RND_EDGE_SCREEN

Overview

Calculate the loss coefficient for a round edged wire screen or bar screen.

Excel Usage

=RND_EDGE_SCREEN(alpha, Re, angle)

• alpha (float, required): Fraction of screen open to flow, [-]
• Re (float, required): Reynolds number of flow through screen (D = space between rods), [-]
• angle (float, optional, default: 0): Angle of inclination (0 = straight, 90 = parallel to flow), [degrees]

Returns (float): Loss coefficient K, [-], or error message (str) if input is invalid.

Examples

Example 1: Basic case (alpha=0.5, Re=100)

Inputs:

alpha	Re
0.5	100

Excel formula:

=RND_EDGE_SCREEN(0.5, 100)

Expected output:

Result
2.1

Example 2: With angle (alpha=0.5, Re=100, angle=45)

Inputs:

alpha	Re	angle
0.5	100	45

Excel formula:

=RND_EDGE_SCREEN(0.5, 100, 45)

Expected output:

Result
1.05

Example 3: Low Reynolds number (Re=20)

Inputs:

alpha	Re
0.3	20

Excel formula:

=RND_EDGE_SCREEN(0.3, 20)

Expected output:

Result
13.1444

Example 4: High Reynolds number (Re=400)

Inputs:

alpha	Re
0.7	400

Excel formula:

=RND_EDGE_SCREEN(0.7, 400)

Expected output:

Result
0.5412

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.filters import round_edge_screen as fluids_round_edge_screen

def rnd_edge_screen(alpha, Re, angle=0):
    """
    Calculate the loss coefficient for a round edged wire screen or bar screen.

    See: https://fluids.readthedocs.io/fluids.filters.html#fluids.filters.round_edge_screen

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

    Args:
        alpha (float): Fraction of screen open to flow, [-]
        Re (float): Reynolds number of flow through screen (D = space between rods), [-]
        angle (float, optional): Angle of inclination (0 = straight, 90 = parallel to flow), [degrees] Default is 0.

    Returns:
        float: Loss coefficient K, [-], or error message (str) if input is invalid.
    """
    # Validate and convert alpha
    try:
        alpha = float(alpha)
    except (ValueError, TypeError):
        return "Error: Alpha must be a number."

    # Validate and convert Re
    try:
        Re = float(Re)
    except (ValueError, TypeError):
        return "Error: Re must be a number."

    # Validate and convert angle
    try:
        angle = float(angle)
    except (ValueError, TypeError):
        return "Error: Angle must be a number."

    # Validate ranges
    if alpha <= 0 or alpha > 1:
        return "Error: Alpha must be between 0 and 1."
    if Re <= 0:
        return "Error: Re must be positive."
    if angle < 0 or angle > 90:
        return "Error: Angle must be between 0 and 90 degrees."

    try:
        result = fluids_round_edge_screen(alpha=alpha, Re=Re, angle=angle)
        if result != result:  # NaN check
            return "nan"
        if result == float('inf'):
            return "inf"
        if result == float('-inf'):
            return "-inf"
        return float(result)
    except Exception as e:
        return f"Error computing round_edge_screen: {str(e)}"

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