HELIX

Overview

Calculate the loss coefficient (K) for a helical coil pipe section.

Excel Usage

=HELIX(Di, rs, pitch, N, fd)

• Di (float, required): Inside diameter of pipe [m]
• rs (float, required): Radius of spiral [m]
• pitch (float, required): Distance between two subsequent coil centers [m]
• N (int, required): Number of coils in the helix [-]
• fd (float, required): Darcy friction factor [-]

Returns (float): Loss coefficient K for the helix [-]

Examples

Example 1: Basic helix coil

Inputs:

Di	rs	pitch	N	fd
0.01	0.1	0.03	10	0.0185

Excel formula:

=HELIX(0.01, 0.1, 0.03, 10, 0.0185)

Expected output:

Result
14.5251

Example 2: Tight pitch helix

Inputs:

Di	rs	pitch	N	fd
0.02	0.15	0.025	5	0.02

Excel formula:

=HELIX(0.02, 0.15, 0.025, 5, 0.02)

Expected output:

Result
6.194

Example 3: Many coils helix

Inputs:

Di	rs	pitch	N	fd
0.01	0.1	0.03	20	0.0185

Excel formula:

=HELIX(0.01, 0.1, 0.03, 20, 0.0185)

Expected output:

Result
29.0503

Example 4: Large radius helix

Inputs:

Di	rs	pitch	N	fd
0.015	0.2	0.05	8	0.018

Excel formula:

=HELIX(0.015, 0.2, 0.05, 8, 0.018)

Expected output:

Result
14.3645

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.fittings import helix as fluids_helix

def helix(Di, rs, pitch, N, fd):
    """
    Calculate the loss coefficient (K) for a helical coil pipe section.

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

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

    Args:
        Di (float): Inside diameter of pipe [m]
        rs (float): Radius of spiral [m]
        pitch (float): Distance between two subsequent coil centers [m]
        N (int): Number of coils in the helix [-]
        fd (float): Darcy friction factor [-]

    Returns:
        float: Loss coefficient K for the helix [-]
    """
    try:
        Di = float(Di)
        rs = float(rs)
        pitch = float(pitch)
        N = int(N)
        fd = float(fd)
    except (ValueError, TypeError):
        return "Error: All parameters must be numbers."

    if Di <= 0:
        return "Error: Di must be positive."
    if rs <= 0:
        return "Error: Rs must be positive."
    if pitch <= 0:
        return "Error: Pitch must be positive."
    if N < 1:
        return "Error: N must be at least 1."
    if fd <= 0:
        return "Error: Fd must be positive."

    try:
        result = fluids_helix(Di=Di, rs=rs, pitch=pitch, N=N, fd=fd)
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

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