蒸氣表 — 飽和蒸氣性質

概述

Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications.

Steam tables provide thermodynamic properties of water and steam at saturation and superheated conditions. The data is essential for sizing steam systems, calculating heat transfer, designing condensate return lines, and determining flash steam losses. Two primary tabulations are used: temperature-based (look up properties by saturation temperature) and pressure-based (look up properties by system pressure).

關键公式

Steam Quality

$x = \frac{m_v}{m_{total}}$

Mass fraction of vapor in a two-phase mixture. Ranges from 0 (saturated liquid) to 1 (saturated vapor).

Enthalpy of Wet Steam

$h = h_f + x \cdot h_{fg}$

Determines the specific enthalpy of a wet steam mixture from the quality and saturated properties.

Flash Steam Generated from Condensate

$m_{flash} = m_{liquid} \; \frac{h_{f1} - h_{f2}}{h_{fg2}}$

Predicts how much steam is produced when high-pressure condensate is discharged to a lower pressure.

Condensate Load from Heat Transfer

$m_c = \frac{Q}{h_{fg}}$

Estimates the mass flow rate of condensate from a known heat duty and latent heat.

Specific Volume of Wet Steam

$v = v_f + x \; (v_g - v_f)$

Used for pipe sizing in two-phase regions.

變量

Saturated Steam — Temperature Table

Saturated Steam — Pressure Table

Saturation Curve — Temperature vs Pressure

Flash Steam Calculator

Use this calculator to estimate the mass of flash steam produced when condensate at one pressure is discharged to a lower pressure.

單位換算器

还原的原始源表

The corrected original source for this route is the Online Saturated Steam Table Calculator page. That source page contains calculator form fields and external calculator references, but no substantive thermodynamic data table in the cached HTML. The saturated steam pressure and temperature data used by the calculator experience is preserved in the interactive tables above.

工程要點

• Interpolation is often required. Steam table data is tabulated at discrete intervals; use linear interpolation between adjacent rows for intermediate conditions.
• Latent heat decreases with pressure. At higher pressures the difference between liquid and vapor enthalpy narrows, which means less energy per kilogram is available for heating in a condensing process.
• Superheated steam tables are separate from saturated tables. Once steam is superheated, its properties depend on both pressure and temperature independently.
• Flash steam recovery is a major energy-savings opportunity in steam systems. High-pressure condensate discharged to atmospheric pressure can flash off roughly 10–15 % of its mass as low-pressure steam.
• Pipe sizing for steam distribution must account for specific volume, which increases dramatically at lower pressures. Using saturated vapor specific volume ($v_g$) is conservative for header sizing.
• Steam quality matters for heat transfer. Wet steam with quality below 0.95 can cause water hammer and reduce heat exchanger performance. Aim for quality ≥ 0.98 at the point of use.
• All values in these tables are based on the IAPWS-IF97 industrial formulation, which is the internationally accepted standard for industrial steam properties.

參考资料

• Original Source — Engineering ToolBox: Steam Tables
• IAPWS-IF97: Industrial Formulation for the Thermodynamic Properties of Water and Steam