Low Pressure Steam Pressure Drop

Reference data and engineering information about low pressure steam pressure drop for steam and condensate applications.

lowpressuresteampressureCalculator

Overview

Engineering reference data for Low Pressure Steam Pressure Drop in steam condensate.

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

Mass fraction of vapor in two-phase mixture.

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

Specific enthalpy of wet steam.

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

Steam generated when condensate flashes to lower pressure.

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

Condensate generated by heat transfer.

Symbol	Description	Unit
$x$	Steam quality	—
$h_f$	Enthalpy of saturated liquid	kJ/kg
$h_{fg}$	Latent heat of vaporization	kJ/kg
$h$	Specific enthalpy	kJ/kg
$Q$	Heat transfer rate	kW

5 rows

Typical pressure drops in low pressure steam pipes
Initial Steam Pressure(psig)	Typical Pressure Drop(psi per 100 ft)
1	0.13
2	0.13
5	0.26
10	0.51
15	1

Source: engineeringtoolbox.com

1 psi (lbf/in²) = 0.001 ksi = 144 psf = 6894.8 Pa (N/m²) = 6.895×10⁻³ N/mm² = 0.06895 bar = 27.68 in H₂O at 4°C/39°F = 2.307 ft H₂O at 4°C/39°F = 703.1 mm H₂O at 4°C/39°F = 2.036 in Hg at 0°C/32°F = 51.71 mm Hg at 0°C/32°F = 703.1 kgf/m² = 0.06805 atm = 16 oz/in²
1 ft = 0.3048 m