oanor
Sign up free
Marketplace Pricing Features Sign in

API · /prandtl-api

Heat Transfer Numbers API

healthy 3,766 Subscribers

Convective heat-transfer dimensionless numbers as an API, computed locally and deterministically. The prandtl endpoint computes the Prandtl number Pr = μ·cp/k (or ν/α), the ratio of momentum to thermal diffusivity that sets the relative thickness of the velocity and thermal boundary layers — air is about 0.71 and water about 7 at 20 °C. The grashof endpoint computes the Grashof number Gr = g·β·|ΔT|·L³/ν², buoyancy versus viscous forces in natural convection (for an ideal gas the thermal-expansion coefficient β ≈ 1/T). The rayleigh endpoint gives the Rayleigh number Ra = Gr·Pr, either from Gr and Pr or from the full natural-convection inputs, which governs the onset of convection (critical ≈ 1708 for a heated horizontal layer). The peclet endpoint computes the Péclet number Pe = Re·Pr = v·L/α, advection versus diffusion of heat. The biot endpoint computes the Biot number Bi = h·L/k and flags whether the lumped-capacitance transient model applies (Bi < 0.1). All inputs are SI. Everything is computed locally and deterministically, so it is instant and private. Ideal for thermal-engineering, HVAC, electronics-cooling, CFD, process-engineering and heat-transfer-education app developers, natural-convection and transient-conduction tools, and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. These are convective heat-transfer groups; for the Reynolds number alone use a Reynolds API and for surface-tension numbers a Weber API.

#prandtl #heat-transfer #grashof #rayleigh #biot #developer-tools
api.oanor.com/prandtl-api
Get an API key Try in playground → Contact provider

Machine-readable spec so AI agents can integrate this API.

/api/prandtl-api/openapi.json
/api/prandtl-api/llms.txt

Discovery: GET /api/index.json lists every API.

API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
84 ms
Server probes · 24h
Subscribers
3,766
active
Total calls
24
last 7 days
status Full status page → · 30 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 3,700 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • 3,700 calls/month
  • 2 req/sec
  • Prandtl + Grashof + Rayleigh + Péclet + Biot
  • No credit card
Sign in to subscribe

Starter

€6.80 /month

  • 35,000 calls / month
  • 6 requests / second
  • Hard cap (429 above quota, no overage)
  • 35,000 calls/month
  • 6 req/sec
  • Natural convection, lumped-capacitance
  • Email support
Sign in to subscribe

Pro

€20.50 /month

  • 172,000 calls / month
  • 15 requests / second
  • Hard cap (429 above quota, no overage)
  • 172,000 calls/month
  • 15 req/sec
  • CFD & electronics-cooling pipelines
  • Priority support
Sign in to subscribe

Mega

€63.00 /month

  • 1,040,000 calls / month
  • 40 requests / second
  • Hard cap (429 above quota, no overage)
  • 1,040,000 calls/month
  • 40 req/sec
  • Platform scale
  • Dedicated SLA
Sign in to subscribe

Built by

P
PremiumApi

Related APIs

Other APIs with overlapping tags.

Newton Cooling & Convection API

Newton's law of cooling and convective heat transfer as an API, computed locally and deterministically. The convection endpoint applies the convective-heat-transfer rate Q = h·A·ΔT — the heat carried away from a surface equals the convection coefficient times the area times the temperature difference between the surface and the fluid — and solves for whichever of the heat rate, the coefficient, the area or the temperature difference you leave out, with typical coefficients for natural and forced air, water, boiling and condensing built in. The cooling endpoint applies Newton's law of cooling, T(t) = T_env + (T0 − T_env)·e^(−k·t): from an initial temperature, the ambient temperature and a cooling constant (or time constant τ = 1/k) it gives the temperature after a time, or the time to reach a target temperature, or it solves the cooling constant from a measured temperature at a known time — the maths behind how a hot drink, a forensic body or a cooling casting approaches room temperature. The coefficient endpoint links the cooling constant to the physical properties, k = h·A/(m·c), and the thermal time constant. Everything is computed locally and deterministically, so it is instant and private. Ideal for thermal-engineering and HVAC tools, food-safety and forensic cooling apps, electronics-cooling and process-control software, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is convection and transient cooling; for steady conduction through walls use a U-value API and for thermal radiation use a Stefan-Boltzmann API.

api.oanor.com/cooling-api

Optical Resolution API

Optical resolution by the Rayleigh criterion as an API, computed locally and deterministically. The angular endpoint gives the smallest angle two points can be apart and still be told apart through a circular aperture, θ = 1.22·λ/D — the diffraction limit set by the wavelength and the aperture diameter — in radians, degrees, arcminutes and arcseconds (a 100 mm telescope resolves about 1.4 arcseconds in green light), and solves the aperture needed for a target resolution. The distance endpoint turns that angle into a real separation at a distance, s = θ·L = 1.22·λ·L/D — how far apart two objects must be to be resolved at a given range. The microscope endpoint computes resolving power from the numerical aperture: the Rayleigh limit d = 0.61·λ/NA and the Abbe limit d = λ/(2·NA), with NA = n·sin(θ) from a refractive index and half-angle, and the maximum useful magnification. Wavelength defaults to 550 nm (visible) and can be set in metres, nanometres or micrometres. Everything is computed locally and deterministically, so it is instant and private. Ideal for astronomy, telescope and binocular tools, microscopy and imaging-system design, camera and optics apps, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the diffraction-limited resolving power; for thin-lens imaging use a lens API and for slit and grating diffraction use a diffraction API.

api.oanor.com/resolution-api

Paracord API

Paracord-craft maths as an API, computed locally and deterministically — the cord-length numbers a paracord crafter cuts a project to. The bracelet endpoint sizes the cord from the finished length and the weave using the well-known rule of thumb — about a foot of cord per inch of work for a cobra (Solomon) bar, double that for a king cobra, less for a fishtail — so an 8-inch cobra bracelet takes around 9 feet of cord including a foot of waste for the tails; give it a wrist measurement instead and it adds the fit ease and the buckle to get the finished length first, so a 7-inch wrist comes out near 10 feet. The weave endpoint generalises it to any project — lanyards, belts, dog leashes — as cord = finished length × cord-per-inch × the number of working strands, with the weave factors built in or your own cord-per-inch, and answers in inches, feet and metres. Everything is computed locally and deterministically, so it is instant and private. Ideal for paracord, survival-gear, scouting, craft and maker app developers, project-estimator and cut-list tools, and DIY software. Pure local computation — no key, no third-party service, instant. Rules of thumb — cut long and trim. Live, nothing stored. 2 compute endpoints.

api.oanor.com/paracord-api

Chainmaille API

Chainmaille maths as an API, computed locally and deterministically — the aspect-ratio and ring numbers a maille artist weaves to. The aspect endpoint computes the all-important Aspect Ratio = inner diameter ÷ wire diameter, and solves for whichever of the three you are missing, then lists the weaves that ring will make: AR, not absolute size, decides everything — too low and the rings won’t close through each other, too high and the weave goes floppy, so a 6.4 mm ID on 1.6 mm wire is AR 4.0, good for European 4-in-1, Byzantine, box chain and more. The ring endpoint does the material maths: wire per ring ≈ π × (inner diameter + wire diameter) — the mean-diameter circumference — so those AR-4 rings take about 25 mm of wire each and weigh roughly 0.4 g in steel; pass a wire length to get how many rings it yields, or a ring count to get the total wire and weight, in any of nine metals from aluminium to silver. Everything is computed locally and deterministically, so it is instant and private. Ideal for chainmaille, jewelry, cosplay-armour and maker app developers, ring-buying and project-estimator tools, and craft software. Pure local computation — no key, no third-party service, instant. Dimensions in mm. Live, nothing stored. 2 compute endpoints. For wire-gauge ↔ mm use a wire-gauge API.

api.oanor.com/chainmaille-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Heat Transfer Numbers API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Heat Transfer Numbers API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Heat Transfer Numbers API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Heat Transfer Numbers API cost?
Heat Transfer Numbers API has a free tier with 100 calls / month. Paid plans start at €6.80 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Heat Transfer Numbers API GDPR-compliant?
All requests to Heat Transfer Numbers API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Pick an endpoint from the list on the left to see its details and try it.

Code snippets

Sign up to get an API key, then call any path under your slug.

curl https://api.oanor.com/prandtl-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/prandtl-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/prandtl-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
    "https://api.oanor.com/prandtl-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

Ratings

Sign in to rate.

No reviews yet.

Discussion

Ask questions, share usage tips, get answers from the provider and other developers. Public — anyone can read.

Sign in to start a thread or reply.

Sign in

New thread

/ 4000

📌 Pinned 🔒 Locked

·

· ·

/ 4000

🔒 This thread is locked — no new replies.

  • No threads yet — start the discussion.

Support

Private 1:1 support with the provider — billing questions, integration issues, account problems. Only you and the provider team can see these threads.

Sign in to open a support ticket.

Sign in

Open new ticket

Describe what you need help with. The provider team gets an email and replies on the ticket page.

  • No tickets yet for this API.

Subscription active — calls can start immediately.

Send your first request —

Subscription active — copy a snippet and fire off your first call.