Engineering Calculators

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Thermo & Fluids Calculators

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Thermo

Ideal Gas Law — PV = nRT

P: kPa, V: m³, n: mol, T: K (R = 0.008314 kPa·m³/mol·K)

Solve for P (kPa) V (m³) n (mol) T (K)

Result–

Thermo

Isentropic Stage (Compressor / Turbine)

Mode P₁ (kPa) T₁ (K) P₂ (kPa) k (γ) cᵨ (kJ/kg·K) η (0–1)

Ideal T₂s (K)–

Actual T₂ (K)–

w (kJ/kg)–

T₂s = T₁·(P₂/P₁)^(k−1)/k. Compressor: T₂ = T₁ + (T₂s−T₁)/η. Turbine: T₂ = T₁ − η·(T₁−T₂s).

Thermo

Brayton Cycle (ideal) Efficiency

k (γ) rᵨ = P₂/P₁

η_th,ideal–

η = 1 − rᵨ^−(k−1)/k

Fluids

Continuity & Reynolds

ρ (kg/m³) D (m) V (m/s) μ (Pa·s)

Area A (m²)–

Flow Q (m³/s)–

Re–

Regime–

Fluids

Pump Power

ρ (kg/m³) Q (m³/s) H (m) η (0–1)

P (kW)–

P = ρ g Q H / η, with g = 9.81 m/s².

Fluids

Bernoulli Equation — P + ½ρV² + ρgz

Solve for unknown at point 2. Assumes steady, incompressible, inviscid flow along a streamline.

Solve for ρ (kg/m³) P₁ (kPa) V₁ (m/s) z₁ (m) P₂ (kPa) V₂ (m/s) z₂ (m)

Result–

P₁ + ½ρV₁² + ρgz₁ = P₂ + ½ρV₂² + ρgz₂ (g = 9.81 m/s²). Pressures in kPa.

Fluids

Darcy-Weisbach — Pipe Head Loss

Major (friction) head loss in a circular pipe.

f (friction factor) L (m) D (m) V (m/s)

h_f (m)–

ΔP (kPa) at ρ=1000–

h_f = f · (L/D) · (V²/2g). ΔP = ρ · g · h_f.

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