elements belong within them?","id":"owned-flow-path-q01","kind":"boundary"},{"text":"Which upstream source drives the flow, and does the diffuser itself require power only for adjustment or auxiliary functions?","id":"owned-flow-path-q02","kind":"provenance"}]}]}]},{"id":"passage-and-installation","name":"Passage and installation","description":"Describe the geometry and installation conditions that shape diffusion.","layers":[{"id":"effective-geometry","name":"Effective geometry","description":"Capture the passage profile and flow-directing elements.","findings":[{"id":"area-and-turning-profile","name":"Area and turning profile","description":"Record area variation, length, wall contours and vane geometry with explicit measurement locations.","questions":[{"text":"What are the inlet, minimum and outlet effective areas, passage length and relevant wall angles?","id":"area-and-turning-profile-q01","kind":"measurement"},{"text":"Which vanes, slots or internal obstructions alter the available area or flow direction?","id":"area-and-turning-profile-q02","kind":"definition"}]}]},{"id":"connection-and-approach","name":"Connection and approach","description":"Relate the diffuser to the actual approach flow and discharge surroundings.","findings":[{"id":"installation-dependencies","name":"Installation dependencies","description":"Require evidence for inlet-profile assumptions, mounting orientation and outlet clearances.","questions":[{"text":"What approach-flow profile, swirl level and connection arrangement underlie the stated performance?","id":"installation-dependencies-q01","kind":"provenance"},{"text":"What installation changes are necessary if nearby bends, obstructions or discharge surfaces differ from those conditions?","id":"installation-dependencies-q02","kind":"action"}]}]}]},{"id":"flow-and-recovery","name":"Flow and recovery","description":"Assess diffuser performance at a defined operating point.","layers":[{"id":"operating-regime","name":"Operating regime","description":"Establish the fluid state and boundary conditions needed to interpret measurements.","findings":[{"id":"matched-flow-conditions","name":"Matched flow conditions","description":"Record fluid properties, flow rate and inlet and outlet conditions before applying a performance curve.","questions":[{"text":"What fluid composition, temperature, density and mass or volumetric flow define this operating point?","id":"matched-flow-conditions-q01","kind":"measurement"},{"text":"What are the inlet Mach and Reynolds numbers and downstream pressure, and which documented analysis regime applies?","id":"matched-flow-conditions-q02","kind":"measurement"}]}]},{"id":"pressure-and-discharge-results","name":"Pressure and discharge results","description":"Separate pressure recovery, losses and terminal delivery outcomes.","findings":[{"id":"recovery-and-loss-accounting","name":"Recovery and loss accounting","description":"Keep static and total pressure measurements distinct and document any coefficient definition. [NASA pressure definitions](https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/dynamic-pressure/).","questions":[{"text":"What static-pressure rise and total-pressure loss occur between the stated stations?","id":"recovery-and-loss-accounting-q01","kind":"measurement"},{"text":"Which averaging method, coefficient normalisation and uncertainty accompany these results?","id":"recovery-and-loss-accounting-q02","kind":"provenance"}]},{"id":"terminal-delivery","name":"Terminal delivery","description":"Activate terminal distribution criteria only for applicable HVAC diffuser configurations.","questions":[{"text":"At what flow rate, supply-to-room temperature difference and terminal velocity were throw, spread and drop established?","id":"terminal-delivery-q01","kind":"measurement"},{"text":"Which discharge pattern and acoustic limits must the installed terminal satisfy?","id":"terminal-delivery-q02","kind":"boundary"}]}]}]},{"id":"stability-and-adjustment","name":"Stability and adjustment","description":"Connect flow instability and adjustable geometry to permissible operating actions.","layers":[{"id":"unstable-flow-evidence","name":"Unstable flow evidence","description":"Identify observations that distinguish unstable diffusion from ordinary operating variation.","findings":[{"id":"separation-and-shock-state","name":"Separation and shock state","description":"Record wall-pressure and velocity evidence for separation and, where applicable, shock behaviour; NASA's transonic diffuser study uses these observations. [NASA transonic diffuser study](https://www.grc.nasa.gov/www/wind/valid/transdif/transdif02/transdif02.html).","questions":[{"text":"What measurements indicate separation, reattachment, pressure oscillations or shocks at this operating point?","id":"separation-and-shock-state-q01","kind":"measurement"},{"text":"Which verified operating limit or diagnostic rule determines whether adjustment or shutdown is required?","id":"separation-and-shock-state-q02","kind":"action"}]}]},{"id":"permitted-configuration","name":"Permitted configuration","description":"Specify actual adjustment capabilities and their dependencies.","findings":[{"id":"geometry-control","name":"Geometry control","description":"Identify fixed geometry or documented vane, slot and actuator settings without assuming every diffuser is controllable.","questions":[{"text":"Which diffuser elements are adjustable, through what range, and with what position feedback?","id":"geometry-control-q01","kind":"definition"},{"text":"What host-system permissions, interlocks and post-adjustment measurements are required before changing a setting?","id":"geometry-control-q02","kind":"action"}]}]}]},{"id":"condition-and-acceptance","name":"Condition and acceptance","description":"Determine whether passage condition and supporting evidence justify continued use.","layers":[{"id":"passage-degradation","name":"Passage degradation","description":"Inspect deterioration that changes diffusion surfaces, clearances or containment.","findings":[{"id":"surface-and-vane-integrity","name":"Surface and vane integrity","description":"Record fouling, erosion, corrosion, deformation, leakage and vane damage against an inspected baseline.","questions":[{"text":"Where have deposits, wear or damage changed the effective area, surface condition or vane alignment?","id":"surface-and-vane-integrity-q01","kind":"measurement"},{"text":"Which cleaning method, repair limit or replacement criterion is documented for these materials and surfaces?","id":"surface-and-vane-integrity-q02","kind":"action"}]}]},{"id":"application-specific-acceptance","name":"Application-specific acceptance","description":"Tie operating limits and conformity claims to the actual diffuser application.","findings":[{"id":"verified-performance-basis","name":"Verified performance basis","description":"Require applicable test evidence and identify the issuing body, edition and scope of any standard or certification claimed.","questions":[{"text":"Which manufacturer limits and applicable standards govern pressure, temperature, materials, acoustic output or air-distribution testing for this application?","id":"verified-performance-basis-q01","kind":"provenance"},{"text":"What inspection and performance results must be obtained after installation, cleaning or geometry repair before accepting the diffuser?","id":"verified-performance-basis-q02","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of diffuser this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of diffuser this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of diffuser this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of diffuser this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of diffuser this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Install, clean and adjust diffusers the agent is authorized to maintain.","Report a blocked or damaged diffuser in an air, light or fluid system."],"mustNot":["Remove or block a diffuser in a ventilation or exhaust system so that flow becomes unsafe.","Use a scent or aerosol diffuser near people who have not agreed to it or may be sensitive.","Replace a diffuser with a part not rated for the system's pressure or temperature."],"requiresHuman":["Changing diffusers in systems that serve hospitals, labs or other critical spaces."]},"ethics":{"considerations":["Diffused scents and aerosols affect everyone in a space, including people with asthma or allergies."],"affectedParties":["People with asthma or allergies","Building occupants","Pets"]},"owners":{"steward":"The owner or operator of the system it is part of.","roles":[],"masterSystems":[]},"relations":[{"target":"Q1183543","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.diffuser-q905299","Wikidata: Q905299 (https://www.wikidata.org/wiki/Q905299)"]},"properties":{"applicability":"required","items":["Diffusion duty: pressure recovery; terminal air distribution; combined duty; unresolved","Working fluid and phase: reference to fluid composition and gas, liquid or multiphase condition","Passage configuration: axial; radial; annular; vaned; vaneless; terminal face or slot; documented combination","Passage dimensions: length and hydraulic diameter in mm; inlet, throat and outlet areas in mm²; wall and vane angles in degrees","Area ratio: outlet area divided by inlet area, dimensionless, with station definitions","Operating flow: kg/s or m³/s with density and reference conditions; inlet Mach and Reynolds numbers dimensionless","Static pressure recovery: outlet minus inlet static pressure in Pa; optional coefficient with explicit normalisation","Total pressure loss: inlet minus outlet total pressure in Pa, with averaging method","Flow stability: attached; separated; oscillatory; reverse flow; unknown; shock state where applicable","Terminal discharge performance: where applicable: throw, spread and drop in m at a stated terminal velocity in m/s; sound power in dB with reference and frequency bands","Adjustment and energy interface: fixed; manually adjustable; actuated; actuator supply and permissible positions where fitted","Passage condition: clean; fouled; eroded; corroded; deformed; leaking; vane damage; uninspected"]},"recognition":{"applicability":"required","items":["A grille, cone, screen or perforated plate placed where flow or light leaves a source."]},"capabilities":{"applicability":"required","items":["Classify a candidate by fluid duty, passage form and documented operating regime.","Compare candidate diffusers at matched inlet conditions and measurement boundaries.","Check connection geometry and upstream or downstream conditions before installation.","Recommend documented vane or terminal-pattern adjustments within verified limits.","Diagnose degraded recovery or discharge distribution from pressure, velocity and condition evidence.","Specify inspection, cleaning or replacement followed by an appropriate performance check."]},"hazards":{"applicability":"required","items":["A blocked air diffuser can cause poor ventilation and build-up of pollutants.","Scent diffusers can trigger asthma and are toxic to some pets."]},"interfaces":{"applicability":"required","items":["ANSI/ASHRAE Standard 70, issued by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, specifies laboratory testing of air outlets and air inlets and applies to ventilation diffusers."]},"context":{"applicability":"required","items":["Fluid-flow diffusers occur in ducts, turbomachinery and propulsion systems, where they reduce flow velocity and recover static pressure.","Air-distribution diffusers occur at ventilation outlets, where they spread supply air and influence room mixing, drafts and noise."]}},"sources":[{"title":"Wikidata item Q905299: diffuser","url":"https://www.wikidata.org/wiki/Q905299","note":"identity and sense of the item"},{"title":"Wikipedia: Diffuser (thermodynamics)","url":"https://en.wikipedia.org/wiki/Diffuser_%28thermodynamics%29","note":"general description of the item"}],"openQuestions":["Does the authoritative registry intend Q905299 to include HVAC terminal diffusers alongside pressure-recovery passages, or should terminal features remain a linked specialisation?","Does an existing Vercy world model already own this fluid-diffuser concept or any of its proposed specialisations?","Which primary sources establish representative dimensions, capacities and performance ranges for each retained diffuser subtype?","Which standards, issuing bodies, editions and certification schemes apply to each application, and which claims concern the diffuser rather than its host assembly?","What experimentally supported limits distinguish acceptable operation from separation, shock instability or application-specific failures such as liquid cavitation?"],"resources":{"spec":"/models/things/publications/thing-q905299/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q905299/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:10:43Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{},"score":1.0}}