Engineering
Overview
Engineering calculations form the computational backbone of design, analysis, and optimization across mechanical, chemical, civil, electrical, and environmental disciplines. From fluid mechanics and thermodynamics to photovoltaics and process control, these tools leverage specialized Python libraries to solve problems that demand precision, industry-standard correlations, and validated property databases.
Fluid Mechanics encompasses the largest collection of engineering tools, addressing pipe flow, compressible flow, control valves, and two-phase systems. The fluids library provides battle-tested implementations of industry correlations like the Colebrook equation for friction factors, the Panhandle equations for natural gas pipelines, and IEC 60534 standards for control valve sizing. Whether calculating Reynolds numbers for regime classification, sizing orifice plates for flow measurement, or determining pressure drops through fittings, these tools handle both laminar and turbulent regimes with appropriate methods automatically selected based on dimensionless parameters.
For friction factor calculations, use FRICTION_FACTOR as the primary entry point—it automatically selects the optimal correlation (Clamond, Colebrook, Churchill, or Haaland) based on Reynolds number and relative roughness. Specialized correlations like BLASIUS (smooth turbulent flow) or MOODY are available when specific methods are required. Compressible flow tools handle gas transmission through pipelines with methods ranging from theoretical ISOTHERMAL_GAS to empirical formulas like WEYMOUTH_FLOW and PANHANDLE_B. Stagnation properties, critical flow conditions, and polytropic efficiency conversions are all available.
Control valve calculations follow IEC 60534 standards for both liquid and gas service, including flow coefficient conversions (Cv, Kv, Av), characteristic curves (linear, equal percentage, quick opening), cavitation and choked flow detection, and noise prediction per IEC 60534-8-3 (gas) and IEC 60534-8-4 (liquid). Use SIZE_CV_LIQUID and SIZE_CV_GAS for valve sizing, and IS_CHOKED_LIQ or IS_CHOKED_GAS to detect critical flow conditions.
Dimensionless numbers characterize flow regimes and similarity: Reynolds number, Froude number for open channel flow, Bond number for surface tension effects, and specialized parameters like Dean number for curved pipes. Drag calculations provide 20+ correlations for sphere drag coefficients optimized for different Reynolds number ranges, from Stokes flow (Re < 1) to high-Re turbulent regimes. The general DRAG_SPHERE function selects appropriate correlations automatically, while terminal velocity and settling calculations support particle separation design.
Flow meters implement differential pressure calculations per ISO 5167 for orifice plates, venturi tubes, and flow nozzles. Tools calculate discharge coefficients, expansibility factors, and non-recoverable pressure drops. Fittings and valves provide loss coefficients (K-factors) for bends, contractions, expansions, and various entrance/exit conditions based on Crane TP-410 and Idelchik correlations. Atmospheric calculations include the US Standard Atmosphere 1976 model and the NRLMSISE-00 model for temperature, pressure, and density at altitude.
Photovoltaic calculations leverage the pvlib-python library for solar energy system design and analysis. Calculate solar position (azimuth, elevation, zenith) for any location and time, determine irradiance components on tilted surfaces accounting for beam, diffuse, and ground-reflected radiation, and model PV module performance using the single-diode equation via I_FROM_V or simplified PVWatts DC models. The CEC model parameters adjust cell performance for temperature and irradiance variations, critical for accurate energy yield predictions.
These engineering tools bridge the gap between spreadsheet accessibility and programmatic power, providing validated implementations of industry standards that would be error-prone to implement manually.