Why separate liquid film load from dynamic viscosity?

Both may display kg/(m·h), but Γ is mass flux per wetted perimeter while μ is a transport property. Separate unit categories prevent picking viscosity units for film-load rows.

Why are tube-side ρ1, μ1, c1, and κ1 manual inputs?

The handbook spreadsheet case supplies process-liquid properties as given data, separate from IAPWS shell steam props. Expand §5 intermediate rows to edit them.

Why does the Excel cross-check show “display precision” notes?

When Γ and m₀ match but ho, Ref, or U differ by ~0.1–1%, the template likely used higher-precision μ/κ internally while cells display 0.68 / 0.59. This is expected when typing displayed values — not a formula bug. Use IAPWS auto props or more significant digits, or read the cross-check badge.

Why does the alumina template show N = 1221 tubes while No from area is 1071?

The handbook case back-calculates tube count from area A using inner diameter Di: Ni = ROUNDUP(A/(π·L·Di)) = 1221; No = 1071 uses outer Do. §2 lets you pick Inner Di / Outer Do / Mean Dm / Custom; the alumina preset defaults to Inner Di. Γ and m₀ follow the effective N. Expand §2 intermediate rows for No/Ni/Nm side-by-side.

Vertical tube falling-film evaporator HTC — overall U & design coefficient

Vertical tube falling-film evaporator heat transfer

This tool follows the eight-section handbook spreadsheet workflow for vertical tube falling-film evaporators in alumina and chemical plants: tube geometry, operating conditions, fouling, shell-side steam condensation, tube-side liquid properties, secondary vapour reference, Re_L-branched liquid-film h_f, and overall U/HTC with optional non-condensable derating. Shell saturated steam and condensate-film props can be auto-filled via IAPWS-IF97 @ t_f; tube-side liquid props are manual inputs. Intermediate rows in §1/2/4/5/7 collapse by default. TEMA and handbook citations are provenance only — not a standard endorsement.

Model assumptions

Default plant preset: Ø57×3.5 mm, 12 m tube, λ = 40 kcal/(m·h·°C), handbook fouling r_o / r_i.
Liquid-film line load Γ uses the liquid film load unit category; dynamic viscosity μ uses dynamic viscosity — same kg/(m·h) symbol, different engineering meaning.
Shell-side saturated steam and condensate-film properties can be auto-filled via IAPWS-IF97 @ t_f; tube-side evaporating liquid properties are manual inputs — this tool does not IAPWS-fill process liquor.
The UI follows eight numbered sections aligned to the handbook calculation sheet; intermediate quantities in §1/2/4/5/7 are collapsed by default and can be expanded from the section header.

Standards & handbook references

TEMA-2019 (Chinese translation) — condensation and exchanger practice (provenance).
H. Obana, Heat Exchanger Design Handbook — falling-film lineage (provenance).
Related workflow: /tools/steam-calculator — saturation T→P and h_fg for shell-side checks.

This tool does not yet encode inputs in the URL; share the page link only.

Excel template cross-check (reference)

Live cross-check output has moved to this engineering note section so the calculator page keeps the eight-section formulas and live results on the first screen. Inputs still recompute locally as you edit.
Tube count: §2 offers Inner D_i / Outer D_o / Mean D_m / Custom. Alumina preset uses Inner D_i → N = 1221 (matches template); N_o = 1071 (outer D_o); N_m uses log-mean D_m. Expand §2 intermediate rows for all three reverse-calculations. Γ and m₀ follow the effective N.
Display precision: Cell display values (e.g. μ_f = 0.68, κ_f = 0.59) may differ from internal digits by ~0.1–1% on h_o, Re_L, or U while Γ and m₀ agree — not a formula defect.
Prefer IAPWS-IF97 @ t_f for shell film props, or enter μ/κ with 3–4 significant figures when reproducing spreadsheet numbers by hand.

Frequently asked questions

Why separate liquid film load from dynamic viscosity?: Both may display kg/(m·h), but Γ is mass flux per wetted perimeter while μ is a transport property. Separate unit categories prevent picking viscosity units for film-load rows.
Why are tube-side ρ₁, μ₁, c₁, and κ₁ manual inputs?: The handbook spreadsheet case supplies process-liquid properties as given data, separate from IAPWS shell steam props. Expand §5 intermediate rows to edit them.
Why does the Excel cross-check show “display precision” notes?: When Γ and m₀ match but h_o, Re_f, or U differ by ~0.1–1%, the template likely used higher-precision μ/κ internally while cells display 0.68 / 0.59. This is expected when typing displayed values — not a formula bug. Use IAPWS auto props or more significant digits, or read the cross-check badge.
Why does the alumina template show N = 1221 tubes while N_o from area is 1071?: The handbook case back-calculates tube count from area A using inner diameter D_i: N_i = ROUNDUP(A/(π·L·D_i)) = 1221; N_o = 1071 uses outer D_o. §2 lets you pick Inner D_i / Outer D_o / Mean D_m / Custom; the alumina preset defaults to Inner D_i. Γ and m₀ follow the effective N. Expand §2 intermediate rows for N_o/N_i/N_m side-by-side.

Extended copy on this page (headings, assumptions, references, FAQs) may be drafted or localized with AI assistance; engineering judgment and governing codes still apply. Numerical models run locally in your browser as implemented. For contract-critical work, cite primary standards and qualified review.