CV_CHAR_QUICK_OP

Computes the normalized quick-opening valve characteristic as a function of fractional opening.

Quick-opening valves produce a large fraction of their total coefficient increase at small openings, then flatten as opening approaches the maximum.

The result is a dimensionless normalized coefficient fraction that is typically near 0 at closed position and near 1 at full opening.

Excel Usage

=CV_CHAR_QUICK_OP(opening)

• opening (float, required): Fractional opening of the valve [0-1].

Returns (float): Flow coefficient characteristic fraction [0-1].

Example 1: Zero opening

Inputs:

opening
0

Excel formula:

=CV_CHAR_QUICK_OP(0)

Expected output:

-3.24793e-19

Example 2: Full opening

Inputs:

opening
1

Excel formula:

=CV_CHAR_QUICK_OP(1)

Expected output:

1

Example 3: Half opening

Inputs:

opening
0.5

Excel formula:

=CV_CHAR_QUICK_OP(0.5)

Expected output:

0.902547

Example 4: Quarter opening

Inputs:

opening
0.25

Excel formula:

=CV_CHAR_QUICK_OP(0.25)

Expected output:

0.788538

Python Code

Show Code

from fluids.control_valve import Cv_char_quick_opening

def cv_char_quick_op(opening):
    """
    Calculates the flow coefficient characteristic for a quick opening control valve.

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

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

    Args:
        opening (float): Fractional opening of the valve [0-1].

    Returns:
        float: Flow coefficient characteristic fraction [0-1].
    """
    try:
      val = float(opening)
      if val < 0 or val > 1:
        return "Error: opening must be between 0 and 1"
      return float(Cv_char_quick_opening(val))
    except Exception as e:
      return f"Error: {str(e)}"

Online Calculator

opening *

Fractional opening of the valve [0-1].