#process-engineering

Fluid-viscosity physics as an API, computed locally and deterministically. The sutherland endpoint gives the dynamic viscosity of a gas at any temperature from Sutherland’s law, μ(T) = μ_ref·(T/T_ref)^1.5·(T_ref+S)/(T+S), with built-in constants for air, nitrogen, oxygen, carbon dioxide, hydrogen, helium and argon (or your own μ_ref, T_ref and S) — air comes out at about 1.72×10⁻⁵ Pa·s at 0 °C, 1.84×10⁻⁵ at 25 °C and 2.17×10⁻⁵ at 100 °C, returned in Pa·s, micro-Pa·s and centipoise. The kinematic endpoint converts between dynamic viscosity μ and kinematic viscosity ν through the density, ν = μ/ρ and μ = ν·ρ, so water at 1.002 cP and 998 kg/m³ becomes about 1.004 cSt. The convert endpoint handles viscosity units both ways — dynamic between Pa·s, centipoise and poise (1 Pa·s = 1000 cP = 10 P) and kinematic between m²/s, centistokes and stokes (1 m²/s = 10⁶ cSt = 10⁴ St). Temperatures are in °C or kelvin. Everything is computed locally and deterministically, so it is instant and private. Ideal for fluid-mechanics, CFD, process-engineering, lubrication, HVAC and chemical-engineering app developers, viscosity-correlation and unit-conversion tools, and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This computes viscosity; for the Reynolds number that uses it use a Reynolds API.

api.oanor.com/viscosity-api

Control-valve flow-coefficient (Cv / Kv) maths as an API, computed locally and deterministically. The liquid endpoint sizes a control valve for liquid service using Q = Kv·√(ΔP/SG): give any two of the flow rate (m³/h), the pressure drop across the valve (bar) and the flow coefficient Kv, and it returns the third — the required Kv to size a valve, the flow a valve passes, or the pressure drop it develops — together with the equivalent Cv. The convert endpoint converts between the three flow coefficients in use around the world: the metric Kv, the US Cv = 1.156·Kv, and the SI Av = 2.4e-5·Cv. The opening endpoint computes how far a valve must open to pass an operating Kv against its rated Kvs, for both a linear trim (opening = Kv/Kvs) and an equal-percentage trim (opening = 1 + ln(Kv/Kvs)/ln(R) for a rangeability R), so you can keep the valve in its controllable 20–80 % travel band. Everything is computed locally and deterministically, so it is instant and private. Ideal for process, instrumentation and HVAC engineering tools, control-valve selection and commissioning, hydronic-balancing and plant-design apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is control-valve sizing; for pump power and head use a pump API and for orifice-plate metering use an orifice API.

api.oanor.com/valveflow-api

Heat-exchanger LMTD and effectiveness-NTU maths as an API, computed locally and deterministically. The lmtd endpoint computes the log mean temperature difference, LMTD = (ΔT1 − ΔT2)/ln(ΔT1/ΔT2), the true average driving temperature of a heat exchanger, from the hot and cold stream inlet and outlet temperatures for either a counterflow or a parallel-flow arrangement, and flags a temperature cross. The duty endpoint applies Q = U·A·LMTD·F — the heat duty equals the overall heat-transfer coefficient times the area times the LMTD times an optional correction factor — and solves for whichever of the duty, the coefficient, the area or the LMTD you leave out, taking the LMTD directly or from the four temperatures. The effectiveness endpoint uses the effectiveness-NTU method: from the hot and cold heat-capacity rates (given directly or as mass flow times specific heat) and the number of transfer units NTU = U·A/Cmin, it returns the capacity ratio, the effectiveness for the arrangement, and — given the inlet temperatures — the maximum and actual heat duty and the outlet temperatures. Everything is computed locally and deterministically, so it is instant and private. Ideal for process, chemical and mechanical engineering tools, HVAC, refrigeration and thermal-design apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is two-stream heat-exchanger analysis; for the sensible heat of a single stream Q = m·c·ΔT use a specific-heat API.

api.oanor.com/lmtd-api