REYNOLDS_FACTOR

Calculates the IEC 60534 Reynolds correction factor F_R for valve sizing in laminar or transitional regimes.

The factor is a function of valve Reynolds number, valve coefficient, diameter, pressure recovery factor, and trim style.

It applies different correlations for full trim and reduced trim to determine the effective correction used in capacity calculations.

Excel Usage

=REYNOLDS_FACTOR(fl_factor, kv, d_valve, re_valve, full_trim)

fl_factor (float, required): Liquid pressure recovery factor (-)
kv (float, required): Flow coefficient Kv (m³/hr)
d_valve (float, required): Valve diameter (m)
re_valve (float, required): Valve Reynolds number (-)
full_trim (bool, optional, default: true): Whether the valve has full trim

Returns (float): Reynolds number factor FR [-]

Example 1: Full trim case

Inputs:

fl_factor	kv	d_valve	re_valve	full_trim
0.9	10	0.05	1000	true

Excel formula:

=REYNOLDS_FACTOR(0.9, 10, 0.05, 1000, TRUE)

Expected output:

0.686935

Example 2: Reduced trim case

Inputs:

fl_factor	kv	d_valve	re_valve	full_trim
0.9	10	0.05	1000	false

Excel formula:

=REYNOLDS_FACTOR(0.9, 10, 0.05, 1000, FALSE)

Expected output:

0.977157

Example 3: High Reynolds

Inputs:

fl_factor	kv	d_valve	re_valve	full_trim
0.9	10	0.05	1000000	true

Excel formula:

=REYNOLDS_FACTOR(0.9, 10, 0.05, 1000000, TRUE)

Expected output:

1.62613

Example 4: Low Reynolds

Inputs:

fl_factor	kv	d_valve	re_valve	full_trim
0.7	50	0.1	10	true

Excel formula:

=REYNOLDS_FACTOR(0.7, 50, 0.1, 10, TRUE)

Expected output:

0.117456

Python Code

Show Code

from fluids.control_valve import Reynolds_factor

def reynolds_factor(fl_factor, kv, d_valve, re_valve, full_trim=True):
    """
    Calculates the Reynolds number factor FR for a valve according to IEC 60534.

    See: https://fluids.readthedocs.io/fluids.control_valve.html#fluids.control_valve.Reynolds_factor

    This example function is provided as-is without any representation of accuracy.

    Args:
        fl_factor (float): Liquid pressure recovery factor (-)
        kv (float): Flow coefficient Kv (m³/hr)
        d_valve (float): Valve diameter (m)
        re_valve (float): Valve Reynolds number (-)
        full_trim (bool, optional): Whether the valve has full trim Default is True.

    Returns:
        float: Reynolds number factor FR [-]
    """
    try:
      fl_factor = float(fl_factor)
      kv = float(kv)
      d_valve = float(d_valve)
      re_valve = float(re_valve)

      if fl_factor <= 0:
        return "Error: Liquid pressure recovery factor must be positive."
      if kv <= 0:
        return "Error: Flow coefficient Kv must be positive."
      if d_valve <= 0:
        return "Error: Valve diameter must be positive."
      if re_valve < 0:
        return "Error: Reynolds number cannot be negative."

      return float(Reynolds_factor(FL=fl_factor, C=kv, d=d_valve, Rev=re_valve, full_trim=full_trim))
    except Exception as e:
      return f"Error: {str(e)}"

Online Calculator

fl_factor *

Liquid pressure recovery factor (-)

kv *

Flow coefficient Kv (m³/hr)

d_valve *

Valve diameter (m)

re_valve *

Valve Reynolds number (-)

full_trim

Whether the valve has full trim