CONTRACTION_SHARP

Overview

Calculate the loss coefficient (K) for a sharp edged pipe contraction (reducer).

Excel Usage

=CONTRACTION_SHARP(Di_large, Di_small, con_sharp_method)

• Di_large (float, required): Inside diameter of original (larger) pipe [m]
• Di_small (float, required): Inside diameter of following (smaller) pipe [m]
• con_sharp_method (str, optional, default: “Rennels”): Calculation method

Returns (float): Loss coefficient K for the sharp contraction (based on smaller pipe) [-]

Examples

Example 1: Basic sharp contraction (1m to 0.4m)

Inputs:

Di_large	Di_small
1	0.4

Excel formula:

=CONTRACTION_SHARP(1, 0.4)

Expected output:

Result
0.5301

Example 2: Small contraction ratio

Inputs:

Di_large	Di_small
0.1	0.08

Excel formula:

=CONTRACTION_SHARP(0.1, 0.08)

Expected output:

Result
0.2303

Example 3: Sharp contraction with Crane method

Inputs:

Di_large	Di_small	con_sharp_method
0.3	0.2	Crane

Excel formula:

=CONTRACTION_SHARP(0.3, 0.2, "Crane")

Expected output:

Result
0.2778

Example 4: Large contraction ratio

Inputs:

Di_large	Di_small
0.5	0.1

Excel formula:

=CONTRACTION_SHARP(0.5, 0.1)

Expected output:

Result
0.5619

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.fittings import contraction_sharp as fluids_contraction_sharp

def contraction_sharp(Di_large, Di_small, con_sharp_method='Rennels'):
    """
    Calculate the loss coefficient (K) for a sharp edged pipe contraction (reducer).

    See: https://fluids.readthedocs.io/fluids.fittings.html#fluids.fittings.contraction_sharp

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

    Args:
        Di_large (float): Inside diameter of original (larger) pipe [m]
        Di_small (float): Inside diameter of following (smaller) pipe [m]
        con_sharp_method (str, optional): Calculation method Valid options: Rennels, Crane, Hooper. Default is 'Rennels'.

    Returns:
        float: Loss coefficient K for the sharp contraction (based on smaller pipe) [-]
    """
    try:
        Di1 = float(Di_large)
        Di2 = float(Di_small)
    except (ValueError, TypeError):
        return "Error: Di_large and Di_small must be numbers."

    if Di1 <= 0 or Di2 <= 0:
        return "Error: Diameters must be positive."
    if Di2 >= Di1:
        return "Error: Di_small must be less than Di_large."

    try:
        result = fluids_contraction_sharp(Di1=Di1, Di2=Di2, method=con_sharp_method)
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

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