DIFF_PRESS_BETA

Overview

Calculate the beta ratio (diameter ratio) for a differential pressure flow meter.

Excel Usage

=DIFF_PRESS_BETA(D, D_two, beta_meter_type)

• D (float, required): Upstream internal pipe diameter (m)
• D_two (float, required): Meter characteristic diameter - orifice hole, venturi throat, cone end, or wedge height (m)
• beta_meter_type (str, optional, default: “ISO 5167 orifice”): Type of differential pressure flow meter

Returns (float): Differential pressure meter diameter ratio (beta) (-)

Examples

Example 1: Standard orifice beta ratio

Inputs:

D	D_two	beta_meter_type
0.1	0.05	ISO 5167 orifice

Excel formula:

=DIFF_PRESS_BETA(0.1, 0.05, "ISO 5167 orifice")

Expected output:

Result
0.5

Example 2: Venturi tube beta ratio

Inputs:

D	D_two	beta_meter_type
0.2	0.12	machined convergent venturi tube

Excel formula:

=DIFF_PRESS_BETA(0.2, 0.12, "machined convergent venturi tube")

Expected output:

Result
0.6

Example 3: Cone meter beta ratio (uses special formula)

Inputs:

D	D_two	beta_meter_type
0.2575	0.184	cone meter

Excel formula:

=DIFF_PRESS_BETA(0.2575, 0.184, "cone meter")

Expected output:

Result
0.6996

Example 4: Wedge meter beta ratio (uses special formula)

Inputs:

D	D_two	beta_meter_type
0.2027	0.0608	wedge meter

Excel formula:

=DIFF_PRESS_BETA(0.2027, 0.0608, "wedge meter")

Expected output:

Result
0.5023

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.flow_meter import differential_pressure_meter_beta

def diff_press_beta(D, D_two, beta_meter_type='ISO 5167 orifice'):
    """
    Calculate the beta ratio (diameter ratio) for a differential pressure flow meter.

    See: https://fluids.readthedocs.io/fluids.flow_meter.html#fluids.flow_meter.differential_pressure_meter_beta

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

    Args:
        D (float): Upstream internal pipe diameter (m)
        D_two (float): Meter characteristic diameter - orifice hole, venturi throat, cone end, or wedge height (m)
        beta_meter_type (str, optional): Type of differential pressure flow meter Valid options: ISO 5167 Orifice, Orifice, Conical Orifice, Eccentric Orifice, Segmental Orifice, Quarter Circle Orifice, Venturi Nozzle, ISA 1932 Nozzle, Long Radius Nozzle, Machined Convergent Venturi Tube, Rough Welded Convergent Venturi Tube, As Cast Convergent Venturi Tube, Cone Meter, Wedge Meter. Default is 'ISO 5167 orifice'.

    Returns:
        float: Differential pressure meter diameter ratio (beta) (-)
    """
    if D <= 0:
        return "Error: D (upstream diameter) must be positive."
    if D_two <= 0:
        return "Error: D_two (meter diameter) must be positive."
    try:
        result = differential_pressure_meter_beta(
            D=D,
            D2=D_two,
            meter_type=beta_meter_type
        )
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

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